Science.gov

Sample records for a-type starch granules

  1. Starch-branching enzymes preferentially associated with A-type starch granules in wheat endosperm.

    PubMed

    Peng, M; Gao, M; Båga, M; Hucl, P; Chibbar, R N

    2000-09-01

    Two starch granule-bound proteins (SGP), SGP-140 and SGP-145, were preferentially associated with A-type starch granules (>10 microm) in developing and mature wheat (Triticum aestivum) kernels. Immunoblotting and N-terminal sequencing suggested that the two proteins were different variants of SBEIc, a 152-kD isoform of wheat starch-branching enzyme. Both SGP-140 and SGP-145 were localized to the endosperm starch granules but were not found in the endosperm soluble fraction or pericarp starch granules younger than 15 d post anthesis (DPA). Small-size starch granules (<10 microm) initiated before 15 DPA incorporated SGP-140 and SGP-145 throughout endosperm development and grew into full-size A-type starch granules (>10 microm). In contrast, small-size starch granules harvested after 15 DPA contained only low amounts of SGP-140 and SGP-145 and developed mainly into B-type starch granules (<10 microm). Polypeptides of similar mass and immunologically related to SGP-140 and/or SGP-145 were also preferentially incorporated into A-type starch granules of barley (Hordeum vulgare), rye (Secale cereale), and triticale (x Triticosecale Wittmack) endosperm, which like wheat endosperm have a bimodal starch granule size distribution.

  2. The biosynthesis of starch granules.

    PubMed

    Smith, A M

    2001-01-01

    Although composed simply of glucose polymers, the starch granule is a complex, semicrystalline structure. Much of this complexity arises from the fact that the two primary enzymes of synthesis-starch synthase and starch-branching enzyme-exist as multiple isoforms. Each form has distinct properties and plays a unique role in the synthesis of the two starch polymers, amylose and amylopectin. The debranching enzyme isoamylase also has a profound influence on the synthesis of amylopectin. Despite much speculation, no acceptable model to explain the interactions of all of these enzymes to produce amylose and amylopectin has thus far emerged. The organization of newly synthesized amylopectin to form the semicrystalline matrix of the granule appears to be a physical process, implying the existence of complex interactions between biological and physical processes at the surface of the growing granule. The synthesis of the amylose component occurs within the amylopectin matrix.

  3. Starch granules: structure and biosynthesis.

    PubMed

    Buléon, A; Colonna, P; Planchot, V; Ball, S

    1998-08-01

    The emphasis of this review is on starch structure and its biosynthesis. Improvements in understanding have been brought about during the last decade through the development of new physicochemical and biological techniques, leading to real scientific progress. All this literature needs to be kept inside the general literature about biopolymers, despite some confusing results or discrepancies arising from the biological variability of starch. However, a coherent picture of starch over all the different structural levels can be presented, in order to obtain some generalizations about its structure. In this review we will focus first on our present understanding of the structures of amylose and amylopectin and their organization within the granule, and we will then give insights on the biosynthetic mechanisms explaining the biogenesis of starch in plants.

  4. Blue maize: morphology and starch synthase characterization of starch granule.

    PubMed

    Utrilla-Coello, Rubi G; Agama-Acevedo, Edith; de la Rosa, Ana Paulina Barba; Martinez-Salgado, Jose L; Rodriguez-Ambriz, Sandra L; Bello-Perez, Luis A

    2009-03-01

    The use of pigmented maize varieties has increased due to their high anthocyanins content, but very few studies are reported about the starch properties of these grains. The aim of this work was to isolate the starch granules from pigmented blue maize and carry out the morphological, physicochemical, and biochemical characterization studies. The proximate composition of starch granules showed high protein contents, after purification, the blue maize starch presented lower protein amount than starch from white maize (control). Although the purity of starch granules was increased, the damaged starch (determined for the Maltase cross absence) was also increased. Scanning electron microscopy showed the presence of some pores and channels in the blue maize starch. The electrophoretic protein profiles showed differences in the bands that correspond to the enzymes involved in the starch biosynthesis; these differences could explain the variation in morphological characteristics of blue maize starches against starch from white maize.

  5. Starch biosynthesis: experiments on how starch granules grow in vivo.

    PubMed

    Mukerjea, Romila; Mukerjea, Rupendra; Robyt, John F

    2009-01-05

    Four varieties of starch granules from potato, wheat, maize, and rice were fractionated into homogeneous 10-microm-sized ranges. The size with the largest amount of granules was reacted with ADP-[(14)C]Glc, washed, and peeled into 7-9 layers, using a controlled peeling process, involving 90:10 volume proportions of Me(2)SO-H(2)O at 10 degrees C. All of the starches showed biosynthesis of starch throughout the granules. Starch synthase activities were determined for each of the layers. Three of the starches had a relatively large amount of synthase activity in the second layer, with only a small amount in the first layer. Potato starch had the largest amount of activity in the first layer. Starch synthase activity was found to alternate between higher and lower activities throughout all of the varieties of granules, showing that the synthesis was not uniform and also was not exclusively occurring at the surface of the starch granules, which had previously been hypothesized. From these results and our previous studies on the mechanism of starch chain elongation by the addition of d-glucose to the reducing end of a growing chain that is covalently attached to the active site of starch synthase, a hypothesis is proposed for how starch granules grow in vivo.

  6. Starch Granule Variability in Wild Solanum Species

    USDA-ARS?s Scientific Manuscript database

    Because most of the dry matter of potato tubers is starch, an understanding of starch properties is important in potato improvement programs. Starch granule size is considered to influence tuber processing quality parameters such as gelatinization temperature, viscosity, and water holding capacity. ...

  7. Development of barley (Hordeum vulgare L.) lines with altered starch granule size distribution.

    PubMed

    Jaiswal, Sarita; Båga, Monica; Ahuja, Geetika; Rossnagel, Brian G; Chibbar, Ravindra N

    2014-03-12

    Microscope analysis of starches prepared from 139 barley genotypes identified a Japanese genotype, Kinai Kyoshinkai-2 (KK-2), with altered starch granule size distribution. Compared to normal barley starch, KK-2 produced consistently higher volumes of starch granules with 5-15 μm diameter and reduced volumes of starch granules with >15 μm diameter when grown in different environments. A cross between KK-2 and normal starch cultivar CDC Kendall was made and led to the production of 154 F5 lines with alterations to the normal 7:3:1 distribution for A-:B-:C-type starch granule volumes. Three F5 lines showed unimodal starch granule size distribution due to apparent lack of very small (<5.0 μm diameter) C-type starch granules, but the phenotype was accompanied by reduced grain weight and total starch concentration. Five F5 lines produced a significantly larger population of large (>15 μm diameter) A-type starch granules as compared to normal starch and showed on average a 10:4:1 distribution for A-:B-:C-type starch granule volumes. The unusual starch phenotypes displayed by the F5 lines confirm starch granule size distribution in barley can be genetically altered.

  8. Formation of Elongated Starch Granules in High-amylose Maize

    USDA-ARS?s Scientific Manuscript database

    GEMS-0067 maize starch contains up to 32% elongated starch granules much higher than amylose-extender (ae) single-mutant maize starch (~7%) and normal (non-mutant) maize starch (0%). These elongated granules are highly resistant to enzymatic hydrolysis at 95-100 C, which function as resistant starc...

  9. Physical association of starch biosynthetic enzymes with starch granules of maize endosperm. Granule-associated forms of starch synthase I and starch branching enzyme II.

    PubMed Central

    Mu-Forster, C; Huang, R; Powers, J R; Harriman, R W; Knight, M; Singletary, G W; Keeling, P L; Wasserman, B P

    1996-01-01

    Antibodies were used to probe the degree of association of starch biosynthetic enzymes with starch granules isolated from maize (Zea mays) endosperm. Graded washings of the starch granule, followed by release of polypeptides by gelatinization in 2% sodium dodecyl sulfate, enables distinction between strongly and loosely adherent proteins. Mild aqueous washing of granules resulted in near-complete solubilization of ADP-glucose pyrophosphorylase, indicating that little, if any, ADP-glucose pyrophosphorylase is granule associated. In contrast, all of the waxy protein plus significant levels of starch synthase I and starch branching enzyme II (BEII) remained granule associated. Stringent washings using protease and detergent demonstrated that the waxy protein, more than 85% total endosperm starch synthase I protein, and more than 45% of BEII protein were strongly associated with starch granules. Rates of polypeptide accumulation within starch granules remained constant during endosperm development. Soluble and granule-derived forms of BEII yielded identical peptide maps and overlapping tryptic fragments closely aligned with deduced amino acid sequences from BEII cDNA clones. These observations provide direct evidence that BEII exits as both soluble and granule-associated entities. We conclude that each of the known starch biosynthetic enzymes in maize endosperm exhibits a differential propensity to associate with, or to become irreversibly entrapped within, the starch granule. PMID:8754683

  10. Starch Synthesis in Arabidopsis. Granule Synthesis, Composition, and Structure1

    PubMed Central

    Zeeman, Samuel C.; Tiessen, Axel; Pilling, Emma; Kato, K. Lisa; Donald, Athene M.; Smith, Alison M.

    2002-01-01

    The aim of this work was to characterize starch synthesis, composition, and granule structure in Arabidopsis leaves. First, the potential role of starch-degrading enzymes during starch accumulation was investigated. To discover whether simultaneous synthesis and degradation of starch occurred during net accumulation, starch was labeled by supplying 14CO2 to intact, photosynthesizing plants. Release of this label from starch was monitored during a chase period in air, using different light intensities to vary the net rate of starch synthesis. No release of label was detected unless there was net degradation of starch during the chase. Similar experiments were performed on a mutant line (dbe1) that accumulates the soluble polysaccharide, phytoglycogen. Label was not released from phytoglycogen during the chase indicating that, even when in a soluble form, glucan is not appreciably degraded during accumulation. Second, the effect on starch composition of growth conditions and mutations causing starch accumulation was studied. An increase in starch content correlated with an increased amylose content of the starch and with an increase in the ratio of granule-bound starch synthase to soluble starch synthase activity. Third, the structural organization and morphology of Arabidopsis starch granules was studied. The starch granules were birefringent, indicating a radial organization of the polymers, and x-ray scatter analyses revealed that granules contained alternating crystalline and amorphous lamellae with a periodicity of 9 nm. Granules from the wild type and the high-starch mutant sex1 were flattened and discoid, whereas those of the high-starch mutant sex4 were larger and more rounded. These larger granules contained “growth rings” with a periodicity of 200 to 300 nm. We conclude that leaf starch is synthesized without appreciable turnover and comprises similar polymers and contains similar levels of molecular organization to storage starches, making Arabidopsis

  11. Starch synthesis in Arabidopsis. Granule synthesis, composition, and structure.

    PubMed

    Zeeman, Samuel C; Tiessen, Axel; Pilling, Emma; Kato, K Lisa; Donald, Athene M; Smith, Alison M

    2002-06-01

    The aim of this work was to characterize starch synthesis, composition, and granule structure in Arabidopsis leaves. First, the potential role of starch-degrading enzymes during starch accumulation was investigated. To discover whether simultaneous synthesis and degradation of starch occurred during net accumulation, starch was labeled by supplying (14)CO(2) to intact, photosynthesizing plants. Release of this label from starch was monitored during a chase period in air, using different light intensities to vary the net rate of starch synthesis. No release of label was detected unless there was net degradation of starch during the chase. Similar experiments were performed on a mutant line (dbe1) that accumulates the soluble polysaccharide, phytoglycogen. Label was not released from phytoglycogen during the chase indicating that, even when in a soluble form, glucan is not appreciably degraded during accumulation. Second, the effect on starch composition of growth conditions and mutations causing starch accumulation was studied. An increase in starch content correlated with an increased amylose content of the starch and with an increase in the ratio of granule-bound starch synthase to soluble starch synthase activity. Third, the structural organization and morphology of Arabidopsis starch granules was studied. The starch granules were birefringent, indicating a radial organization of the polymers, and x-ray scatter analyses revealed that granules contained alternating crystalline and amorphous lamellae with a periodicity of 9 nm. Granules from the wild type and the high-starch mutant sex1 were flattened and discoid, whereas those of the high-starch mutant sex4 were larger and more rounded. These larger granules contained "growth rings" with a periodicity of 200 to 300 nm. We conclude that leaf starch is synthesized without appreciable turnover and comprises similar polymers and contains similar levels of molecular organization to storage starches, making Arabidopsis

  12. Granule structure and distribution of allomorphs in C-type high-amylose rice starch granule modified by antisense RNA inhibition of starch branching enzyme.

    PubMed

    Wei, Cunxu; Qin, Fengling; Zhou, Weidong; Yu, Huaguang; Xu, Bin; Chen, Chong; Zhu, Lijia; Wang, Youping; Gu, Minghong; Liu, Qiaoquan

    2010-11-24

    C-type starch, which is a combination of both A-type and B-type crystal starch, is usually found in legumes and rhizomes. We have developed a high-amylose transgenic line of rice (TRS) by antisense RNA inhibition of starch branching enzymes. The starch in the endosperm of this TRS was identified as typical C-type crystalline starch, but its fine granular structure and allomorph distribution remained unclear. In this study, we conducted morphological and spectroscopic studies on this TRS starch during acid hydrolysis to determine the distribution of A- and B-type allomorphs. The morphology of starch granules after various durations of acid hydrolysis was compared by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that amorphous regions were located at the center part of TRS starch subgranules. During acid hydrolysis, starch was degraded from the interior of the subgranule to the outer surface, while the peripheral part of the subgranules and the surrounding band of the starch granule were highly resistant to acid hydrolysis. The spectroscopic changes detected by X-ray powder diffraction, 13C cross-polarization magic-angle spinning NMR, and attenuated total reflectance Fourier transform infrared showed that the A-type allomorph was hydrolyzed more rapidly than the B-type, and that the X-ray diffraction profile gradually changed from a native C-type to a CB-type with increasing hydrolysis time. Our results showed that, in TRS starch, the A-type allomorph was located around the amorphous region, and was surrounded by the B-type allomorph located in the peripheral region of the subgranules and the surrounding band of the starch granule. Thus, the positions of A- and B-type allomorphs in the TRS C-type starch granule differ markedly from those in C-type legume and rhizome starch.

  13. Second Harmonic Generation Mediated by Aligned Water in Starch Granules.

    PubMed

    Cisek, Richard; Tokarz, Danielle; Krouglov, Serguei; Steup, Martin; Emes, Michael J; Tetlow, Ian J; Barzda, Virginijus

    2014-12-26

    The origin of second harmonic generation (SHG) in starch granules was investigated using ab initio quantum mechanical modeling and experimentally examined using polarization-in, polarization-out (PIPO) second harmonic generation microscopy. Ab initio calculations revealed that the largest contribution to the SHG signal from A- and B-type allomorphs of starch originates from the anisotropic organization of hydroxide and hydrogen bonds mediated by aligned water found in the polymers. The hypothesis was experimentally tested by imaging maize starch granules under various hydration and heat treatment conditions that alter the hydrogen bond network. The highest SHG intensity was found in fully hydrated starch granules, and heat treatment diminished the SHG intensity. The PIPO SHG imaging showed that dried starch granules have a much higher nonlinear optical susceptibility component ratio than fully hydrated granules. In contrast, deuterated starch granules showed a smaller susceptibility component ratio demonstrating that SHG is highly sensitive to the organization of the hydroxyl and hydrogen bond network. The polarization SHG imaging results of potato starch granules, representing starch allomorph B, were compared to those of maize starch granules representing allomorph A. The results showed that the amount of aligned water was higher in the maize granules. Nonlinear microscopy of starch granules provides evidence that varying hydration conditions leads to significant changes in the nonlinear susceptibility ratio as well as the SHG intensity, supporting the hypothesis from ab initio calculations that the dominant contribution to SHG is due to the ordered hydroxide and hydrogen bond network.

  14. Effect of drought stress on the development of endosperm starch granules and the composition and physicochemical properties of starches from soft and hard wheat.

    PubMed

    Yu, Xurun; Li, Bo; Wang, Leilei; Chen, Xinyu; Wang, Wenjun; Gu, Yunjie; Wang, Zhong; Xiong, Fei

    2016-06-01

    The objectives of this study were to: (1) observe the effects of drought stress (DS) on the structural development of endosperm starch granules; (2) investigate the effects of DS on composition and physicochemical properties of starches; and (3) compare the different responses to DS between soft and hard wheat. DS resulted in large A-type starch granules at 12 d after anthesis (DAA) and a high percentage of B-type starch granules at 18 DAA in endosperm cells of the two wheat cultivars. DS decreased the 1000-grain weight, total starch and amylose contents, and amylose-to-amylopectin ratio of both starches. DS also decreased the percentage of B-type starch granules in NM13 and increased the number of hollows on the surface of A-type starch granules in XM33. DS further increased the swelling power and affected pasting properties of both starches. DS also significantly enhanced the hydrolysis degrees of starches by pancreatic α-amylase, Aspergillus niger amyloglucosidase, and HCl in NM13. DS altered the contents of rapidly digestible, slowly digestible, and resistant starches in native, gelatinised, and retrograded starches. Overall, DS can affect the development of endosperm starch granules and the physicochemical properties of starches, thus affecting the qualities of the final wheat products. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  15. Effects of granule swelling on starch saccharification by granular starch hydrolyzing enzyme.

    PubMed

    Li, Zhaofeng; Cai, Liming; Gu, Zhengbiao; Shi, Yong-Cheng

    2014-08-13

    The effects of granule swelling on enzymatic saccharification of normal corn starch by granular starch hydrolyzing enzyme were investigated. After swelling, Km values for the saccharification of granular starch decreased compared with native granular starch, indicating that granule swelling caused granular starch hydrolyzing enzyme to have higher affinity for starch granules. The partial swelling of starch granules enhanced starch saccharification. Furthermore, the enhancement at an earlier stage of enzymatic reaction was much more significant than that at later stages. For granular starch pretreated at 67.5 °C for 30 min, conversions to glucose after incubation with the enzyme at 32 °C for 4 and 24 h were approximately 3-fold and 26% higher than for native granular starch, respectively. As a result, proper heat pretreatment of granular starch before simultaneous saccharification and fermentation has great potential to facilitate industrial production of ethanol by use of granular starch hydrolyzing enzyme.

  16. Effect of enzymatic hydrolysis on native starch granule structure.

    PubMed

    Blazek, Jaroslav; Gilbert, Elliot Paul

    2010-12-13

    Enzymatic digestion of six starches of different botanical origin was studied in real time by in situ time-resolved small-angle neutron scattering (SANS) and complemented by the analysis of native and digested material by X-ray diffraction, differential scanning calorimetry, small-angle X-ray scattering, and scanning electron microscopy with the aim of following changes in starch granule nanostructure during enzymatic digestion. This range of techniques enables coverage over five orders of length-scale, as is necessary for this hierarchically structured material. Starches studied varied in their digestibility and displayed structural differences in the course of enzymatic digestion. The use of time-resolved SANS showed that solvent-drying of digested residues does not induce any structural artifacts on the length scale followed by small-angle scattering. In the course of digestion, the lamellar peak intensity gradually decreased and low-q scattering increased. These trends were more substantial for A-type than for B-type starches. These observations were explained by preferential digestion of the amorphous growth rings. Hydrolysis of the semicrystalline growth rings was explained on the basis of a liquid-crystalline model for starch considering differences between A-type and B-type starches in the length and rigidity of amylopectin spacers and branches. As evidenced by differing morphologies of enzymatic attack among varieties, the existence of granular pores and channels and physical penetrability of the amorphous growth ring affect the accessibility of the enzyme to the substrate. The combined effects of the granule microstructure and the nanostructure of the growth rings influence the opportunity of the enzyme to access its substrate; as a consequence, these structures determine the enzymatic digestibility of granular starches more than the absolute physical densities of the amorphous growth rings and amorphous and crystalline regions of the semicrystalline

  17. Identification of a major QTL controlling the content of B-type starch granules in Aegilops

    PubMed Central

    Howard, Thomas; Rejab, Nur Ardiyana; Griffiths, Simon; Leigh, Fiona; Leverington-Waite, Michelle; Simmonds, James; Uauy, Cristobal; Trafford, Kay

    2011-01-01

    Starch within the endosperm of most species of the Triticeae has a unique bimodal granule morphology comprising large lenticular A-type granules and smaller near-spherical B-type granules. However, a few wild wheat species (Aegilops) are known to lack B-granules. Ae. peregrina and a synthetic tetraploid Aegilops with the same genome composition (SU) were found to differ in B-granule number. The synthetic tetraploid had normal A- and B-type starch granules whilst Ae. peregrina had only A-granules because the B-granules failed to initiate. A population segregating for B-granule number was generated by crossing these two accessions and was used to study the genetic basis of B-granule initiation. A combination of Bulked Segregant Analysis and QTL mapping identified a major QTL located on the short arm of chromosome 4S that accounted for 44.4% of the phenotypic variation. The lack of B-granules in polyploid Aegilops with diverse genomes suggests that the B-granule locus has been lost several times independently during the evolution of the Triticeae. It is proposed that the B-granule locus is susceptible to silencing during polyploidization and a model is presented to explain the observed data based on the assumption that the initiation of B-granules is controlled by a single major locus per haploid genome. PMID:21227932

  18. Ultrasonic modification of starch - Impact on granules porosity.

    PubMed

    Sujka, Monika

    2017-07-01

    Rice, corn, wheat, and potato starch granules suspended in water or ethanol were treated with ultrasounds at frequency of 20kHz and power 170W for 30min. Porosity of starch was investigated in terms of specific surface area (SBET), average pore size and pore size distribution using low-temperature nitrogen adsorption method. The significant increase of SBET was noted for all the studied starches sonicated in water and for potato starch modified in ethanol. Ultrasonic treatment influenced the average diameter of mesopores (2nmstarches suspended in ethanol and for potato starch granules suspended in water, but in the case of corn starch, the obtained value was slightly lower after sonication in water. Modification of starch with ultrasounds resulted in the formation of new pores in the studied range of diameter. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Physicochemical properties of starches and proteins in alkali-treated mungbean and cassava starch granules.

    PubMed

    Israkarn, Kamolwan; Na Nakornpanom, Nantarat; Hongsprabhas, Parichat

    2014-05-25

    This study explored the influences of envelope integrity of cooked starch granules on physicochemical and thermophysical properties of mungbean and cassava starches. Alkali treatment was used to selectively leach amylose from the amorphous region of both starches and partially fragmented starch molecules into lower-molecular-weight polymers. It was found that despite the loss of 40% of the original content of amylose, both mungbean and cassava starches retained similar crystallinities, gelatinization temperature ranges, and pasting profiles compared to the native starches. However, the loss of granule-bound starch synthases during alkali treatment and subsequent alkali cooking in excess water played significant roles in determining granular disintegration. The alterations in envelope integrity due to the negative charge repulsion among polymers within the envelope of swollen granules, and the fragmentation of starch molecules, were responsible for the alterations in thermophysical properties of mungbean and cassava starches cooked under alkaline conditions.

  20. Visualization of internal structure of banana starch granule through AFM.

    PubMed

    Peroni-Okita, Fernanda H G; Gunning, A Patrick; Kirby, Andrew; Simão, Renata A; Soares, Claudinéia A; Cordenunsi, Beatriz R

    2015-09-05

    Atomic force microscopy (AFM) is a high resolution technique for studying the external and internal structures of starch granules. For this purpose granules were isolated from bananas and embedded in a non-penetrating resin. To achieve image contrast of the ultrastructure, the face of the cut blocks were wetted in steam and force modulation mode imaging was used. Images of starch from green bananas showed large variation of height across the granule due to a locational specific absorption of water and swelling of amorphous regions; the data reveal that the center of the granules are structurally different and have different viscoelastic properties. Images of starches from ripe bananas showed an even greater different level of organization: absence of growth rings around the hilum; the central region of the granule is richer in amylose; very porous surface with round shaped dark structures; the size of blocklets are larger than the green fruits.

  1. Particle size distribution of wheat starch granules in relation to baking properties of frozen dough.

    PubMed

    Tao, Han; Wang, Pei; Wu, Fengfeng; Jin, Zhengyu; Xu, Xueming

    2016-02-10

    The impact of freezing on the wheat starches with different particle size was studied using a range of characterization methods including X-ray diffraction, differential scanning calorimetry, the Rapid Visco Analyser and a reconstitution dough system. Wheat starches were fractionated into A- and B-type granules, and then subjected to freezing/thawing treatment for 3 cycles. The freezing treatment did not cause apparent damage on A-type granular surface but induced cracked structure on B-type granules. It facilitated materials such as amylose, proteins, and lipids leaching from starch granule and an increase in gelatinization temperatures, melting enthalpy, and pasting viscosities. A smaller bread specific volume was obtained from freezing-treated B-granules while the crumb firmness significantly increased (p>0.05). No marked differences were observed in the counterparts of A-granules after freezing treatment. It seemed that the B-type granules were more sensitive to the freezing/thawing treatment, thus facilitating structural transformations from dough to bread. Results indicated that the deterioration in frozen bread quality derived from starch could be minimized by increasing the A-granules content.

  2. Control of starch granule numbers in Arabidopsis chloroplasts.

    PubMed

    Crumpton-Taylor, Matilda; Grandison, Scott; Png, Kenneth M Y; Bushby, Andrew J; Smith, Alison M

    2012-02-01

    The aim of this work was to investigate starch granule numbers in Arabidopsis (Arabidopsis thaliana) leaves. Lack of quantitative information on the extent of genetic, temporal, developmental, and environmental variation in granule numbers is an important limitation in understanding control of starch degradation and the mechanism of granule initiation. Two methods were developed for reliable estimation of numbers of granules per chloroplast. First, direct measurements were made on large series of consecutive sections of mesophyll tissue obtained by focused ion beam-scanning electron microscopy. Second, average numbers were calculated from the starch contents of leaves and chloroplasts and estimates of granule mass based on granule dimensions. Examination of wild-type plants and accumulation and regulation of chloroplast (arc) mutants with few, large chloroplasts provided the following new insights. There is wide variation in chloroplast volumes in cells of wild-type leaves. Granule numbers per chloroplast are correlated with chloroplast volume, i.e. large chloroplasts have more granules than small chloroplasts. Mature leaves of wild-type plants and arc mutants have approximately the same number of granules per unit volume of stroma, regardless of the size and number of chloroplasts per cell. Granule numbers per unit volume of stroma are also relatively constant in immature leaves but are greater than in mature leaves. Granule initiation occurs as chloroplasts divide in immature leaves, but relatively little initiation occurs in mature leaves. Changes in leaf starch content over the diurnal cycle are largely brought about by changes in the volume of a fixed number of granules.

  3. Molecular disassembly of starch granules during gelatinization and its effect on starch digestibility: a review.

    PubMed

    Wang, Shujun; Copeland, Les

    2013-11-01

    Starch is the most important glycemic carbohydrate in foods. The relationship between the rate and extent of starch digestion to produce glucose for absorption into the bloodstream and risk factors for diet-related diseases is of considerable nutritional interest. Native starch is attacked slowly by enzymes, but after hydrothermal processing its susceptibility to enzymatic breakdown is greatly increased. Most starch consumed by humans has undergone some form of processing or cooking, which causes native starch granules to gelatinize, followed by retrogradation on cooling. The extent of gelatinization and retrogradation are major determinants of the susceptibility of starch to enzymatic digestion and its functional properties for food processing. The type and extent of changes that occur in starch as a result of gelatinization, pasting and retrogradation are determined by the type of the starch, processing and storage conditions. A mechanistic understanding of the molecular disassembly of starch granules during gelatinization is critical to explaining the effects of processing or cooking on starch digestibility. This review focuses on the molecular disassembly of starch granules during starch gelatinization over a wide range of water levels, and its consequential effect on in vitro starch digestibility and in vivo glycemic index.

  4. Phenotypic diversity of starch granules in cassava germplasm.

    PubMed

    Vasconcelos, L M; Brito, A C; Carmo, C D; Oliveira, P H G A; Oliveira, E J

    2017-04-13

    Demand for the development of cassava varieties with different native starches has guided the search for these characteristics in the germplasm of Manihot esculenta Crantz. Therefore, the objective of this study was to estimate the genetic diversity of cassava accessions for root and starch granule characteristics to guide the future industrial application of this species. Starches from 56 accessions were evaluated for the number of granules in 1 g of starch (NTG), area (AG, μm(2)), length (LG, μm), width (WG, μm), starch granule roundness (Round), dry matter content in the roots (DMC, %), pulp color (PulCo), and cyanogenic compounds (HCN). Images captured by light microscopy were used to determine the average phenotypic values, and these were further analyzed by principal component analysis (PCA) considering mixed data (quantitative and qualitative). Significant differences between the cassava accessions for all traits measured revealed wide variability in starch granule characteristics. Four diversity groups with better fitness for the classification of cassava accessions based on PulCo were identified, in comparison with HCN. Accessions with differential starch characteristics were identified, and crossings for the generation of segregating populations in order to obtain table and industry varieties have been proposed.

  5. Deficiency of Starch Synthase IIIa and IVb Alters Starch Granule Morphology from Polyhedral to Spherical in Rice Endosperm1

    PubMed Central

    Toyosawa, Yoshiko; Kawagoe, Yasushi; Matsushima, Ryo; Ogawa, Masahiro; Fukuda, Masako; Kumamaru, Toshihiro; Okazaki, Yozo; Kusano, Miyako; Saito, Kazuki; Toyooka, Kiminori; Sato, Mayuko; Ai, Yongfeng; Fujita, Naoko

    2016-01-01

    Starch granule morphology differs markedly among plant species. However, the mechanisms controlling starch granule morphology have not been elucidated. Rice (Oryza sativa) endosperm produces characteristic compound-type granules containing dozens of polyhedral starch granules within an amyloplast. Some other cereal species produce simple-type granules, in which only one starch granule is present per amyloplast. A double mutant rice deficient in the starch synthase (SS) genes SSIIIa and SSIVb (ss3a ss4b) produced spherical starch granules, whereas the parental single mutants produced polyhedral starch granules similar to the wild type. The ss3a ss4b amyloplasts contained compound-type starch granules during early developmental stages, and spherical granules were separated from each other during subsequent amyloplast development and seed dehydration. Analysis of glucan chain length distribution identified overlapping roles for SSIIIa and SSIVb in amylopectin chain synthesis, with a degree of polymerization of 42 or greater. Confocal fluorescence microscopy and immunoelectron microscopy of wild-type developing rice seeds revealed that the majority of SSIVb was localized between starch granules. Therefore, we propose that SSIIIa and SSIVb have crucial roles in determining starch granule morphology and in maintaining the amyloplast envelope structure. We present a model of spherical starch granule production. PMID:26747287

  6. Amylolytic hydrolysis of native starch granules affected by granule surface area.

    PubMed

    Kim, J C; Kong, B W; Kim, M J; Lee, S H

    2008-11-01

    Initial stage of hydrolysis of native starch granules with various amylolytic enzymes, alpha-amylase from Bacillus subtilis, glucoamylase I (GA-I) and II (GA-II) from Aspergillus niger, and beta-amylase from sweet potato showed that the reaction was apparently affected by a specific surface area of the starch granules. The ratios of the reciprocal of initial velocity of each amylolytic hydrolysis for native potato and maize starch to that for rice with the amylolytic enzymes were nearly equivalent to the ratio of surface area per mass of the 2 starch granules to that of rice, that is, 6.94 and 2.25, respectively. Thus, the reciprocal of initial velocity of each enzymatic hydrolysis as expressed in a Lineweaver-Burk plot was a linear function of the reciprocal of surface area for each starch granule. As a result, it is concluded that amylolytic hydrolysis of native starch granules is governed by the specific surface area, not by the mass concentration, of each granule.

  7. Differences of Starch Granule Distribution in Grains from Different Spikelet Positions in Winter Wheat

    PubMed Central

    Yu, Anling; Li, Yong; Ni, Yingli; Yang, Weibing; Yang, Dongqing; Cui, Zhengyong; Wang, Zhenlin; Yin, Yanping

    2014-01-01

    Wheat starch development is a complex process and is markedly difference by changes in spikelet spatial position. The present study deals with endosperm starch granule distribution and spatial position during filling development. The study was conducted with pure starch isolated from wheat (Triticum aestivum L.), Jimai20 and Shannong1391, at 7–35 days after anthesis (DAA). The results showed that grain number, spikelet weight and grain weight per spikelet in different spatial position showed parabolic changes. Upper spikelets had highest starch and amylose content followed by basal spikelets, then middle spikelets. The paper also suggested the volume percents of B-type and A-type granule in grain of middle spikelets were remarkably higher and lower than those of basal and upper spikelets, respectively. However, no significant difference occurred in the number percents of the two type granule. The ratio of amylase to amylopectin was positively correlated with the volume proportion of 22.8–42.8 µm, but was negatively related to the volume proportion of <9.9 µm. The results indicated that the formation and distribution of starch granules were affected significantly by spikelet position, and grains at upper and basal spikelet had the potential of increasing grain weight through increasing the volume of B-type granules. PMID:25514032

  8. A new proposed sweet potato starch granule structure--pomegranate concept.

    PubMed

    Xijun, Lian; Lin, Li; Kunsheng, Zhang; Ying, Xu; Jiaxin, Lu

    2012-04-01

    There are two competing concepts about organization of starch granule, fibrillar concept (or amylopectin clustering concept) and blocklet concept. A new micrograph of gelatinized sweet potato starch mixed with lactose might combine the two concepts and recover the mysterious structure of starch granule. Here we propose a possible granule structure of sweet potato starch by analyzing its gelatinization micrographs mixed with different carbohydrates. As the structure of pomegranate, out-layer of granule is equivalent to skin of pomegranate, blocklets are same to garnet of pomegranate, the amylopectin clusters with one reducing end at hilum, equivalent to primary body of pomegranate, constitute the basic structure of granule, in the special parts of the clusters, lots of blocklets form and increase, very like the born of garnet of pomegranate. At the same time double helix appears in blocklets, the arrangements of blocklets, same as garnet in pomegranate, form the semi-crystalline growth rings. The crystal type of starch is determined by arrangement of blocklet on it, hexagonal for A type, monoclinic for B type. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Physical characteristics of starch granules and susceptibility to enzymatic degradation.

    PubMed

    Gallant, D J; Bouchet, B; Buléon, A; Pérez, S

    1992-10-01

    Starch, the most abundant component of the diet, is characterized by its variety as well as the versatility of its derivatives in foods. This paper is an overview of the main physical characteristics of the native starch granule. Three different levels of organization are presented: macromolecular structure, crystalline organization and ultrastructure. Starch consists of amylose and amylopectin. Amylose is an essentially linear polymer composed of alpha-1,4-linked D-anhydroglucose units (AGU); amylopectin is a branched polymer clustering a large amount of short linear chains by the linkage of alpha-1,6-bonds, constituting about 5% of the total glycosidic bonds. In the native starch granules, a large number of the macromolecular chains are organized in crystalline structures. Three forms have been found, the A, B and C patterns. So far only A and B starch crystals have been modelled. There is a variation in the susceptibility of the starch granules to enzymatic digestion. This is explained by variation in the morphology of the granules and their crystalline organization.

  10. Plantain and banana starches: granule structural characteristics explain the differences in their starch degradation patterns.

    PubMed

    Soares, Claudinéia Aparecida; Peroni-Okita, Fernanda Helena Gonçalves; Cardoso, Mateus Borba; Shitakubo, Renata; Lajolo, Franco Maria; Cordenunsi, Beatriz Rosana

    2011-06-22

    Different banana cultivars were used to investigate the influences of starch granule structure and hydrolases on degradation. The highest degrees of starch degradation were observed in dessert bananas during ripening. Scanning electron microscopy images revealed smooth granule surface in the green stage in all cultivars, except for Mysore. The small and round granules were preferentially degraded in all of the cultivars. Terra demonstrated a higher degree of crystallinity and a short amylopectin chain length distribution, resulting in high starch content in the ripe stage. Amylose content and the crystallinity index were more strongly correlated than the distribution of amylopectin branch chain lengths in banana starches. α- and β-amylase activities were found in both forms, soluble in the pulp and associated with the starch granule. Starch-phosphorylase was not found in Mysore. On the basis of the profile of α-amylase in vitro digestion and the structural characteristics, it could be concluded that the starch of plantains has an arrangement of granules more resistant to enzymes than the starch of dessert bananas.

  11. Homologs of PROTEIN TARGETING TO STARCH Control Starch Granule Initiation in Arabidopsis Leaves[OPEN

    PubMed Central

    David, Laure C.; Abt, Melanie; Lu, Kuan-Jen

    2017-01-01

    The molecular mechanism that initiates the synthesis of starch granules is poorly understood. Here, we discovered two plastidial proteins involved in granule initiation in Arabidopsis thaliana leaves. Both contain coiled coils and a family-48 carbohydrate binding module (CBM48) and are homologs of the PROTEIN TARGETING TO STARCH (PTST) protein; thus, we named them PTST2 and PTST3. Chloroplasts in mesophyll cells typically contain five to seven granules, but remarkably, most chloroplasts in ptst2 mutants contained zero or one large granule. Chloroplasts in ptst3 had a slight reduction in granule number compared with the wild type, while those of the ptst2 ptst3 double mutant contained even fewer granules than ptst2. The ptst2 granules were larger but similar in morphology to wild-type granules, but those of the double mutant had an aberrant morphology. Immunoprecipitation showed that PTST2 interacts with STARCH SYNTHASE4 (SS4), which influences granule initiation and morphology. Overexpression of PTST2 resulted in chloroplasts containing many small granules, an effect that was dependent on the presence of SS4. Furthermore, isothermal titration calorimetry revealed that the CBM48 domain of PTST2, which is essential for its function, interacts with long maltooligosaccharides. We propose that PTST2 and PTST3 are critical during granule initiation, as they bind and deliver suitable maltooligosaccharide primers to SS4. PMID:28684429

  12. Homologs of PROTEIN TARGETING TO STARCH Control Starch Granule Initiation in Arabidopsis Leaves.

    PubMed

    Seung, David; Boudet, Julien; Monroe, Jonathan; Schreier, Tina B; David, Laure C; Abt, Melanie; Lu, Kuan-Jen; Zanella, Martina; Zeeman, Samuel C

    2017-07-01

    The molecular mechanism that initiates the synthesis of starch granules is poorly understood. Here, we discovered two plastidial proteins involved in granule initiation in Arabidopsis thaliana leaves. Both contain coiled coils and a family-48 carbohydrate binding module (CBM48) and are homologs of the PROTEIN TARGETING TO STARCH (PTST) protein; thus, we named them PTST2 and PTST3. Chloroplasts in mesophyll cells typically contain five to seven granules, but remarkably, most chloroplasts in ptst2 mutants contained zero or one large granule. Chloroplasts in ptst3 had a slight reduction in granule number compared with the wild type, while those of the ptst2 ptst3 double mutant contained even fewer granules than ptst2 The ptst2 granules were larger but similar in morphology to wild-type granules, but those of the double mutant had an aberrant morphology. Immunoprecipitation showed that PTST2 interacts with STARCH SYNTHASE4 (SS4), which influences granule initiation and morphology. Overexpression of PTST2 resulted in chloroplasts containing many small granules, an effect that was dependent on the presence of SS4. Furthermore, isothermal titration calorimetry revealed that the CBM48 domain of PTST2, which is essential for its function, interacts with long maltooligosaccharides. We propose that PTST2 and PTST3 are critical during granule initiation, as they bind and deliver suitable maltooligosaccharide primers to SS4. © 2017 American Society of Plant Biologists. All rights reserved.

  13. Study of quantitative interactions of potato and corn starch granules with ions in diluted solutions of heavy metal salts.

    PubMed

    Szymońska, Joanna; Molenda, Marcin; Wieczorek, Jerzy

    2015-12-10

    Interactions of potato and corn starch granules with ions in diluted solutions of silver, lead, copper or iron salts were investigated. It was shown experimentally that granules accumulated the cations in amounts depending on the granule structure and water content as well as a type of both metal and counter-ions present in solution. Potato starch retained almost three times more cations compared to corn starch what was proportional to the total phosphorous content in these starches. Quantity of milligrams of cations bound by 1g of starch was inversely correlated with the cation hydration. Ag(+), Pb(2+) and Cu(2+) were connected in stoichiometric amounts of moles to semicrystalline and amorphous parts of the granules. Fe(3+) ions were accumulated in higher than stoichiometric quantities mainly in granule amorphous regions. Metal ions penetrated into granules together with anions except nitrates which remained on surface of potato starch granules. Cations facilitated the starch thermal decomposition in accordance with values of their standard redox potentials. Nitrates supported this process only in the presence of base metal cations.

  14. Proteome and phosphoproteome analysis of starch granule-associated proteins from normal maize and mutants affected in starch biosynthesis.

    PubMed

    Grimaud, Florent; Rogniaux, Hélène; James, Martha G; Myers, Alan M; Planchot, Véronique

    2008-01-01

    In addition to the exclusively granule-bound starch synthase GBSSI, starch granules also bind significant proportions of other starch biosynthetic enzymes, particularly starch synthases (SS) SSI and SSIIa, and starch branching enzyme (BE) BEIIb. Whether this association is a functional aspect of starch biosynthesis, or results from non-specific entrapment during amylopectin crystallization, is not known. This study utilized genetic, immunological, and proteomic approaches to investigate comprehensively the proteome and phosphoproteome of Zea mays endosperm starch granules. SSIII, BEI, BEIIa, and starch phosphorylase were identified as internal granule-associated proteins in maize endosperm, along with the previously identified proteins GBSS, SSI, SSIIa, and BEIIb. Genetic analyses revealed three instances in which granule association of one protein is affected by the absence of another biosynthetic enzyme. First, eliminating SSIIa caused reduced granule association of SSI and BEIIb, without affecting GBSS abundance. Second, eliminating SSIII caused the appearance of two distinct electrophoretic mobility forms of BEIIb, whereas only a single migration form of BEIIb was observed in wild type or any other mutant granules examined. Third, eliminating BEIIb caused significant increases in the abundance of BEI, BEIIa, SSIII, and starch phosphorylase in the granule, without affecting SSI or SSIIa. Analysis of the granule phosphoproteome with a phosphorylation-specific dye indicated that GBSS, BEIIb, and starch phosphorylase are all phosphorylated as they occur in the granule. These results suggest the possibility that starch metabolic enzymes located in granules are regulated by post-translational modification and/or protein-protein interactions.

  15. Proteome Profile of Starch Granules Purified from Rice (Oryza sativa) Endosperm

    PubMed Central

    Xing, Shihai; Meng, Xiaoxi; Zhou, Lihui; Mujahid, Hana; Zhao, Chunfang; Zhang, Yadong; Wang, Cailin; Peng, Zhaohua

    2016-01-01

    Starch is the most important food energy source in cereals. Many of the known enzymes involved in starch biosynthesis are partially or entirely granule-associated in the endosperm. Studying the proteome of rice starch granules is critical for us to further understand the mechanisms underlying starch biosynthesis and packaging of starch granules in rice amyloplasts, consequently for the improvement of rice grain quality. In this article, we developed a protocol to purify starch granules from mature rice endosperm and verified the quality of purified starch granules by microscopy observations, I2 staining, and Western blot analyses. In addition, we found the phenol extraction method was superior to Tris-HCl buffer extraction method with respect to the efficiency in recovery of starch granule associated proteins. LC-MS/MS analysis showed identification of already known starch granule associated proteins with high confidence. Several proteins reported to be involved in starch synthesis in prior genetic studies in plants were also shown to be enriched with starch granules, either directly or indirectly, in our studies. In addition, our results suggested that a few additional candidate proteins may also be involved in starch synthesis. Furthermore, our results indicated that some starch synthesis pathway proteins are subject to protein acetylation modification. GO analysis and KEGG pathway enrichment analysis showed that the identified proteins were mainly located in plastids and involved in carbohydrate metabolism. This study substantially advances the understanding of the starch granule associated proteome in rice and post translational regulation of some starch granule associated proteins. PMID:27992503

  16. Degradation of Glucan Primers in the Absence of Starch Synthase 4 Disrupts Starch Granule Initiation in Arabidopsis*

    PubMed Central

    Lu, Kuan-Jen; Stettler, Michaela; Streb, Sebastian

    2016-01-01

    Arabidopsis leaf chloroplasts typically contain five to seven semicrystalline starch granules. It is not understood how the synthesis of each granule is initiated or how starch granule number is determined within each chloroplast. An Arabidopsis mutant lacking the glucosyl-transferase, STARCH SYNTHASE 4 (SS4) is impaired in its ability to initiate starch granules; its chloroplasts rarely contain more than one large granule, and the plants have a pale appearance and reduced growth. Here we report that the chloroplastic α-amylase AMY3, a starch-degrading enzyme, interferes with granule initiation in the ss4 mutant background. The amy3 single mutant is similar in phenotype to the wild type under normal growth conditions, with comparable numbers of starch granules per chloroplast. Interestingly, the ss4 mutant displays a pleiotropic reduction in the activity of AMY3. Remarkably, complete abolition of AMY3 (in the amy3 ss4 double mutant) increases the number of starch granules produced in each chloroplast, suppresses the pale phenotype of ss4, and nearly restores normal growth. The amy3 mutation also restores starch synthesis in the ss3 ss4 double mutant, which lacks STARCH SYNTHASE 3 (SS3) in addition to SS4. The ss3 ss4 line is unable to initiate any starch granules and is thus starchless. We suggest that SS4 plays a key role in granule initiation, allowing it to proceed in a way that avoids premature degradation of primers by starch hydrolases, such as AMY3. PMID:27458017

  17. Recreating the synthesis of starch granules in yeast

    PubMed Central

    Pfister, Barbara; Sánchez-Ferrer, Antoni; Diaz, Ana; Lu, Kuanjen; Otto, Caroline; Holler, Mirko; Shaik, Farooque Razvi; Meier, Florence; Mezzenga, Raffaele; Zeeman, Samuel C

    2016-01-01

    Starch, as the major nutritional component of our staple crops and a feedstock for industry, is a vital plant product. It is composed of glucose polymers that form massive semi-crystalline granules. Its precise structure and composition determine its functionality and thus applications; however, there is no versatile model system allowing the relationships between the biosynthetic apparatus, glucan structure and properties to be explored. Here, we expressed the core Arabidopsis starch-biosynthesis pathway in Saccharomyces cerevisiae purged of its endogenous glycogen-metabolic enzymes. Systematic variation of the set of biosynthetic enzymes illustrated how each affects glucan structure and solubility. Expression of the complete set resulted in dense, insoluble granules with a starch-like semi-crystalline organization, demonstrating that this system indeed simulates starch biosynthesis. Thus, the yeast system has the potential to accelerate starch research and help create a holistic understanding of starch granule biosynthesis, providing a basis for the targeted biotechnological improvement of crops. DOI: http://dx.doi.org/10.7554/eLife.15552.001 PMID:27871361

  18. Two Distinct Waxy Alleles Impact the Granule-Bound Starch Synthase in Sorghum

    USDA-ARS?s Scientific Manuscript database

    The granule-bound starch synthase (GBSS) is the enzyme responsible for amylose synthesis in starch granules. Loss of GBSS activity results in starch granules containing mostly amylopectin and little or no amylose, a phenotype described as waxy. Previously, two phenotypic classes of waxy alleles we...

  19. PROTEIN TARGETING TO STARCH Is Required for Localising GRANULE-BOUND STARCH SYNTHASE to Starch Granules and for Normal Amylose Synthesis in Arabidopsis

    PubMed Central

    Seung, David; Soyk, Sebastian; Coiro, Mario; Maier, Benjamin A.; Eicke, Simona; Zeeman, Samuel C.

    2015-01-01

    The domestication of starch crops underpinned the development of human civilisation, yet we still do not fully understand how plants make starch. Starch is composed of glucose polymers that are branched (amylopectin) or linear (amylose). The amount of amylose strongly influences the physico-chemical behaviour of starchy foods during cooking and of starch mixtures in non-food manufacturing processes. The GRANULE-BOUND STARCH SYNTHASE (GBSS) is the glucosyltransferase specifically responsible for elongating amylose polymers and was the only protein known to be required for its biosynthesis. Here, we demonstrate that PROTEIN TARGETING TO STARCH (PTST) is also specifically required for amylose synthesis in Arabidopsis. PTST is a plastidial protein possessing an N-terminal coiled coil domain and a C-terminal carbohydrate binding module (CBM). We discovered that Arabidopsis ptst mutants synthesise amylose-free starch and are phenotypically similar to mutants lacking GBSS. Analysis of granule-bound proteins showed a dramatic reduction of GBSS protein in ptst mutant starch granules. Pull-down assays with recombinant proteins in vitro, as well as immunoprecipitation assays in planta, revealed that GBSS physically interacts with PTST via a coiled coil. Furthermore, we show that the CBM domain of PTST, which mediates its interaction with starch granules, is also required for correct GBSS localisation. Fluorescently tagged Arabidopsis GBSS, expressed either in tobacco or Arabidopsis leaves, required the presence of Arabidopsis PTST to localise to starch granules. Mutation of the CBM of PTST caused GBSS to remain in the plastid stroma. PTST fulfils a previously unknown function in targeting GBSS to starch. This sheds new light on the importance of targeting biosynthetic enzymes to sub-cellular sites where their action is required. Importantly, PTST represents a promising new gene target for the biotechnological modification of starch composition, as it is exclusively involved

  20. PROTEIN TARGETING TO STARCH is required for localising GRANULE-BOUND STARCH SYNTHASE to starch granules and for normal amylose synthesis in Arabidopsis.

    PubMed

    Seung, David; Soyk, Sebastian; Coiro, Mario; Maier, Benjamin A; Eicke, Simona; Zeeman, Samuel C

    2015-02-01

    The domestication of starch crops underpinned the development of human civilisation, yet we still do not fully understand how plants make starch. Starch is composed of glucose polymers that are branched (amylopectin) or linear (amylose). The amount of amylose strongly influences the physico-chemical behaviour of starchy foods during cooking and of starch mixtures in non-food manufacturing processes. The GRANULE-BOUND STARCH SYNTHASE (GBSS) is the glucosyltransferase specifically responsible for elongating amylose polymers and was the only protein known to be required for its biosynthesis. Here, we demonstrate that PROTEIN TARGETING TO STARCH (PTST) is also specifically required for amylose synthesis in Arabidopsis. PTST is a plastidial protein possessing an N-terminal coiled coil domain and a C-terminal carbohydrate binding module (CBM). We discovered that Arabidopsis ptst mutants synthesise amylose-free starch and are phenotypically similar to mutants lacking GBSS. Analysis of granule-bound proteins showed a dramatic reduction of GBSS protein in ptst mutant starch granules. Pull-down assays with recombinant proteins in vitro, as well as immunoprecipitation assays in planta, revealed that GBSS physically interacts with PTST via a coiled coil. Furthermore, we show that the CBM domain of PTST, which mediates its interaction with starch granules, is also required for correct GBSS localisation. Fluorescently tagged Arabidopsis GBSS, expressed either in tobacco or Arabidopsis leaves, required the presence of Arabidopsis PTST to localise to starch granules. Mutation of the CBM of PTST caused GBSS to remain in the plastid stroma. PTST fulfils a previously unknown function in targeting GBSS to starch. This sheds new light on the importance of targeting biosynthetic enzymes to sub-cellular sites where their action is required. Importantly, PTST represents a promising new gene target for the biotechnological modification of starch composition, as it is exclusively involved

  1. Tribology of swollen starch granule suspensions from maize and potato.

    PubMed

    Zhang, Bin; Selway, Nichola; Shelat, Kinnari J; Dhital, Sushil; Stokes, Jason R; Gidley, Michael J

    2017-01-02

    The tribological properties of suspensions of cooked swollen starch granules are characterised for systems based on maize starch and potato starch. These systems are known as granule 'ghosts' due to the release (and removal) of polymer from their structure during cooking. Maize starch ghosts are less swollen than potato starch ghosts, resulting in a higher packing concentration and greater mechanical stability. In a soft-tribological contact, maize ghost suspensions reduce friction compared to the solvent (water), generate bell-shaped tribological profiles characteristic of particle entrainment and show a marked concentration dependence, whereas potato ghost suspensions exhibit lubrication behaviour similar to water. Microscopy analysis of the samples following tribological testing suggests that this is due to the rapid break-up of potato ghosts under the shear and rolling conditions within the tribological contact. A reduction in the small deformation moduli (associated with a weak gel structure) is also observed when the potato ghost suspensions are subjected to steady shear using parallel plate rheometry; both microscopy and particle size analysis show that this is accompanied by the partial shear-induced breakage of ghost particles. This interplay between particle microstructure and the resultant rheological and lubrication dynamics of starch ghost suspensions contributes to an enhanced mechanistic understanding of textural and other functional properties of cooked starches in food and other applications.

  2. Comparison of starch granule development and physicochemical properties of starches in wheat pericarp and endosperm.

    PubMed

    Yu, Xurun; Zhou, Liang; Zhang, Jing; Yu, Heng; Xiong, Fei; Wang, Zhong

    2015-01-01

    The objectives of this study were: (i) to characterize structural development of starch granule in pericarp and endosperm during wheat caryopsis growth; (ii) to compare physicochemical properties of starches in pericarp and endosperm; (iii) to further discover the relationships between pericarp starches and endosperm starches. Wheat pericarp and endosperm at different development stages were observed by light microscopy and scanning electron microscopy, respectively. Structural properties of starches were determined using X-ray power diffraction and (13) C solid nuclear magnetic resonance. Pericarp starch granules (PSG) accumulated in amyloplasts and chloroplasts, and showed a typical accumulation peak at 5 days after fertilization (DAF), and then gradually decomposed during 5-22 DAF. PSG in the abdominal region showed a higher rate of decomposition compared to the dorsal region of pericarp. Endosperm starch granules (ESG) accumulated in amyloplasts, and occurred in endosperm cells at 5 DAF, then rapidly enriched the endosperm cells until 22 DAF. Compared with ESG, PSG were compound granules of irregular shape and small size distribution. The results also suggested lower amylose content and V-type single-helix content and higher proportions of double helices for PSG compared to ESG. Based on the structural development of PSG and ESG, we speculated that the saccharides resulting from decomposition of PSG, on one hand, enabled the pericarp to survive before maturity of wheat caryopsis and, on the other hand, provided extra nutrition for the growth of ESG. © 2014 Society of Chemical Industry.

  3. C-type starch from high-amylose rice resistant starch granules modified by antisense RNA inhibition of starch branching enzyme.

    PubMed

    Wei, Cunxu; Xu, Bin; Qin, Fengling; Yu, Huaguang; Chen, Chong; Meng, Xianglen; Zhu, Lijia; Wang, Youping; Gu, Minghong; Liu, Qiaoquan

    2010-06-23

    High-amylose starch is a source of resistant starch (RS) which has a great benefit on human health. A transgenic rice line (TRS) enriched amylose and RS had been developed by antisense RNA inhibition of starch branching enzymes. In this study, the native starch granules were isolated from TRS grains as well as the wild type, and their crystalline type was carefully investigated before and after acid hydrolysis. In high-amylose TRS rice, the C-type starch, which might result from the combination of both A-type and B-type starch, was observed and subsequently confirmed by multiple physical techniques, including X-ray powder diffraction, solid-state nuclear magnetic resonance, and Fourier transform infrared. Moreover, the change of starch crystalline structure from C- to B-type during acid hydrolysis was also observed in this RS-rich rice. These data could add to our understanding of not only the polymorph structure of cereal starch but also why high-amylose starch is more resistant to digestion.

  4. Concerted suppression of all starch branching enzyme genes in barley produces amylose-only starch granules

    PubMed Central

    2012-01-01

    Background Starch is stored in higher plants as granules composed of semi-crystalline amylopectin and amorphous amylose. Starch granules provide energy for the plant during dark periods and for germination of seeds and tubers. Dietary starch is also a highly glycemic carbohydrate being degraded to glucose and rapidly absorbed in the small intestine. But a portion of dietary starch, termed “resistant starch” (RS) escapes digestion and reaches the large intestine, where it is fermented by colonic bacteria producing short chain fatty acids (SCFA) which are linked to several health benefits. The RS is preferentially derived from amylose, which can be increased by suppressing amylopectin synthesis by silencing of starch branching enzymes (SBEs). However all the previous works attempting the production of high RS crops resulted in only partly increased amylose-content and/or significant yield loss. Results In this study we invented a new method for silencing of multiple genes. Using a chimeric RNAi hairpin we simultaneously suppressed all genes coding for starch branching enzymes (SBE I, SBE IIa, SBE IIb) in barley (Hordeum vulgare L.), resulting in production of amylose-only starch granules in the endosperm. This trait was segregating 3:1. Amylose-only starch granules were irregularly shaped and showed peculiar thermal properties and crystallinity. Transgenic lines retained high-yield possibly due to a pleiotropic upregualtion of other starch biosynthetic genes compensating the SBEs loss. For gelatinized starch, a very high content of RS (65 %) was observed, which is 2.2-fold higher than control (29%). The amylose-only grains germinated with same frequency as control grains. However, initial growth was delayed in young plants. Conclusions This is the first time that pure amylose has been generated with high yield in a living organism. This was achieved by a new method of simultaneous suppression of the entire complement of genes encoding starch branching enzymes. We

  5. Starch synthase 4 is essential for coordination of starch granule formation with chloroplast division during Arabidopsis leaf expansion

    PubMed Central

    Crumpton-Taylor, Matilda; Pike, Marilyn; Lu, Kuan-Jen; Hylton, Christopher M; Feil, Regina; Eicke, Simona; Lunn, John E; Zeeman, Samuel C; Smith, Alison M

    2013-01-01

    Arabidopsis thaliana mutants lacking the SS4 isoform of starch synthase have strongly reduced numbers of starch granules per chloroplast, suggesting that SS4 is necessary for the normal generation of starch granules. To establish whether it plays a direct role in this process, we investigated the circumstances in which granules are formed in ss4 mutants. Starch granule numbers and distribution and the accumulation of starch synthase substrates and products were investigated during ss4 leaf development, and in ss4 mutants carrying mutations or transgenes that affect starch turnover or chloroplast volume. We found that immature ss4 leaves have no starch granules, but accumulate high concentrations of the starch synthase substrate ADPglucose. Granule numbers are partially restored by elevating the capacity for glucan synthesis (via expression of bacterial glycogen synthase) or by increasing the volumes of individual chloroplasts (via introduction of arc mutations). However, these granules are abnormal in distribution, size and shape. SS4 is an essential component of a mechanism that coordinates granule formation with chloroplast division during leaf expansion and determines the abundance and the flattened, discoid shape of leaf starch granules. PMID:23952675

  6. Novel FT-IR Microspectroscopic Census of Simple Starch Granules for Octenyl Succinate Ester Modification

    SciTech Connect

    Bai, Y.; Shi, Y; Wetzel, D

    2009-01-01

    Fourier transform infrared (FT-IR) microspectroscopy was used to investigate reaction homogeneity of octenyl succinic anhydride modification on waxy maize starch and detect uniformity of blends of modified and native starches. For the first time, the level and uniformity of chemical substitution on individual starch granules were analyzed by FT-IR microspectroscopy. More than 100 starch granules of each sample were analyzed one by one by FT-IR microspectroscopy. In comparison to the native starch, modified starch had two additional bands at 1723 and 1563 cm{sup -1}, indicative of ester formation in the modified starch. For the 3% modification level, the degree of substitution (DS) was low (0.019) and the distribution of the ester group was not uniform among starch granules. For the modified starch with DS of 0.073, 99% of individual starch granules had a large carbonyl band area, indicating that most granules were modified to a sufficient extent that the presence of their carbonyl ester classified them individually as being modified. However, the octenyl succinate concentration varied between granules, suggesting that the reaction was not uniform. When modified starch (DS = 0.073) was blended with native starch (3:7, w/w) to achieve a mixture with an average DS of 0.019, FT-IR microspectroscopy was able to detect heterogeneity of octenyl succinate in the blend and determine the ratio of the modified starch to the native starch granules.

  7. The starch granule associated proteomes of commercially purified starch reference materials from rice and maize.

    PubMed

    Koziol, Adam G; Marquez, Benazir K; Huebsch, Matthew P; Smith, Jeffrey C; Altosaar, Illimar

    2012-01-04

    Commercially available reference materials are integral components of many experimental protocols, as it is critical to compare one's results to those derived from well-characterized standards. Most reference materials are well defined, with all their components being cataloged. However, certain reference materials, such as commercially prepared starch samples, can have undefined components, potentially limiting their usefulness as standards. The proteome of commercially prepared starch has not been documented, and to that end, we initiated a mass spectrometry-based survey of the proteins associated with starch granules in commercially prepared rice and maize starch samples. We performed direct trypsin treatments of starch samples and sequenced both the water-soluble peptides liberated into the aqueous supernatant and the peptides released from the starch granule surface by isopropanol solvent washing. We discovered that the majority of proteins, in both rice and maize samples, were involved in either carbohydrate metabolism or storage. We also documented proteins that are markers for seed maturity and for starch mobilization. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Formation and Deposition of Amylose in the Potato Tuber Starch Granule Are Affected by the Reduction of Granule-Bound Starch Synthase Gene Expression.

    PubMed Central

    Kuipers, AGJ.; Jacobsen, E.; Visser, RGF.

    1994-01-01

    The synthesis of amylose in amyloplasts is catalyzed by granule-bound starch synthase (GBSS). GBSS gene expression was inhibited via antisense RNA in Agrobacterium rhizogenes-transformed potato plants. Analysis of starch production and starch granule composition in transgenic tubers revealed that reduction of GBSS activity always resulted in a reduction of the production of amylose. Field experiments, performed over a 2-year period, showed that stable inhibition of GBSS gene expression can be obtained. Microscopic evaluation of iodine-stained starch granules was shown to be a sensitive system for qualitative and quantitative examination of amylose formation in starch granules of transgenic potato tubers. In plants showing inhibition of GBSS gene expression, the reduced amylose content in tuber starch was not a consequence of a lower amylose content throughout the entire starch granule. Starch granules of transgenic tubers were found to contain amylose at a percentage similar to wild-type starch in a core of varying size at the hilum of each granule. This indicated that reduced GBSS gene expression results in amylose formation in a restricted zone of the granules. The size of this zone is suggested to be dependent on the GBSS protein level. During development of the granules, the available GBSS protein is thought to become limiting, resulting in the formation of starch that lacks amylose. RNA gel blot analysis of tuber tissue showed that inhibition of GBSS gene expression resulted in a reduced GBSS mRNA level but did not affect the expression level of other starch synthesizing enzymes. Antisense RNA could only be detected in leaf tissue of the transgenic plants. PMID:12244219

  9. Physicochemical properties of A- and B-starch granules isolated from hard red and soft red winter wheat.

    PubMed

    Li, Wenhao; Shan, Yulin; Xiao, Xinlong; Luo, Qingui; Zheng, Jianmei; Ouyang, Shaohui; Zhang, Guoquan

    2013-07-03

    Large A- and small B-starch granules separated from hard red and soft red winter wheat grains were investigated for their morphological, structural, and physicochemical properties. A-granules displayed a disk or lenticular shape, and B-granules showed a spherical or polygonal shape according to SEM. XRD analysis showed that both A- and B-granules had A-type crystallinity. A-granules contained a higher amount of amylose and a lower protein content and amylopectin/amylose ratio than B-granules. A-type granules exhibited a higher hydrolysis extent and swelling power and a lower iodine affinity than did B-granules. A-granules showed a higher peak, trough, breakdown and final viscosity, and gelatinization enthalpy than did B-granules, while B-granules exhibited a higher gelatinization temperature. The study demonstrated that the A- and B-granules separated from both hard red and soft red winter wheat grains exhibited a similar structure and very different physicochemical properties.

  10. Comparison of waxy and normal potato starch remaining granules after chemical surface gelatinization: pasting behavior and surface morphology.

    PubMed

    Huang, Junrong; Chen, Zhenghong; Xu, Yalun; Li, Hongliang; Liu, Shuxing; Yang, Daqing; Schols, Henk A

    2014-02-15

    To understand the contribution of granule inner portion to the pasting property of starch, waxy potato starch and two normal potato starches and their acetylated starch samples were subjected to chemical surface gelatinization by 3.8 mol/L CaCl2 to obtain remaining granules. Native and acetylated, original and remaining granules of waxy potato starch had similar rapid visco analyzer (RVA) pasting profiles, while those of two normal potato starches behaved obviously different from each other. All remaining granules had lower peak viscosity than the corresponding original granules. Contribution of waxy potato starch granule's inner portion to the peak viscosity was significant more than those of normal potato starches. The shell structure appearing on the remaining granule surface for waxy potato starch was smoother and thinner than that for normal potato starches as observed by scanning electron microscopy, indicating a more regular structure of shell and a more ordered packing of shell for waxy potato starch granules. The blocklet size of waxy potato starch was smaller and more uniform than those of normal potato starches as shown by atomic force microscopy images of original and remaining granules. In general, our results provided the evidence for the spatial structure diversity between waxy and normal potato starch granules: outer layer and inner portion of waxy potato starch granule had similar structure, while outer layer had notably different structure from inner portion for normal potato starch granule. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Porcine pancreatic alpha-amylase hydrolysis of native starch granules as a function of granule surface area.

    PubMed

    Kong, Byoung-Wook; Kim, Jung-In; Kim, Myo-Jeong; Kim, Jae Cherl

    2003-01-01

    Porcine pancreatic alpha-amylase activity on native starch granules is more accurately described as a function of surface area of the granules rather than of substrate concentration. The apparent K(m) of alpha-amylolysis of native starch from potato, maize, and rice expressed as a function of substrate concentration was largest for potato with a single value of V(max). However, the ratio of the slope of a Lineweaver-Burk plot to that of rice for enzymatic hydrolysis of native potato and maize starch were 7.78 and 2.58, respectively, which were very close to the ratio of surface area per mass of the two starch granules to that of rice. Therefore, the reciprocal of initial velocity was a linear function of the reciprocal of surface area for each starch granule. Surface area was calculated assuming the starch granules were spherical. The values obtained by this calculation were in good agreement with the value obtained by the photomicrographic method. By comparing enzymatic digestion of native maize granules to that of rice granules, it was concluded that the presence of pores in maize granules appeared to significantly affect overall rate of digestion after sufficient reaction time, but not at the very initial stage of hydrolysis.

  12. Surface Localization of Zein Storage Proteins in Starch Granules from Maize Endosperm1

    PubMed Central

    Mu-Forster, Chen; Wasserman, Bruce P.

    1998-01-01

    Starch granules from maize (Zea mays) contain a characteristic group of polypeptides that are tightly associated with the starch matrix (C. Mu-Forster, R. Huang, J.R. Powers, R.W. Harriman, M. Knight, G.W. Singletary, P.L. Keeling, B.P. Wasserman [1996] Plant Physiol 111: 821–829). Zeins comprise about 50% of the granule-associated proteins, and in this study their spatial distribution within the starch granule was determined. Proteolysis of starch granules at subgelatinization temperatures using the thermophilic protease thermolysin led to selective removal of the zeins, whereas granule-associated proteins of 32 kD or above, including the waxy protein, starch synthase I, and starch-branching enzyme IIb, remained refractory to proteolysis. Granule-associated proteins from maize are therefore composed of two distinct classes, the surface-localized zeins of 10 to 27 kD and the granule-intrinsic proteins of 32 kD or higher. The origin of surface-localized δ-zein was probed by comparing δ-zein levels of starch granules obtained from homogenized whole endosperm with granules isolated from amyloplasts. Starch granules from amyloplasts contained markedly lower levels of δ-zein relative to granules prepared from whole endosperm, thus indicating that δ-zein adheres to granule surfaces after disruption of the amyloplast envelope. Cross-linking experiments show that the zeins are deposited on the granule surface as aggregates. In contrast, the granule-intrinsic proteins are prone to covalent modification, but do not form intermolecular cross-links. We conclude that individual granule intrinsic proteins exist as monomers and are not deposited in the form of multimeric clusters within the starch matrix. PMID:9536075

  13. Morphology, structure and gelatinization properties of heterogeneous starch granules from high-amylose maize.

    PubMed

    Cai, Canhui; Zhao, Lingxiao; Huang, Jun; Chen, Yifang; Wei, Cunxu

    2014-02-15

    High-amylose cereal endosperm is rich in heterogeneous starch granules. In this paper, we investigated the morphology, structure and gelatinization properties of high-amylose maize endosperm starch. Starch had individual, aggregate and elongated heterogeneous granules. Most of individual granules were round with small size and had one central hilum. Aggregate and elongated granules consisted of many subgranules with central hila, and had irregular and rod/filamentous shapes, respectively. Iodine stained starch granules showed five types of polarization colors: blue, purple, fuchsia, dark red, and interior dark blue and exterior brown. Most of individual and aggregate granules had the color of dark red, that of elongated granules the color of interior dark blue and exterior brown. Amylose was mainly distributed in the hilum region and the circumference of starch granules. Aggregate and elongated granules had higher amylose content than individual granules. Elongated and individual granules had the highest and the lowest gelatinization resistance among high-amylose maize heterogeneous starch granules, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Reduction of starch granule size by expression of an engineered tandem starch-binding domain in potato plants.

    PubMed

    Ji, Qin; Oomen, Ronald J F J; Vincken, Jean-Paul; Bolam, David N; Gilbert, Harry J; Suurs, Luc C J M; Visser, Richard G F

    2004-05-01

    Granule size is an important parameter when using starch in industrial applications. An artificial tandem repeat of a family 20 starch-binding domain (SBD2) was engineered by two copies of the SBD derived from Bacillus circulans cyclodextrin glycosyltransferase via the Pro-Thr-rich linker peptide from Xyn10A from Cellulomonas fimi. SBD2 and a single SBD were introduced into the amylose-free potato mutant, amf, using appropriate signal sequences. The accumulation of SBD2 into transgenic starch granules was much higher than that of SBD. In a number of transformants, particularly amfSS3, the starch granules were much smaller than in control plants. The amfSS3 mean granule size was 7.8 microm, compared with 15.2 microm in the control, whereas other starch properties were unaltered. This new starch combines the advantage of the high purity of potato starch with that of the small granule size of other crop species, such as cassava, taro and wheat. This starch may find application in the manufacture of biodegradable plastic films. Both genes were also expressed in Escherichia coli and the affinity for soluble starch of the purified recombinant proteins was determined. SBD2 had an approximately 10-fold higher affinity for starch than SBD, indicating that the two appended SBDs act in synergy when binding to their target polysaccharide ligand.

  15. Determination of hydrophobicity of dry-heated wheat starch granules using sucrose fatty acid esters (SFAE).

    PubMed

    Tabara, Aya; Oneda, Hiroshi; Murayama, Ryuji; Matsui, Yuko; Hirano, Akira; Seguchi, Masaharu

    2014-01-01

    Sucrose fatty acid esters (SFAE) were adsorbed onto dry-heated (120 °C for 10, 20, 40, 60, and 120 min) wheat starch granules and extracted with ethyl ether in a Soxhlet apparatus without gelatinization of the starch granules. The amount of sucrose in the extracted SFAE was determined by the phenol sulfate method. A gradual increase of the sucrose from 159 to 712 μg, in SFAE per gram of starch, occurred with increasing dry-heating time and demonstrated the increased hydrophobicity of the starch granules. Increase of the SFAE was highly correlated (r = 0.9816) to increase of the oil-binding capacity of the dry-heated wheat starch granules. Non-waxy rice, waxy rice, sweet potato, and potato starch granules also showed higher hydrophobicity after dry-heating by this method.

  16. Starch granule initiation is controlled by a heteromultimeric isoamylase in potato tubers

    PubMed Central

    Bustos, Regla; Fahy, Brendan; Hylton, Christopher M.; Seale, Robert; Nebane, N. Miranda; Edwards, Anne; Martin, Cathie; Smith, Alison M.

    2004-01-01

    Starch granule initiation is not understood, but recent evidence implicates a starch debranching enzyme, isoamylase, in the control of this process. Potato tubers contain isoamylase activity attributable to a heteromultimeric protein containing Stisa1 and Stisa2, the products of two of the three isoamylase genes of potato. To discover whether this enzyme is involved in starch granule initiation, activity was reduced by expression of antisense RNA for Stisa1 or Stisa2. Transgenic tubers accumulated a small amount of a soluble glucan, similar in structure to the phytoglycogen of cereal, Arabidopsis, and Chlamydomonas mutants lacking isoamylase. The major effect, however, was on the number of starch granules. Transgenic tubers accumulated large numbers of tiny granules not seen in normal tubers. These data indicate that the heteromultimeric isoamylase functions during starch synthesis to suppress the initiation of glucan molecules in the plastid stroma that would otherwise crystallize to nucleate new starch granules. PMID:14766984

  17. Digital image analysis of starch granules for recognizing hard red and soft red winter wheats

    NASA Astrophysics Data System (ADS)

    Zayas, Inna Y.; Bechtel, D. B.; Wilson, J. D.; Dempster, Richard E.

    1993-05-01

    The relationship between isolated starch granule morphometry and wheat hardness was studied. Starch granule size and shape may relate to grain millability, rheological properties of dough, and baking quality. Twenty four Kansas wheats were studied: 14 hard red winter (HRW) and 10 soft red winter (SRW). Isolated starch granules were viewed with light microscopy to obtain black and white images which were recorded on video tape. A program was designed to keep track of the taped images and measure starch granules without operator intervention. The data base of starch granule size and shape features of the 24 samples contained 152,237 granule observations. The number of observations per sample varied from 3,238 to 14,671. Distinguishing HRW from SRW wheat samples was accomplished by evaluation of starch granule morphometry. Several data manipulations and transformations were performed in analysis of the data. Information carried in two shape descriptors, which reflect aspect ratio and equivalent diameter distribution, was used to distinguish starch granules of HRW and SRW wheats. The percentage of starch granules in the aspect ratio range of 1.65 - 1.95 was 25.8 - 31.5% for HRW and 19.9 - 25.4% for SRW.

  18. Starch Granule Re-Structuring by Starch Branching Enzyme and Glucan Water Dikinase Modulation Affects Caryopsis Physiology and Metabolism

    PubMed Central

    Shaik, Shahnoor S.; Obata, Toshihiro; Hebelstrup, Kim H.; Schwahn, Kevin; Fernie, Alisdair R.; Mateiu, Ramona V.; Blennow, Andreas

    2016-01-01

    Starch is of fundamental importance for plant development and reproduction and its optimized molecular assembly is potentially necessary for correct starch metabolism. Re-structuring of starch granules in-planta can therefore potentially affect plant metabolism. Modulation of granule micro-structure was achieved by decreasing starch branching and increasing starch-bound phosphate content in the barley caryopsis starch by RNAi suppression of all three Starch Branching Enzyme (SBE) isoforms or overexpression of potato Glucan Water Dikinase (GWD). The resulting lines displayed Amylose-Only (AO) and Hyper-Phosphorylated (HP) starch chemotypes, respectively. We studied the influence of these alterations on primary metabolism, grain composition, starch structural features and starch granule morphology over caryopsis development at 10, 20 and 30 days after pollination (DAP) and at grain maturity. While HP showed relatively little effect, AO showed significant reduction in starch accumulation with re-direction to protein and β-glucan (BG) accumulation. Metabolite profiling indicated significantly higher sugar accumulation in AO, with re-partitioning of carbon to accumulate amino acids, and interestingly it also had high levels of some important stress-related metabolites and potentially protective metabolites, possibly to elude deleterious effects. Investigations on starch molecular structure revealed significant increase in starch phosphate and amylose content in HP and AO respectively with obvious differences in starch granule morphology at maturity. The results demonstrate that decreasing the storage starch branching resulted in metabolic adjustments and re-directions, tuning to evade deleterious effects on caryopsis physiology and plant performance while only little effect was evident by increasing starch-bound phosphate as a result of overexpressing GWD. PMID:26891365

  19. Starch Granule Re-Structuring by Starch Branching Enzyme and Glucan Water Dikinase Modulation Affects Caryopsis Physiology and Metabolism.

    PubMed

    Shaik, Shahnoor S; Obata, Toshihiro; Hebelstrup, Kim H; Schwahn, Kevin; Fernie, Alisdair R; Mateiu, Ramona V; Blennow, Andreas

    2016-01-01

    Starch is of fundamental importance for plant development and reproduction and its optimized molecular assembly is potentially necessary for correct starch metabolism. Re-structuring of starch granules in-planta can therefore potentially affect plant metabolism. Modulation of granule micro-structure was achieved by decreasing starch branching and increasing starch-bound phosphate content in the barley caryopsis starch by RNAi suppression of all three Starch Branching Enzyme (SBE) isoforms or overexpression of potato Glucan Water Dikinase (GWD). The resulting lines displayed Amylose-Only (AO) and Hyper-Phosphorylated (HP) starch chemotypes, respectively. We studied the influence of these alterations on primary metabolism, grain composition, starch structural features and starch granule morphology over caryopsis development at 10, 20 and 30 days after pollination (DAP) and at grain maturity. While HP showed relatively little effect, AO showed significant reduction in starch accumulation with re-direction to protein and β-glucan (BG) accumulation. Metabolite profiling indicated significantly higher sugar accumulation in AO, with re-partitioning of carbon to accumulate amino acids, and interestingly it also had high levels of some important stress-related metabolites and potentially protective metabolites, possibly to elude deleterious effects. Investigations on starch molecular structure revealed significant increase in starch phosphate and amylose content in HP and AO respectively with obvious differences in starch granule morphology at maturity. The results demonstrate that decreasing the storage starch branching resulted in metabolic adjustments and re-directions, tuning to evade deleterious effects on caryopsis physiology and plant performance while only little effect was evident by increasing starch-bound phosphate as a result of overexpressing GWD.

  20. Tracking sulfur and phosphorus within single starch granules using synchrotron X-ray microfluorescence mapping.

    PubMed

    Buléon, Alain; Cotte, Marine; Putaux, Jean-Luc; d'Hulst, Christophe; Susini, Jean

    2014-01-01

    Native starch accumulates as granules containing two glucose polymers: amylose and amylopectin. Phosphate (0.2-0.5%) and proteins (0.1-0.7%) are also present in some starches. Phosphate groups play a major role in starch metabolism while granule-bound starch synthase 1 (GBSS1) which represents up to 95% of the proteins bound to the granule is responsible for amylose biosynthesis. Synchrotron micro-X-ray fluorescence (μXRF) was used for the first time for high-resolution mapping of GBSS1 and phosphate groups based on the XRF signal of sulfur (S) and phosphorus (P), respectively. Wild-type starches were studied as well as their related mutants lacking GBSS1 or starch-phosphorylating enzyme. Wild-type potato and maize starch exhibited high level of phosphorylation and high content of sulfur respectively when compared to mutant potato starch lacking glucan water dikinase (GWD) and mutant maize starch lacking GBSS1. Phosphate groups are mostly present at the periphery of wild-type potato starch granules, and spread all over the granule in the amylose-free mutant. P and S XRF were also measured within single small starch granules from Arabidopsis or Chlamydomonas not exceeding 3-5μm in diameter. Imaging GBSS1 (by S mapping) in potato starch sections showed that the antisense technique suppresses the expression of GBSS1 during biosynthesis. P mapping confirmed that amylose is mostly present in the center of the granule, which had been suggested before. μXRF is a potentially powerful technique to analyze the minor constituents of starch and understand starch structure/properties or biosynthesis by the use of selected genetic backgrounds. © 2013.

  1. Allomorph distribution and granule structure of lotus rhizome C-type starch during gelatinization.

    PubMed

    Cai, Canhui; Cai, Jinwen; Man, Jianmin; Yang, Yang; Wang, Zhifeng; Wei, Cunxu

    2014-01-01

    The allomorph distribution and granule structure of C-type starch from lotus rhizomes were investigated using a combination of techniques during gelatinization. The disruption of crystallinity during gelatinization began from the end distant from the eccentric hilum and then propagated into the center of granule. The periphery of hilum end was finally gelatinized, accompanied by high swelling. The crystallinity changed from C-type to A-type via CA-type during gelatinization, and finally became amorphous structure. The amylose content, crystal degree, helix content, ratio of 1045/1022cm(-1), and peak intensity of crystalline lamellae of gelatinizing starch significantly decreased after 70°C. The amorphous content and ratio of 1022/995cm(-1) increased after 70°C. This study elucidated that B-type allomorph was mainly arranged in the distal region of eccentric hilum, A-type allomorph was mainly located in the periphery of hilum end, and the center of granule was a mixed distribution of A- and B-type allomorphs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Investigation on the pitting of potato starch granules during high frequency ultrasound treatment.

    PubMed

    Bai, Wenzhe; Hébraud, Pascal; Ashokkumar, Muthupandian; Hemar, Yacine

    2017-03-01

    In this paper, the pitting of potato starch granules in aqueous suspensions (1%) by high-frequency high-power ultrasound (850kHz at a power of 0.2W, 2W or 3.7W; and also 500kHz and 1MHz at a power of 2W) is reported. The number of pits per starch granules was found to be independent of the amylose content of starches, and the surface properties of starch granules as modified through SDS and ethanol washing. At 850kHz, the maximum number of pits per starch granule, for both normal and waxy starches, did not exceed 11. However, a close inspection of fractionated starch granules based on their sizes showed that there is an optimum granule size for which a maximum pit number is obtained. For example, starch granules with diameter size range of ∼15 to ∼30μm had a maximum pit number (between 10 and 20 pits per granule) when sonicated (2W, 850kHz and 30min); while sonication of small (<10μm) and very large (>45μm) granules resulted in a smaller number of pits per granule (∼5). Further, the maximum number of pits per granules is also found to be proportional to the ultrasound frequency, with values of approximately 7, 10 and 11 at 0.50, 0.85, and 1MHz, respectively. FTIR measurements did not show any breakup of starch molecules. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Suppression of starch synthase I expression affects the granule morphology and granule size and fine structure of starch in wheat endosperm

    PubMed Central

    2014-01-01

    Studies in Arabidopsis and rice suggest that manipulation of starch synthase I (SSI) expression in wheat may lead to the production of wheat grains with novel starch structure and properties. This work describes the suppression of SSI expression in wheat grains using RNAi technology, which leads to a low level of enzymatic activity for SSI in the developing endosperm, and a low abundance of SSI protein inside the starch granules of mature grains. The amylopectin fraction of starch from the SSI suppressed lines showed an increased frequency of very short chains (degree of polymerization, dp 6 and 7), a lower proportion of short chains (dp 8–12), and more intermediate chains (dp 13–20) than in the grain from their negative segregant lines. In the most severely affected line, amylose content was significantly increased, the morphology of starch granules was changed, and the proportion of B starch granules was significantly reduced. The change of the fine structure of the starch in the SSI-RNAi suppression lines alters the gelatinization temperature, swelling power, and viscosity of the starch. This work demonstrates that the roles of SSI in the determination of starch structure and properties are similar among different cereals and Arabidopsis. PMID:24634486

  4. Suppression of starch synthase I expression affects the granule morphology and granule size and fine structure of starch in wheat endosperm.

    PubMed

    McMaugh, Stephen J; Thistleton, Jenny L; Anschaw, Emma; Luo, Jixun; Konik-Rose, Christine; Wang, Hong; Huang, Min; Larroque, Oscar; Regina, Ahmed; Jobling, Stephen A; Morell, Matthew K; Li, Zhongyi

    2014-05-01

    Studies in Arabidopsis and rice suggest that manipulation of starch synthase I (SSI) expression in wheat may lead to the production of wheat grains with novel starch structure and properties. This work describes the suppression of SSI expression in wheat grains using RNAi technology, which leads to a low level of enzymatic activity for SSI in the developing endosperm, and a low abundance of SSI protein inside the starch granules of mature grains. The amylopectin fraction of starch from the SSI suppressed lines showed an increased frequency of very short chains (degree of polymerization, dp 6 and 7), a lower proportion of short chains (dp 8-12), and more intermediate chains (dp 13-20) than in the grain from their negative segregant lines. In the most severely affected line, amylose content was significantly increased, the morphology of starch granules was changed, and the proportion of B starch granules was significantly reduced. The change of the fine structure of the starch in the SSI-RNAi suppression lines alters the gelatinization temperature, swelling power, and viscosity of the starch. This work demonstrates that the roles of SSI in the determination of starch structure and properties are similar among different cereals and Arabidopsis.

  5. Mutation of the maize sbe1a and ae genes alters morphology and physical behavior of wx-type endosperm starch granules.

    PubMed

    Li, Ji-Hong; Guiltinan, Mark J; Thompson, Donald B

    2007-12-10

    In maize, three isoforms of starch-branching enzyme, SBEI, SBEIIa, and SBEIIb, are encoded by the Sbe1a, Sbe2a, and Amylose extender (Ae) genes, respectively. The objective of this research was to explore the effects of null mutations in the Sbe1a and Ae genes alone and in combination in wx background on kernel characteristics and on the morphology and physical behavior of endosperm starch granules. Differences in kernel morphology and weight, starch accumulation, starch granule size and size distribution, starch microstructure, and thermal properties were observed between the ae wx and sbe1a ae wx plants but not between the sbe1a wx mutants when compared to wx. Starch from sbe1a ae wx plants exhibited a larger granule size with a wider gelatinization temperature range and a lower endotherm enthalpy than ae wx. Microscopy shows weaker iodine staining in sbe1a ae wx starch granules. X-ray diffraction revealed A-type crystallinity in wx and sbe1a wx starches and B-type in sbe1a ae wx and ae wx. This study suggests that, while the SBEIIb isoform plays a dominant role in maize endosperm starch synthesis, SBEI also plays a role, which is only observable in the presence of the ae mutation.

  6. Thermal, pasting and morphological properties of starch granules of wheat (Triticum aestivum L.) varieties.

    PubMed

    Kumar, Rajesh; Khatkar, B S

    2017-07-01

    Large (A) and small (B) granules of wheat starch were separated and their morphological, thermal, structural and pasting properties were investigated. The pasting properties of starches from two wheat varieties showed significant differences. For wheat variety C-306, the unfractionated starch showed higher peak, trough, breakdown, final, and setback viscosities than the starch isolated from wheat variety WH-147. On the contrary, unfractionated starch of variety WH-147 has higher pasting temperature than the starch of the variety C-306. Differential scanning calorimetry results showed that unfractionated starch exhibited the higher gelatinization enthalpy, peak and conclusion temperatures than the isolated A- and B-starch granules from both the varieties. Scanning electron microscopy results revealed that large A-granules appeared to be smooth and displayed disk or lenticular shape having diameter 13-35 μm, while B-granules showed a spherical shape with diameter of 2-6 μm. The variations in structures and content would result in starch granules with different chemical and physical properties.

  7. Effect of starch 1500 as a binder and disintegrant in lamivudine tablets prepared by high shear wet granulation.

    PubMed

    Rahman, Bytul M; Ibne-Wahed, Mir Imam; Khondkar, Proma; Ahmed, Maruf; Islam, Robiul; Barman, Ranjan K; Islam, M Anwarul

    2008-10-01

    High shear wet granulation is a preferred manufacturing method of tablets. It allowed for rapid production of compressible granulations. The resultant granulation characteristics depend on a combination of formulation properties and processing parameters. Fully pregelatinized starches are currently being used as binders in wet granulated formulations. But due to the gelatinization, much of the disintegration properties are lost. Partially pregelatinized starches (starch 1,500) have a mixture of properties of both native and fully gelatinized starches; made them useful as both a binder and a disintegrant in wet granulated formulations. Starch 1,500 performed as an excellent binder producing a granulation that was compressible and produced lamivudine tablets of improved hardness and friability compared with those prepared with povidone. The formulation of lamivudine tablets with starch 1,500 exceeded the disintegration and dissolution performance of the povidone formulation that utilized a super disintegrant. High shear wet granulation is also well suited for the use of partially pregelatinized starches.

  8. Uptake of Cu2+ by starch granules as affected by counterions.

    PubMed

    Szymońska, J; Wieczorek, J; Molenda, M; Bielańska, E

    2008-06-11

    Potato and wheat starch granules were soaked in 1% aqueous solutions of copper(II) salts: acetate, chloride, and sulfate. Such treatment caused sorption of Cu(2+) ions at the granule surface and their penetration into the granule interior as was proven, for sectioned granules of investigated starch, by scanning electron microscopy combined with an X-ray microanalysis system (energy dispersive spectroscopy). Copper ions incorporated into the granules influenced the starch thermal stability. Uptake of Cu(2+) by potato, determined by flame atomic absorption spectrometry, was much higher than obtained for the wheat starch. Moreover, it was dependent on copper counteranions present in the solution. In all investigated granules, the most effective sorption occurred in the acetate solution. Starch dehydration or/and freezing and thawing, affecting the water-dependent inner structure of the granules, also influenced the amount of Cu(2+) taken from the solutions. Thus, compared to that in native starch, this value was considerably higher in Cu(CH 3COO)2, almost unchanged in CuSO4, and significantly lower in the case of CuCl2 solution. The influence of chloride and sulfate anions seemed to correlate with their water structure-making and structure-breaking ability, affecting the migration of Cu(2+) in the amorphous parts of the granules. However, high Cu uptake observed for acetate solution could be explained on the basis of acetate anion hydrolysis activating the polysaccharide matrix for cation binding. The obtained results provide new information about interactions of starch granules with salt solution and therefore support our understanding of starch properties.

  9. Heterogeneous structure and spatial distribution in endosperm of high-amylose rice starch granules with different morphologies.

    PubMed

    Cai, Canhui; Huang, Jun; Zhao, Lingxiao; Liu, Qiaoquan; Zhang, Changquan; Wei, Cunxu

    2014-10-15

    Starch granules from high-amylose cereal mutants or transgenic lines usually have different morphologies. It is not clear whether the structure and spatial distribution of starch granules with different morphologies in endosperm is homogeneous or heterogeneous. In the present study, the structure and spatial distribution in endosperm of morphologically different starch granules from high-amylose transgenic rice line (TRS) were investigated. The TRS endosperm had individual, aggregate, elongated, and interior hollow starch granules. The individual and interior hollow granules had the lowest and the highest amylose content and gelatinization resistance, respectively, among the four types of granules. The individual granules were mainly distributed in the middle of the endosperm; the aggregate granules in the starchy endosperm cells between the subaleurone layer and the middle of the endosperm; the elongated granules in the peripheral starchy endosperm cells adjacent to the subaleurone layer; and the interior hollow granules in the subaleurone layer cells.

  10. Fourier transform infrared (FT-IR) microspectroscopic census of single starch granules for octenyl succinate ester modification.

    PubMed

    Bai, Yanjie; Shi, Yong-Cheng; Wetzel, David L

    2009-07-22

    Fourier transform infrared (FT-IR) microspectroscopy was used to investigate reaction homogeneity of octenyl succinic anhydride modification on waxy maize starch and detect uniformity of blends of modified and native starches. For the first time, the level and uniformity of chemical substitution on individual starch granules were analyzed by FT-IR microspectroscopy. More than 100 starch granules of each sample were analyzed one by one by FT-IR microspectroscopy. In comparison to the native starch, modified starch had two additional bands at 1723 and 1563 cm(-1), indicative of ester formation in the modified starch. For the 3% modification level, the degree of substitution (DS) was low (0.019) and the distribution of the ester group was not uniform among starch granules. For the modified starch with DS of 0.073, 99% of individual starch granules had a large carbonyl band area, indicating that most granules were modified to a sufficient extent that the presence of their carbonyl ester classified them individually as being modified. However, the octenyl succinate concentration varied between granules, suggesting that the reaction was not uniform. When modified starch (DS = 0.073) was blended with native starch (3:7, w/w) to achieve a mixture with an average DS of 0.019, FT-IR microspectroscopy was able to detect heterogeneity of octenyl succinate in the blend and determine the ratio of the modified starch to the native starch granules.

  11. Investigating the Mechanisms of Amylolysis of Starch Granules by Solution-State NMR

    PubMed Central

    2015-01-01

    Starch is a prominent component of the human diet and is hydrolyzed by α-amylase post-ingestion. Probing the mechanism of this process has proven challenging, due to the intrinsic heterogeneity of individual starch granules. By means of solution-state NMR, we demonstrate that flexible polysaccharide chains protruding from the solvent-exposed surfaces of waxy rice starch granules are highly mobile and that during hydrothermal treatment, when the granules swell, the number of flexible residues on the exposed surfaces increases by a factor of 15. Moreover, we show that these flexible chains are the primary substrates for α-amylase, being cleaved in the initial stages of hydrolysis. These findings allow us to conclude that the quantity of flexible α-glucan chains protruding from the granule surface will greatly influence the rate of energy acquisition from digestion of starch. PMID:25815624

  12. Stokes vector based polarization resolved second harmonic microscopy of starch granules

    PubMed Central

    Mazumder, Nirmal; Qiu, Jianjun; Foreman, Matthew R.; Romero, Carlos Macías; Török, Peter; Kao, Fu-Jen

    2013-01-01

    We report on the measurement and analysis of the polarization state of second harmonic signals generated by starch granules, using a four-channel photon counting based Stokes-polarimeter. Various polarization parameters, such as the degree of polarization (DOP), the degree of linear polarization (DOLP), the degree of circular polarization (DOCP), and anisotropy are extracted from the 2D second harmonic Stokes images of starch granules. The concentric shell structure of a starch granule forms a natural photonic crystal structure. By integration over all the solid angle, it will allow very similar SHG quantum efficiency regardless of the angle or the states of incident polarization. Given type I phase matching and the concentric shell structure of a starch granule, one can easily infer the polarization states of the input beam from the resulting SH micrograph. PMID:23577289

  13. Heterogeneity in maize starch granule internal architecture deduced from diffusion of fluorescent dextran probes.

    PubMed

    Dhital, Sushil; Shelat, Kinnari J; Shrestha, Ashok K; Gidley, Michael J

    2013-04-02

    Heterogeneity in maize starch granules was investigated by studying the diffusion of fluorescent dextran probes (20, 70 and 150kDa) inside granules using fluorescence recovery after photobleaching combined with confocal microscopy. Access of probes to the interior of granules was greatly enhanced by limited (2.4%) amylolysis. The diffusion of probes within granules was found to be either 'fast' with diffusion coefficients in the order of 10(-6)cm(2)s(-1) or 'slow' with diffusion coefficients in the order of 10(-7)cm(2)s(-1), independent of the size of dextran probes or prior treatment of the granules by α-amylase. Results were compared with observations of pores and channels in granules by electron microscopy and by confocal microscopy after labelling with 8-amino-1,3,6-pyrenetrisulfonic acid. It is proposed that there is an inherent heterogeneity of internal architecture in maize starch granules due to the presence or absence in individual granules of (a) pores leading to a central cavity, resulting in 'fast' diffusion of dextran probes and (b) accessibility of the starch polymer matrix to dextran probes, leading to 'slow' diffusion behaviour. The observed heterogeneity of maize starch granule porosity has implications for chemical modification reactions and the kinetics of digestion with amylases. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Critical roles of soluble starch synthase SSIIIa and granule-bound starch synthase Waxy in synthesizing resistant starch in rice

    PubMed Central

    Zhou, Hongju; Wang, Lijun; Liu, Guifu; Meng, Xiangbing; Jing, Yanhui; Shu, Xiaoli; Kong, Xiangli; Sun, Jian; Yu, Hong; Smith, Steven M.; Wu, Dianxing; Li, Jiayang

    2016-01-01

    Changes in human lifestyle and food consumption have resulted in a large increase in the incidence of type-2 diabetes, obesity, and colon disease, especially in Asia. These conditions are a growing threat to human health, but consumption of foods high in resistant starch (RS) can potentially reduce their incidence. Strategies to increase RS in rice are limited by a lack of knowledge of its molecular basis. Through map-based cloning of a RS locus in indica rice, we have identified a defective soluble starch synthase gene (SSIIIa) responsible for RS production and further showed that RS production is dependent on the high expression of the Waxya (Wxa) allele, which is prevalent in indica varieties. The resulting RS has modified granule structure; high amylose, lipid, and amylose–lipid complex; and altered physicochemical properties. This discovery provides an opportunity to increase RS content of cooked rice, especially in the indica varieties, which predominates in southern Asia. PMID:27791174

  15. Plantain starch granules morphology, crystallinity, structure transition, and size evolution upon acid hydrolysis.

    PubMed

    Hernández-Jaimes, C; Bello-Pérez, L A; Vernon-Carter, E J; Alvarez-Ramirez, J

    2013-06-05

    Plantain native starch was hydrolysed with sulphuric acid for twenty days. Hydrolysis kinetics was described by a logistic function, with a zero-order rate during the first seven days, followed by a slower kinetics dynamics at longer times. X-ray diffraction results revealed a that gradual increase in crystallinity occurred during the first seven days, followed by a decrease to values similar to those found in the native starch. Differential scanning calorimetry analysis suggested a sharp structure transition by the seventh day probably due to a molecular rearrangement of the starch blocklets and inhomogeneous erosion of the amorphous regions and semi crystalline lamellae. Scanning electron micrographs showed that starch granules morphology was continually degraded from an initial oval-like shape to irregular shapes due to aggregation effects. Granule size distribution broadened as hydrolysis time proceeded probably due to fragmentation and agglomeration phenomena of the hydrolysed starch granules.

  16. Structural and physical properties of granule stabilized starch obtained by branching enzyme treatment.

    PubMed

    Jensen, Susanne L; Zhu, Fan; Vamadevan, Varatharajan; Bertoft, Eric; Seetharaman, Koushik; Bandsholm, Ole; Blennow, Andreas

    2013-11-06

    Chemical cross-linking of starch is an important modification used in the industry for granule stabilization. It has been demonstrated that treatment with branching enzyme (BE) can stabilize the granular structure of starch and such treatment thereby provides a potential clean alternative for chemical modification. This study demonstrates that such BE-assisted stabilization of starch granules led to partial protection from BE catalysis of both amylose (AM) and amylopectin (AP) in their native state as assessed by triiodide complexation, X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The granule stabilizing effects were inversely linked to hydration of the starch granules, which was increased by the presence of starch-phosphate esters and suppressed by extreme substrate concentration. The data support that the granule stabilization is due to the intermolecular transglycosylation occurring in the initial stages of the reaction prior to AM-AP phase separation. The enzyme activity needed to obtain granule stabilization was therefore dependent on the hydration capability of the starch used.

  17. Corn starch granules with enhanced load-carrying capacity via citric acid treatment.

    PubMed

    Kim, Jong-Yea; Huber, Kerry C

    2013-01-02

    This research investigated conditions by which maize starch granule porosity and load-carrying capacity (LCC) might be enhanced via treatment with varying citric acid concentrations (0.5-1.5 M), temperatures (40-60 °C), and lengths of treatment (1-8 h). At the lowest temperatures (40 and 50 °C), citric acid treatment induced minimal physicochemical changes to granules. In contrast, both aqueous and oil LCCs of starches treated at 60 °C (0.5 M citric acid, 2 h) were almost doubled (15.69 and 14.48 mL/10 g starch, respectively), recovering 92% of the granular starch after treatment. Such treatment increased starch hydration capacity (0.97-1.91) and reduced gelatinization enthalpy (10.6-7.4 J/g). More severe treatment conditions adversely impacted aqueous LCC (due to excessive granule swelling), but improved oil absorption. The basis for LCC enhancement by citric acid treatment was ascribed to leaching of starch material from granules and partial disruption of the granule crystalline structure, as opposed to starch hydrolysis or chemical substitution.

  18. Starch granule formation and protein deposition in wheat (Triticum aestivum L.) starchy endosperm cells is altered by high temperature during grain fill

    NASA Astrophysics Data System (ADS)

    Hurkman, William J.; Wood, Delilah F.

    2010-06-01

    High temperatures during wheat grain fill decrease starch and protein levels, adversely affecting wheat yield and flour quality. To determine the effect of high temperature on starchy endosperm cell development, grain (Triticum aestivum L. 'Butte 86') was produced under a 24/17°C or 37/28°C day/night regimen imposed from flowering to maturity and starch and protein deposition examined using scanning electron microscopy. The high temperature regimen shortened the duration of grain fill from 40 to 18 days. Under the 37/28°C regimen, A- and B-type starch granules decreased in size. A-type starch granules also exhibited pitting, suggesting enhanced action of starch degradative enzymes. Under both temperature regimens, protein bodies originated early in development and coalesced during mid to late development to form a continuous protein matrix surrounding the starch granules. Under the 37/28°C regimen, the proportion of protein matrix increased in endosperm cells of mature grain. Taken together, the changes in starch granule number and size and in protein matrix amount provide clues for understanding how high temperature during grain fill can affect end use properties of wheat flour.

  19. Wheat genome specific granule-bound starch synthase I differentially influence grain starch synthesis.

    PubMed

    Ahuja, Geetika; Jaiswal, Sarita; Hucl, Pierre; Chibbar, Ravindra N

    2014-12-19

    Wheat grain development is a complex process and is characterized by changes in physicochemical and structural properties of starch. The present study deals with endosperm starch physicochemical properties and structure during development in different granule-bound starch synthase I (GBSSI) null also known as waxy (Wx) genotypes. The study was conducted with pure starch isolated from wheat grains at 3-30 days post anthesis (DPA), at 3-day intervals. Amylose concentration increased throughout grain development in non-waxy (7.2-30.5%) and partial waxy genotypes (6.0-26.8%). Completely waxy genotype showed 7.0% amylose at 3 and 6 DPA, which declined during development and reached non-detectable quantities by 30 DPA. Amylopectin structure had a higher content of short chains at 3 DPA, which decreased continuously until 12 DPA, after which there were only minor changes in amylopectin chain length distribution. Similarly, the average degree of polymerization (DP) increased from 3 DPA (12.3) to 12 DPA (15.0), and then did not differ significantly up to 30 DPA (15.0). This suggests the formation of basic amylopectin architecture in wheat by 12 DPA. Wx-B and Wx-D affected amylopectin short chains mostly of DP 6-8 at 3 and 6 DPA. Wx-A affected the same fraction of chains at 9 and 12 DPA, and Wx-D affected DP 18-25 chains from 18 to 30 DPA, suggesting differential effect of waxy isoproteins on amylopectin structure formation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Control of Starch Granule Numbers in Arabidopsis Chloroplasts1[W][OA

    PubMed Central

    Crumpton-Taylor, Matilda; Grandison, Scott; Png, Kenneth M.Y.; Bushby, Andrew J.; Smith, Alison M.

    2012-01-01

    The aim of this work was to investigate starch granule numbers in Arabidopsis (Arabidopsis thaliana) leaves. Lack of quantitative information on the extent of genetic, temporal, developmental, and environmental variation in granule numbers is an important limitation in understanding control of starch degradation and the mechanism of granule initiation. Two methods were developed for reliable estimation of numbers of granules per chloroplast. First, direct measurements were made on large series of consecutive sections of mesophyll tissue obtained by focused ion beam-scanning electron microscopy. Second, average numbers were calculated from the starch contents of leaves and chloroplasts and estimates of granule mass based on granule dimensions. Examination of wild-type plants and accumulation and regulation of chloroplast (arc) mutants with few, large chloroplasts provided the following new insights. There is wide variation in chloroplast volumes in cells of wild-type leaves. Granule numbers per chloroplast are correlated with chloroplast volume, i.e. large chloroplasts have more granules than small chloroplasts. Mature leaves of wild-type plants and arc mutants have approximately the same number of granules per unit volume of stroma, regardless of the size and number of chloroplasts per cell. Granule numbers per unit volume of stroma are also relatively constant in immature leaves but are greater than in mature leaves. Granule initiation occurs as chloroplasts divide in immature leaves, but relatively little initiation occurs in mature leaves. Changes in leaf starch content over the diurnal cycle are largely brought about by changes in the volume of a fixed number of granules. PMID:22135430

  1. EVIDENCE FOR GRANULATION IN EARLY A-TYPE STARS

    SciTech Connect

    Kallinger, Thomas; Matthews, Jaymie M.

    2010-03-01

    Stars with spectral types earlier than about F0 on (or close) to the main sequence have long been believed to lack observable surface convection, although evolutionary models of A-type stars do predict very thin surface convective zones. We present evidence for granulation in two {delta} Scuti stars of spectral type A2: HD 174936 and HD 50844. Recent analyses of space-based CoRoT data revealed up to some 1000 frequencies in the photometry of these stars. The frequencies were interpreted as individual pulsation modes. If true, there must be large numbers of nonradial modes of very high degree l which should suffer cancellation effects in disk-integrated photometry (even of high space-based precision). The p-mode interpretation of all the frequencies in HD 174936 and HD 50844 depends on the assumption of white (frequency-independent) noise. Our independent analyses of the data provide an alternative explanation: most of the peaks in the Fourier spectra are the signature of non-white granulation background noise, and less than about 100 of the frequencies are actual stellar p-modes in each star. We find granulation timescales which are consistent with scaling relations that describe cooler stars with known surface convection. If the granulation interpretation is correct, the hundreds of low-amplitude Fourier peaks reported in recent studies are falsely interpreted as independent pulsation modes and a significantly lower number of frequencies are associated with pulsation, consistent with only modes of low degree.

  2. Effects of granule size of cross-linked and hydroxypropylated sweet potato starches on their physicochemical properties.

    PubMed

    Zhao, Jianwei; Chen, Zhenghong; Jin, Zhengyu; Buwalda, Piet; Gruppen, Harry; Schols, Henk A

    2015-05-13

    Sweet potato starch was modified by cross-linking, hydroxypropylation, and combined cross-linking and hydroxypropylation, and the starches were subsequently sieved to obtain differently sized granule fractions. The effects of granule size of native and modified sweet potato starch fractions and all fractions were investigated with respect to their physicochemical properties. The large-size granule fraction (27-30 μm) showed a 16-20% higher chemical phosphorylation and a 4-7% higher hydroxypropylation than the small-size granule fraction (14-16 μm). The large-size granule fractions of native and modified sweet potato starches showed lower transition temperatures (0.7-3.1 °C for peak temperature of gelatinization) and lower enthalpy changes (0.6-1.9 J/g) during gelatinization than the small-size granule fractions, making the sweet potato starch different from cereal starches. The large-size granule fraction of native starch showed a higher paste viscosity (78-244 cP) than the corresponding small-size granule fraction. In addition, cross-linking and hydroxypropylation affected the paste viscosity of the large-size granule fraction significantly more than that of the small-size granule fraction when compared to the corresponding parental starch fractions. The large-size granule fraction of native and dual-modified starches showed a lower syneresis after freeze-thaw treatments than the small-size granule fractions. The difference in swelling power between large- and small-size granule fractions was not significant. In general, the large-size granule fraction of sweet potato starch was more susceptible for cross-linking and hydroxypropylation and the physicochemical properties were changed to a higher extent compared to the corresponding small-size granule fraction.

  3. Regulation of starch accumulation by granule-associated plant 14-3-3 proteins

    PubMed Central

    Sehnke, Paul C.; Chung, Hwa-Jee; Wu, Ke; Ferl, Robert J.

    2001-01-01

    In higher plants the production of starch is orchestrated by chloroplast-localized biosynthetic enzymes, namely starch synthases, ADP-glucose pyrophosphorylase, and starch branching and debranching enzymes. Diurnal regulation of these enzymes, as well as starch-degrading enzymes, influences both the levels and composition of starch, and is dependent in some instances upon phosphorylation-linked regulation. The phosphoserine/threonine-binding 14-3-3 proteins participate in environmentally responsive phosphorylation-related regulatory functions in plants, and as such are potentially involved in starch regulation. We report here that reduction of the ɛ subgroup of Arabidopsis 14-3-3 proteins by antisense technology resulted in a 2- to 4-fold increase in leaf starch accumulation. Dark-governed starch breakdown was unaffected in these “antisense plants,” indicating an unaltered starch-degradation pathway and suggesting a role for 14-3-3 proteins in regulation of starch synthesis. Absorption spectra and gelatinization properties indicate that the starch from the antisense plants has an altered branched glucan composition. Biochemical characterization of protease-treated starch granules from both Arabidopsis leaves and maize endosperm showed that 14-3-3 proteins are internal intrinsic granule proteins. These data suggest a direct role for 14-3-3 proteins in starch accumulation. The starch synthase III family is a possible target for 14-3-3 protein regulation because, uniquely among plastid-localized starch metabolic enzymes, all members of the family contain the conserved 14-3-3 protein phosphoserine/threonine-binding consensus motif. This possibility is strengthened by immunocapture using antibodies to DU1, a maize starch synthase III family member, and direct interaction with biotinylated 14-3-3 protein, both of which demonstrated an association between 14-3-3 proteins and DU1 or DU1-like proteins. PMID:11149942

  4. Kinetic analysis of glucoamylase-catalyzed hydrolysis of starch granules from various botanical sources.

    PubMed

    Tatsumi, Hirosuke; Katano, Hajime; Ikeda, Tokuji

    2007-04-01

    The kinetics of glucoamylase-catalyzed hydrolysis of starch granules from six different botanical sources (rice, wheat, maize, cassava, sweet potato, and potato) was studied by the use of an electrochemical glucose sensor. A higher rate of hydrolysis was obtained as a smaller size of starch granules was used. The adsorbed amount of glucoamylase on the granule surface per unit area did not vary very much with the type of starch granules examined, while the catalytic constants of the adsorbed enzyme (k(0)) were determined to be 23.3+/-4.4, 14.8+/-6.0, 6.2+/-1.8, 7.1+/-4.1, 4.6+/-3.0, and 1.6+/-0.6 s(-1) for rice, wheat, maize, cassava, sweet potato, and potato respectively, showing that k(0) was largely influenced by the type of starch granules. A comparison of the k(0)-values in relation to the crystalline structure of the starch granules suggested that k(0) increases as the crystalline structure becomes dense.

  5. Manipulation of starch granule size distribution in potato tubers by modulation of plastid division.

    PubMed

    de Pater, Sylvia; Caspers, Martien; Kottenhagen, Marijke; Meima, Henk; ter Stege, Renaldo; de Vetten, Nick

    2006-01-01

    Starch granule size is an important parameter for starch applications in industry. Starch granules are formed in amyloplasts, which are, like chloroplasts, derived from proplastids. Division processes and associated machinery are likely to be similar for all plastids. Essential roles for FtsZ proteins in plastid division in land plants have been revealed. FtsZ forms the so-called Z ring which, together with inner and outer plastid division rings, brings about constriction of the plastid. It has been shown that modulation of the expression level of FtsZ may result in altered chloroplast size and number. To test whether FtsZ is also involved in amyloplast division and whether this, in turn, may affect the starch granule size in crop plants, FtsZ protein levels were either reduced or increased in potato. As shown previously in other plant species, decreased StFtsZ1 protein levels in leaves resulted in a decrease in the number of chloroplasts in guard cells. More interestingly, plants with increased StFtsZ1 protein levels in tubers resulted in less, but larger, starch granules. This suggests that the stoichiometry between StFtsZ1 and other components of the plastid division machinery is important for its function. Starch from these tubers also had altered pasting properties and phosphate content. The importance of our results for the starch industry is discussed.

  6. Extraction and proteome analysis of starch granule-associated proteins in mature wheat kernel (Triticum aestivum L.).

    PubMed

    Bancel, Emmanuelle; Rogniaux, Hélène; Debiton, Clément; Chambon, Christophe; Branlard, Gérard

    2010-06-04

    Starch consists of the two glucose polymers, amylose and amylopectin, and is deposited as semicrystalline granules inside plastids. The starch granule proteome is particularly challenging to study due to the amount of interfering compounds (sugars, storage proteins), the very low starch granule-associated protein content and also the dynamic range of abundant proteins. Here we present the protocol for extraction and 2-DE of wheat starch granule-associated proteins whose most important steps are: (i) washing and sonication to remove interfering compounds (storage proteins) from the surface of the granules, (ii) scanning electron microscopy (SEM) observations to monitor purification and granules swelling, (iii) appropriate protein extraction and solubilization to obtain enough proteins for Coomassie blue staining and proteomic analysis. Our objective was to minimize the amount of contamination by storage proteins and to preserve the structure of the starch and of starch-associated proteins and to maximize the number of polypeptides that can be resolved. For quantitative proteomic analysis of proteins associated with wheat starch granules, we developed a two-step protein extraction protocol including TCA/acetone precipitation and phenol extraction. With this protocol, proteins were extracted from wheat starch granules and solubilized and satisfactory blue-stained 2-DE protein maps were obtained. The majority of the spots associated with starch granules were identified by peptide mass fingerprinting and MS/MS and functionally classified into carbohydrate metabolism and stress defense.

  7. Does viscosity or structure govern the rate at which starch granules are digested?

    PubMed

    Hardacre, Allan K; Lentle, Roger G; Yap, Sia-Yen; Monro, John A

    2016-01-20

    The rates of in vitro digestion of incompletely or fully gelatinised potato and corn starch were measured at 37 °C over 20 min in a rheometer fitted with cup and vane geometry at shear rates of 0.1, 1 and 10 s(-1). Shear rate did not influence the rate of starch digestion provided it was close to physiological levels. However, rates of digestion were significantly reduced when shear rates were below the physiological range (0.1 s(-1)) or when gelatinisation was incomplete. At physiological shear rates the relationship between starch digestion and viscosity was sigmoid in form and following a short initial slow phase a rapid decline in viscosity occurred as starch was digested and the structural integrity of the granules was lost. Conversely, when shear rate was reduced below physiological levels or gelatinisation was incomplete, digestion was hindered, granule integrity was maintained and the relationship between starch and viscosity became linear.

  8. Molecular rearrangement of waxy and normal maize starch granules during in vitro digestion.

    PubMed

    Teng, Anju; Witt, Torsten; Wang, Kai; Li, Ming; Hasjim, Jovin

    2016-03-30

    The objective of the present study is to understand the changes in starch structures during digestion and the structures contributing to slow digestion properties. The molecular, crystalline, and granular structures of native waxy maize, normal maize, high-amylose maize, and normal potato starch granules were monitored using SEC, XRD, DSC, and SEM. The amylose and amylopectin molecules of all four starches were hydrolyzed to smaller dextrins, with some having linear molecular structure. Neither the A- nor B-type crystallinity was resistant to enzyme hydrolysis. Starch crystallites with melting temperature above 120°C appeared in waxy and normal maize starches after digestion, suggesting that the linear dextrins retrograded into thermally stable crystalline structure. These crystallites were also observed for high-amylose maize starch before and after digestion, contributing to its low enzyme digestibility. On the contrary, the enzyme-resistant granular structure of native normal potato starch was responsible for its low susceptibility to enzyme hydrolysis.

  9. Internal structure of normal maize starch granules revealed by chemical surface gelatinization.

    PubMed

    Pan, D D; Jane, J I

    2000-01-01

    Normal maize starch was fractionated into two sizes: large granules with diameters more than 5 microns and small granules with diameters less than 5 microns. The large granules were surface gelatinized by treating them with an aqueous LiCl solution (13 M) at 22-23 degrees C. Surface-gelatinized remaining granules were obtained by mechanical blending, and gelatinized surface starch was obtained by grinding with a mortar and a pestle. Starches of different granular sizes and radial locations, obtained after different degrees of surface gelatinization, were subjected to scanning electron microscopy, iodine potentiometric titration, gel-permeation chromatography, and amylopectin branch chain length analysis. Results showed that the remaining granules had a rough surface with a lamella structure. Amylose was more concentrated at the periphery than at the core of the granule. Amylopectin had longer long B-chains at the core than at the periphery of the granule. Greater proportions of the long B-chains were present at the core than at the periphery of the granule.

  10. Mango starch degradation. II. The binding of alpha-amylase and beta-amylase to the starch granule.

    PubMed

    Peroni, Fernanda Helena Gonçalves; Koike, Claudia; Louro, Ricardo Pereira; Purgatto, Eduardo; do Nascimento, João Roberto Oliveira; Lajolo, Franco Maria; Cordenunsi, Beatriz Rosana

    2008-08-27

    During mango ripening, soluble sugars that account for mango sweetening are accumulated through carbon supplied by both photosynthesis and starch degradation. The cultivar Keitt has a characteristic dependence on sugar accumulation during starch degradation, which takes place during ripening, only a few days after detachment from the tree. Most knowledge about starch degradation is based on seeds and leaves currently used as models. However, information about the mango fruit is scarce. This work presents the evaluation of alpha- and beta-amylases in the starch granule surface during fruit development and ripening. Extractable proteins were assayed for amylase activity and detected by immunofluorescence microscopy and correlated to gene expression. The results suggest that both amylases are involved in starch degradation during mango ripening, probably under the dependence of another signal triggered by the detachment from the mother-plant.

  11. Expression of an engineered granule-bound Escherichia coli glycogen branching enzyme in potato results in severe morphological changes in starch granules.

    PubMed

    Huang, Xing-Feng; Nazarian-Firouzabadi, Farhad; Vincken, Jean-Paul; Ji, Qin; Suurs, Luc C J M; Visser, Richard G F; Trindade, Luisa M

    2013-05-01

    The Escherichia coli glycogen branching enzyme (GLGB) was fused to either the C- or N-terminus of a starch-binding domain (SBD) and expressed in two potato genetic backgrounds: the amylose-free mutant (amf) and an amylose-containing line (Kardal). Regardless of background or construct used, a large amount of GLGB/SBD fusion protein was accumulated inside the starch granules, however, without an increase in branching. The presence of GLGB/SBD fusion proteins resulted in altered morphology of the starch granules in both genetic backgrounds. In the amf genetic background, the starch granules showed both amalgamated granules and porous starch granules, whereas in Kardal background, the starch granules showed an irregular rough surface. The altered starch granules in both amf and Kardal backgrounds were visible from the initial stage of potato tuber development. High-throughput transcriptomic analysis showed that expression of GLGB/SBD fusion protein in potato tubers did not affect the expression level of most genes directly involved in the starch biosynthesis except for the up-regulation of a beta-amylase gene in Kardal background. The beta-amylase protein could be responsible for the degradation of the extra branches potentially introduced by GLGB.

  12. Molecular, mesoscopic and microscopic structure evolution during amylase digestion of maize starch granules.

    PubMed

    Shrestha, Ashok K; Blazek, Jaroslav; Flanagan, Bernadine M; Dhital, Sushil; Larroque, Oscar; Morell, Matthew K; Gilbert, Elliot P; Gidley, Michael J

    2012-09-01

    Cereal starch granules with high (>50%) amylose content are a promising source of nutritionally desirable resistant starch, i.e. starch that escapes digestion in the small intestine, but the structural features responsible are not fully understood. We report the effects of partial enzyme digestion of maize starch granules on amylopectin branch length profiles, double and single helix contents, gelatinisation properties, crystallinity and lamellar periodicity. Comparing results for three maize starches (27, 57, and 84% amylose) that differ in both structural features and amylase-sensitivity allows conclusions to be drawn concerning the rate-determining features operating under the digestion conditions used. All starches are found to be digested by a side-by-side mechanism in which there is no major preference during enzyme attack for amylopectin branch lengths, helix form, crystallinity or lamellar organisation. We conclude that the major factor controlling enzyme susceptibility is granule architecture, with shorter length scales not playing a major role as inferred from the largely invariant nature of numerous structural measures during the digestion process (XRD, NMR, SAXS, DSC, FACE). Results are consistent with digestion rates being controlled by restricted diffusion of enzymes within densely packed granular structures, with an effective surface area for enzyme attack determined by external dimensions (57 or 84% amylose - relatively slow) or internal channels and pores (27% amylose - relatively fast). Although the process of granule digestion is to a first approximation non-discriminatory with respect to structure at molecular and mesoscopic length scales, secondary effects noted include (i) partial crystallisation of V-type helices during digestion of 27% amylose starch, (ii) preferential hydrolysis of long amylopectin branches during the early stage hydrolysis of 27% and 57% but not 84% amylose starches, linked with disruption of lamellar repeating structure

  13. Association of alpha-amylase and the R1 protein with starch granules precedes the initiation of net starch degradation in turions of Spirodela polyrhiza.

    PubMed

    Reimann, Rezarta; Ritte, Gerhard; Steup, Martin; Appenroth, Klaus-J

    2002-01-01

    In turions of Spirodela polyrhiza (L.) Schleiden, net degradation of storage starch is controlled by a special low fluence response of phytochrome requiring illumination for several days. This light effect has been used to study protein-starch interactions that occur prior to and during net degradation of starch. Following various pretreatments on S. polyrhiza turions, native starch granules were isolated and two fractions of starch-related proteins were distinguished: proteins enclosed within the starch particles (starch-internalized proteins) and those attached to the surface (starch-associated proteins). The pattern of starch-associated proteins as resolved by SDS-PAGE was more complex than that of starch-internalized proteins and varied depending upon the pretreatment of the turions. Two starch associated proteins were identified immunochemically as alpha-amylase (EC 3.2.1.1) and the R1 protein (Lorberth et al. (1998) Nature Biotechnology 16: 473-477). Dark-pretreatment of non-dormant turions does not induce starch net degradation. Under these conditions, alpha-amylase and R1 were bound to the surface of the starch granules. Continuous illumination with red light induces a rapid degradation of starch. Within the first 24 h of illumination the level of starch-associated alpha-amylase transiently increased and subsequently decreased rapidly. Similarly, the amount of the starch-associated R1 also decreased during illumination. The dissociation of both alpha-amylase and R1 from the starch granules preceded the decrease in starch content. However, binding of the two proteins to starch granules remained unchanged when the turions did not perform net starch degradation (as observed during continuous darkness, orthophosphate deficiency, or dormancy of the turions). Thus, during net starch degradation, so far unidentified changes are postulated to occur at the surface of the starch particles that are relevant for protein binding. This conclusion was supported by in

  14. Effect of alkali treatment on structure and function of pea starch granules.

    PubMed

    Wang, Shujun; Copeland, Les

    2012-12-01

    The effect of alkaline treatment on the structural and functional properties of pea starch granules was studied using a range of characterization methods including amylose content, scanning electron microscopy (SEM), X-ray diffraction (XRD), (13)C nuclear magnetic resonance (NMR), swelling power, differential scanning calorimetry (DSC), the Rapid Visco Analyser (RVA) and in vitro digestibility. The amylose content decreased by about 20-25% after 15days of alkaline treatment and there were small decreases in relative crystallinity and double helix content. Deformations were observed on the surface of alkali-treated granules, and there was evidence of adhesion between some of the granules. There was a 25-30% reduction in peak and final RVA pasting viscosities, but only a small reduction in swelling power. The endothermic transition of alkali-treated starch was broadened with a shift of the endothermic peak to higher temperature. However, the endothermic enthalpy remained largely unaffected. Alkali-treatment greatly increased the rate of in vitro enzymatic breakdown of the pea starch. More prolonged alkaline treatment for 30days did not cause further significant changes to the structural and functional properties of the starch granules. The effects of alkali on structure and function of pea starch are explained on the basis of limited gelatinization of the granules.

  15. Quantification of high-power ultrasound induced damage on potato starch granules using light microscopy.

    PubMed

    Zuo, Yue Yue J; Hébraud, Pascal; Hemar, Yacine; Ashokkumar, Muthupandian

    2012-05-01

    A simple light microscopic technique was developed in order to quantify the damage inflicted by high-power low-frequency ultrasound (0-160 W, 20 kHz) treatment on potato starch granules in aqueous dispersions. The surface properties of the starch granules were modified using ethanol and SDS washing methods, which are known to displace proteins and lipids from the surface of the starch granules. The study showed that in the case of normal and ethanol-washed potato starch dispersions, two linear regions were observed. The number of defects first increased linearly with an increase in ultrasound power up to a threshold level. This was then followed by another linear dependence of the number of defects on the ultrasound power. The power threshold where the change-over occurred was higher for the ethanol-washed potato dispersions compared to non-washed potato dispersions. In the case of SDS-washed potato starch, although the increase in defects was linear with the ultrasound power, the power threshold for a second linear region was not observed. These results are discussed in terms of the different possible mechanisms of cavitation induced-damage (hydrodynamic shear stresses and micro-jetting) and by taking into account the hydrophobicity of the starch granule surface. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Morphology, associated protein analysis, and identification of 58-kDa starch synthase in mungbean (Vigna radiata L. cv. KPS1) starch granule preparations.

    PubMed

    Ko, Yuan-Tih; Dong, Yu-Ling; Hsieh, Ying-Fang; Kuo, Ja-Chi

    2009-05-27

    Raw starch granules of mature mungbean (Vigna radiata L. cv. KPS1) seeds were prepared by two methods into crude and cesium chloride (CsCl)-washed forms. The purity, shape, size distribution, and associated protein profiles were examined. The appearance of raw starch granules showed a bimodal type distribution in which average granules had typical ovoid shapes, whereas the small ones were spherical. Abnormal granule surface with distinct tumor-like or dented hole features were also observed in raw starch granules. CsCl-washed granules had a smooth surface compared to that of the crude form. The granule size distribution ranged from 6-35 μm; most 15-25 μm (∼53%), followed by 25-35 μm (∼26%). Small granules (<15 μm) amounted to ∼18%, and granules >35 μm consisted of ∼3%. The two forms were further refined by trichloroacetic (TCA) treatment to reveal surface proteins on the crude granules or tightly bound proteins on CsCl-washed granules. In the washed-refined granules, only a few integral proteins were retained. The major 58-kDa protein was identified to be granule-bound starch synthase I by sequence homology with that in cowpea (Vigna unguiculata) and maize (Zea mays) using MALDI-TOF mass and Mascot search.

  17. In vitro and in vivo digestibility of native maize starch granules varying in amylose contents.

    PubMed

    Morita, Tatsuya; Ito, Yusuke; Brown, Ian Lewis; Ando, Ryuichi; Kiriyama, Shuhachi

    2007-01-01

    Digestibility of maize starch granules with different amylose content (AL-0, 22, 54, 68, 80, or 90%) was investigated. Measurement of the in vivo resistant starch (RS) content of the starches was performed using surgically prepared ileorectostomized rats. The rats were fed a purified diet containing one of the starches at 652.5 g/kg diet. The in vivo RS content was determined based on the fecal starch excretion. The dietary fiber (DF) value increased as a function of the amylose content in the starch and showed a positive linear correlation with the gelatinization temperature of the granules. In contrast, the in vitro RS content was likely to depend on both the surface area and amylose contents of the starch granules. The maximum in vitro RS content was obtained with AL-68 (54.4%). In vivo RS content showed a significant correlation with the amount of in vitro RS but not in respect to the DF detected. The in vivo RS content of AL-68 (43.4%) was higher than that found in AL-90 (37.8%). A profound gap was observed for AL-54 between the amount of DF (6.4%) and RS (in vitro = 46.6% and in vivo = 40.9%) present. The results suggest that both in vitro and in vivo digestibility of maize starch is affected by the amylose content and surface area of the granules. The current evaluation suggests that the physiological occurrence of RS from maize starch might be predictable by reference to the in vitro RS value.

  18. Crystallite orientation maps in starch granules from polarized Raman spectroscopy (PRS) data.

    PubMed

    Galvis, Leonardo; Bertinetto, Carlo G; Putaux, Jean-Luc; Montesanti, Nicole; Vuorinen, Tapani

    2016-12-10

    In this work, polarized Raman spectroscopy (PRS) was used to determine orientation maps of crystallites present in Phajus grandifolius starch granules based on the anisotropic response of the glycosidic Raman band at 865cm(-1). The response of this band was preliminarily evaluated using model A-amylose crystals as standard. The A-amylose crystals oriented "in plane" showed a maximal intensity ratio of ∼3.0 for bands 865/1343cm(-1) when the polarization of the laser was along the chain axis of the crystal, i.e., parallel to the axis of the amylose double helices, and a minimal intensity ratio of ∼0.25 when perpendicular. The orientation maps of Phajus grandifolius starch granules showed two distinct regions: one isotropic and the other with a highly anisotropic response. The origin of the difference might be changes in both organization/concentration and orientation of the crystallites across the starch granules.

  19. Electron microscopic investigation of the diffusion of Bacillus licheniformis alpha-amylase into corn starch granules.

    PubMed

    Helbert, W; Schülein, M; Henrissat, B

    1996-10-01

    A method for the direct electron microscopic observation of amylases in interaction with starch granules is presented. The technique involves immuno-gold labeling of the enzymes and cross-sectioning of hydrated starch granules. This approach allows the analysis of the internal degradation of starch with a concomitant visualization of enzymes at the sites of hydrolysis. The visualization of enzymes at the surface, inside the channel and inside the core of the degraded granules shows that the alpha-amylase molecules first proceed from the surface toward the center (centripetal hydrolysis). Then the core is completely degraded from within by erosion of its periphery (centrifugal hydrolysis). In the first case (centripetal hydrolysis), the enzymes act by progressing along the polysaccharide chains. By contrast, the centrifugal hydrolysis leads to even erosion, indicative of a more diffusive motion of the enzymes.

  20. Polymeric tannins significantly alter properties and in vitro digestibility of partially gelatinized intact starch granule.

    PubMed

    Amoako, Derrick B; Awika, Joseph M

    2016-10-01

    Excess calorie intake is a growing global problem. This study investigated effect of complexing partially gelatinized starch with condensed tannins on in vitro starch digestibility. Extracts from tannin and non-tannin sorghum, and cellulose control, were reacted with normal and waxy maize starch in 30% (30E) and 50% ethanol (50E) solutions at 70°C/20min. More tannins complexed with the 30E than 50E starches (mean 6.2 vs 3.5mg/g, respectively). In the 30E treatments, tannins significantly increased crystallinity, pasting temperature, peak viscosity, and slow digesting starch (from 100 to 274mg/g) in normal, but not waxy starch, suggesting intragranular cross-linking with amylose. Tannins doubled resistant starch (RS) to approx. 300mg/g in both starches. In 50E treatments, tannins made both maize starches behave like raw potato starch (>90% RS), suggesting granule surface interactions dominated. Non-tannin treatments generally behaved similar to cellulose. Condensed tannins could be used to favorably alter starch digestion profile. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Synchrotron Infrared Confocal Microspectroscopical Detection of Heterogeneity Within Chemically Modified Single Starch Granules

    SciTech Connect

    Wetzel, D.; Shi, Y; Reffner, J

    2010-01-01

    This reports the first detection of chemical heterogeneity in octenyl succinic anhydride modified single starch granules using a Fourier transform infrared (FT-IR) microspectroscopical technique that combines diffraction-limited infrared microspectroscopy with a step size that is less than the mask projected spot size focused on the plane of the sample. The high spatial resolution was achieved with the combination of the application of a synchrotron infrared source and the confocal image plane masking system of the double-pass single-mask Continuum{reg_sign} infrared microscope. Starch from grains such as corn and wheat exists in granules. The size of the granules depends on the plant producing the starch. Granules used in this study typically had a median size of 15 {micro}m. In the production of modified starch, an acid anhydride typically is reacted with OH groups of the starch polymer. The resulting esterification adds the ester carbonyl (1723 cm{sup -1}) organic functional group to the polymer and the hydrocarbon chain of the ester contributes to the CH{sub 2} stretching vibration to enhance the intensity of the 2927 cm{sup -1} band. Detection of the relative modifying population on a single granule was accomplished by ratioing the baseline adjusted peak area of the carbonyl functional group to that of a carbohydrate band. By stepping a confocally defined infrared beam as small as 5 {micro}m x 5 {micro}m across a starch granule 1 {micro}m at a time in both the x and y directions, the heterogeneity is detected with the highest possible spatial resolution.

  2. Temperature Related Structural Changes in Wheat and Corn Starch Granules and Their Effects on Gels and Dry Foam

    USDA-ARS?s Scientific Manuscript database

    The effect of processing temperature on structural changes in wheat, corn, and high amylose corn starch granules was investigated and related to the mechanical properties of gels and microcellular foam (MCF). Scanning electron micrographs (SEM) showed that wheat starch granules form ghosts with thic...

  3. Structural design approaches for creating fat droplet and starch granule mimetics.

    PubMed

    McClements, David Julian; Chung, Cheryl; Wu, Bi-Cheng

    2017-02-22

    This article focuses on hydrogel-based strategies for creating reduced calorie foods with desirable physicochemical, sensory, and nutritional properties. Initially, the role of fat droplets and starch granules in foods is discussed, and then different methods for fabricating hydrogel beads are reviewed, including phase separation, antisolvent precipitation, injection, and emulsion template methods. Finally, the potential application of hydrogel beads as fat droplet and starch granule replacements is discussed. There is still a need for large-scale, high-throughout, and economical methods of fabricating hydrogel beads suitable for utilization within the food industry.

  4. Effect of granule organisation on the behaviour of starches in the NMMO (N-methyl morpholine N-oxide) solvent system.

    PubMed

    Koganti, Nagamani; Mitchell, John; MacNaughtan, William; Hill, Sandra; Foster, Tim

    2015-02-13

    The response of starches of different botanical origin to heating in 78% N-methyl morpholine N-oxide (NMMO) is compared with their behaviour in water. For all starches studied an exothermic transition is obtained in the NMMO system rather than the endothermic transition in water. In NMMO the transition temperatures are lower for A-type starches (wheat, rice and tapioca) than the C-type starches (sago and pea) and also potato which has a B-type polymorph. Observations using a hot stage microscope show two different types of initial behaviour in NMMO; erosion of the granule from the surface or disruption into fragments. In both cases the final outcome is dissolution but for the most resistant C-type starches (pea and sago) some intact granules could be seen following heating at 95 °C in 78% NMMO and subsequent precipitation in ethanol. The results are discussed in terms of what is known from previous structural studies on these six starches and the behaviour of maize starch in NMMO and ionic liquids. The work is relevant to the co-dissolution of starch and cellulose to form novel polysaccharide based materials. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Structural variability between starch granules in wild type and in ae high-amylose mutant maize kernels.

    PubMed

    Liu, Dongli; Parker, Mary L; Wellner, Nikolaus; Kirby, Andrew R; Cross, Kathryn; Morris, Victor J; Cheng, Fang

    2013-09-12

    Starch granule structure within wild-type and ae high-amylose mutant maize kernels has been mapped in situ using light, electron and atomic force microscopy, and both Raman and infra-red spectroscopy. The population of wild-type starch granules is found to be homogenous. The ae mutant granule population is heterogeneous. Heterogeneity in chemical and physical structure is observed within individual granules, between granules within cells, and spatially within the kernel. The highest level of heterogeneity is observed in the region where starch is first deposited during kernel development. Light microscopy demonstrates structural diversity through use of potassium iodide/iodine staining and polarised microscopy. Electron and atomic force microscopy, and infra-red and Raman spectroscopy defined the nature of the structural changes within granules. The methodology provides novel information on the changes in starch structure resulting from kernel development. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Engineering the Chloroplast Targeted Malarial Vaccine Antigens in Chlamydomonas Starch Granules

    PubMed Central

    Dauvillée, David; Delhaye, Stéphane; Gruyer, Sébastien; Slomianny, Christian; Moretz, Samuel E.; d'Hulst, Christophe; Long, Carole A.; Ball, Steven G.; Tomavo, Stanislas

    2010-01-01

    Background Malaria, an Anopheles-borne parasitic disease, remains a major global health problem causing illness and death that disproportionately affects developing countries. Despite the incidence of malaria, which remains one of the most severe infections of human populations, there is no licensed vaccine against this life-threatening disease. In this context, we decided to explore the expression of Plasmodium vaccine antigens fused to the granule bound starch synthase (GBSS), the major protein associated to the starch matrix in all starch-accumulating plants and algae such as Chlamydomonas reinhardtii. Methods and Findings We describe the development of genetically engineered starch granules containing plasmodial vaccine candidate antigens produced in the unicellular green algae Chlamydomonas reinhardtii. We show that the C-terminal domains of proteins from the rodent Plasmodium species, Plasmodium berghei Apical Major Antigen AMA1, or Major Surface Protein MSP1 fused to the algal granule bound starch synthase (GBSS) are efficiently expressed and bound to the polysaccharide matrix. Mice were either immunized intraperitoneally with the engineered starch particles and Freund adjuvant, or fed with the engineered particles co-delivered with the mucosal adjuvant, and challenged intraperitoneally with a lethal inoculum of P. Berghei. Both experimental strategies led to a significantly reduced parasitemia with an extension of life span including complete cure for intraperitoneal delivery as assessed by negative blood thin smears. In the case of the starch bound P. falciparum GBSS-MSP1 fusion protein, the immune sera or purified immunoglobulin G of mice immunized with the corresponding starch strongly inhibited in vitro the intra-erythrocytic asexual development of the most human deadly plasmodial species. Conclusion This novel system paves the way for the production of clinically relevant plasmodial antigens as algal starch-based particles designated herein as

  7. Non-contact AFM investigation of influence of freezing process on the surface structure of potato starch granule

    NASA Astrophysics Data System (ADS)

    Krok, F.; Szymońska, J.; Tomasik, P.; Szymoński, M.

    2000-04-01

    To assess the influence of the freezing process on the surface structure of a potato starch granule, a non-contact Atomic Force Microscopy (NC-AFM) investigation at ambient conditions has been undertaken. The observations were carried out for dried (oven-dried) and native (air-dried) starch. The obtained AFM images of the native starch granule surface demonstrated it as not uniformly smooth and having rough undulating appearance with layers of adsorbed water which could be removed by oven drying in 130°C. After freezing, the dried starch granule surface still consisted of nodules of about 100 nm in diameter. Significant changes in the granule surface appearance can be seen for dried starch samples frozen with some excess of water as well as for native starch samples frozen with its original water. Then the aggregation and polishing of the granules was observed and their surface revealed a microstructure with distinct ring-like protrusions of about 300 nm in diameter. Our observations tally with the amylopectine "blocket" starch granule structure model proposed in the literature and allowed to conclude that freezing may be a useful tool, among other methods, for modifying starch granule properties.

  8. In vitro utilization of amylopectin and high-amylose maize (Amylomaize) starch granules by human colonic bacteria.

    PubMed

    Wang, X; Conway, P L; Brown, I L; Evans, A J

    1999-11-01

    It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (M(r)) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (<66,000). It was concluded that Bifidobacterium spp. and C. butyricum degraded and utilized granules of amylomaize starch.

  9. Identification of genes encoding granule-bound starch synthase involved in amylose metabolism in banana fruit.

    PubMed

    Miao, Hongxia; Sun, Peiguang; Liu, Weixin; Xu, Biyu; Jin, Zhiqiang

    2014-01-01

    Granule-bound starch synthase (GBSS) is responsible for amylose synthesis, but the role of GBSS genes and their encoded proteins remains poorly understood in banana. In this study, amylose content and GBSS activity gradually increased during development of the banana fruit, and decreased during storage of the mature fruit. GBSS protein in banana starch granules was approximately 55.0 kDa. The protein was up-regulated expression during development while it was down-regulated expression during storage. Six genes, designated as MaGBSSI-1, MaGBSSI-2, MaGBSSI-3, MaGBSSI-4, MaGBSSII-1, and MaGBSSII-2, were cloned and characterized from banana fruit. Among the six genes, the expression pattern of MaGBSSI-3 was the most consistent with the changes in amylose content, GBSS enzyme activity, GBSS protein levels, and the quantity or size of starch granules in banana fruit. These results suggest that MaGBSSI-3 might regulate amylose metabolism by affecting the variation of GBSS levels and the quantity or size of starch granules in banana fruit during development or storage.

  10. Identification of Genes Encoding Granule-Bound Starch Synthase Involved in Amylose Metabolism in Banana Fruit

    PubMed Central

    Liu, Weixin; Xu, Biyu; Jin, Zhiqiang

    2014-01-01

    Granule-bound starch synthase (GBSS) is responsible for amylose synthesis, but the role of GBSS genes and their encoded proteins remains poorly understood in banana. In this study, amylose content and GBSS activity gradually increased during development of the banana fruit, and decreased during storage of the mature fruit. GBSS protein in banana starch granules was approximately 55.0 kDa. The protein was up-regulated expression during development while it was down-regulated expression during storage. Six genes, designated as MaGBSSI-1, MaGBSSI-2, MaGBSSI-3, MaGBSSI-4, MaGBSSII-1, and MaGBSSII-2, were cloned and characterized from banana fruit. Among the six genes, the expression pattern of MaGBSSI-3 was the most consistent with the changes in amylose content, GBSS enzyme activity, GBSS protein levels, and the quantity or size of starch granules in banana fruit. These results suggest that MaGBSSI-3 might regulate amylose metabolism by affecting the variation of GBSS levels and the quantity or size of starch granules in banana fruit during development or storage. PMID:24505384

  11. Impact of full range of amylose contents on the architecture of starch granules.

    PubMed

    Goldstein, Avi; Annor, George; Putaux, Jean-Luc; Hebelstrup, Kim H; Blennow, Andreas; Bertoft, Eric

    2016-08-01

    The effects of amylose deposition on crystalline regions of barley starch granules were studied in granules containing zero to 99.1% amylose using "waxy" (WBS, 0% amylose), normal (NBS, 18% amylose) and amylose-only barley lines (AOS, 99.1% amylose). The effects were probed after hydrolysis of amorphous regions of starch granules in dilute HCl generating lintners, which typically represent the crystalline lamella of starch granules. Compared to NBS and WBS, AOS granules exhibited an irregular, multilobular morphology with a rough surface texture. AOS displayed lower rates of acid hydrolysis than WBS, and AOS reached a plateau at ∼45wt% acid hydrolysis. High-performance anion-exchange chromatography of lintners at equivalent levels of hydrolysis (45wt%) revealed the average degree of polymerization (DP) of AOS lintners was 21, substantially smaller than that of NBS and WBS (DP 42). AOS lintners contained the lowest number of chains (NC) per molecule (1.1) compared to NBS (2.8) and WBS (3.3) and the average chain length of AOS, NBS and WBS lintners was 19, 15 and 13, respectively. Hence, both NC and the average chain length correlated with amylose content. The size distribution profile of AOS lintners revealed a repeat motif in the molecules corresponding to 5-6 glucose residues.

  12. Structure of lintnerized starch is related to X-ray diffraction pattern and susceptibility to acid and enzyme hydrolysis of starch granules.

    PubMed

    Srichuwong, Sathaporn; Isono, Naoto; Mishima, Takashi; Hisamatsu, Makoto

    2005-11-15

    Acid-resistant residues (lintnerized starches, Ls) were prepared from starches showing A-, B- and C- X-ray diffraction patterns. Ls retained the same X-ray crystalline type as their native counterparts with an improvement in diffraction intensity. Fluorophore-assisted capillary electrophoresis (FACE) study indicated that structural characteristics of Ls were associated with X-ray diffraction patterns. Double helices originated from linear chains with an approximate average degree of polymerisation (DP) 14, 16, and 15 would span the entire length of crystalline lamellae of A-, B-, and C-type starches, respectively. The proportion of singly branched materials (SB) with DP 25 protected in Ls was higher for A-type Ls (10-17%) than for B-type Ls (4-6%) and C-type Ls (8%). The structures of SB were similar in which branched chain (DP 13-15) was longer than main chain (DP 10-12). The structural characteristics of Ls are discussed in relation to acid and enzymatic degradations of starch granules.

  13. Influence of lipid extraction process on the rheological characteristics, swelling power, and granule size of rice starches in excess water.

    PubMed

    Kar, Aditi; Jacquier, Jean-Christophe; Morgan, Desmond J; Lyng, James G; McKenna, Brian M

    2005-10-19

    The influence of the lipid extraction process on both macroscopic and microscopic characteristics of nonwaxy rice starch gelatinization in excess water was examined. Surface lipids extraction did not change the thermodynamics of starch gelatinization but lead to a significant reduction (33%) in the enthalpy of starch-lipid complex melting at high temperature, resulting in less viscous dispersions. Internal lipid extraction using hot aqueous alcoholic solutions resulted in an irreversible increase in starch granule diameter (50% increase in D[4,3]) and a dramatic change in cooking characteristics of the starch. Instead of the bimodal swelling observed for native nonwaxy rice starch, only one broad transition in swelling, solubility, granule size, and viscosity was observed in the case of the totally defatted starch. While the total removal of lipids resulted in a slight increase in starch swelling at intermediate temperatures, the harshness of the process caused irreparable changes leading to notably lower swelling at high temperatures.

  14. Effect of disintegrants on the properties of multiparticulate tablets comprising starch pellets and excipient granules.

    PubMed

    Mehta, Samata; De Beer, Thomas; Remon, Jean Paul; Vervaet, Chris

    2012-01-17

    A design of experiments (DOE) approach (2-level full factorial design) was used to investigate the effect of several formulation and process variables on the properties of fast disintegrating tablets comprising starch-based pellets and excipient granules and to optimize and validate the design space. The percentage of starch pellets (30-50%, w/w), type of disintegrants (Ac-di-sol, Explotab, Polyplasdone), percentage of external disintegrant (4-8%, w/w) and compression force (5-15 kN) were the evaluated factors (24 runs+9 centre points=33 experiments), while tablet hardness, friability and disintegration time were the studied tablet properties (responses). Starch pellets were prepared by extrusion-spheronisation. Excipient granules containing microcrystalline cellulose, lactose, internal disintegrant (8%) and polyvinylpyrrolidone K-30 (4%) were prepared by wet granulation. Pellets, granules (700-1000 μm) and external disintegrant were mixed and compressed into oblong tablets (17.1mm long, 8.2mm wide). Evaluation of the effects calculated from the DOE results showed that a lower concentration of starch pellets and higher compression force were required to yield tablets with a high hardness, a low friability (<1%) and short disintegration time (<3 min). Polyplasdone granules had the lowest porosity and friability which was reflected in the DOE study, where the Polyplasdone-containing tablets were harder, less friable and disintegrated faster compared to Ac-di-sol and Explotab-containing tablets. Monte carlo simulations at the optimal factor settings (30% starch pellets, 4% Polyplasdone and 10 kN compression force) indicated that a robust system was formed as the probability to exceed the limits was low for all responses. Validation of the design space (at optimal settings) showed that the results predicted via the DOE models correlated well with the observed experimental data.

  15. In situ mapping of the effect of additional mutations on starch granule structure in amylose-extender (ae) maize kernels.

    PubMed

    Liu, Dongli; Wellner, Nikolaus; Parker, Mary L; Morris, Victor J; Cheng, Fang

    2015-03-15

    Optical (KI/I2-staining, polarised) and FTIR microscopy has been used to monitor starch granule structure within wild-type (wt), GEMS-0067 and waxy-amylose-extender (wx-ae) maize mutant kernels. In the GEMS-0067 mutant containing the high amylose modifier (HAM) gene(s) plus the recessive ae gene, structural heterogeneity characteristic of the ae mutation was reduced markedly. However, enhanced variation in granule shape and size was observed distributed spatially within the kernel, which appears to be related to new heterogeneity in internal starch granule structure. In wx-ae starch mutants the ae gene led to heterogeneity of starch granule structure equivalent to that in single ae mutants, plus new structural heterogeneity coincident with novel induced variation in granule size and shape. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Thixotropic properties of normal potato starch depending on the degree of the granules pasting.

    PubMed

    Sikora, Marek; Adamczyk, Greta; Krystyjan, Magdalena; Dobosz, Anna; Tomasik, Piotr; Berski, Wiktor; Lukasiewicz, Marcin; Izak, Piotr

    2015-05-05

    The aim of this paper was the study of the rheological instability (thixotropy and/or antithixotropy) of normal potato starch (NPS) pastes depending on their concentration (2-5%) and degree of pasting. Flow curves with hysteresis loops, apparent viscosity at constant shear rate and in-shear structural recovery tests were carried out. Granule size profiles, the pasting characteristic of corresponding starch suspensions and the transmittance of the pastes, the molecular weights and polydispersity of granular starch and its pastes prepared at 80, 95 and 121°C were also studied. The degree of pasting was dependent on the temperature and the concentration and influenced strongly the rheological behavior of the pastes. All pastes belonged to the non-Newtonian liquids thinned by shear and were rheologically unstable to the various extent. Thixotropic properties were connected to the size and the number of the starch granules in the pastes as well as depended on the measuring method used. In the 2 and 3% samples pasted at 80°C the swelling of the granules prevailed their destruction (thixotropy was observed). In the other samples the destruction predominated the swelling (antithixotropy observed).

  17. Incorporation of dietary fibre-rich oyster mushroom (Pleurotus sajor-caju) powder improves postprandial glycaemic response by interfering with starch granule structure and starch digestibility of biscuit.

    PubMed

    Ng, Sze Han; Robert, Sathyasurya Daniel; Wan Ahmad, Wan Amir Nizam; Wan Ishak, Wan Rosli

    2017-07-15

    The purpose of this study was to determine the effects of Pleurotus sajor-caju (PSC) powder addition at 0, 4, 8 and 12% levels on the nutritional values, pasting properties, thermal characteristics, microstructure, in vitro starch digestibility, in vivo glycaemic index (GI) and sensorial properties of biscuits. Elevated incorporation levels of PSC powder increased the dietary fibre (DF) content and reduced the pasting viscosities and starch gelatinisation enthalpy value of biscuits. The addition of DF-rich PSC powder also interfered with the integrity of the starch granules by reducing the sizes and inducing the uneven spherical shapes of the starch granules, which, in turn, resulted in reduced starch susceptibility to digestive enzymes. The restriction starch hydrolysis rate markedly reduced the GI of biscuits. The incorporation of 8% PSC powder in biscuits (GI=49) could be an effective way of developing a nutritious and low-GI biscuit without jeopardizing its desirable sensorial properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Preparation and characterization of modified starch granules with high hydrophobicity and flowability.

    PubMed

    Chang, Fengdan; He, Xiaowei; Fu, Xiong; Huang, Qiang; Qiu, Yaofang

    2014-01-01

    Normal cornstarch (NC) was chemically modified by octenylsuccinic anhydride (OSA) and Al2(SO4)3. The effects of the concentration of NaOH, OSA, and Al2(SO4)3 on the properties of modified starch(OS-starch-Al) were investigated. The OS-starch-Al was characterized by repose angle, activation index, inductively coupled plasma-atomic emission spectrometry (ICP-OES), light microscopy, SEM, FT-IR, and (27)Al NMR. The results showed that pH 4 was the optimum condition for Al(3+) cross-linking with OS-starch and for obtaining high flowability and hydrophobicity. When the concentration of OSA and Al2(SO4)3 was 2%, the OS-starch-Al was characterized by high flowability. A concentration of 4% OSA and Al2(SO4)3 yielded the highest activation index. The moisture content affected the flowability of native NC, but had a minor effect on OS-starch-Al. SEM and polarized microscopy revealed that the modification had slight effects on the crystalline structure and morphology of NC. During the preparation, some dust particles functioning as flow additives were produced on the surface of starch granules. The results of FT-IR, ICP-OES, and (27)Al NMR confirmed the formation of ester group and the cross-link with Al(3+). Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Fitting of different models for water vapour sorption on potato starch granules

    NASA Astrophysics Data System (ADS)

    Czepirski, L.; Komorowska-Czepirska, E.; Szymońska, J.

    2002-08-01

    Water vapour adsorption isotherms for native and modified potato starch were investigated. To obtain the best fit for the experimental data several models based on the BET approach were evaluated. The hypothesis that water is adsorbed on the starch granules at the primary and secondary adsorption sites as well as a concept considering the adsorbent fractality were also tested. It was found, that the equilibrium adsorption points in the examined range of relative humidity (0.03-0.90) were most accurately predicted by using a three-parameter model proposed by Kats and Kutarov.

  20. Surface-associated proteins of wheat starch granules: suitability of wheat starch for celiac patients.

    PubMed

    Kasarda, Donald D; Dupont, Frances M; Vensel, William H; Altenbach, Susan B; Lopez, Rocio; Tanaka, Charlene K; Hurkman, William J

    2008-11-12

    Wheat starch is used to make baked products for celiac patients in several European countries but is avoided in the United States because of uncertainty about the amounts of associated grain storage (gluten) proteins. People with celiac disease (CD) must avoid wheat, rye, and barley proteins and products that contain them. These proteins are capable of initiating damage to the absorptive lining of the small intestine in CD patients, apparently as a consequence of undesirable interactions with the innate and adaptive immune systems. In this study, starch surface-associated proteins were extracted from four commercial wheat starches, fractionated by high-performance liquid chromatography and gel electrophoresis, and identified by tandem mass spectrometry analysis. More than 150 proteins were identified, many of which (for example, histones, purothionins, and glutenins) had not been recognized previously as starch-associated. The commercial starches were analyzed by the R-5 enzyme-linked immunosorbent assay method to estimate the amount of harmful gluten protein present. One of these starches had a low gluten content of 7 ppm and actually fell within the range proposed as a new Codex Alimentarius Standard for naturally gluten-free foods (maximum 20 ppm). This low level of gluten indicates that the starch should be especially suitable for use by celiac patients, although wheat starches with levels up to 100 ppm are deemed safe in the proposed Codex standards.

  1. Size characterization of barley starch granules by gravitational field-flow fractionation: a rapid, low-cost method to assess the brewing capability of different strains.

    PubMed

    Reschiglian, Pierluigi; Zattoni, Andrea; Casolari, Sonia; Krumlova, Andrea; Budinska, Marcela; Chmelík, Josef

    2002-04-01

    Cereal starch occurs as two types of micrometer-sized granules, large and small. Large starch granules are more susceptible to enzymatic hydrolysis. When cereal starch is used for fermentation processes, as in brewing of barley malt, the barley strains with the highest content of large starch granules should be preferred. Gravitational field-flow fractionation (GFFF) is a separation method able to fractionate starch samples at low cost and short analysis time. In this work, the search for the best GFFF conditions for the analytical separation of barley starch within an inter-laboratory approach is presented. For different barley strains cultivated under monitored conditions the size distributions of starch granules is here quickly monitored and characterized by GFFF. As a consequence, dimensional characterization of barley starch can allow for the selection of the most suitable strains with the lowest content of non-degradable starch.

  2. Starch granule size distribution of hard red winter and hard red spring wheat: Its effects on mixing and breadmaking quality.

    USDA-ARS?s Scientific Manuscript database

    Starch was isolated from 98 hard red winter (HRW) wheat and 99 hard red spring (HRS) wheat. Granule size/volume distributions of the isolated starches were analyzed using a laser diffraction particle size analyzer. There were significant differences in the size distribution between HRW and HRS whe...

  3. The Starch Granule-Associated Protein EARLY STARVATION1 Is Required for the Control of Starch Degradation in Arabidopsis thaliana Leaves[OPEN

    PubMed Central

    Feike, Doreen; Seung, David; Graf, Alexander; Bischof, Sylvain; Ellick, Tamaryn; Coiro, Mario; Soyk, Sebastian; Eicke, Simona; Mettler-Altmann, Tabea; Lu, Kuan Jen; Trick, Martin; Zeeman, Samuel C.

    2016-01-01

    To uncover components of the mechanism that adjusts the rate of leaf starch degradation to the length of the night, we devised a screen for mutant Arabidopsis thaliana plants in which starch reserves are prematurely exhausted. The mutation in one such mutant, named early starvation1 (esv1), eliminates a previously uncharacterized protein. Starch in mutant leaves is degraded rapidly and in a nonlinear fashion, so that reserves are exhausted 2 h prior to dawn. The ESV1 protein and a similar uncharacterized Arabidopsis protein (named Like ESV1 [LESV]) are located in the chloroplast stroma and are also bound into starch granules. The region of highest similarity between the two proteins contains a series of near-repeated motifs rich in tryptophan. Both proteins are conserved throughout starch-synthesizing organisms, from angiosperms and monocots to green algae. Analysis of transgenic plants lacking or overexpressing ESV1 or LESV, and of double mutants lacking ESV1 and another protein necessary for starch degradation, leads us to propose that these proteins function in the organization of the starch granule matrix. We argue that their misexpression affects starch degradation indirectly, by altering matrix organization and, thus, accessibility of starch polymers to starch-degrading enzymes. PMID:27207856

  4. Analysis of octenylsuccinate rice and tapioca starches: Distribution of octenylsuccinic anhydride groups in starch granules.

    PubMed

    Whitney, Kristin; Reuhs, Bradley L; Ovando Martinez, Maribel; Simsek, Senay

    2016-11-15

    Characterization of the fine structure of octenylsuccinic anhydride (OSA) starch would lead to a better understanding of functional properties. OSA rice and tapioca starches were analyzed using microscopy, liquid chromatography and nuclear magnetic resonance. Chain length distribution of amylopectin changed significantly (P<0.05) after OSA esterification. Weight averaged degree of polymerization (DPw) decreased significantly (P<0.05) from 16.47 to 13.29 and from 14.87 to 12.47 in native and OSA rice and tapioca starches, respectively. The chain length distribution of pure amylopectin fractions suggested that OSA groups were not present in the amylopectin portion of the starch. (1)H NMR analysis of pure amylose and amylopectin fractions indicated that OSA substitution was present only in amylose fractions of rice and tapioca starches. Esterification with 3% OSA results in starch that has OSA substituted mainly on amylose chains or possibly on amylopectin chains that have been hydrolyzed from the amylopectin molecules during esterification. Published by Elsevier Ltd.

  5. Distribution of phosphorus and hydroxypropyl groups within granules of modified sweet potato starches as determined after chemical peeling.

    PubMed

    Zhao, Jianwei; Schols, Henk A; Chen, Zhenghong; Jin, Zhengyu; Buwalda, Piet; Gruppen, Harry

    2015-11-05

    The distributions of phosphorus and hydroxypropyl groups within granules of cross-linked and hydroxypropylated sweet potato starches were investigated. Chemical surface peeling of starch granules was performed after sieving of native and modified starches into large-size (diameter ≥ 20 μm) and small-size (diameter < 20 μm) fractions. Starch granules were surface gelatinized in a 4M calcium chloride solution at different levels. After the peeling step, the remaining starch granules were analysed for the content of phosphorus and hydroxypropyl groups. The phosphorus level of the parental starch gradually decreased from periphery to core of the granules. The increase in phosphorus content after cross-linking in periphery was higher than that in core. The subsequent hydroxypropylation reaction resulted in lower phosphate levels. Hydroxypropylation resulted in a gradient of hydroxypropyl group concentration from periphery to core. Cross-linking prior to the hydroxypropylation resulted in lower levels of hydroxypropyl groups and less pronounced differences between periphery and core. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Rheological Behavior, Granule Size Distribution and Differential Scanning Calorimetry of Cross-Linked Banana (Musa paradisiaca) Starch.

    NASA Astrophysics Data System (ADS)

    Núñez-Santiago, María C.; Maristany-Cáceres, Amira J.; Suárez, Francisco J. García; Bello-Pérez, Arturo

    2008-07-01

    Rheological behavior at 60 °C, granule size distribution and Differential Scanning Calorimetry (DSC) tests were employed to study the effect of diverse reaction conditions: adipic acid concentration, pH and temperature during cross-linking of banana (Musa paradisiaca) starch. These properties were determined in native banana starch pastes for the purpose of comparison. Rheological behavior from pastes of cross-linked starch at 60 °C did not show hysteresis, probably due the cross-linkage of starch that avoided disruption of granules, elsewhere, native starch showed hysteresis in a thixotropic loop. All pastes exhibited non-Newtonian shear thinning behavior. In all cases, size distribution showed a decrease in the median diameter in cross-linked starches. This condition produces a decrease in swelling capacity of cross-linked starch. The median diameter decreased with an increase of acid adipic concentration; however, an increase of pH and Temperature produced an increase in this variable. Finally, an increase in gelatinization temperature and entalphy (ΔH) were observed as an effect of cross-linkage. An increase in acid adipic concentration produced an increase in Tonset and a decrease in ΔH. pH and temperature. The cross-linked of banana starch produced granules more resistant during the pasting procedure.

  7. The surface-associated proteins of wheat starch granules: suitability of wheat starch for celiac patients

    USDA-ARS?s Scientific Manuscript database

    Wheat starch is used to make baked products for celiac patients in several European countries, but is avoided in the US because of uncertainty about the amounts of associated grain storage (gluten) proteins. People with celiac disease (CD) must avoid wheat, rye and barley proteins and products that...

  8. Effect of granule size on the properties of lotus rhizome C-type starch.

    PubMed

    Lin, Lingshang; Huang, Jun; Zhao, Lingxiao; Wang, Juan; Wang, Zhifeng; Wei, Cunxu

    2015-12-10

    Lotus rhizome C-type starch was separated into different size fractions. Starch morphologies changed from irregular to elongated, ellipsoid, oval, and spherical with decreasing granule size. The small- and very-small-sized fractions had a centric hilum, and the other size fractions had an eccentric hilum. The different size fractions all showed C-type crystallinity, pseudoplasticity and shear-thinning rheological properties. The range of amylose content was 25.6 to 26.6%, that of relative crystallinity was 23.9 to 25.8%, that of swelling power was 29.0 to 31.4 g/g, and that of gelatinization enthalpy was 12.4 to 14.2J/g. The very-small-sized fraction had a significantly lower short-range ordered degree and flow behavior index and higher scattering peak intensity, water solubility, gelatinization peak temperature, gelatinization conclusion temperature, consistency coefficient, hydrolysis degrees, and digestion rate than the large-sized fraction. Granule size significantly positively influenced short-range ordered structure and swelling power and negatively influenced scattering peak intensity, water solubility, hydrolysis and digestion of starch (p<0.01). Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. The barley amo1 locus is tightly linked to the starch synthase IIIa gene and negatively regulates expression of granule-bound starch synthetic genes

    PubMed Central

    Li, Zhongyi; Li, Dehong; Du, Xihua; Wang, Hong; Larroque, Oscar; Jenkins, Colin L. D.; Jobling, Stephen A.; Morell, Matthew K.

    2011-01-01

    In this study of barley starch synthesis, the interaction between mutations at the sex6 locus and the amo1 locus has been characterized. Four barley genotypes, the wild type, sex6, amo1, and the amo1sex6 double mutant, were generated by backcrossing the sex6 mutation present in Himalaya292 into the amo1 ‘high amylose Glacier’. The wild type, amo1, and sex6 genotypes gave starch phenotypes consistent with previous studies. However, the amo1sex6 double mutant yielded an unexpected phenotype, a significant increase in starch content relative to the sex6 phenotype. Amylose content (as a percentage of starch) was not increased above the level observed for the sex6 mutation alone; however, on a per seed basis, grain from lines containing the amo1 mutation (amo1 mutants and amo1sex6 double mutants) synthesize significantly more amylose than the wild-type lines and sex6 mutants. The level of granule-bound starch synthase I (GBSSI) protein in starch granules is increased in lines containing the amo1 mutation (amo1 and amo1sex6). In the amo1 genotype, starch synthase I (SSI), SSIIa, starch branching enzyme IIa (SBEIIa), and SBEIIb also markedly increased in the starch granules. Genetic mapping studies indicate that the ssIIIa gene is tightly linked to the amo1 locus, and the SSIIIa protein from the amo1 mutant has a leucine to arginine residue substitution in a conserved domain. Zymogram analysis indicates that the amo1 phenotype is not a consequence of total loss of enzymatic activity although it remains possible that the amo1 phenotype is underpinned by a more subtle change. It is therefore proposed that amo1 may be a negative regulator of other genes of starch synthesis. PMID:21813797

  10. In vitro digestibility and glycemic response of potato starch is related to granule size and degree of gelatinization.

    PubMed

    Parada, Javier; Aguilera, José M

    2009-01-01

    Starch granule microstructure affects the digestion of starch and its nutritional impact; however, the exact relationship between both factors is not clear. This study reports quantitative relationships between granule size (length and polygonal area), degree of gelatinization (DG), in vitro digestibility (by enzymatic methods), and glycemic response of potato starch granules gelatinized to various extents by heating at several constant temperatures in the range of 55 to 65 degrees C. DG measured by differential scanning calorimetry was closely related with heating temperature (R(2)= 0.997), size parameters of granules (measured by image analysis), in vitro digestion, and in vivo glycemic response (R(2) of adjusted models > 0.9); shape parameters of granules (measured by image analysis) were not related with DG. Results demonstrate that DG of starch strongly affects its digestibility in vitro, and may influence the postpandrial glycemic response. Future studies should be performed to investigate the effect of potato starch gelatinization on the nutritional impact at other temperatures and in more complex matrices.

  11. Controlled peeling of the surfaces of starch granules by gelatinization in aqueous dimethyl sulfoxide at selected temperatures.

    PubMed

    Mukerjea, Romila; Mukerjea, Rupendra; Robyt, John F

    2006-05-01

    Microscopic examination of starch granules in 90:10 (v/v) Me(2)SO-H(2)O indicated that the granules were slowly being gelatinized from their surfaces. The rate of gelatinization was dependent on two variables: (1) the amount of water in Me(2)SO and (2) the temperature. An increase of water in Me(2)SO and/or an increase in temperature increased the rate of gelatinization and vice versa. Specific ratios of Me(2)SO and H(2)O (85:15-95:5) and temperatures (0-15 degrees C) were found to give controlled sequential peeling/gelatinization of eight kinds of starch granules in 1-12h, with amounts of 10-25% gelatinization per hour. It was observed that the percent of starch granule remaining versus time gave curves that were linear and others that had linear parts separated by one or more abrupt changes. No two starches had a similar gelatinization curve for the same two conditions of the amount of water and the temperature. It is hypothesized that these curves reflect different structural characteristics for the individual kinds of starch granules.

  12. Digestion of Starch Granules from Maize, Potato and Wheat by Larvae of the the Yellow Mealworm, Tenebrio molitor and the Mexican Bean Weevil, Zabrotes subfasciatus

    PubMed Central

    Meireles, Elaine A.; Carneiro, Cíntia N. B.; DaMatta, Renato A.; Samuels, Richard I.; Silva, Carlos P.

    2009-01-01

    Scanning electron microscopy images were taken of starch granules from different sources following exposure in vivo and in vitro to gut α-amylases isolated from Tenebrio molitor L. (Coleoptera: Tenebrionidae) and Zabrotes subfasciatus Boheman (Coleoptera: Bruchidae). One α-amylase was isolated from whole larval midguts of T. molitor using non-denaturing SDS-PAGE, while two other α-amylase fractions were isolated from whole larval midguts of Z. subfasciatus using hydrophobic interaction chromatography., Digested starch granules from larvae fed on maize, potato or wheat were isolated from midgut contents. Combinations of starch granules with isolated α-amylases from both species showed similar patterns of granule degradation. In vitro enzymatic degradation of maize starch granules by the three different α-amylase fractions began by creating small holes and crater-like areas on the surface of the granules. Over time, these holes increased in number and area resulting in extensive degradation of the granule structure. Granules from potato did not show formation of pits and craters on their surface, but presented extensive erosion in their interior. For all types of starch, as soon as the interior of the starch granule was reached, the inner layers of amylose and amylopectin were differentially hydrolyzed, resulting in a striated pattern. These data support the hypothesis that the pattern of starch degradation depends more on the granule type than on the α-amylase involved. PMID:19619014

  13. Digestion of starch granules from maize, potato and wheat by larvae of the the yellow mealworm, Tenebrio molitor and the Mexican bean weevil, Zabrotes subfasciatus.

    PubMed

    Meireles, Elaine A; Carneiro, Cíntia N B; DaMatta, Renato A; Samuels, Richard I; Silva, Carlos P

    2009-01-01

    Scanning electron microscopy images were taken of starch granules from different sources following exposure in vivo and in vitro to gut alpha-amylases isolated from Tenebrio molitor L. (Coleoptera: Tenebrionidae) and Zabrotes subfasciatus Boheman (Coleoptera: Bruchidae). One alpha-amylase was isolated from whole larval midguts of T. molitor using non-denaturing SDS-PAGE, while two other alpha-amylase fractions were isolated from whole larval midguts of Z. subfasciatus using hydrophobic interaction chromatography., Digested starch granules from larvae fed on maize, potato or wheat were isolated from midgut contents. Combinations of starch granules with isolated alpha-amylases from both species showed similar patterns of granule degradation. In vitro enzymatic degradation of maize starch granules by the three different alpha-amylase fractions began by creating small holes and crater-like areas on the surface of the granules. Over time, these holes increased in number and area resulting in extensive degradation of the granule structure. Granules from potato did not show formation of pits and craters on their surface, but presented extensive erosion in their interior. For all types of starch, as soon as the interior of the starch granule was reached, the inner layers of amylose and amylopectin were differentially hydrolyzed, resulting in a striated pattern. These data support the hypothesis that the pattern of starch degradation depends more on the granule type than on the alpha-amylase involved.

  14. Starch granule evidence for the earliest potato use in North America.

    PubMed

    Louderback, Lisbeth A; Pavlik, Bruce M

    2017-07-18

    The prehistory of wild potato use, leading to its domestication and diversification, has been well-documented in, and confined to, South America. At least 20 tuber-bearing, wild species of Solanum are known from North and Central America, yet their importance in ancient diets has never been assessed from the archaeological record. Here, we report the earliest evidence of wild potato use in North America at 10,900-10,100 calendar years (cal) B.P. in the form of well-preserved starch granules extracted from ground stone tools at North Creek Shelter, southern Utah. These granules have been identified as those of Solanum jamesii Torr. (Four Corners potato), a tuber-bearing species native to the American Southwest. Identification was based on applying five strictly defined diagnostic characteristics (eccentric hilum, longitudinal fissure, lack of fissure branching, fissure ratio, and maximum granule size) to each of 323 archaeological granules. Of those, nine were definitively assigned to S. jamesii based on possession of all characteristics, and another 61 were either likely or possibly S. jamesii depending on the number of characteristics they possessed. The oldest granules were found in substratum 4k (10,900-10,100 cal B.P.). Younger deposits, dating to ∼6,900 cal B.P., also contained tools with S. jamesii granules, indicating at least 4,000 y of intermittent use. Ethnographic and historical accounts extend the period of use to more than 10,000 y. The question then arises as to whether some S. jamesii populations could have undergone transport, cultivation, and eventual domestication over such a long period of time.

  15. Three-dimensional structural imaging of starch granules by second-harmonic generation circular dichroism.

    PubMed

    Zhuo, G-Y; Lee, H; Hsu, K-J; Huttunen, M J; Kauranen, M; Lin, Y-Y; Chu, S-W

    2014-03-01

    Chirality is one of the most fundamental and essential structural properties of biological molecules. Many important biological molecules including amino acids and polysaccharides are intrinsically chiral. Conventionally, chiral species can be distinguished by interaction with circularly polarized light, and circular dichroism is one of the best-known approaches for chirality detection. As a linear optical process, circular dichroism suffers from very low signal contrast and lack of spatial resolution in the axial direction. It has been demonstrated that by incorporating nonlinear interaction with circularly polarized excitation, second-harmonic generation circular dichroism can provide much higher signal contrast. However, previous circular dichroism and second-harmonic generation circular dichroism studies are mostly limited to probe chiralities at surfaces and interfaces. It is known that second-harmonic generation, as a second-order nonlinear optical effect, provides excellent optical sectioning capability when combined with a laser-scanning microscope. In this work, we combine the axial resolving power of second-harmonic generation and chiral sensitivity of second-harmonic generation circular dichroism to realize three-dimensional chiral detection in biological tissues. Within the point spread function of a tight focus, second-harmonic generation circular dichroism could arise from the macroscopic supramolecular packing as well as the microscopic intramolecular chirality, so our aim is to clarify the origins of second-harmonic generation circular dichroism response in complicated three-dimensional biological systems. The sample we use is starch granules whose second-harmonic generation-active molecules are amylopectin with both microscopic chirality due to its helical structure and macroscopic chirality due to its crystallized packing. We found that in a starch granule, the second-harmonic generation for right-handed circularly polarized excitation is

  16. A soluble starch synthase I gene, IbSSI, alters the content, composition, granule size and structure of starch in transgenic sweet potato.

    PubMed

    Wang, Yannan; Li, Yan; Zhang, Huan; Zhai, Hong; Liu, Qingchang; He, Shaozhen

    2017-05-24

    Soluble starch synthase I (SSI) is a key enzyme in the biosynthesis of plant amylopectin. In this study, the gene named IbSSI, was cloned from sweet potato, an important starch crop. A high expression level of IbSSI was detected in the leaves and storage roots of the sweet potato. Its overexpression significantly increased the content and granule size of starch and the proportion of amylopectin by up-regulating starch biosynthetic genes in the transgenic plants compared with wild-type plants (WT) and RNA interference plants. The frequency of chains with degree of polymerization (DP) 5-8 decreased in the amylopectin fraction of starch, whereas the proportion of chains with DP 9-25 increased in the IbSSI-overexpressing plants compared with WT plants. Further analysis demonstrated that IbSSI was responsible for the synthesis of chains with DP ranging from 9 to 17, which represents a different chain length spectrum in vivo from its counterparts in rice and wheat. These findings suggest that the IbSSI gene plays important roles in determining the content, composition, granule size and structure of starch in sweet potato. This gene may be utilized to improve the content and quality of starch in sweet potato and other plants.

  17. In vitro amylolysis of pulse and hylon VII starches explained in terms of their composition, morphology, granule architecture and interaction between hydrolysed starch chains.

    PubMed

    Maaran, S; Hoover, R; Vamadevan, V; Waduge, R N; Liu, Q

    2016-02-01

    The objective of this study was to understand the factors underlying the susceptibility of pulse (lablab bean, navy bean, rice bean, tepary bean, velvet bean, and wrinkled pea) and hylon VII starches towards in vitro hydrolysis by the combined action of pancreatin and amyloglucosidase. The time taken to reach an equivalent level of hydrolysis (50%) varied significantly among the starches. Changes to molecular order, crystallinity, double helical content, radial orientation of starch chains (polarized light), enthalpy and apparent amylose content during the progress of hydrolysis showed that rate and extent of hydrolysis were influenced both by the structure of the native starches at different levels (molecular, mesoscopic, microscopic) of granule organization, and by the extent of retrogradation between hydrolysed starch chains.

  18. Novel, Starch-Like Polysaccharides Are Synthesized by an Unbound Form of Granule-Bound Starch Synthase in Glycogen-Accumulating Mutants of Chlamydomonas reinhardtii1

    PubMed Central

    Dauvillée, David; Colleoni, Christophe; Shaw, Eudean; Mouille, Gregory; D'Hulst, Christophe; Morell, Matthew; Samuel, Michael S.; Bouchet, Brigitte; Gallant, Daniel J.; Sinskey, Anthony; Ball, Steven

    1999-01-01

    In vascular plants, mutations leading to a defect in debranching enzyme lead to the simultaneous synthesis of glycogen-like material and normal starch. In Chlamydomonas reinhardtii comparable defects lead to the replacement of starch by phytoglycogen. Therefore, debranching was proposed to define a mandatory step for starch biosynthesis. We now report the characterization of small amounts of an insoluble, amylose-like material found in the mutant algae. This novel, starch-like material was shown to be entirely dependent on the presence of granule-bound starch synthase (GBSSI), the enzyme responsible for amylose synthesis in plants. However, enzyme activity assays, solubilization of proteins from the granule, and western blots all failed to detect GBSSI within the insoluble polysaccharide matrix. The glycogen-like polysaccharides produced in the absence of GBSSI were proved to be qualitatively and quantitatively identical to those produced in its presence. Therefore, we propose that GBSSI requires the presence of crystalline amylopectin for granule binding and that the synthesis of amylose-like material can proceed at low levels without the binding of GBSSI to the polysaccharide matrix. Our results confirm that amylopectin synthesis is completely blocked in debranching-enzyme-defective mutants of C. reinhardtii. PMID:9880375

  19. The activity of barley alpha-amylase on starch granules is enhanced by fusion of a starch binding domain from Aspergillus niger glucoamylase.

    PubMed

    Juge, Nathalie; Nøhr, Jane; Le Gal-Coëffet, Marie-Françoise; Kramhøft, Birte; Furniss, Caroline S M; Planchot, Véronique; Archer, David B; Williamson, Gary; Svensson, Birte

    2006-02-01

    High affinity for starch granules of certain amylolytic enzymes is mediated by a separate starch binding domain (SBD). In Aspergillus niger glucoamylase (GA-I), a 70 amino acid O-glycosylated peptide linker connects SBD with the catalytic domain. A gene was constructed to encode barley alpha-amylase 1 (AMY1) fused C-terminally to this SBD via a 37 residue GA-I linker segment. AMY1-SBD was expressed in A. niger, secreted using the AMY1 signal sequence at 25 mg x L(-1) and purified in 50% yield. AMY1-SBD contained 23% carbohydrate and consisted of correctly N-terminally processed multiple forms of isoelectric points in the range 4.1-5.2. Activity and apparent affinity of AMY1-SBD (50 nM) for barley starch granules of 0.034 U x nmol(-1) and K(d) = 0.13 mg x mL(-1), respectively, were both improved with respect to the values 0.015 U x nmol(-1) and 0.67 mg x mL(-1) for rAMY1 (recombinant AMY1 produced in A. niger). AMY1-SBD showed a 2-fold increased activity for soluble starch at low (0.5%) but not at high (1%) concentration. AMY1-SBD hydrolysed amylose DP440 with an increased degree of multiple attack of 3 compared to 1.9 for rAMY1. Remarkably, at low concentration (2 nM), AMY1-SBD hydrolysed barley starch granules 15-fold faster than rAMY1, while higher amounts of AMY-SBD caused molecular overcrowding of the starch granule surface.

  20. Development of hydrocolloid microgels as starch granule mimetics: Hydrogel particles fabricated from gelatin and pectin.

    PubMed

    Wu, Bi-Cheng; McClements, David Julian

    2015-12-01

    In this study, hydrocolloid microgels fabricated by electrostatic complexation of gelatin and pectin were developed as possible starch mimetics. The impact of covalent cross-linking on the physicochemical and structural properties of the microgels was investigated. Microgels were formed by acidifying a mixture of gelatin (0.5wt.%) and pectin (0.01wt.%) from pH10 to 5 at 40°C, followed by cross-linking with glutaraldehyde (0 to 2mM). At low glutaraldehyde levels (<0.5mM), cross-linking occurred primarily within the microgels and did not affect particle dimensions, whereas at high levels (2mM), cross-linking connected adjacent microgels leading to the formation of large flocs. Rheological and microscopic analysis showed that the degree of cross-linking impacted the thermal transitions of the microgels. A simulated oral processing study indicated that the melt-in-the-mouth behavior of the hydrocolloid microgels could be made to be similar to that of starch granules by controlling the degree of cross-linking. This study may be useful for designing starch mimetics with improved texture-modifying properties and reduced-calories. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Characterization of Function of the GlgA2 Glycogen/Starch Synthase in Cyanobacterium sp. Clg1 Highlights Convergent Evolution of Glycogen Metabolism into Starch Granule Aggregation.

    PubMed

    Kadouche, Derifa; Ducatez, Mathieu; Cenci, Ugo; Tirtiaux, Catherine; Suzuki, Eiji; Nakamura, Yasunori; Putaux, Jean-Luc; Terrasson, Amandine Durand; Diaz-Troya, Sandra; Florencio, Francisco Javier; Arias, Maria Cecilia; Striebeck, Alexander; Palcic, Monica; Ball, Steven G; Colleoni, Christophe

    2016-07-01

    At variance with the starch-accumulating plants and most of the glycogen-accumulating cyanobacteria, Cyanobacterium sp. CLg1 synthesizes both glycogen and starch. We now report the selection of a starchless mutant of this cyanobacterium that retains wild-type amounts of glycogen. Unlike other mutants of this type found in plants and cyanobacteria, this mutant proved to be selectively defective for one of the two types of glycogen/starch synthase: GlgA2. This enzyme is phylogenetically related to the previously reported SSIII/SSIV starch synthase that is thought to be involved in starch granule seeding in plants. This suggests that, in addition to the selective polysaccharide debranching demonstrated to be responsible for starch rather than glycogen synthesis, the nature and properties of the elongation enzyme define a novel determinant of starch versus glycogen accumulation. We show that the phylogenies of GlgA2 and of 16S ribosomal RNA display significant congruence. This suggests that this enzyme evolved together with cyanobacteria when they diversified over 2 billion years ago. However, cyanobacteria can be ruled out as direct progenitors of the SSIII/SSIV ancestral gene found in Archaeplastida. Hence, both cyanobacteria and plants recruited similar enzymes independently to perform analogous tasks, further emphasizing the importance of convergent evolution in the appearance of starch from a preexisting glycogen metabolism network.

  2. Optimization of experimental conditions for the separation of small and large starch granules by gravitational field-flow fractionation.

    PubMed

    Janousková, J; Budinská, M; Plocková, J; Chmelík, J

    2001-04-20

    Separation of small and large barley starch granules by gravitational field-flow fractionation was investigated from the point of view of sample pre-treatment, amount of injected sample, and elution conditions. The sample pre-treatment study resulted in the conclusion that it is reasonable to soak the starch granules for at least 24 h prior to separation. The experiments with different amounts of injected sample show that it is possible to increase as well as decrease twofold the sample amount usually used without any change in retention ratios. The implementation of flow-rate gradients for elution of the starch granules reduced total separation time. However, the applied flow-rate gradients did not improve the resolution of peaks A and B compared with the generally used constant flow-rate. Thus, for barley starch granules, the constant flow-rates within the range from 0.8 to 1.0 ml/min seem to provide the best compromise of total separation time, peak resolution and instrumental expense.

  3. Coaggregation of mineral filler particles and starch granules as a basis for improving filler-fiber interaction in paper production.

    PubMed

    Li, Ting; Fan, Jun; Chen, Wensen; Shu, Jiayan; Qian, Xueren; Wei, Haifeng; Wang, Qingwen; Shen, Jing

    2016-09-20

    The sustainable, efficient use of renewable bio-based additives in the production of various materials fits well into the concept of sustainability. Here, the concept of coaggregation of mineral filler particles and starch granules for improving filler-fiber interaction in paper-based cellulosic networks is presented. Coaggregation of precipitated calcium carbonate filler particles and uncooked, unmodified corn starch granules by cationic polyacrylamide (a cationic high molecular weight polymer flocculant) in combination with bentonite (an anionic microparticle) prior to addition to cellulosic fiber slurry delivered enhanced filler bondability with cellulosic fibers. For instance, under the conditions studied, preaggregation resulted in an increase in filler bondability factor from 9.24 to 15.21 at starch dosage of 1% (on the basis of the dry weight of papermaking stock). The swelling and gelatinization of the starch granules in starch-filler preaggregates or hybrids enabled the "bridging" of the gaps in cellulosic networks, leading to structural consolidation and strength enhancement. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Size, shape and surface morphology of starch granules from Norway spruce needles revealed by transmission electron microscopy and atomic force microscopy: effects of elevated CO(2) concentration.

    PubMed

    Cabálková, Jana; Pribyl, Jan; Skládal, Petr; Kulich, Pavel; Chmelík, Josef

    2008-10-01

    We compared the effects of ambient (350 ppm) and elevated CO(2) concentration (700 ppm) on the size and shape of starch granules in Norway spruce (Picea abies (L.) Karst.) needles during one growing season. Starch granules were isolated from needles by alkaline digestion and analyzed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Measurements made with a particle size analyzer indicated that starch granules ranged between 0.5 and 10 microm. Granule size and shape varied according to needle developmental stage and CO(2) concentration. Generally, elevated CO(2) concentration increased the size of the starch granules. Fine surface structures (< 10 nm in size) studied by AFM were characterized by the presence of protrusions, furrows and pores.

  5. Study of heat-moisture treatment of potato starch granules by chemical surface gelatinization.

    PubMed

    Bartz, Josiane; da Rosa Zavareze, Elessandra; Dias, Alvaro Renato Guerra

    2017-08-01

    Native potato starch was subjected to heat-moisture treatment (HMT) at 12%, 15%, 18%, 21%, and 24% of moisture content at 110 °C for 1 h, and the effects on morphology, structure, and thermal and physicochemical properties were investigated. To reveal the internal structure, 30% and 50% of the granular surface were removed by chemical surface gelatinization in concentrated LiCl solution. At moisture contents of 12% and 15%, HTM reduced the gelatinization temperatures and relative crystallinity of the starches, while at moisture contents of 21% and 24 % both increased. The alterations on morphology, X-ray pattern, physicochemical properties, and increase of amylose content were more intense with the increase of moisture content of HMT. The removal of granular layers showed that the changes promoted by HMT occur throughout the whole granule and were pronounced at the core or peripheral region, depending of the moisture content applied during HMT. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  6. High-pressure potato starch granule gelatinization: synchrotron radiation micro-SAXS/WAXS using a diamond anvil cell.

    PubMed

    Gebhardt, R; Hanfland, M; Mezouar, M; Riekel, C

    2007-07-01

    Potato starch granules have been examined by synchrotron radiation small- and wide-angle scattering in a diamond anvil cell (DAC) up to 750 MPa. Use of a 1 microm synchrotron radiation beam allowed the mapping of individual granules at several pressure levels. The data collected at 183 MPa show an increase in the a axis and lamellar period from the edge to the center of the granule, probably due to a gradient in water content of the crystalline and amorphous lamellae. The average granules radius increases up to the onset of gelatinization at about 500 MPa, but the a axis and the lamellar periodicity remain constant or even show a decrease, suggesting an initial hydration of amorphous growth rings. The onset of gelatinization is accompanied by (i) an increase in the average a axis and lamellar periodicity, (ii) the appearance of an equatorial SAXS streak, and (iii) additional short-range order peaks.

  7. Physical structure and absorption properties of tailor-made porous starch granules produced by selected amylolytic enzymes.

    PubMed

    Jung, Yi-Seul; Lee, Byung-Hoo; Yoo, Sang-Ho

    2017-01-01

    Porous starch granules (PSGs) with various pores and cavity sizes were prepared by amylolysis enzymes. The greatest hydrolysis rate on corn starch granule was observed with α-amylase, followed by gluco- and β-amylases. Temperature increase enhanced glucoamylase reaction rate more drastically than other enzyme treatments. Final hydrolysis level with glucoamylase reached to 66.9%, close to 67.5% of α-amylolysis. The α-amylase-treated PSGs displayed the greatest pore size and ratio of cavity-to-granule diameters. Gelatinization onset temperatures of PSGs increased to 72.1 (α-), 68.7 (β-), and 68.1°C (gluco-amylolysis) after 8 h; enthalpy changes of β- and gluco-amylase-treated PSGs increased to 13.4, and 13.1 J/g but α-amylase-treated one showed slightly reduced value of 8.5 J/g. Water holding capacities of PSGs were 209.7 (α-), 94.6 (β-), and 133.8% (gluco-amylolysis), and the untreated control had 89.1%; oil holding capacities of them showed 304.5, 182.7, and 211.5%, respectively, while the untreated control had 161.8%. Thus, enzyme types and their reaction conditions can be applied to generate desirable cavity and pore sizes in starch granules. This biocatalytic approach could contribute to develop tailor-made PSGs with distinct internal structure for specific uses in wide range of food, pharmaceutical and other industrial applications.

  8. Glucose 1-phosphate is efficiently taken up by potato (Solanum tuberosum) tuber parenchyma cells and converted to reserve starch granules.

    PubMed

    Fettke, Joerg; Albrecht, Tanja; Hejazi, Mahdi; Mahlow, Sebastian; Nakamura, Yasunori; Steup, Martin

    2010-02-01

    Reserve starch is an important plant product but the actual biosynthetic process is not yet fully understood. Potato (Solanum tuberosum) tuber discs from various transgenic plants were used to analyse the conversion of external sugars or sugar derivatives to starch. By using in vitro assays, a direct glucosyl transfer from glucose 1-phosphate to native starch granules as mediated by recombinant plastidial phosphorylase was analysed. Compared with labelled glucose, glucose 6-phosphate or sucrose, tuber discs converted externally supplied [(14)C]glucose 1-phosphate into starch at a much higher rate. Likewise, tuber discs from transgenic lines with a strongly reduced expression of cytosolic phosphoglucomutase, phosphorylase or transglucosidase converted glucose 1-phosphate to starch with the same or even an increased rate compared with the wild-type. Similar results were obtained with transgenic potato lines possessing a strongly reduced activity of both the cytosolic and the plastidial phosphoglucomutase. Starch labelling was, however, significantly diminished in transgenic lines, with a reduced concentration of the plastidial phosphorylase isozymes. Two distinct paths of reserve starch biosynthesis are proposed that explain, at a biochemical level, the phenotype of several transgenic plant lines.

  9. Contribution of the net charge to the regulatory effects of amino acids and epsilon-poly(L-lysine) on the gelatinization behavior of potato starch granules.

    PubMed

    Ito, Azusa; Hattori, Makoto; Yoshida, Tadashi; Takahashi, Koji

    2006-01-01

    The effects of lysine (Lys), monosodium glutamate (GluNa), glycine, alanine and epsilon-poly(L-lysine) (PL) with different degrees of polymerization on the gelatinization behavior of potato starch granules were investigated by DSC, viscosity and swelling measurements, microscopic observation, and measurement of the retained amino acid amount to clarify the contribution of the net charge to their regulatory effects on the gelatinization behavior. The amino acids and PL each contributed to an increase in the gelatinization temperature, and a decrease in the peak viscosity and swelling. These effects strongly depended on the absolute value of their net charge. The disappearance of a negative or positive net charge by adjusting the pH value weakened the contribution. The swelling index and size of the potato starch granules changed according to replacement of the swelling medium. The amino acids and PL were easily retained by the swollen potato starch granules according to replacement of the outer solution of the starch granules.

  10. OsBT1 encodes an ADP-glucose transporter involved in starch synthesis and compound granule formation in rice endosperm

    PubMed Central

    Li, Sanfeng; Wei, Xiangjin; Ren, Yulong; Qiu, Jiehua; Jiao, Guiai; Guo, Xiuping; Tang, Shaoqing; Wan, Jianmin; Hu, Peisong

    2017-01-01

    Starch is the main storage carbohydrate in higher plants. Although several enzymes and regulators for starch biosynthesis have been characterized, a complete regulatory network for starch synthesis in cereal seeds remains elusive. Here, we report the identification and characterization of the rice Brittle1 (OsBT1) gene, which is expressed specifically in the developing endosperm. The osbt1 mutant showed a white-core endosperm and a significantly lower grain weight than the wild-type. The formation and development of compound starch granules in osbt1 was obviously defective: the amyloplast was disintegrated at early developmental stages and the starch granules were disperse and not compound in the endosperm cells in the centre region of osbt1 seeds. The total starch content and amylose content was decreased and the physicochemical properties of starch were altered. Moreover, the degree of polymerization (DP) of amylopectin in osbt1 was remarkably different from that of wild-type. Map-based cloning of OsBT1 indicated that it encodes a putatively ADP-glucose transporter. OsBT1 coded protein localizes in the amyloplast envelope membrane. Furthermore, the expression of starch synthesis related genes was also altered in the osbt1 mutant. These findings indicate that OsBT1 plays an important role in starch synthesis and the formation of compound starch granules. PMID:28054650

  11. Structural changes from native waxy maize starch granules to cold-water-soluble pyrodextrin during thermal treatment.

    PubMed

    Bai, Yanjie; Cai, Liming; Doutch, James; Gilbert, Elliot P; Shi, Yong-Cheng

    2014-05-07

    The structural changes occurring during the thermal conversion of insoluble native waxy maize starch granules to cold-water-soluble pyrodextrin under acidic conditions have been investigated by multiple techniques, including synchrotron small-angle X-ray scattering (SAXS), wide-angle X-ray scattering, differential scanning calorimetry, and gel permeation chromatography. In a mixture of water/glycerol (20/80, w/w), the SAXS characteristic peak at ca. 0.6 nm(-1) decreased in intensity as pyrodextrin solubility increased. The peak disappeared as pyrodextrin solubility reached 100%. Starch crystal size, its associated melting enthalpy, and pyrodextrin molecular size decreased as solubility increased. Although starch structure changed during thermal conversion, the pyrodextrins appeared identical to the native starch when observed in glycerol under a normal and polarized light microscope. It is proposed that the starch backbone is hydrolyzed by acid in the amorphous region and the crystalline region with starch molecules being hydrolyzed into small molecular fractions but persisting in a radial arrangement.

  12. Biochemical Evidence for the Role of the Waxy Protein from Pea (Pisum sativum L.) as a Granule-Bound Starch Synthase.

    PubMed

    Sivak, M. N.; Wagner, M.; Preiss, J.

    1993-12-01

    Proteins were solubilized from starch extracted from developing pea (Pisum sativum L.) embryos and chromatography of these proteins on a Mono-Q column separated two peaks of starch synthase activity. The major activity peak comprised more than 80% of the total activity. This fraction contained only the Waxy protein, as shown by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate followed by staining for proteins or by immunoblot. A 77-kD polypeptide associated with the starch granules and presumed by others to be a starch synthase could not be detected in any of the active fractions. The native molecular weight of the solubilized starch synthase was 59,600 [plus or minus] 1700 as determined by sucrose density gradient. It is concluded that in pea seeds the Waxy protein and the starch synthase bound to the granule are the same protein.

  13. Raster microdiffraction with synchrotron radiation of hydrated biopolymers with nanometre step-resolution: case study of starch granules.

    PubMed

    Riekel, C; Burghammer, M; Davies, R J; Di Cola, E; König, C; Lemke, H T; Putaux, J L; Schöder, S

    2010-11-01

    X-ray radiation damage propagation is explored for hydrated starch granules in order to reduce the step resolution in raster-microdiffraction experiments to the nanometre range. Radiation damage was induced by synchrotron radiation microbeams of 5, 1 and 0.3 µm size with ∼0.1 nm wavelength in B-type potato, Canna edulis and Phajus grandifolius starch granules. A total loss of crystallinity of granules immersed in water was found at a dose of ∼1.3 photons nm(-3). The temperature dependence of radiation damage suggests that primary radiation damage prevails up to about 120 K while secondary radiation damage becomes effective at higher temperatures. Primary radiation damage remains confined to the beam track at 100 K. Propagation of radiation damage beyond the beam track at room temperature is assumed to be due to reactive species generated principally by water radiolysis induced by photoelectrons. By careful dose selection during data collection, raster scans with 500 nm step-resolution could be performed for granules immersed in water.

  14. Raster microdiffraction with synchrotron radiation of hydrated biopolymers with nanometre step-resolution: case study of starch granules

    PubMed Central

    Riekel, C.; Burghammer, M.; Davies, R. J.; Di Cola, E.; König, C.; Lemke, H.T.; Putaux, J.-L.; Schöder, S.

    2010-01-01

    X-ray radiation damage propagation is explored for hydrated starch granules in order to reduce the step resolution in raster-microdiffraction experiments to the nanometre range. Radiation damage was induced by synchrotron radiation microbeams of 5, 1 and 0.3 µm size with ∼0.1 nm wavelength in B-type potato, Canna edulis and Phajus grandifolius starch granules. A total loss of crystallinity of granules immersed in water was found at a dose of ∼1.3 photons nm−3. The temperature dependence of radiation damage suggests that primary radiation damage prevails up to about 120 K while secondary radiation damage becomes effective at higher temperatures. Primary radiation damage remains confined to the beam track at 100 K. Propagation of radiation damage beyond the beam track at room temperature is assumed to be due to reactive species generated principally by water radiolysis induced by photoelectrons. By careful dose selection during data collection, raster scans with 500 nm step-resolution could be performed for granules immersed in water. PMID:20975219

  15. Correlated changes in structure and viscosity during gelatinization and gelation of tapioca starch granules.

    PubMed

    Huang, Hsien-Kai; Sheu, Hwo-Shuenn; Chuang, Wei-Tsung; Jeng, U-Ser; Su, An-Chung; Wu, Wei-Ru; Liao, Kuei-Fen; Chen, Chun-Yu; Chang, Shing-Yun; Lai, Hsi-Mei

    2014-11-01

    Melting of native tapioca starch granules in aqueous pastes upon heating is observed in situ using simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS) and solution viscometry. Correlated structure and viscosity changes suggest closely associated amylose and amylopectin chains in the semicrystalline layers, and the release of amylose chains for enhanced solution viscosity occurs largely after melting of the semicrystalline structure. Before melting, WAXS results reveal mixed crystals of A- and B-types (∼4:1 by weight), whereas SAXS results indicate that the semicrystalline layers are composed of lamellar blocklets of ca 43 nm domain size, with polydisperse crystalline (≃7.5 nm) and amorphous (≃1.1 nm) layers alternatively assembled into a lamellar spacing of ≃8.6 nm with 20% polydispersity. Upon melting, the semicrystalline lamellae disintegrate into disperse and molten amylopectin nanoclusters with dissolved and partially untangled amylose chains in the aqueous matrix which leads to increased solution viscosity. During subsequent cooling, gelation starts at around 347 K; successively increased solution viscosity coincides with the development of nanocluster aggregation to a fractal dimension ≃2.3 at 303 K, signifying increasing intercluster association through collapsed amylose chains owing to decreased solvency of the aqueous medium with decreasing temperature.

  16. Correlated changes in structure and viscosity during gelatinization and gelation of tapioca starch granules

    PubMed Central

    Huang, Hsien-Kai; Sheu, Hwo-Shuenn; Chuang, Wei-Tsung; Jeng, U-Ser; Su, An-Chung; Wu, Wei-Ru; Liao, Kuei-Fen; Chen, Chun-Yu; Chang, Shing-Yun; Lai, Hsi-Mei

    2014-01-01

    Melting of native tapioca starch granules in aqueous pastes upon heating is observed in situ using simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS) and solution viscometry. Correlated structure and viscosity changes suggest closely associated amylose and amylopectin chains in the semicrystalline layers, and the release of amylose chains for enhanced solution viscosity occurs largely after melting of the semicrystalline structure. Before melting, WAXS results reveal mixed crystals of A- and B-types (∼4:1 by weight), whereas SAXS results indicate that the semicrystalline layers are composed of lamellar blocklets of ca 43 nm domain size, with polydisperse crystalline (≃7.5 nm) and amorphous (≃1.1 nm) layers alternatively assembled into a lamellar spacing of ≃8.6 nm with 20% polydispersity. Upon melting, the semicrystalline lamellae disintegrate into disperse and molten amylopectin nanoclusters with dissolved and partially untangled amylose chains in the aqueous matrix which leads to increased solution viscosity. During subsequent cooling, gelation starts at around 347 K; successively increased solution viscosity coincides with the development of nanocluster aggregation to a fractal dimension ≃2.3 at 303 K, signifying increasing intercluster association through collapsed amylose chains owing to decreased solvency of the aqueous medium with decreasing temperature. PMID:25485122

  17. Gamma irradiation of sorghum flour: Effects on microbial inactivation, amylase activity, fermentability, viscosity and starch granule structure

    NASA Astrophysics Data System (ADS)

    Mukisa, Ivan M.; Muyanja, Charles M. B. K.; Byaruhanga, Yusuf B.; Schüller, Reidar B.; Langsrud, Thor; Narvhus, Judith A.

    2012-03-01

    Malted and un-malted sorghum ( Sorghum bicolor (L.) Moench) flour was gamma irradiated with a dose of 10 kGy and then re-irradiated with 25 kGy. The effects of irradiation on microbial decontamination, amylase activity, fermentability (using an amylolytic L. plantarum MNC 21 strain), starch granule structure and viscosity were determined. Standard methods were used during determinations. The 10 kGy dose had no effect on microbial load of un-malted flour but reduced that of malted flour by 3 log cycles. Re-irradiation resulted in complete decontamination. Irradiation of malt caused a significant ( p<0.05) reduction in alpha and beta amylase activity (22% and 32%, respectively). Irradiation of un-malted flour increased the rates of utilization of glucose and maltose by 53% and 100%, respectively, during fermentation. However, microbial growth, rate of lactic acid production, final lactic acid concentration and pH were not affected. Starch granules appeared normal externally even after re-irradiation, however, granules ruptured and dissolved easily after hydration and gelatinization. Production of high dry matter density porridge (200 g dry matter/L) with a viscosity of 3500 cP was achieved by irradiation of un-malted flout at 10 kGy. Gamma irradiation can be used to decontaminate flours and could be utilized to produce weaning porridge from sorghum.

  18. Soft and Hard Textured Wheat Differ in Starch Properties as Indicated by Trimodal Distribution, Morphology, Thermal and Crystalline Properties

    PubMed Central

    Kumar, Rohit; Kumar, Aman; Sharma, Nand Kishor; Kaur, Navneet; Chunduri, Venkatesh; Chawla, Meenakshi; Sharma, Saloni; Singh, Kashmir; Garg, Monika

    2016-01-01

    Starch and proteins are major components in the wheat endosperm that affect its end product quality. Between the two textural classes of wheat i.e. hard and soft, starch granules are loosely bound with the lipids and proteins in soft wheat due to higher expression of interfering grain softness proteins. It might have impact on starch granules properties. In this work for the first time the physiochemical and structural properties of different sized starch granules (A-, B- and C-granules) were studied to understand the differences in starches with respect to soft and hard wheat. A-, B- and C-type granules were separated with >95% purity. Average number and proportion of A-, B-, and C-type granules was 18%, 56%, 26% and 76%, 19%, 5% respectively. All had symmetrical birefringence pattern with varied intensity. All displayed typical A-type crystallites. A-type granules also showed V-type crystallinity that is indicative of starch complexes with lipids and proteins. Granules differing in gelatinization temperature (ΔH) and transition temperature (ΔT), showed different enthalpy changes during heating. Substitution analysis indicated differences in relative substitution pattern of different starch granules. Birefringence, percentage crystallinity, transmittance, gelatinization enthalpy and substitution decreased in order of A>B>C being higher in hard wheat than soft wheat. Amylose content decreased in order of A>B>C being higher in soft wheat than hard wheat. Reconstitution experiment showed that starch properties could be manipulated by changing the composition of starch granules. Addition of A-granules to total starch significantly affected its thermal properties. Effect of A-granule addition was higher than B- and C-granules. Transmittance of the starch granules paste showed that starch granules of hard wheat formed clear paste. These results suggested that in addition to differences in protein concentration, hard and soft wheat lines have differences in starch

  19. Soft and Hard Textured Wheat Differ in Starch Properties as Indicated by Trimodal Distribution, Morphology, Thermal and Crystalline Properties.

    PubMed

    Kumar, Rohit; Kumar, Aman; Sharma, Nand Kishor; Kaur, Navneet; Chunduri, Venkatesh; Chawla, Meenakshi; Sharma, Saloni; Singh, Kashmir; Garg, Monika

    2016-01-01

    Starch and proteins are major components in the wheat endosperm that affect its end product quality. Between the two textural classes of wheat i.e. hard and soft, starch granules are loosely bound with the lipids and proteins in soft wheat due to higher expression of interfering grain softness proteins. It might have impact on starch granules properties. In this work for the first time the physiochemical and structural properties of different sized starch granules (A-, B- and C-granules) were studied to understand the differences in starches with respect to soft and hard wheat. A-, B- and C-type granules were separated with >95% purity. Average number and proportion of A-, B-, and C-type granules was 18%, 56%, 26% and 76%, 19%, 5% respectively. All had symmetrical birefringence pattern with varied intensity. All displayed typical A-type crystallites. A-type granules also showed V-type crystallinity that is indicative of starch complexes with lipids and proteins. Granules differing in gelatinization temperature (ΔH) and transition temperature (ΔT), showed different enthalpy changes during heating. Substitution analysis indicated differences in relative substitution pattern of different starch granules. Birefringence, percentage crystallinity, transmittance, gelatinization enthalpy and substitution decreased in order of A>B>C being higher in hard wheat than soft wheat. Amylose content decreased in order of A>B>C being higher in soft wheat than hard wheat. Reconstitution experiment showed that starch properties could be manipulated by changing the composition of starch granules. Addition of A-granules to total starch significantly affected its thermal properties. Effect of A-granule addition was higher than B- and C-granules. Transmittance of the starch granules paste showed that starch granules of hard wheat formed clear paste. These results suggested that in addition to differences in protein concentration, hard and soft wheat lines have differences in starch

  20. FLOURY ENDOSPERM6 encodes a CBM48 domain-containing protein involved in compound granule formation and starch synthesis in rice endosperm.

    PubMed

    Peng, Cheng; Wang, Yihua; Liu, Feng; Ren, Yulong; Zhou, Kunneng; Lv, Jia; Zheng, Ming; Zhao, Shaolu; Zhang, Long; Wang, Chunming; Jiang, Ling; Zhang, Xin; Guo, Xiuping; Bao, Yiqun; Wan, Jianmin

    2014-03-01

    Starch is the most widespread form of energy storage in the plant kingdom. Although many enzymes and related factors have been identified for starch biosynthesis, unknown players remain to be identified, given that it is a complicated and sophisticated process. The endosperm of rice (Oryza sativa) has been used for the study of starch synthesis. Here, we report the cloning and characterization of the FLOURY ENDOSPERM6 (FLO6) gene in rice. In the flo6 mutant, the starch content is decreased and the normal physicochemical features of starch are changed. Significantly, flo6 mutant endosperm cells show obvious defects in compound granule formation. Map-based cloning showed that FLO6 encodes a protein of unknown function. It harbors an N-terminal transit peptide that ensures its correct localization and functions in the plastid, and a C-terminal carbohydrate-binding module 48 (CBM48) domain that binds to starch. Furthermore, FLO6 can interact with isoamylase1 (ISA1) both in vitro and in vivo, whereas ISA1 does not bind to starch directly. We thus propose that FLO6 may act as a starch-binding protein involved in starch synthesis and compound granule formation through a direct interaction with ISA1 in developing rice seeds. Our data provide a novel insight into the role of proteins with the CBM48 domain in plant species. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  1. Relationships of damaged starch granules and particle size distribution with pasting and thermal profiles of milled MR263 rice flour.

    PubMed

    Asmeda, R; Noorlaila, A; Norziah, M H

    2016-01-15

    This research was conducted to investigate the effects of different grinding techniques (dry, semi-wet and wet) of milled rice grains on the damaged starch and particle size distribution of flour produced from a new variety, MR263, specifically related to the pasting and thermal profiles. The results indicated that grinding techniques significantly (p<0.05) affected starch damage content and particle size distribution of rice flour. Wet grinding process yields flour with lowest percentage of starch damage (7.37%) and finest average particle size (8.52μm). Pasting and gelatinization temperature was found in the range of 84.45-89.63°C and 59.86-75.31°C, respectively. Dry ground flour attained the lowest pasting and gelatinization temperature as shown by the thermal and pasting profiles. Correlation analysis revealed that percentage of damaged starch granules had a significant, negative relationship with pasting temperature while average particle size distribution had a significant, strong negative relationship with gelatinization temperature. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Expression of the Granule-Bound Starch Synthase I (Waxy) Gene from Snapdragon Is Developmentally and Circadian Clock Regulated1

    PubMed Central

    Mérida, Angel; Rodríguez-Galán, José M.; Vincent, Coral; Romero, José M.

    1999-01-01

    The granule-bound starch synthase I (GBSSI or waxy) enzyme catalyzes one of the enzymatic steps of starch synthesis. This enzyme is responsible for the synthesis of amylose and is also involved in building the final structure of amylopectin. Little is known about expression of GBSSI genes in tissues other than storage organs, such as seeds, endosperm, and tuber. We have isolated a gene encoding the GBSSI from snapdragon (Antirrhinum majus). This gene is present as a single copy in the snapdragon genome. There is a precise spatial and developmental regulation of its expression in flowers. GBSSI expression was observed in all floral whorls at early developmental stages, but it was restricted to carpel before anthesis. These results give new insights into the role of starch in later reproductive events such as seed filling. In leaves the mRNA level of GBSSI is regulated by an endogenous circadian clock, indicating that the transition from day to night may be accompanied by abolition of expression of starch synthesis genes. This mechanism does not operate in sink tissues such as roots when grown in the dark. PMID:10364391

  3. Effects of short-term high temperature on grain quality and starch granules of rice (Oryza sativa L.) at post-anthesis stage.

    PubMed

    Chen, Jianlin; Tang, Liang; Shi, Peihua; Yang, Baohua; Sun, Ting; Cao, Weixing; Zhu, Yan

    2017-03-01

    High temperature causes negative effects on grain yield and quality of rice (Oryza sativa L.). In this study, the effects of short-term high temperature (SHT) on grain quality and starch granules were investigated in two rice cultivars Nanjing 41 (NJ41, heat-sensitive) and Wuxiangjing 14 (WJ14, heat-tolerant) at post-anthesis stage (anthesis and early grain-filling stage). The results of rice quality analysis showed that chalky rate and chalkiness increased while brown rice rate, milled rice rate, and head rice rate decreased in two rice cultivars with the increase of high temperature and prolonged duration. Moreover, SHT stress reduced the accumulation of amylose as well as starch accumulation. The starch accumulation and eating quality were more sensitive to SHT than the appearance and milling quality. The starch structure data observed by scanning electron microscope further showed that the starch granules are arranged loosely and more single starch granules appeared after SHT treatment. The extent of change in rice quality and starch traits of WJ14 under SHT was lower than that of NJ41. The effects of SHT at anthesis stage were greater than that at grain-filling stage. Taken together, the results could help further understand the physiological and biochemical processes governing rice quality under high-temperature conditions.

  4. Alpha-amylase starch binding domains: cooperative effects of binding to starch granules of multiple tandemly arranged domains.

    PubMed

    Guillén, D; Santiago, M; Linares, L; Pérez, R; Morlon, J; Ruiz, B; Sánchez, S; Rodríguez-Sanoja, R

    2007-06-01

    The Lactobacillus amylovorus alpha-amylase starch binding domain (SBD) is a functional domain responsible for binding to insoluble starch. Structurally, this domain is dissimilar from other reported SBDs because it is composed of five identical tandem modules of 91 amino acids each. To understand adsorption phenomena specific to this SBD, the importance of their modular arrangement in relationship to binding ability was investigated. Peptides corresponding to one, two, three, four, or five modules were expressed as His-tagged proteins. Protein binding assays showed an increased capacity of adsorption as a function of the number of modules, suggesting that each unit of the SBD may act in an additive or synergic way to optimize binding to raw starch.

  5. Molecular Genetic Analysis of Glucan Branching Enzymes from Plants and Bacteria in Arabidopsis Reveals Marked Differences in Their Functions and Capacity to Mediate Starch Granule Formation1[OPEN

    PubMed Central

    Lu, Kuan-Jen; Streb, Sebastian; Meier, Florence; Pfister, Barbara; Zeeman, Samuel C.

    2015-01-01

    The major component of starch is the branched glucan amylopectin, the branching pattern of which is one of the key factors determining its ability to form semicrystalline starch granules. Here, we investigated the functions of different branching enzyme (BE) types by expressing proteins from maize (Zea mays BE2a), potato (Solanum tuberosum BE1), and Escherichia coli (glycogen BE [EcGLGB]) in Arabidopsis (Arabidopsis thaliana) mutant plants that are deficient in their endogenous BEs and therefore, cannot make starch. The expression of each of these three BE types restored starch biosynthesis to differing degrees. Full complementation was achieved using the class II BE ZmBE2a, which is most similar to the two endogenous Arabidopsis isoforms. Expression of the class I BE from potato, StBE1, resulted in partial complementation and high amylose starch. Expression of the glycogen BE EcGLGB restored only minimal amounts of starch production, which had unusual chain length distribution, branch point distribution, and granule morphology. Nevertheless, each type of BE together with the starch synthases and debranching enyzmes were able to create crystallization-competent amylopectin polymers. These data add to the knowledge of how the properties of the BE influence the final composition of starch and fine structure of amylopectin. PMID:26358415

  6. Starch gelatinization.

    PubMed

    Ratnayake, Wajira S; Jackson, David S

    2009-01-01

    Starch occurs as highly organized structures, known as starch granules. Starch has unique thermal properties and functionality that have permitted its wide use in food products and industrial applications. When heated in water, starch undergoes a transition process, during which the granules break down into a mixture of polymers-in-solution, known as gelatinization. The sequence of structural transformations that the starch granule undergoes during this order-to-disorder transition has been extensively researched. None of the published starch gelatinization theories can fully and adequately explain the exact mechanism of sequential structural changes that starch granules undergo during gelatinization. This chapter analyzes several published theories and summarizes our current understanding of the starch gelatinization process.

  7. Identification and characterization of granule bound starch synthase I (GBSSI) gene of tartary buckwheat (Fagopyrum tataricum Gaertn.).

    PubMed

    Wang, Xun; Feng, Bo; Xu, Zhibin; Sestili, Francesco; Zhao, Guojun; Xiang, Chao; Lafiandra, Domenico; Wang, Tao

    2014-01-25

    Tartary buckwheat (Fagopyrum tataricum Gaertn.) is increasingly considered as an important functional food material because of its rich nutraceutical compounds. Reserve starch is the major component of tartary buckwheat seed. However, the gene sequences and the molecular mechanism of tartary buckwheat starch synthesis are unknown so far. In this study, the complete genomic sequence and full-size cDNA coding tartary buckwheat granule-bound starch synthase I (FtGBSSI), which is responsible for amylose synthesis, were isolated and analyzed. The genomic sequence of the FtGBSSI contained 3947 nucleotides and was composed of 14 exons and 13 introns. The cDNA coding sequence of FtGBSSI shared 63.3%-75.1% identities with those of dicots and 56.6%-57.5% identities with monocots (Poaceae). In deduced amino acid sequence of FtGBSSI, eight motifs conserved among plant starch synthases were identified. A cleavage at the site IVC↓G of FtGBSSI protein produces the chloroplast transit sequence of 78 amino acids and the mature protein of 527 amino acids. The FtGBSSI mature protein showed an identity of 73.4%-77.8% with dicot plants, and 67.6%-70.4% with monocot plants (Poaceae). The mature protein was composed of 20 α-helixes and 16 β-strands, and folds into two main domains, N- and C-terminal domains. The critical residues which are involved in ADP and sugar binding were predicted. These results will be useful to modulate starch composition of buckwheat kernels with the aim to produce novel improved varieties in future breeding programs. © 2013.

  8. Digestion of legume starch granules by larvae of Zabrotes subfasciatus (Coleoptera: bruchidae) and the induction of alpha-amylases in response to different diets.

    PubMed

    Silva, C P; Terra, W R; Xavier-Filho, J; Grossi de Sá, M F; Isejima, E M; DaMatta, R A; Miguens, F C; Bifano, T D

    2001-01-01

    Zabrotes subfasciatus larvae possess three alpha-amylase isoforms as determined by in gel assays following SDS-PAGE. The two minor isoforms present lower electrophoretic mobility than the major form, and seem to occur as a heterodimer. When developed inside Vigna unguiculata (cowpea) seeds, fourth instar larvae have minor quantities of the slow-migrating forms, but when reared on seeds of Phaseolus vulgaris (common bean) or Phaseolus lunatus, the two slow-migrating forms are expressed in higher amounts, while activity of the major form was independent of the host seed. Larvae developing inside cowpea seeds at the beginning of the fourth instar were fed on flour from cotyledons of cowpea or common bean. Larvae fed on the common bean flour started to express the dimer in higher amounts when compared with the control larvae fed on cowpea flour. In an attempt to correlate differences between starch granules and the induction of alpha-amylases, a detailed study on the digestive process of the granules was conducted. Incorporation of purified starch granules into artificial diets did not induce the two minor alpha-amylases. The in vitro hydrolysis rates of purified granules and the pattern of dextrins liberated by the different alpha-amylases were similar for the two legume species. The starch granules enter the midgut extensively damaged, which may facilitate the access to the more susceptible parts of the granules to enzymatic attack.

  9. The Other Double Helix--The Fascinating Chemistry of Starch

    NASA Astrophysics Data System (ADS)

    Hancock, Robert D.; Tarbet, Bryon J.

    2000-08-01

    Current textbooks deal only briefly with the chemistry of starch. A short review with 21 references is presented, describing the structure of starch and indicating the double helix structure of A-type and B-type starch. The structure of the starch granule is examined, pointing out the existence of growth rings of alternating crystalline and noncrystalline starch, with growing amylopectin molecules extending from the hilum (point of origin) to the surface of the starch granule. The swelling of starch granules in water, above the gelatinization temperature of about 60 °C, is discussed. The process of gelatinization involves unraveling of the starch helix and a manyfold increase in volume of the starch granule as water is imbibed and bound to the unraveled starch polymer by hydrogen bonding. Baking bread or pastries causes unraveling of the starch helix, and the process by which these products become stale corresponds primarily to the re-forming of the starch helix. The importance of this phenomenon in food science is discussed. The absorption of nonpolar linear molecules such as I2, or linear nonpolar portions of molecules such as n-butanol or fats and phospholipids, by the C-type helix of starch is examined. The way in which starch is structurally modified to retard staling is discussed in relation to food technology.

  10. Making starch.

    PubMed

    Smith, A M

    1999-06-01

    Improvements in understanding the structure of the starch granule and the nature and roles of starch-synthesising enzymes have allowed detailed mechanisms of the synthesis of the amylopectin and amylose components of the granule to be suggested. However, none of these proposed mechanisms has yet been shown to operate in vivo. Several critical aspects of granule synthesis, including granule initiation and the formation of the growth rings, remain a mystery.

  11. Organocatalytic acetylation of starch: effect of reaction conditions on DS and characterisation of esterified granules.

    PubMed

    Tupa, Maribel Victoria; Ávila Ramírez, Jhon Alejandro; Vázquez, Analía; Foresti, María Laura

    2015-03-01

    Starch acetates with varying degree of substitution (DS) were prepared by a novel solvent-free organocatalytic methodology. The acetylation protocol involved a non-toxic biobased α-hydroxycarboxylic acid as catalyst, and proceeded with high efficiency in absence of solvents. The effect of reaction conditions including reaction temperature (90-140 °C), catalyst load (0-2.3 g/g starch), acetic anhydride/starch weight ratio (6.5-13.5 g/g), and starch moisture content (0.6-14.8%) on the DS of the esters was evaluated. The analysis performed showed that the increase of temperature and catalyst concentration resulted in higher DS values, and evidenced a beneficial contribution of native starch moisture content on the substitution level achieved. Variation of reaction conditions allowed starch esters to be obtained with DS in the 0.03-2.93 range. Starch esters were characterised in terms of morphology, chemical structure, thermal properties, and distribution in polar/non polar liquid systems.

  12. Hydrothermal treatment and iodine binding provide insights into the organization of glucan chains within the semi-crystalline lamellae of corn starch granules.

    PubMed

    Vamadevan, Varatharajan; Hoover, Ratnajothi; Bertoft, Eric; Seetharaman, Koushik

    2014-08-01

    The importance of glucan chains that pass through both the amorphous and crystalline lamellae (tie chains) in the organization of corn starch granules was studied using heat-moisture treatment (HMT), annealing (ANN), and iodine binding. Molecular structural analysis showed that hylon starches (HV, HVII, and HVIII) contained higher proportion of intermediate glucan chains (HVIII > HVII > HV) than normal corn (CN) starch. Wide angle X-ray scattering revealed that on HMT, the extent of polymorphic transition in hylon starches decreased with increasing proportion of intermediate and long chains. Iodine treated hylon starches exhibited increased order in the V-type polymorphism as evidenced by the intense peak at 20° 2θ and the strong reflection intensity at 7.5° 2θ and the extent of the change depended on the type of hylon starch. DSC results showed that the gelatinization enthalpy of CN and waxy corn starch (CW) remained unchanged after ANN. However, hylon starches showed a significant increase in enthalpy with more distinct endotherms after ANN. It can be concluded that tie chains influence the organization of crystalline lamellae in amylose extender mutant starches. © 2014 Wiley Periodicals, Inc.

  13. Impact on molecular organization of amylopectin in starch granules upon annealing.

    PubMed

    Vamadevan, Varatharajan; Bertoft, Eric; Soldatov, Dmitriy V; Seetharaman, Koushik

    2013-10-15

    This study investigated the influence of the internal structure of amylopectin on annealing (3h, 24h) of starches from four different types of amylopectin (Bertoft, Koch, & Aman, 2012; Bertoft, Piyachomkwan, Chatakanonda, & Sriroth, 2008). Regardless of the starch source and incubation time, annealing significantly increased the onset gelatinization temperature (To) and narrowed and deepened the amylopectin endotherm. However, the extent of the change in the melting temperature (Tm) and the enthalpy of gelatinization (ΔH) differed among the types. In terms of the To and Tm, starches from type 1 (oat, rye, barley, and waxy barley) showed the most significant response to annealing. The Tm of starches belonging to type 2 (waxy maize, rice, waxy rice, and sago) remained unchanged after 3h of annealing. Type 1 and type 2 starches with the lowest gelatinization temperatures showed the greatest increase in melting temperature after annealing. However, type 3 (tapioca, mung bean, and arrowroot) and type 4 (potato, waxy potato, canna, and yam) starches were not in line with these observations. Instead, starches from type 3 and type 4 showed a pronounced increase in the ΔH. The inter-block chain length (IB-CL) (distance between tightly branched units within a cluster) correlated positively (r=0.93, p<0.01) with the change in enthalpy after 24h of annealing. These data indicate that a short IB-CL affects the optimum registration of double helices within the crystalline lamellae. The relationship between the gelatinization parameters before and after annealing suggests that type 1 and 2 starches might possess a high number of unpacked double helices (type 1>type 2) compared to other types. Longer IB-CLs, which facilitate the parallel packing of splayed double helices, and the lengthening of double helices likely increased the ΔH in type 3 and type 4 starches. It is concluded that annealing can be used as a probe for visualizing the organization of glucan chains (alignment

  14. Identification of an abundant 56 kDa protein implicated in food allergy as granule-bound starch synthase.

    PubMed

    Krishnan, Hari B; Chen, Ming-Hsuan

    2013-06-05

    Rice, the staple food of south and east Asian counties, is considered to be hypoallergenic. However, several clinical studies have documented rice-induced allergy in sensitive patients. Rice proteins with molecular weights of 14-16, 26, 33, and 56 kDa have been identified as allergens. Recently, it was documented that the 56 kDa rice allergen was responsible for rice-induced anaphylaxis. The 14-16 kDa allergens have been identified as α-amylase inhibitors; the 26 kDa protein has been identified as α-globulin; and the 33 kDa protein has been identified as glyoxalase I. However, the identity of the 56 kDa rice allergen has not yet been determined. In this study, we demonstrate that serum from patients allergic to maize shows IgE binding to a 56 kDa protein that was present in both maize and rice but not in the oil seeds soybean and peanut. The 56 kDa IgE-binding protein was abundant in the rice endosperm. We have purified this protein from rice endosperm and demonstrated its reactivity to IgE antibodies from the serum of maize-allergic patients. The purified protein was subjected to matrix-assisted laser desorption ionization-time of flight-tandem mass spectrometry analysis, resulting in identification of this rice allergen as granule-bound starch synthase, a product of the Waxy gene. Immunoblot analysis using protein extracts from a waxy mutant of rice revealed the absence of the 56 kDa IgE-binding protein. Our results demonstrate that the 56 kDa rice allergen is granule-bound starch synthase and raise the possibility of using waxy mutants of rice as a potential source of the hypoallergenic diet for patients sensitized to the 56 kDa rice allergen.

  15. Genetic Evidence That Chain Length and Branch Point Distributions Are Linked Determinants of Starch Granule Formation in Arabidopsis1[W][OPEN

    PubMed Central

    Pfister, Barbara; Lu, Kuan-Jen; Eicke, Simona; Feil, Regina; Lunn, John E.; Streb, Sebastian; Zeeman, Samuel C.

    2014-01-01

    The major component of starch is the branched glucan amylopectin. Structural features of amylopectin, such as the branching pattern and the chain length distribution, are thought to be key factors that enable it to form semicrystalline starch granules. We varied both structural parameters by creating Arabidopsis (Arabidopsis thaliana) mutants lacking combinations of starch synthases (SSs) SS1, SS2, and SS3 (to vary chain lengths) and the debranching enzyme ISOAMYLASE1-ISOAMYLASE2 (ISA; to alter branching pattern). The isa mutant accumulates primarily phytoglycogen in leaf mesophyll cells, with only small amounts of starch in other cell types (epidermis and bundle sheath cells). This balance can be significantly shifted by mutating different SSs. Mutation of SS1 promoted starch synthesis, restoring granules in mesophyll cell plastids. Mutation of SS2 decreased starch synthesis, abolishing granules in epidermal and bundle sheath cells. Thus, the types of SSs present affect the crystallinity and thus the solubility of the glucans made, compensating for or compounding the effects of an aberrant branching pattern. Interestingly, ss2 mutant plants contained small amounts of phytoglycogen in addition to aberrant starch. Likewise, ss2ss3 plants contained phytoglycogen, but were almost devoid of glucan despite retaining other SS isoforms. Surprisingly, glucan production was restored in the ss2ss3isa triple mutants, indicating that SS activity in ss2ss3 per se is not limiting but that the isoamylase suppresses glucan accumulation. We conclude that loss of only SSs can cause phytoglycogen production. This is readily degraded by isoamylase and other enzymes so it does not accumulate and was previously unnoticed. PMID:24965177

  16. Inhibition of the gene expression for granule-bound starch synthase I by RNA interference in sweet potato plants.

    PubMed

    Otani, Motoyasu; Hamada, Tatsuro; Katayama, Kenji; Kitahara, Kakefumi; Kim, Sun-Hyung; Takahata, Yasuhiro; Suganuma, Toshihiko; Shimada, Takiko

    2007-10-01

    Granule-bound starch synthase I (GBSSI) is one of the key enzymes catalyzing the formation of amylose, a linear alpha(1,4)D-glucan polymer, from ADP-glucose. Amylose-free transgenic sweet potato plants were produced by inhibiting sweet potato GBSSI gene expression through RNA interference. The gene construct consisting of an inverted repeat of the first exon separated by intron 1 of GBSSI driven by the CaMV 35S promoter was integrated into the sweet potato genome by Agrobacterium tumefaciens-mediated transformation. In over 70% of the regenerated transgenic plants, the expression of GBSSI was inactivated giving rise to storage roots containing amylopectin but not amylose. Electrophoresis analysis failed to detect the GBSSI protein, suggesting that gene silencing of the GBSSI gene had occurred. These results clearly demonstrate that amylose synthesis is completely inhibited in storage roots of sweet potato plants by the constitutive production of the double-stranded RNA of GBSSI fragments. We conclude that RNA interference is an effective method for inhibiting gene expression in the starch metabolic pathway.

  17. Phleum pratense pollen starch granules induce humoral and cell-mediated immune responses in a rat model of allergy.

    PubMed

    Motta, A; Peltre, G; Dormans, J A M A; Withagen, C E T; Lacroix, G; Bois, F; Steerenberg, P A

    2004-02-01

    Timothy grass (Phleum pratense) pollen allergens are an important cause of allergic symptoms. However, pollen grains are too large to penetrate the deeper airways. Grass pollen is known to release allergen-bearing starch granules (SG) upon contact with water. These granules can create an inhalable allergenic aerosol capable of triggering an early asthmatic response and are implicated in thunderstorm-associated asthma. We studied the humoral (IgE) and bronchial lymph node cells reactivities to SG from timothy grass pollen in pollen-sensitized rats. Brown-Norway rats were sensitized (day 0) and challenged (day 21) intratracheally with intact pollen and kept immunized by pollen intranasal instillation by 4 weeks intervals during 3 months. Blood and bronchial lymph nodes were collected 7 days after the last intranasal challenge. SG were purified from fresh timothy grass pollen using 5 microm mesh filters. To determine the humoral response (IgE) to SG, we developed an original ELISA inhibition test, based on competition between pollen allergens and purified SG. The cell-mediated response to SG in the bronchial lymph node cells was determined by measuring the uptake of [3H]thymidine in a proliferation assay. An antibody response to SG was induced, and purified SG were able to inhibit the IgE ELISA absorbance by 45%. Pollen extract and intact pollen gave inhibitions of 55% and 52%, respectively. A cell-mediated response was also found, as pollen extract, intact pollen and SG triggered proliferation of bronchial lymph node cells. It was confirmed that timothy grass pollen contains allergen-loaded SG, which are released upon contact with water. These granules were shown to be recognized by pollen-sensitized rats sera and to trigger lymph node cell proliferation in these rats. These data provide new arguments supporting the implication of grass pollen SG in allergic asthma.

  18. Characterization of rice starches extracted from Indian cultivars.

    PubMed

    Gani, Adil; Wani, S M; Masoodi, F A; Salim, Rehana

    2013-04-01

    Physicochemical, morphological and pasting properties of starches isolated from four rice cultivars grown in India were studied. The amylose content ranged between 4.7 and 30.2% of starch, highest in K332 starch and lowest in SR1 starch. Swelling power, water solubility and water absorption capacity of starches increased with increase in temperature from 50 to 90 °C at 10 °C intervals. Highest swelling and water absorption was found in SR1 and lowest in K332 starches but reverse was observed in case of solubility that was highest for K332 and lowest for SR1 starch. The microstructure of starch granules from different rice cultivars showed the presence of mainly polyhedral granules having average size in the range of 4.0-5.2 µm. K332 showed the presence of smallest granules, whereas SR1 starch showed the presence of largest granules. X-ray diffraction pattern of rice starch from different cultivars showed typical A-type crystallinity. Pasting properties of starches differed significantly. Pasting temperature was highest for K332 and lowest for SR1, while peak viscosity was highest for aromatic rice and lowest for K448 starches. Higher setback was observed in K332 and lowest in SR1.

  19. Comparative susceptibility of starch granules of double- and triple-mutants containing amylose-extender, waxy, sugary-1, sugary-2 and dull genes of maize inbred OH43 (Zea mays L.) to amylase.

    PubMed

    Fuwa, H; Glover, D V; Sugimoto, Y

    1979-01-01

    Starch granules were prepared from 14 double- and 26 triple-mutants containing amylose-extender (ae), 14 double- and 18 triple-mutants containing waxy (wx), 15 double- and 20 triple-mutants containing sugary-1 (su1), 13 double- and 23 triple-mutants containing sugary-2 (su2), and 14 double- and 19 triple-mutants containing dull (du) of maize inbred Oh43 (Zea mays L.). The relative susceptibilities of these starch granules to fungal glucoamylase were determined and the starch granules were examined by scanning electron microscopy. A commercial normal maize starch was used as a control. Starch granules of the double- and triple-mutants containing su1 and su2 were digested two to eight times faster than normal. The ae gene reduced susceptibility and seems to be epistatic to su1 and su2. Starch granules of the double- and triple-mutants containing wx were digested about two times faster than normal and those containing shrunken-2 (sh2) were digested 1.2 to eight times faster than normal. Starch granules of triple-mutant combinations with opaque-2 (o2) showed digestion properties which were comparable to those of their respective monopaque double-mutant counterpart.

  20. Differences between the Bud End and Stem End of Potatoes in Dry Matter Content, Starch Granule Size, and Carbohydrate Metabolic Gene Expression at the Growing and Sprouting Stages.

    PubMed

    Liu, Bailin; Zhang, Guodong; Murphy, Agnes; De Koeyer, David; Tai, Helen; Bizimungu, Benoit; Si, Huaijun; Li, Xiu-Qing

    2016-02-10

    Potatoes usually have the tuber bud end dominance in growth during tuber bulking and in tuber sprouting, likely using carbohydrates from the tuber stem end. We hypothesized that the tuber bud end and tuber stem end coordination in carbohydrate metabolism gene expression is different between the bulking dominance and sprouting dominance of the tuber bud end. After comparing the growing tubers at harvest from a green vine and the stage that sprouts just started to emerge after storage of tubers at room temperature, we found the following: (1) Dry matter content was higher in the tuber stem end than the tuber bud end at both stages. (2) The starch granule size was larger in the tuber bud end than in the tuber stem end. (3) The tuber bud end had higher gene expression for starch synthesis but a lower gene expression of sucrose transporters than the tuber stem end during tuber growing. (4) The tuber stem end at the sprouting stage showed more active gene expression in both starch degradation and resynthesis, suggesting more active export of carbohydrates, than the tuber bud end. The results indicate that the starch accumulation mechanism in the tuber bud end was different between field growing and post-harvest sprouting tubers and that tubers already increased dry matter and average starch granule sizes in the tuber bud end prior to the rapid growth of sprouts.

  1. Effects of heat treatment and moisture contents on interactions between lauric acid and starch granules.

    PubMed

    Chang, Fengdan; He, Xiaowei; Fu, Xiong; Huang, Qiang; Jane, Jay-lin

    2014-08-06

    This study aimed to understand the effects of the moisture content of granular normal cornstarch (NC), heat treatment at 80 °C, and order of adding lauric acid (LA) to starch before or after the heat treatment on the physicochemical properties and digestibility of the starch. LA was added to NC priority heated with different moisture contents (10, 20, 30, 40, and 50%) or added to dried NC and then heated with different moisture contents. The hydrothermal/LA treatments increased the pasting temperature but decreased the peak viscosity of the NC. Light and scanning electron microscopy revealed that the addition of LA retarded gelatinization. The hydrothermal/LA treatments changed the X-ray pattern of the NC to a mixture of A- and V-type patterns. The thermal property and digestibility analysis showed that 40% was the optimum moisture content for the formation of the amylose-LA complex and adding LA prior to heating the NC favored the formation of slowly digestible starch.

  2. Two secondary carbohydrate binding sites on the surface of barley alpha-amylase 1 have distinct functions and display synergy in hydrolysis of starch granules.

    PubMed

    Nielsen, Morten M; Bozonnet, Sophie; Seo, Eun-Seong; Mótyán, János A; Andersen, Joakim M; Dilokpimol, Adiphol; Abou Hachem, Maher; Gyémánt, Gyöngyi; Naested, Henrik; Kandra, Lili; Sigurskjold, Bent W; Svensson, Birte

    2009-08-18

    Some polysaccharide processing enzymes possess secondary carbohydrate binding sites situated on the surface far from the active site. In barley alpha-amylase 1 (AMY1), two such sites, SBS1 and SBS2, are found on the catalytic (beta/alpha)(8)-barrel and the noncatalytic C-terminal domain, respectively. Site-directed mutagenesis of Trp(278) and Trp(279), stacking onto adjacent ligand glucosyl residues at SBS1, and of Tyr(380) and His(395), making numerous ligand contacts at SBS2, suggested that SBS1 and SBS2 act synergistically in degradation of starch granules. While SBS1 makes the major contribution to binding and hydrolysis of starch granules, SBS2 exhibits a higher affinity for the starch mimic beta-cyclodextrin. Compared to that of wild-type AMY1, the K(d) of starch granule binding by the SBS1 W278A, W279A, and W278A/W279A mutants thus increased 15-35 times; furthermore, the k(cat)/K(m) of W278A/W279A was 2%, whereas both affinity and activity for Y380A at SBS2 were 10% of the wild-type values. Dual site double and triple SBS1/SBS2 substitutions eliminated binding to starch granules, and the k(cat)/K(m) of W278A/W279A/Y380A AMY1 was only 0.4% of the wild-type value. Surface plasmon resonance analysis of mutants showed that beta-cyclodextrin binds to SBS2 and SBS1 with K(d,1) and K(d,2) values of 0.07 and 1.40 mM, respectively. A model that accounts for the observed synergy in starch hydrolysis, where SBS1 and SBS2 bind ordered and free alpha-glucan chains, respectively, thus targeting the enzyme to single alpha-glucan chains accessible for hydrolysis, is proposed. SBS1 and SBS2 also influence the kinetics of hydrolysis for amylose and maltooligosaccharides, the degree of multiple attack on amylose, and subsite binding energies.

  3. In depth study of a new highly efficient raw starch hydrolyzing α-amylase from Rhizomucor sp.

    PubMed

    Tawil, Georges; Viksø-Nielsen, Anders; Rolland-Sabaté, Agnès; Colonna, Paul; Buléon, Alain

    2011-01-10

    A new α-amylase from Rhizomucor sp. (RA) was studied in detail due to its very efficient hydrolysis of raw starch granules at low temperature (32 °C). RA contains a starch binding domain (SBD) connected to the core amylase catalytic domain by a O-glycosylated linker. The mode of degradation of native maize starch granules and, in particular, the changes in the starch structure during the hydrolysis, was monitored for hydrolysis of raw starch at concentrations varying between 0.1 and 31%. RA was compared to porcine pancreatic α-amylase (PPA), which has been widely studied either on resistant starch or as a model enzyme in solid starch hydrolysis studies. RA is particularly efficient on native maize starch and release glucose only. The hydrolysis rate reaches 75% for a 31% starch solution and is complete at 0.1% starch concentration. The final hydrolysis rate was dependent on both starch concentration and enzyme amount applied. RA is also very efficient in hydrolyzing the crystalline domains in the maize starch granule. The major A-type crystalline structure is more rapidly degraded than amorphous domains in the first stages of hydrolysis. This is in agreement with the observed preferential hydrolysis of amylopectin, the starch constituent that forms the backbone of the crystalline part of the granule. Amylose-lipid complexes present in most cereal starches are degraded in a second stage, yielding amylose fragments that then reassociate into B-type crystalline structures, forming the final resistant fraction.

  4. Heterogeneity of poly(A) sites in the granule-bound starch synthase I gene in sweet potato (Ipomoea batatas (L.) Lam.).

    PubMed

    Kimura, Takashi; Saito, Akira

    2010-01-01

    Analysis of the cDNAs of granule-bound starch synthase I (GBSSI) in sweet potato indicated that six types of GBSSI were expressed in the tuberous root, and that the poly(A) sites in GBSSI were highly heterogeneous. Several poly(A) sites were located within or downstream of the polymorphic TA repeat. The GBSSI gene has a 23-nucleotide A-rich sequence in the 3' untranslated region, and we believe that the main near-upstream elements of the poly(A) signal are included in this sequence.

  5. Preparation of acetylated waxy, normal, and high-amylose maize starches with intermediate degrees of substitution in aqueous solution and their properties.

    PubMed

    Luo, Zhi-Gang; Shi, Yong-Cheng

    2012-09-19

    Acetylated waxy, normal, and high-amylose maize starches with intermediate degrees of substitution (DS) were prepared in aqueous solution with 20% (w/w) sodium hydroxide as a catalyst. The level of DS was in the order high-amylose maize starch > waxy maize starch > normal maize starch. Settling volume indicated that during the early reaction, normal maize starch swelled to a lesser extent compared with waxy and high-amylose maize starches. The settling volume of all three starches increased initially but decreased after long reaction time. Aggregation of granules was observed as DS increased. The A-type X-ray diffraction pattern of acetylated normal and waxy maize starches weakened as DS increased, whereas the diffraction peaks disappeared in acetylated high-amylose starch when DS was 0.95. Low DS promoted the swelling of the starches in water, but at high DS, the starches became more hydrophobic and the peak viscosity of acetylated starches decreased.

  6. The deposition and characterization of starch in Brachypodium distachyon

    PubMed Central

    Tanackovic, Vanja; Svensson, Jan T.; Jensen, Susanne L.; Buléon, Alain; Blennow, Andreas

    2014-01-01

    Brachypodium distachyon is a non-domesticated cereal. Nonetheless, Brachypodium was recently introduced as a model plant for temperate cereals. This study compares grain starch metabolism in Brachypodium and barley (Hordeum vulgare). In Brachypodium, we identified and annotated 28 genes involved in starch metabolism and identified important motifs including transit peptides and putative carbohydrate-binding modules (CBMs) of the families CBM20, CBM45, CBM48, and CBM53. Starch content was markedly lower in Brachypodium grains (12%) compared to barley grains (47%). Brachypodium starch granules were doughnut shaped and bimodally distributed into distinct small B-type (2.5–10 µm) and very small C-type (0.5–2.5 µm) granules. Large A-type granules, typical of cereals, were absent. Starch-bound phosphate, important for starch degradation, was 2-fold lower in Brachypodium compared with barley indicating different requirements for starch mobilization. The amylopectin branch profiles were similar and the amylose content was only slightly higher compared with barley cv. Golden Promise. The crystallinity of Brachypodium starch granules was low (10%) compared to barley (20%) as determined by wide-angle X-ray scattering (WAXS) and molecular disorder was confirmed by differential scanning calorimetry (DSC). The expression profiles in grain for most genes were distinctly different for Brachypodium compared to barley, typically showing earlier decline during the course of development, which can explain the low starch content and differences in starch molecular structure and granule characteristics. High transitory starch levels were observed in leaves of Brachypodium (2.8% after 14h of light) compared to barley (1.9% after 14h of light). The data suggest important pre-domesticated features of cereals. PMID:25056772

  7. The deposition and characterization of starch in Brachypodium distachyon.

    PubMed

    Tanackovic, Vanja; Svensson, Jan T; Jensen, Susanne L; Buléon, Alain; Blennow, Andreas

    2014-10-01

    Brachypodium distachyon is a non-domesticated cereal. Nonetheless, Brachypodium was recently introduced as a model plant for temperate cereals. This study compares grain starch metabolism in Brachypodium and barley (Hordeum vulgare). In Brachypodium, we identified and annotated 28 genes involved in starch metabolism and identified important motifs including transit peptides and putative carbohydrate-binding modules (CBMs) of the families CBM20, CBM45, CBM48, and CBM53. Starch content was markedly lower in Brachypodium grains (12%) compared to barley grains (47%). Brachypodium starch granules were doughnut shaped and bimodally distributed into distinct small B-type (2.5-10 µm) and very small C-type (0.5-2.5 µm) granules. Large A-type granules, typical of cereals, were absent. Starch-bound phosphate, important for starch degradation, was 2-fold lower in Brachypodium compared with barley indicating different requirements for starch mobilization. The amylopectin branch profiles were similar and the amylose content was only slightly higher compared with barley cv. Golden Promise. The crystallinity of Brachypodium starch granules was low (10%) compared to barley (20%) as determined by wide-angle X-ray scattering (WAXS) and molecular disorder was confirmed by differential scanning calorimetry (DSC). The expression profiles in grain for most genes were distinctly different for Brachypodium compared to barley, typically showing earlier decline during the course of development, which can explain the low starch content and differences in starch molecular structure and granule characteristics. High transitory starch levels were observed in leaves of Brachypodium (2.8% after 14h of light) compared to barley (1.9% after 14h of light). The data suggest important pre-domesticated features of cereals.

  8. Loss of Starch Granule Initiation Has a Deleterious Effect on the Growth of Arabidopsis Plants Due to an Accumulation of ADP-Glucose1[W

    PubMed Central

    Ragel, Paula; Streb, Sebastian; Feil, Regina; Sahrawy, Mariam; Annunziata, Maria Grazia; Lunn, John E.; Zeeman, Samuel; Mérida, Ángel

    2013-01-01

    STARCH SYNTHASE4 (SS4) is required for proper starch granule initiation in Arabidopsis (Arabidopsis thaliana), although SS3 can partially replace its function. Unlike other starch-deficient mutants, ss4 and ss3/ss4 mutants grow poorly even under long-day conditions. They have less chlorophyll and carotenoids than the wild type and lower maximal rates of photosynthesis. There is evidence of photooxidative damage of the photosynthetic apparatus in the mutants from chlorophyll a fluorescence parameters and their high levels of malondialdehyde. Metabolite profiling revealed that ss3/ss4 accumulates over 170 times more ADP-glucose (Glc) than wild-type plants. Restricting ADP-Glc synthesis, by introducing mutations in the plastidial phosphoglucomutase (pgm1) or the small subunit of ADP-Glc pyrophosphorylase (aps1), largely restored photosynthetic capacity and growth in pgm1/ss3/ss4 and aps1/ss3/ss4 triple mutants. It is proposed that the accumulation of ADP-Glc in the ss3/ss4 mutant sequesters a large part of the plastidial pools of adenine nucleotides, which limits photophosphorylation, leading to photooxidative stress, causing the chlorotic and stunted growth phenotypes of the plants. PMID:23872660

  9. Loss of starch granule initiation has a deleterious effect on the growth of arabidopsis plants due to an accumulation of ADP-glucose.

    PubMed

    Ragel, Paula; Streb, Sebastian; Feil, Regina; Sahrawy, Mariam; Annunziata, Maria Grazia; Lunn, John E; Zeeman, Samuel; Mérida, Ángel

    2013-09-01

    STARCH SYNTHASE4 (SS4) is required for proper starch granule initiation in Arabidopsis (Arabidopsis thaliana), although SS3 can partially replace its function. Unlike other starch-deficient mutants, ss4 and ss3/ss4 mutants grow poorly even under long-day conditions. They have less chlorophyll and carotenoids than the wild type and lower maximal rates of photosynthesis. There is evidence of photooxidative damage of the photosynthetic apparatus in the mutants from chlorophyll a fluorescence parameters and their high levels of malondialdehyde. Metabolite profiling revealed that ss3/ss4 accumulates over 170 times more ADP-glucose (Glc) than wild-type plants. Restricting ADP-Glc synthesis, by introducing mutations in the plastidial phosphoglucomutase (pgm1) or the small subunit of ADP-Glc pyrophosphorylase (aps1), largely restored photosynthetic capacity and growth in pgm1/ss3/ss4 and aps1/ss3/ss4 triple mutants. It is proposed that the accumulation of ADP-Glc in the ss3/ss4 mutant sequesters a large part of the plastidial pools of adenine nucleotides, which limits photophosphorylation, leading to photooxidative stress, causing the chlorotic and stunted growth phenotypes of the plants.

  10. AtCCR4a and AtCCR4b are Involved in Determining the Poly(A) Length of Granule-bound starch synthase 1 Transcript and Modulating Sucrose and Starch Metabolism in Arabidopsis thaliana.

    PubMed

    Suzuki, Yuya; Arae, Toshihiro; Green, Pamela J; Yamaguchi, Junji; Chiba, Yukako

    2015-05-01

    Removing the poly(A) tail is the first and rate-limiting step of mRNA degradation and apparently an effective step not only for modulating mRNA stability but also for translation of many eukaryotic transcripts. Carbon catabolite repressor 4 (CCR4) has been identified as a major cytoplasmic deadenylase in Saccharomyces cerevisiae. The Arabidopsis thaliana homologs of the yeast CCR4, AtCCR4a and AtCCR4b, were identified by sequence-based analysis; however, their role and physiological significance in plants remain to be elucidated. In this study, we revealed that AtCCR4a and AtCCR4b are localized to cytoplasmic mRNA processing bodies, which are specific granules consisting of many enzymes involved in mRNA turnover. Double mutants of AtCCR4a and AtCCR4b exhibited tolerance to sucrose application but not to glucose. The levels of sucrose in the seedlings of the atccr4a/4b double mutants were reduced, whereas no difference was observed in glucose levels. Further, amylose levels were slightly but significantly increased in the atccr4a/4b double mutants. Consistent with this observation, we found that the transcript encoding granule-bound starch synthase 1 (GBSS1), which is responsible for amylose synthesis, is accumulated to a higher level in the atccr4a/4b double mutant plants than in the control plants. Moreover, we revealed that GBSS1 has a longer poly(A) tail in the double mutant than in the control plant, suggesting that AtCCR4a and AtCCR4b can influence the poly(A) length of transcripts related to starch metabolism. Our results collectively suggested that AtCCR4a and AtCCR4b are involved in sucrose and starch metabolism in A. thaliana.

  11. Protein-protein interactions among enzymes of starch biosynthesis in high-amylose barley genotypes reveal differential roles of heteromeric enzyme complexes in the synthesis of A and B granules.

    PubMed

    Ahmed, Zaheer; Tetlow, Ian J; Ahmed, Regina; Morell, Matthew K; Emes, Michael J

    2015-04-01

    The present study investigated the role of protein phosphorylation, and protein complex formation between key enzymes of amylopectin synthesis, in barley genotypes exhibiting "high amylose" phenotypes. Starch branching enzyme (SBE) down-regulated lines (ΔSBEIIa and ΔSBEIIb), starch synthase (SS)IIa (ssiia(-), sex6) and SSIII (ssiii(-), amo1) mutants were compared to a reference genotype, OAC Baxter. Down-regulation of either SBEIIa or IIb caused pleiotropic effects on SSI and starch phosphorylase (SP) and resulted in formation of novel protein complexes in which the missing SBEII isoform was substituted by SBEI and SP. In the ΔSBEIIb down-regulated line, soluble SP activity was undetectable. Nonetheless, SP was incorporated into a heteromeric protein complex with SBEI and SBEIIa and was readily detected in starch granules. In amo1, unlike other mutants, the data suggest that both SBEIIa and SBEIIb are in a protein complex with SSI and SSIIa. In the sex6 mutant no protein complexes involving SBEIIa or SBEIIb were detected in amyloplasts. Studies with Pro-Q Diamond revealed that GBSS, SSI, SSIIa, SBEIIb and SP are phosphorylated in their granule bound state. Alteration in the granule proteome in ΔSBEIIa and ΔSBEIIb lines, suggests that different protein complexes are involved in the synthesis of A and B granules. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Effect of gamma irradiation on the physicochemical properties of alkali-extracted rice starch

    NASA Astrophysics Data System (ADS)

    Ashwar, Bilal Ahmad; Shah, Asima; Gani, Asir; Rather, Sajad Ahmad; Wani, Sajad Mohd.; Wani, Idrees Ahmed; Masoodi, Farooq Ahmad; Gani, Adil

    2014-06-01

    Starches isolated from two newly released rice varieties (K-322 and K-448) were subject to irradiation at 0, 5, 10, and 20 kGy doses. Comparative study between native (not irradiated) and irradiated starch samples was carried out to evaluate the changes in physicochemical, morphological and pasting properties due to gamma irradiation. Significant decrease was found in apparent amylose content, pH, swelling power, syneresis, and pasting properties, whereas carboxyl content, water absorption capacity, and transmittance were found to increase with the increase in irradiation dose. Granule morphology of native and irradiated starches under scanning electron microscope revealed that granules were polygonal or irregular in shape. The starch granules were somewhat deformed by gamma irradiation. X-ray diffraction pattern showed A type of pattern in native as well as irradiated starches.

  13. Recrystallization characteristics of high hydrostatic pressure gelatinized normal and waxy corn starch.

    PubMed

    Li, Wenhao; Tian, Xiaoling; Wang, Peng; Saleh, Ahmed S M; Luo, Qingui; Zheng, Jianmei; Ouyang, Shaohui; Zhang, Guoquan

    2016-02-01

    High hydrostatic pressure (HHP) can lead to starch gelatinization at room temperature, while the retrogradation mechanism of HHP gelatinized starch is not well known. HHP gelatinized normal and waxy corn starches were stored at room temperature for 192 h in order to investigate the retrogradation characteristics. The scanning electron microscopy (SEM), polarised light microscopy and differential scanning calorimetric (DSC) analysis showed that the pressurization of normal and waxy corn starch suspensions with concentration of 30% (w/v) at 600 MPa for 15 min resulted in a complete gelatinization. In addition, the pressure-gelatinized normal and waxy corn starch gels were stored and subjected to X-ray diffraction (XRD) analysis, resistant starch content determination, swelling power and pasting behavior. The retrograded normal maize and waxy maize starch showed a substantial loss of A-type crystallinity. Both pressure-gelatinized normal and waxy corn starches showed an increase in resistant starch content and relative crystallinity degree with the increase of storage time. In addition, restricted starch swelling power and lower pasting viscosities were observed for these two retrograded starches. The amylose molecule within starch granules has been regarded as the main factor to affect the structural and physicochemical properties during the retrogradation process of HHP-gelatinized starch granules. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Determination of the molecular and structural characteristics of okenia, mango, and banana starches.

    PubMed

    Millan-Testa, C E; Mendez-Montealvo, M G; Ottenhof, M-A; Farhat, I A; Bello-Pérez, L A

    2005-02-09

    Starches were isolated from nonconventional sources (banana, mango, and okenia) and their characteristics were examined using polarized light microscopy, X-ray diffraction pattern, Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). Banana starch granules were of an ellipsoidal shape with size between approximately 8 and 20 microm; okenia had the smallest granule size, between approximately 2 and 5 microm. The three starches showed the Maltese cross, indicative of an intact granule structure. Okenia and mango starches had the A-type X-ray diffraction pattern, common to native cereal starches, whereas banana starch showed a mixture between A- and B-type pattern. Banana starch had the highest temperature (77.6 degrees C) and enthalpy (23.4 J/g) of gelatinization in excess water conditions; okenia had the lowest temperature (71.2 degrees C) and enthalpy (15 J/g), which may be related to the X-ray diffraction pattern and its small granule size. Both the okenia and mango starches had a higher molar mass and gyration radius than banana starch, which may be related to the differences determined in their crystalline structures.

  15. Comparison of starches from five plants of Sect. Stenophora Uline and Sect. Lasiophyton Uline of Dioscorea grown in China.

    PubMed

    Jiang, Qian-Qian; Gao, Wen-Yuan; Shi, Yan-Peng; Li, Xia; Wang, Hai-Yang

    2015-03-15

    Dioscorea resources with vital medicinal and functional values are abundant in south-west regions of China, especially in Sichuan Province. However, the resource in this region has received less attention compared with that of the north. D. zingiberensis, D. collettii, D. kamoonensis cv. Emei and Jinfo, and D. melanophyma from Sichuan Province and Chongqing City were studied with regard to the most abundant carbohydrate (starch) to search for new medicinal and food resources. The starches were small round granules or small oval granules and large elongated granules, except D. zingiberensis starch granules, which were disc-like in shape. D. zingiberensis and D. collettii starches showed higher values in total starch content, water-binding capacity and infrared ratio of absorbance bands at 1047/1035 and 1047/1022 cm⁻¹. Differential scanning calorimetry analysis demonstrated a higher gelatinisation temperature required more energy during the gelatinisation process. D. zingiberensis and D. collettii starches showed higher resistant starch content of 724.0 and 693.2 g kg⁻¹, respectively, with lower hydrolysis index and estimation of glycaemic index. All the starches exhibited an A-type pattern except D. melanophyma starch, which showed a C-type pattern evaluated by X-ray diffraction. These results showed that the starches with their low hydrolysis index values possessed potential values as healthy food. © 2014 Society of Chemical Industry.

  16. [X-ray diffraction study of high hydrostatic pressure on crystalline structure of different type starches].

    PubMed

    Liu, Pei-Ling; Shen, Qun; Hu, Xiao-Song; Wu, Ji-Hong

    2012-09-01

    Crystalline changes of different type starches after high hydrostatic pressure treated under 300, 450, 600 MPa were studied by X-ray diffraction. Waxy maize (A type, 100% amylopectin), hylon VII (B type, 30% amylopectin) and tapioca starch (C type, 83% amylopectin) were chosen. The results indicated that for waxy maize starch, annealing effect was observed at 300 MPa, disappearance of crystalline structure happened at 450 MPa and retrogradation at 600 MPa. The results proved that the granule under high hydrostatic pressure processing experiences "three development stages" including annealling effect, disappearance of crystalline structure and recrystalline after granule disintegration.

  17. Structural properties of hydrolyzed high-amylose rice starch by α-amylase from Bacillus licheniformis.

    PubMed

    Qin, Fengling; Man, Jianmin; Xu, Bin; Hu, Maozhi; Gu, Minghong; Liu, Qiaoquan; Wei, Cunxu

    2011-12-14

    High-amylose cereal starch has a great benefit on human health through its resistant starch (RS) content. Enzyme hydrolysis of native starch is very helpful in understanding the structure of starch granules and utilizing them. In this paper, native starch granules were isolated from a transgenic rice line (TRS) enriched with amylose and RS and hydrolyzed by α-amylase. Structural properties of hydrolyzed TRS starches were studied by X-ray powder diffraction, Fourier transform infrared, and differential scanning calorimetry. The A-type polymorph of TRS C-type starch was hydrolyzed faster than the B-type polymorph, but the crystallinity did not significantly change during enzyme hydrolysis. The degree of order in the external region of starch granule increased with increasing enzyme hydrolysis time. The amylose content decreased at first and then went back up during enzyme hydrolysis. The hydrolyzed starches exhibited increased onset and peak gelatinization temperatures and decreased gelatinization enthalpy on hydrolysis. These results suggested that the B-type polymorph and high amylose that formed the double helices and amylose-lipid complex increased the resistance to BAA hydrolysis. Furthermore, the spectrum results of RS from TRS native starch digested by pancreatic α-amylase and amyloglucosidase also supported the above conclusion.

  18. Isolation and partial characterization of mango (Magnifera indica L.) starch: morphological, physicochemical and functional studies.

    PubMed

    Bello-Pérez, L A; Aparicio-Saguilán, A; Méndez-Montealvo, G; Solorza-Feria, J; Flores-Huicochea, E

    2005-03-01

    Mango (Mangifera indica) is a fruit that grows in tropical regions. The aim of this work was to isolate the starch from two varieties of mango highly consumed in Mexico ("criollo" and "manila"), and to evaluate its chemical composition, along with some morphological, physicochemical and functional properties. Mango starch had an amylose content of about 13%, the fat content of "criollo" variety starch (0.1-0.12%), was similar to that of commercial corn starch used as control (0.2%); both mango starches had higher ash amount (0.2-0.4%) than corn starch. Mango starches presented a smaller granule size (10 microm) than corn starch (15 microm), along with an A-type X-ray diffraction pattern with slight tendency to a C-type. All values of water retention capacity (WRC) increased with the temperature. When the temperature increased, solubility and swelling values increased and in general, mango starches had higher values than corn starch. Both mango starches had gelatinization temperatures lower than the control, but "criollo" variety starch presented higher enthalpy values than "manila" variety and corn starches. Overall, it was concluded that due to its morphological, physicochemical and functional properties, mango starches could be a feasible starch source with adequate properties, suitable for using in the food industry.

  19. Effect of acid hydrolysis on morphology, structure and digestion property of starch from Cynanchum auriculatum Royle ex Wight.

    PubMed

    Wang, Xingchi; Wen, Fanting; Zhang, Shurong; Shen, Ruru; Jiang, Wei; Liu, Jun

    2017-03-01

    Effect of acid hydrolysis on the morphology, structure and digestion property of starch from Cynanchum auriculatum Royle ex Wight was investigated in this study. The hydrolysis degree of C. auriculatum starch rapidly increased to 63.69% after 4days and reached 78.67% at the end of 9days. Morphology observation showed that the starch granules remained intact during the first 4days of hydrolysis. However, serious erosion phenomenon was observed after 5days and starch granules completely fell into pieces after 7days. During acid hydrolysis process, the crystal type of hydrolyzed starch changed from original CB-type to final A-type. Small-angle X-ray scattering patterns showed the semi-crystalline growth rings started to be hydrolyzed after 4days. The proportions of single helix and amorphous components as well as amylose content in starch gradually decreased, whereas the proportion of double helix components continuously increased during acid hydrolysis. However, the contents of rapidly digestible starch, slowly digestible starch and resistant starch were almost constant during acid hydrolysis process, indicating the in vitro digestion property of C. auriculatum starch was not affected by acid hydrolysis. Our results provided novel information on the inner structure of C. auriculatum starch granules. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Diversification of Genes Encoding Granule-Bound Starch Synthase in Monocots and Dicots Is Marked by Multiple Genome-Wide Duplication Events

    PubMed Central

    Qiu, Wen-Ming; Li, Jing; Zhou, Hui; Zhang, Qiong; Guo, Wenwu; Zhu, Tingting; Peng, Junhua; Sun, Fengjie; Li, Shaohua; Korban, Schuyler S.; Han, Yuepeng

    2012-01-01

    Starch is one of the major components of cereals, tubers, and fruits. Genes encoding granule-bound starch synthase (GBSS), which is responsible for amylose synthesis, have been extensively studied in cereals but little is known about them in fruits. Due to their low copy gene number, GBSS genes have been used to study plant phylogenetic and evolutionary relationships. In this study, GBSS genes have been isolated and characterized in three fruit trees, including apple, peach, and orange. Moreover, a comprehensive evolutionary study of GBSS genes has also been conducted between both monocots and eudicots. Results have revealed that genomic structures of GBSS genes in plants are conserved, suggesting they all have evolved from a common ancestor. In addition, the GBSS gene in an ancestral angiosperm must have undergone genome duplication ∼251 million years ago (MYA) to generate two families, GBSSI and GBSSII. Both GBSSI and GBSSII are found in monocots; however, GBSSI is absent in eudicots. The ancestral GBSSII must have undergone further divergence when monocots and eudicots split ∼165 MYA. This is consistent with expression profiles of GBSS genes, wherein these profiles are more similar to those of GBSSII in eudicots than to those of GBSSI genes in monocots. In dicots, GBSSII must have undergone further divergence when rosids and asterids split from each other ∼126 MYA. Taken together, these findings suggest that it is GBSSII rather than GBSSI of monocots that have orthologous relationships with GBSS genes of eudicots. Moreover, diversification of GBSS genes is mainly associated with genome-wide duplication events throughout the evolutionary course of history of monocots and eudicots. PMID:22291904

  1. Structural changes of high-amylose rice starch residues following in vitro and in vivo digestion.

    PubMed

    Man, Jianmin; Yang, Yang; Zhang, Changquan; Zhou, Xinghua; Dong, Ying; Zhang, Fengmin; Liu, Qiaoquan; Wei, Cunxu

    2012-09-12

    High-amylose cereal starch has a great benefit on human health through its resistant starch content. In this paper, starches were isolated from mature grains of high-amylose transgenic rice line (TRS) and its wild-type rice cultivar Te-qing (TQ) and digested in vitro and in vivo. The structural changes of digestive starch residues were characterized using DSC, XRD, (13)C CP/MAS NMR, and ATR-FTIR. TQ starch was very susceptible to digestion; its residues following in vitro and in vivo digestion showed similar structural characteristics with TQ control starch, which suggested that both amorphous and crystalline structures were simultaneously digested. Both amorphous and the long-range order structures were also simultaneously hydrolyzed in TRS starch, but the short-range order (double helix) structure in the external region of TRS starch granule increased with increasing digestion time. The A-type polymorph of TRS C-type starch was hydrolyzed more rapidly than the B-type polymorph. These results suggested that B-type crystallinity and short-range order structure in the external region of starch granule made TRS starch resistant to digestion.

  2. Effect of high hydrostatic pressure on the supramolecular structure of corn starch with different amylose contents.

    PubMed

    Yang, Zhi; Swedlund, Peter; Hemar, Yacine; Mo, Guang; Wei, Yanru; Li, Zhihong; Wu, Zhonghua

    2016-04-01

    Corn starches with amylose contents ranging from 0 to 80% were suspended in 60 wt% water or ethanol and subjected to high hydrostatic pressure (HHP) up to 600 MPa. The impact of HHP treatment on the granule morphology, lamellae structures, and crystalline characteristics were examined with a combination of SAXS, WAXS and optical microscopy. All starch dispersed in water showed a decrease in area of the lamellar peak in the SAXS data at q∼0.6 nm(-1). The lamellae thickness (d) increased for pressurized waxy, normal, and Gelose80 corn starches, suggesting water is forced into starch lamellae during HHP. However, for Gelose50 corn starch, the d remained constant over the whole pressure range and light microscopy showed no obvious granule swelling. WAXS studies demonstrated that HHP partially converted A-type starches (waxy and normal corn) to starches with a faint B-type pattern while starches with a B+V-type pattern (Gelose50 and Gelose80), were not affected by HHP. All corn starches suspended in ethanol showed no detectable changes in either granule morphology, or the fractal, the lamellae, and the crystalline structures. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Simple organocatalytic route for the synthesis of starch esters.

    PubMed

    Tupa, Maribel; Maldonado, Lorena; Vázquez, Analía; Foresti, María L

    2013-10-15

    Starch acetates and starch butyrates with degree of substitution (DS) in the range of 0.06-1.54 were prepared by a simple direct solvent-free organocatalytic methodology of starch acylation. The starch esters synthesized have important applications in the food and pharmaceutical industries, among others. The acylation methodology used involves a non-toxic biobased α-hydroxycarboxylic acid as catalyst, and proceeds with high efficiency in absence of solvents. The effect of reaction time on the advance of starch modification was studied as a simple way to control the level of substitution achieved, when all other reaction parameters were kept constant. Starch esters were characterized by means of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). FTIR spectroscopy qualitatively confirmed the esterification of starch by the appearance of bands which are associated with esters groups. Scanning electron microscopy showed that the granular structure of the polysaccharide was preserved upon acylation, although acylated granules had rougher surfaces; and wrinkles, grooves and deformed zones appeared in some granules at high DS. Thermogravimetric analysis showed a gradual reduction in the water content of acylated starches, as well as noticeable changes in their thermal properties at increasing DS. X-ray diffraction analysis showed that the acetylation treatment led to lower crystallinity at increasing DS, although characteristic corn starch A-type patterns could be identified even at the highest DS achieved (DS=1.23). Specific bands and weight losses derived from FTIR and TGA data could be very well correlated with the substitution degree achieved in acetylated starches at DS lower/equal than 0.6. The organocatalytic methodology described for the synthesis of starch acetates and butyrates has the potential to be easily extended to the synthesis of other starch esters using a

  4. Structure and physicochemical properties of starches in lotus (Nelumbo nucifera Gaertn.) rhizome

    PubMed Central

    Yu, Huaguang; Cheng, Libao; Yin, Jingjing; Yan, Shunjun; Liu, Kejun; Zhang, Fengmin; Xu, Bin; Li, Liangjun

    2013-01-01

    The type and content of starch are believed to be the most critical factors in determining the storage and processing quality of lotus rhizome species, and the intention of this study is to survey the structure and properties of starches isolated from rhizomes of two lotus cultivars using X-ray powder diffraction, solid-state nuclear magnetic resonance spectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscope, differential scanning calorimetry, and rapid viscosity analyzer (RVA). Starch in rhizome of cultivar Meirenhong exhibited C-type X-ray diffraction pattern, while starch in rhizome of cultivar Wawalian showed A-type pattern. 13C cross-polarization magic-angle spinning nuclear magnetic resonance (13C CP-MAS NMR) also confirmed the polymorphs. The relative crystallinity of two starches was quantitatively estimated from two methods and compared. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) results indicated that the external regions of the starch granules had a great level of ordered structure. Starch granules in Meirenhong showed oval-shaped granules, while starch granules in Wawalian were elongated and oval in shape with relatively large size. Gelatinization temperatures of starch in Meirenhong and Wawalian were 330.5 and 342.4 K, respectively, and the gelatinization temperature range of Meirenhong was significantly wider than that of Wawalian. Starch in rhizome of cultivar Meirenhong showed lower pasting temperature, lower hot and cool viscosities, lower setback, and higher peak viscosity and breakdown than those of Wawalian in RVA pasting profiles at 6% starch concentration. PMID:24804031

  5. Starch metabolism in leaves.

    PubMed

    Orzechowski, Sławomir

    2008-01-01

    Starch is the most abundant storage carbohydrate produced in plants. The initiation of transitory starch synthesis and degradation in plastids depends mainly on diurnal cycle, post-translational regulation of enzyme activity and starch phosphorylation. For the proper structure of starch granule the activities of all starch synthase isoenzymes, branching enzymes and debranching enzymes are needed. The intensity of starch biosynthesis depends mainly on the activity of AGPase (adenosine 5'-diphosphate glucose pyrophosphorylase). The key enzymes in starch degradation are beta-amylase, isoamylase 3 and disproportionating enzyme. However, it should be underlined that there are some crucial differences in starch metabolism between heterotrophic and autotrophic tissues, e.g. is the ability to build multiprotein complexes responsible for biosynthesis and degradation of starch granules in chloroplasts. The observed huge progress in understanding of starch metabolism was possible mainly due to analyses of the complete Arabidopsis and rice genomes and of numerous mutants with altered starch metabolism in leaves. The aim of this paper is to review current knowledge on transient starch metabolism in higher plants.

  6. Modification of granular corn starch with 4-alpha-glucanotransferase from Thermotoga maritima: effects on structural and physical properties.

    PubMed

    Oh, E J; Choi, S J; Lee, S J; Kim, C H; Moon, T W

    2008-04-01

    Corn starch was converted using alpha-1,4-glucanotransferase from Thermotoga maritima (Tm alpha GT), a hyperthermophilic bacterium, without inducing gelatinization, and the structural changes and physical properties of the modified starches were investigated. Enzyme modification was induced at 65 degrees C for 8, 16, or 24 h, and the morphology of the modified starches was observed with light and scanning electron microscopy. Granule integrity was mostly maintained after enzyme treatment, although some granules were partially fragmented as evidenced by enlarged surface pores and some cracks. The modified starches had lower apparent amylose levels than raw starch. The molecular weights of amylose and amylopectin molecules in the treated starches were lower than those of raw starch, and the amount of branched molecules, which had much lower molecular weights, also increased in the treated starches. The chain-length distribution of amylopectin showed an increased number of shorter branched chains. The modified starches showed a wider melting temperature range and a lower melting enthalpy than that of raw starch. The X-ray diffraction pattern of the modified starches showed typical A-type starch peaks, but the relative crystallinities were lower than that of raw starch. The solubility and paste clarity of the modified starches were much higher than those of raw starch. The modified starch gels maintained their rigidity over the whole frequency range tested and showed thermoreversibility between 4 and 75 degrees C. These results suggest that Tm alpha GT can be used to produce granular corn starch, which contains amylose and amylopectin having lower molecular weights and a thermoreversible gelation property.

  7. Plant-crafted starches for bioplastics production.

    PubMed

    Sagnelli, Domenico; Hebelstrup, Kim H; Leroy, Eric; Rolland-Sabaté, Agnès; Guilois, Sophie; Kirkensgaard, Jacob J K; Mortensen, Kell; Lourdin, Denis; Blennow, Andreas

    2016-11-05

    Transgenically-produced amylose-only (AO) starch was used to manufacture bioplastic prototypes. Extruded starch samples were tested for crystal residues, elasticity, glass transition temperature, mechanical properties, molecular mass and microstructure. The AO starch granule crystallinity was both of the B- and Vh-type, while the isogenic control starch was mainly A-type. The first of three endothermic transitions was attributed to gelatinization at about 60°C. The second and third peaks were identified as melting of the starch and amylose-lipid complexes, respectively. After extrusion, the AO samples displayed Vh- and B-type crystalline structures, the B-type polymorph being the dominant one. The AO prototypes demonstrated a 6-fold higher mechanical stress at break and 2.5-fold higher strain at break compared to control starch. Dynamic mechanical analysis showed a significant increase in the storage modulus (E') for AO samples compared to the control. The data support the use of pure starch-based bioplastics devoid of non-polysaccharide fillers.

  8. Preparation, structure, and digestibility of crystalline A- and B-type aggregates from debranched waxy starches.

    PubMed

    Cai, Liming; Shi, Yong-Cheng

    2014-05-25

    Highly crystalline A- and B-type aggregates were prepared from short linear α-1,4 glucans generated from completely debranched waxy maize and waxy potato starches by manipulating the chain length and crystallization conditions including starch solids concentration and crystallization temperature. The A-type crystalline products were more resistant to enzyme digestion than the B-type crystalline products, and the digestibility of the A- and B-type allomorphs was not correlated with the size of the aggregates formed. Annealing increased the peak melting temperature of the B-type crystallites, making it similar to that of the A-type crystallites, but did not improve the enzyme resistance of the B-type crystalline products. The possible reason for these results was due to the compact morphology as well as the denser packing pattern of double helices in A-type crystallites. Our observations counter the fact that most B-type native starches are more enzyme-resistant than A-type native starches. Crystalline type per se does not seem to be the key factor that controls the digestibility of native starch granules; the resistance of native starches with a B-type X-ray diffraction pattern is probably attributed to the other structural features in starch granules.

  9. Characterization of starch nanoparticles

    NASA Astrophysics Data System (ADS)

    Szymońska, J.; Targosz-Korecka, M.; Krok, F.

    2009-01-01

    Nanomaterials already attract great interest because of their potential applications in technology, food science and medicine. Biomaterials are biodegradable and quite abundant in nature, so they are favoured over synthetic polymer based materials. Starch as a nontoxic, cheap and renewable raw material is particularly suitable for preparation of nanoparticles. In the paper, the structure and some physicochemical properties of potato and cassava starch particles of the size between 50 to 100 nm, obtained by mechanical treatment of native starch, were presented. We demonstrated, with the aim of the Scanning Electron Microscopy (SEM) and the non-contact Atomic Force Microscopy (nc-AFM), that the shape and dimensions of the obtained nanoparticles both potato and cassava starch fit the blocklets - previously proposed as basic structural features of native starch granules. This observation was supported by aqueous solubility and swelling power of the particles as well as their iodine binding capacity similar to those for amylopectin-type short branched polysaccharide species. Obtained results indicated that glycosidic bonds of the branch linkage points in the granule amorphous lamellae might be broken during the applied mechanical treatment. Thus the released amylopectin clusters could escape out of the granules. The starch nanoparticles, for their properties qualitatively different from those of native starch granules, could be utilized in new applications.

  10. Slow digestion property of native cereal starches.

    PubMed

    Zhang, Genyi; Ao, Zihua; Hamaker, Bruce R

    2006-11-01

    The slow digestion property of native cereal starches, represented by normal maize starch, was investigated. The in vitro Englyst test showed that 53.0% of the maize starch is slowly digestible starch (SDS), and scanning electron microscopy (SEM) revealed that SDS starts from an increase of pore size until almost complete fragmentation of starch granules. However, similar amounts of SDS ( approximately 50%) were shown for partially digested fragmented starch residuals, which would normally be considered resistant to digestion based on the Englyst assay. Molecularly, both amylopectin (AP) and amylose (AM) contributed to the amount of SDS as evidenced by a similar ratio of AP to AM at different digestion times. Consistently, similar degrees of crystallinity, comparable gelatinization behavior, and similar debranched profiles of starch residuals following different digestion times indicated that the crystalline and amorphous regions of starch granules were evenly digested through a mechanism of side-by-side digestion of concentric layers of semicrystalline shells of native starch granules.

  11. Starch granule size distribution of hard red winter and hard red spring wheat: Their relationship to wheat, flour and breadmaking quality

    USDA-ARS?s Scientific Manuscript database

    Starch constitutes the greatest weight portion of the wheat endosperm (65-75%), and contributes its own unique functional qualities such as texture, volume, consistency, aesthetics, moisture, and shelf stability to various baked products. Starch was isolated from 98 hard red winter wheats (HRW) and...

  12. Fabrication and characterization of size-controlled starch-based nanoparticles as hydrophobic drug carriers.

    PubMed

    Han, Fei; Gao, Chunmei; Liu, Mingzhu

    2013-10-01

    Acetylated corn starch was successfully synthesized and optimized by the reaction of native corn starch with acetic anhydride and acetic acid in the presence of sulfuric acid as a catalyst. The optimal degree of substitution of 2.85 was obtained. Starch-based nanoparticles were fabricated by a simple and novel nanoprecipitation procedure, by the dropwise addition of water to acetone solution of acetylated starch under stirring. Fourier transform infrared spectrometry showed that acetylated starch had some new bands at 1750, 1375 and 1240 cm(-1) while acetylated starch nanoparticles presented the identical peaks as the drug-loaded acetylated starch nanoparticles and the acetylated starch. Wide angle X-ray diffraction indicated that A-type pattern of native starch was completely transformed into the V-type pattern of Acetylated starch and starch-based nanoparticles show the similar type pattern with the acetylated starch. The scanning electron microscopy showed that the different sizes of pores formed on the acetylated starch granules were utterly converted into the uniform-sized spherical nanoparticles after the nanoprecipitation. The encapsulation efficiency and diameter of nanoparticle can be adjusted by the degree of substitution, the volume ratio of nonsolvent to solvent and the weight ratio of acetylated starch to drug. It was also depicted that the release behaviors of drug-loaded nanoparticles depend on the size of nanoparticles and the degree of substitution of the acetylated starch. Release studies prove that the starch-based nanoparticles with uniform size can be used for the encapsulation of hydrophobic drug and attained the sustained and controllable drug release carriers.

  13. Physicochemical and structural characteristics of rice starch modified by irradiation.

    PubMed

    Polesi, Luís Fernando; Sarmento, Silene Bruder Silveira; Moraes, Jaqueline de; Franco, Célia Maria Landi; Canniatti-Brazaca, Solange Guidolin

    2016-01-15

    This work evaluated the physicochemical and structural properties of rice starch of the cultivars IAC 202 and IRGA 417 modified by irradiation. Starch samples were irradiated by (60)Co in doses 1, 2 and 5kGy, on a rate of 0.4kGy/h. A control not irradiated was used for comparison. The granule morphology and A-type X-ray diffraction pattern were not altered by irradiation. There was an increase in amylose content, carboxyl content and acidity with irradiation. Gamma radiation did not affect the thermal properties of IAC202, but increased gelatinization temperature of IRGA417, in the higher dose (5kGy). The number of long chains of amylopectin was reduced and short chains were increased for IAC202, whereas for IRGA 417, the opposite was observed, probably due to cross-linking of starch chains. Starches had their physicochemical and structural properties modified by irradiation differently.

  14. Autophagy Contributes to Leaf Starch Degradation[C][W

    PubMed Central

    Wang, Yan; Yu, Bingjie; Zhao, Jinping; Guo, Jiangbo; Li, Ying; Han, Shaojie; Huang, Lei; Du, Yumei; Hong, Yiguo; Tang, Dingzhong; Liu, Yule

    2013-01-01

    Transitory starch, a major photosynthetic product in the leaves of land plants, accumulates in chloroplasts during the day and is hydrolyzed to maltose and Glc at night to support respiration and metabolism. Previous studies in Arabidopsis thaliana indicated that the degradation of transitory starch only occurs in the chloroplasts. Here, we report that autophagy, a nonplastidial process, participates in leaf starch degradation. Excessive starch accumulation was observed in Nicotiana benthamiana seedlings treated with an autophagy inhibitor and in autophagy-related (ATG) gene-silenced N. benthamiana and in Arabidopsis atg mutants. Autophagic activity in the leaves responded to the dynamic starch contents during the night. Microscopy showed that a type of small starch granule-like structure (SSGL) was localized outside the chloroplast and was sequestered by autophagic bodies. Moreover, an increased number of SSGLs was observed during starch depletion, and disruption of autophagy reduced the number of vacuole-localized SSGLs. These data suggest that autophagy contributes to transitory starch degradation by sequestering SSGLs to the vacuole for their subsequent breakdown. PMID:23564204

  15. Preparation and physicochemical properties of three types of modified glutinous rice starches.

    PubMed

    Yang, Liping; Zhou, Yibin; Wu, Yiming; Meng, Xin; Jiang, Yamei; Zhang, Haiwei; Wang, Haisong

    2016-02-10

    Hydroxypropylated, phosphorylated, and hydroxypropyl-phosphorylated starches were prepared from glutinous rice starch, and their physicochemical and structural properties were investigated. With increasing reaction time, the molar or degree of substitution of modified starches increased. SEM micrographs revealed that phosphorylated starch granules retained their relative integrity, while some cracks appeared on the surface of hydroxypropylated and hydroxypropyl-phosphorylated starch granules. RVA analyses revealed that pasting properties improved after chemical modification. Additionally, chemical modification improved freeze-thaw stability, especially in hydroxypropyl-phosphorylated starch. DSC analyses showed that onset temperature and gelatinization enthalpy decreased with increasing reaction time, especially in the dual-modified starch. X-ray diffraction patterns revealed that native and modified starches had A-type crystalline patterns. FT-IR spectra showed some minor spectral differences after modification. (13)C CP/MAS NMR spectra showed that a novel peak appeared at 20 ppm after hydroxypropylation and that the relative intensity signals in the C4 region increased after phosphorylation.

  16. Starch digestion capacity of poultry.

    PubMed

    Svihus, B

    2014-09-01

    Starch is quantitatively the most important nutrient in poultry diets and will to a large extent be present as intact starch granules due to very limited extent of gelatinization during pelleting. Although native starch is difficult to digest due to a semi-crystalline structure, even fast-growing broiler chickens appears to be able to digest this starch more or less completely during passage through the jejunum. However, reduced starch digestibility has been observed, particularly in pelleted diets containing large quantities of wheat. Although properties of the starch granule such as size and components on the granule surface may affect digestibility, the entrapment of starch granules in cell walls and a protein matrix may be even more important factors impeding starch digestion. In that case, this and the fact that amylase secretion is normally very high in poultry may explain the lack of convincing effects of exogenous α-amylase added to the diet. However, few well-designed experiments assessing mechanisms of starch digestion and the effect of α-amylase supplementation have been carried out, and thus more research is needed in this important area. © 2014 Poultry Science Association Inc.

  17. Morphological features and physicochemical properties of waxy wheat starch.

    PubMed

    Zhang, Huanxin; Zhang, Wei; Xu, Chunzhong; Zhou, Xing

    2013-11-01

    Morphological features, granule composition, and physicochemical properties of waxy wheat starch were compared with those of normal wheat starch. The morphologies and granule populations were found to be similar for the two starches. However, waxy wheat starch contained a smaller proportion of B-type granules, had a larger average granule diameter, and a higher degree of crystallinity than normal wheat starch, as measured by particle size analysis and differential scanning calorimetry. These differences resulted in a higher gelatinization temperature, transition enthalpy, peak viscosity, breakdown, swelling power, lower peak viscosity temperature and final viscosity in waxy wheat starch. These points suggest that waxy wheat starch should have greater resistance to retrogradation during cooling and higher water-holding capacity under dry conditions. Highlighting the differences in physicochemical properties of waxy and normal wheat starches should help point toward effective applications of waxy wheat starch in the food industry.

  18. Effects of single and dual physical modifications on pinhão starch.

    PubMed

    Pinto, Vânia Zanella; Vanier, Nathan Levien; Deon, Vinicius Gonçalves; Moomand, Khalid; El Halal, Shanise Lisie Mello; Zavareze, Elessandra da Rosa; Lim, Loong-Tak; Dias, Alvaro Renato Guerra

    2015-11-15

    Pinhão starch was modified by annealing (ANN), heat-moisture (HMT) or sonication (SNT) treatments. The starch was also modified by a combination of these treatments (ANN-HMT, ANN-SNT, HMT-ANN, HMT-SNT, SNT-ANN, SNT-HMT). Whole starch and debranched starch fractions were analyzed by gel-permeation chromatography. Moreover, crystallinity, morphology, swelling power, solubility, pasting and gelatinization characteristics were evaluated. Native and single ANN and SNT-treated starches exhibited a CA-type crystalline structure while other modified starches showed an A-type structure. The relative crystallinity increased in ANN-treated starches and decreased in single HMT- and SNT-treated starches. The ANN, HMT and SNT did not provide visible cracks, notches or grooves to pinhão starch granule. SNT applied as second treatment was able to increase the peak viscosity of single ANN- and HMT-treated starches. HMT used alone or in dual modifications promoted the strongest effect on gelatinization temperatures and enthalpy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Development of an efficient agrobacterium-mediated gene targeting system for rice and analysis of rice knockouts lacking granule-bound starch synthase (Waxy) and β1,2-xylosyltransferase.

    PubMed

    Ozawa, Kenjirou; Wakasa, Yuhya; Ogo, Yuko; Matsuo, Kouki; Kawahigashi, Hiroyuki; Takaiwa, Fumio

    2012-04-01

    We have developed a high-frequency method for Agrobacterium-mediated gene targeting by combining an efficient transformation system using rice suspension-cultured calli and a positive/negative selection system. Compared with the conventional transformation system using calli on solid medium, transformation using suspension-cultured calli resulted in a 5- to 10-fold increase in the number of resistant calli per weight of starting material after positive/negative selection. Homologous recombination occurred in about 1.5% of the positive/negative selected calli. To evaluate the efficacy of our method, we show in this report that knockout rice plants containing either a disrupted Waxy (granule-bound starch synthase) or a disrupted Xyl (β1,2-xylosyltransferase) gene can be easily obtained by homologous recombination. Study of gene function using homologous recombination in higher plants can now be considered routine work as a direct result of this technical advance.

  20. Food microstructure and starch digestion.

    PubMed

    Singh, Jaspreet; Kaur, Lovedeep; Singh, Harjinder

    2013-01-01

    Microstructural characteristics of starch-based natural foods such as parenchyma or cotyledon cell shape, cell size and composition, and cell wall composition play a key role in influencing the starch digestibility during gastrointestinal digestion. The stability of cell wall components and the arrangement of starch granules in the cells may affect the free access of amylolytic enzymes during digestion. Commonly used food processing techniques such as thermal processing, extrusion cooking, and post-cooking refrigerated storage alter the physical state of starch (gelatinization, retrogradation, etc.) and its digestibility. Rheological characteristics (viscosity) of food affect the water availability during starch hydrolysis and, consequently, the absorption of digested carbohydrates in the gastrointestinal tract. The nonstarch ingredients and other constituents present in food matrix, such as proteins and lipids interact with starch during processing, which leads to an alteration in the overall starch digestibility and physicochemical characteristics of digesta. Starch digestibility can be controlled by critically manipulating the food microstructure, processing techniques, and food composition.

  1. Physicochemical Properties of Starch from Dioscorea pyrifolia tubers.

    PubMed

    Elmi Sharlina, M S; Yaacob, W A; Lazim, Azwan Mat; Fazry, Shazrul; Lim, Seng Joe; Abdullah, Sapina; Noordin, Akram; Kumaran, Malina

    2017-04-01

    Starch from Dioscorea pyrifolia tubers was characterized for its proximate composition, physicochemical properties and toxicity. This starch contains 44.47±1.86% amylose, 4.84±0.29% moisture, 0.88±0.21% ash, 1.34±0.11% proteins and 92.73±0.48% carbohydrates. X-ray diffraction (XRD) analysis showed a type-C starch with a relative crystallinity of 23.31±2.41%. The starch granules are polyhedral, with a diameter of 2.8 to 5.6μm and average size of 3.93±1.47μm. Initial, peak and finishing gelatinization temperatures for the starch were 71.51±0.07, 75.05±0.15, and 78.25±0.18°C, respectively; the gelatinization enthalpy was 3.86±0.02J/g, and the peak height index was 1.09±0.05. Thermogravimetric analysis showed a weight loss of 85.81±0.52% and a decomposition temperature of 320.16±0.35°C, which indicated that there was good thermal stability of the starch. Fish embryo toxicity (FET) showed that the starch was not toxic and that it was suitable for food and non-food industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Starch granule formation and protein deposition in wheat (Triticum aestivum L.) starchy endosperm cells is altered by high temperature during grain fill

    USDA-ARS?s Scientific Manuscript database

    High temperatures during wheat grain fill decrease starch and protein levels, adversely affecting wheat yield and flour quality. To determine the effect of high temperature on starchy endosperm cell development, grain (Triticum aestivum L. "Butte 86") was produced under a 24/17°C or 37/28°C day/nigh...

  3. Starch granule formation and protein deposition in wheat (Triticum aestivum L.) starchy endosperm cells are altered by high temperature during grain fill

    USDA-ARS?s Scientific Manuscript database

    High temperatures during wheat grain fill decrease starch and protein levels, adversely affecting wheat yield and flour quality. To determine the effect of high temperature on starchy endosperm cell development, grain (Triticum aestivum L. ‘Butte 86’) was produced under a 24/17°C or 37/28°C day/nigh...

  4. Evolution of amylopectin structure in developing wheat endosperm starch.

    PubMed

    Kalinga, Danusha N; Bertoft, Eric; Tetlow, Ian; Liu, Qiang; Yada, Rickey Y; Seetharaman, Koushik

    2014-11-04

    In this study, starches extracted from wheat grains harvested at 7, 14, 28, and 35 days after anthesis (DAA) were used as a means of examining the molecular structure of amylopectin (AP) from developing wheat grain. Scanning electron microscopy of wheat grain cross-sections revealed the presence of endosperm at 7 DAA and contained lenticular-shaped developing large (A-type) granules. From 14 DAA onward, spherical-shaped small (B-type) granules coexisted with large granules in the endosperm. During granule development, the fine structure of AP varied with maturity in both large and small granules. Towards the end of the pre-physiological maturity stage (28 DAA), AP in small and large granules had shortest external chain length (ECL), longest internal chain length (ICL) and lowest amount of A-chains. At physiological maturity (35 DAA), these changes in ECL, ICL and amount of A-chains were reversed when compared to 28 DAA. In both large and small granules, the external AP structure was apparently more organized at physiological maturity than at pre-physiological maturity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Characterization of starch from tubers of yam bean (Pachyrhizus ahipa).

    PubMed

    Forsyth, Jane L; Ring, Steve G; Noel, Timothy R; Parker, Roger; Cairns, Paul; Findlay, Kim; Shewry, Peter R

    2002-01-16

    Detailed studies of the starch present in tubers of six accessions of Pachyrhizus ahipa (ahipa) have been carried out using starches from tubers of P. erosus (Mexican yam bean) and seeds of ahipa and wheat for comparison. Starch accounted for 56-58% of the tuber dry weight with granules occurring in a range of geometric forms and in sizes from below 5 microm to about 35 microm (mean about 10 microm in all accessions except two). The amylose content ranged from 11.6 to 16.8% compared with 16.9% in P. erosus tubers and over 23% in the seed starches. X- ray diffraction analysis showed A-type or C(A)-type diffraction patterns. The chain-length distribution of the amylopectin after enzyme debranching showed a peak at DP11 similar to that of wheat starch, but had a less marked shoulder at DP 21-22 and contained a higher proportion of longer chains. Differential scanning calorimitry showed an endothermic peak corresponding to gelatinization with T(max) ranging from 59 to 63 degrees C, which was similar to the T(max) of wheat (about 64 degrees C). The composition of the ahipa starch may mean that it is suitable for food applications that require low amylose content and low retrogradation after processing.

  6. Starch nanoparticles: a review.

    PubMed

    Le Corre, Déborah; Bras, Julien; Dufresne, Alain

    2010-05-10

    Starch is a natural, renewable, and biodegradable polymer produced by many plants as a source of stored energy. It is the second most abundant biomass material in nature. The starch structure has been under research for years, and because of its complexity, an universally accepted model is still lacking (Buleon, A.; et al. Int. J. Biol. Macromol. 1998, 23, 85-112). However, the predominant model for starch is a concentric semicrystalline multiscale structure that allows the production of new nanoelements: (i) starch nanocrystals resulting from the disruption of amorphous domains from semicrystalline granules by acid hydrolysis and (ii) starch nanoparticles produced from gelatinized starch. This paper intends to give a clear overview of starch nanoparticle preparation, characterization, properties, and applications. Recent studies have shown that they could be used as fillers to improve mechanical and barrier properties of biocomposites. Their use for industrial packaging, continuously looking for innovative solutions for efficient and sustainable systems, is being investigated. Therefore, recently, starch nanoparticles have been the focus of an exponentially increasing number of works devoted to develop biocomposites by blending starch nanoparticles with different biopolymeric matrices. To our knowledge, this topic has never been reviewed, despite several published strategies and conclusions.

  7. Preparation and characterization of octenylsuccinylated plantain starch.

    PubMed

    Bello-Flores, Christopher A; Nuñez-Santiago, Maria C; San Martín-Gonzalez, María F; BeMiller, James N; Bello-Pérez, Luis A

    2014-09-01

    Plantain starch was esterified with octenylsuccinic anhydride (OSA) at two concentrations (3 and 15% w/w) of OSA. The morphology, granule size distribution, pasting, gelatinization, swelling, and solubility of granules and structural features of the starch polymers were evaluated. Granules of the OSA-modified starches increased in size during cooking more than did the granules of the native starch, and the effect was greater at the higher OSA concentration. Pasting viscosities also increased, but gelatinization and pasting temperatures and enthalpy of gelatinization decreased in the OSA-modified starches. It was concluded that insertion of OS groups effected disorder in the granular structure. Solubility, weight average molar mass, Mw¯, and z-average radius of gyration, RGz, of the amylopectin decreased as the OSA concentration increased, indicating a decrease in molecular size.

  8. New Starch Phenotypes Produced by TILLING in Barley

    PubMed Central

    Sparla, Francesca; Falini, Giuseppe; Botticella, Ermelinda; Pirone, Claudia; Talamè, Valentina; Bovina, Riccardo; Salvi, Silvio; Tuberosa, Roberto; Sestili, Francesco; Trost, Paolo

    2014-01-01

    Barley grain starch is formed by amylose and amylopectin in a 1∶3 ratio, and is packed into granules of different dimensions. The distribution of granule dimension is bimodal, with a majority of small spherical B-granules and a smaller amount of large discoidal A-granules containing the majority of the starch. Starch granules are semi-crystalline structures with characteristic X-ray diffraction patterns. Distinct features of starch granules are controlled by different enzymes and are relevant for nutritional value or industrial applications. Here, the Targeting-Induced Local Lesions IN Genomes (TILLING) approach was applied on the barley TILLMore TILLING population to identify 29 new alleles in five genes related to starch metabolism known to be expressed in the endosperm during grain filling: BMY1 (Beta-amylase 1), GBSSI (Granule Bound Starch Synthase I), LDA1 (Limit Dextrinase 1), SSI (Starch Synthase I), SSIIa (Starch Synthase IIa). Reserve starch of nine M3 mutant lines carrying missense or nonsense mutations was analysed for granule size, crystallinity and amylose/amylopectin content. Seven mutant lines presented starches with different features in respect to the wild-type: (i) a mutant line with a missense mutation in GBSSI showed a 4-fold reduced amylose/amylopectin ratio; (ii) a missense mutations in SSI resulted in 2-fold increase in A:B granule ratio; (iii) a nonsense mutation in SSIIa was associated with shrunken seeds with a 2-fold increased amylose/amylopectin ratio and different type of crystal packing in the granule; (iv) the remaining four missense mutations suggested a role of LDA1 in granule initiation, and of SSIIa in determining the size of A-granules. We demonstrate the feasibility of the TILLING approach to identify new alleles in genes related to starch metabolism in barley. Based on their novel physicochemical properties, some of the identified new mutations may have nutritional and/or industrial applications. PMID:25271438

  9. Thermoplastic starch-waxy maize starch nanocrystals nanocomposites.

    PubMed

    Angellier, Hélène; Molina-Boisseau, Sonia; Dole, Patrice; Dufresne, Alain

    2006-02-01

    Waxy maize starch nanocrystals obtained by hydrolysis of native granules were used as a reinforcing agent in a thermoplastic waxy maize starch matrix plasticized with glycerol. Compared to our previous studies on starch nanocrystals reinforced natural rubber (NR) [Macromolecules 2005, 38, 3783; 2005, 38, 9161], the present system presents two particularities: (i) thermoplastic starch is a polar matrix, contrarily to NR, and (ii) the chemical structures of the matrix and the filler are similar. The influence of the glycerol content, filler content, and aging on the reinforcing properties of waxy maize starch nanocrystals (tensile tests, DMA) and crystalline structure (X-ray diffraction) of materials were studied. It was shown that the reinforcing effect of starch nanocrystals can be attributed to strong filler/filler and filler/matrix interactions due to the establishment of hydrogen bonding. The presence of starch nanocrystals leads to a slowing down of the recrystallization of the matrix during aging in humid atmosphere.

  10. The cold storage of green bananas affects the starch degradation during ripening at higher temperature.

    PubMed

    Peroni-Okita, Fernanda H G; Cardoso, Mateus B; Agopian, Roberta G D; Louro, Ricardo P; Nascimento, João R O; Purgatto, Eduardo; Tavares, Maria I B; Lajolo, Franco M; Cordenunsi, Beatriz R

    2013-07-01

    The aim of this work was to investigate the starch degradation of bananas stored at low temperature (13°C, cold-stored group) and bananas stored at 19°C (control group) during ripening. The starch granules were isolated during different stages of banana ripening, and their structure was investigated using different techniques. The activities of α-amylase and β-amylase associated to the starch granules were determined, and their presence was confirmed using immunolocalization assays. The increased molecular mobility likely facilitated the intake and action of α-amylase on the granule surface, where it was the prevalent enzyme in bananas stored at low temperature. The 10 days of storage at low temperature also influenced the sizes and shapes of the granules, with a predominance of rounded granules and pits on the surface along with superior amylose content, the higher amounts of amylopectin A-chains and the subtle increase in the A-type allomorph content. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Issues of Starch in Sugarcane Processing and Prospects of Breeding for Low Starch Content in Sugarcane

    USDA-ARS?s Scientific Manuscript database

    Starch is a sugarcane impurity that adversely affects the quantity and quality of sugar processes and products. The increased production of combine and green harvested sugarcane has increased delivery of starch to sugarcane factories. Starch occurs as granules composed of amylose and amylopectin p...

  12. Development of waxy cassava with different Biological and physico-chemical characteristics of starches for industrial applications.

    PubMed

    Zhao, Shan-Shan; Dufour, Dominique; Sánchez, Teresa; Ceballos, Hernan; Zhang, Peng

    2011-08-01

    The quality of cassava starch, an important trait in cassava breeding programs, determines its applications in various industries. For example, development of waxy (having a low level of amylose) cassava is in demand. Amylose is synthesized by granule-bound starch synthase I (GBSSI) in plants, and therefore, down-regulation of GBSSI expression in cassava might lead to reduced amylose content. We produced 63 transgenic cassava plant lines that express hair-pin dsRNAs homologous to the cassava GBSSI conserved region under the control of the vascular-specific promoter p54/1.0 from cassava (p54/1.0::GBSSI-RNAi) or cauliflower mosaic virus (CaMV) 35S (35S::GBSSI-RNAi). After the screening storage roots and starch granules from field-grown plants with iodine staining, the waxy phenotype was discovered: p54/1.0::GBSSI-RNAi line A8 and 35S::GBSSI-RNAi lines B9, B10, and B23. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that there was no detectable GBSSI protein in the starch granules of plants with the waxy phenotype. Further, the amylose content of transgenic starches was significantly reduced (<5%) compared with the level in starch granules from the wild-type (about 25%). The inner structure of the waxy starch granules differed from that of the untransformed ones, as revealed by transmission electron microscopy analysis as well as morphological changes in the iodine-starch complex. Endothermic enthalpy was reduced in waxy cassava starches, according to differential scanning calorimeter analysis. Except B9, all waxy starches displayed the A-type X-ray diffraction pattern. Amylogram patterns of the waxy cassava starches were analyzed using a rapid viscosity analyzer and found to have increased values for clarity, peak viscosity, gel breakdown, and swelling index. Setback, consistency, and solubility were notably reduced. Therefore, waxy cassava with novel starch in its storage roots was produced using the biotechnological approach, promoting its

  13. Starch biosynthesis in cereal endosperm.

    PubMed

    Jeon, Jong-Seong; Ryoo, Nayeon; Hahn, Tae-Ryong; Walia, Harkamal; Nakamura, Yasunori

    2010-06-01

    Stored starch generally consists of two d-glucose homopolymers, the linear polymer amylose and a highly branched glucan amylopectin that connects linear chains. Amylopectin structurally contributes to the crystalline organization of the starch granule in cereals. In the endosperm, amylopectin biosynthesis requires the proper execution of a coordinated series of enzymatic reactions involving ADP glucose pyrophosphorylase (AGPase), soluble starch synthase (SS), starch branching enzyme (BE), and starch debranching enzyme (DBE), whereas amylose is synthesized by AGPase and granule-bound starch synthase (GBSS). It is highly possible that plastidial starch phosphorylase (Pho1) plays an important role in the formation of primers for starch biosynthesis in the endosperm. Recent advances in our understanding of the functions of individual enzyme isoforms have provided new insights into how linear polymer chains and branch linkages are synthesized in cereals. In particular, genetic analyses of a suite of mutants have formed the basis of a new model outlining the role of various enzyme isoforms in cereal starch production. In our current review, we summarize the recent research findings related to starch biosynthesis in cereal endosperm, with a particular focus on rice.

  14. Factors affecting the digestibility of raw and gelatinized potato starches.

    PubMed

    Noda, T; Takigawa, S; Matsuura-Endo, C; Suzuki, T; Hashimoto, N; Kottearachchi, N S; Yamauchi, H; Zaidul, I S M

    2008-09-15

    The enzymatic digestibilities of raw and gelatinized starches in various potato starches, as well as sweet potato, cassava, and yam starches, were estimated, along with other starch properties, such as the phosphorus content, median granule size, and rapid visco analyzer (RVA) pasting properties. Furthermore, correlation coefficients were calculated between the hydrolysis rates (HR) by amylase and other starch quality parameters. A larger granule size was closely associated with a lower HR in raw starch, while the HR in gelatinized starch did not correlate with the median granule size. An increase in phosphorus content resulted in a definitely lower HR in raw starch and tended to decrease the HR in gelatinized starch for the composite of potato and other starches. In contrast, no correlation coefficients of the phosphorus content with the HRs in raw and gelatinized starches were observed within potato starches. Starches with higher peak viscosity and breakdown showed a lower HR in raw starch, while few or no effects of these RVA parameters on the HR in gelatinized starch were observed for the composite of potato and other starches or among potato starches, respectively. Copyright © 2008 Elsevier Ltd. All rights reserved.

  15. Sedimentation field flow fractionation monitoring of rice starch amylolysis.

    PubMed

    Morelon, X; Battu, S; Salesse, C; Begaud-Grimaud, G; Cledat, D; Cardot, P J P

    2005-11-04

    Enzymatic starch granule hydrolysis is one of the most important reactions in many industrial processes. In this work, we investigated the capacity of SdFFF to monitor the native rice starch amylolysis. In order to determine if fractogram changes observed were correlated to granule biophysical modifications which occurred during amylolysis, SdFFF separation was associated with particle size distribution analysis. The results showed that SdFFF is an effective tool to monitor amylolysis of native rice starch. SdFFF analysis was a rapid (less than 10 min), simple and specific method to follow biophysical modifications of starch granules. These results suggested many different applications such as testing series of enzymes and starches. By using sub-population sorting, SdFFF could be also used to better understand starch hydrolysis mechanisms or starch granule structure.

  16. Operation performance and granule characterization of upflow anaerobic sludge blanket (UASB) reactor treating wastewater with starch as the sole carbon source.

    PubMed

    Lu, Xueqin; Zhen, Guangyin; Estrada, Adriana Ledezma; Chen, Mo; Ni, Jialing; Hojo, Toshimasa; Kubota, Kengo; Li, Yu-You

    2015-03-01

    Long-term performance of a lab-scale UASB reactor treating starch wastewater was investigated under different hydraulic retention times (HRT). Successful start-up could be achieved after 15days' operation. The optimal HRT was 6h with organic loading rate (OLR) 4g COD/Ld at COD concentration 1000mg/L, attaining 81.1-98.7% total COD removal with methane production rate of 0.33L CH4/g CODremoved. Specific methane activity tests demonstrated that methane formation via H2-CO2 and acetate were the principal degradation pathways. Vertical characterizations revealed that main reactions including starch hydrolysis, acidification and methanogenesis occurred at the lower part of reactor ("main reaction zone"); comparatively, at the up converting acetate into methane predominated ("substrate-shortage zone"). Further reducing HRT to 3h caused volatile fatty acids accumulation, sludge floating and performance deterioration. Sludge floating was ascribed to the excess polysaccharides in extracellular polymeric substances (EPS). More efforts are required to overcome sludge floating-related issues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Physicochemical properties of kiwifruit starch.

    PubMed

    Li, Dongxing; Zhu, Fan

    2017-04-01

    Three varieties of golden kiwifruit (Actinidia chinensis) (Gold3, Gold9 and Hort16A) were collected at the commercial harvesting time, and physicochemical properties of starches from core and outer pericarp were studied. Starch contents (dry weight basis) in outer pericarp and core tissues ranged from 38.6 to 51.8% and 34.6 to 40.7%, respectively. All the kiwifruit starches showed B-type polymorph. Compared to the outer pericarp starches, amylose content and enzyme susceptibility of core starches were higher, and the degree of crystallinity, granule size and gelatinization parameters of core starches were somewhat lower. This suggests different biosynthetic properties between these two starches. The enthalpy changes of gelatinization of outer pericarp starches were high (∼21J/g). Rheological properties of outer pericarp starches were compared with normal maize and potato starches showed high yield stress of flow properties. This study revealed the unique properties of kiwifruit starch among various types of starches.

  18. Granulator Selection

    SciTech Connect

    Gould, T H; Armantrout, G

    1999-08-02

    Following our detailed review of the granulation reports and additional conversations with process and development personnel, we have reached a consensus position regarding granulator selection. At this time, we recommend going forward with implementation of the tumbling granulator approach (GEMCO) based on our assessment of the tested granulation techniques using the established criteria. The basis for this selection is summarized in the following sections, followed by our recommendations for proceeding with implementation of the tumbling granulation approach. All five granulation technologies produced granulated products that can be made into acceptable sintered pucks. A possible exception is the product from the fluidized bed granulator. This material has been more difficult to press into uniform pucks without subsequent cracking of the puck during the sintering cycle for the pucks in this series of tests. This problem may be an artifact of the conditions of the particular granulation demonstration run involved, but earlier results have also been mixed. All granulators made acceptable granulated feed from the standpoint of transfer and press feeding, though the roller compactor and fluidized bed products were dustier than the rest. There was also differentiation among the granulators in the operational areas of (1) potential for process upset, (2) plant implementation and operational complexity, and (3) maintenance concerns. These considerations will be discussed further in the next section. Note that concerns also exist regarding the extension of the granulation processes to powders containing actinides. Only the method that involves tumbling and moisture addition has been tested with uranium, and in that instance, significant differences were found in the granulation behavior of the powders.

  19. Preparation, characterization and utilization of starch nanoparticles.

    PubMed

    Kim, Hee-Young; Park, Sung Soo; Lim, Seung-Taik

    2015-02-01

    Starch is one of the most abundant biopolymers in nature and is typically isolated from plants in the form of micro-scale granules. Recent studies reported that nano-scale starch particles could be readily prepared from starch granules, which have unique physical properties. Because starch is environmentally friendly, starch nanoparticles are suggested as one of the promising biomaterials for novel utilization in foods, cosmetics, medicines as well as various composites. An overview of the most up-to-date information regarding the starch nanoparticles including the preparation processes and physicochemical characterization will be presented in this review. Additionally, the prospects and outlooks for the industrial utilization of starch nanoparticles will be discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. The cereal starch endosperm development and its relationship with other endosperm tissues and embryo.

    PubMed

    Zheng, Yankun; Wang, Zhong

    2015-01-01

    The cereal starch endosperm is the central part of endosperm, and it is rich in starch and protein which are the important resources for human food. The starch and protein are separately accumulated in starch granules and protein bodies. Content and configuration of starch granules and protein bodies affect the quality of the starch endosperm. The development of starch endosperm is mediated by genes, enzymes, and hormones, and it also has a close relationship with other endosperm tissues and embryo. This paper reviews the latest investigations on the starch endosperm and will provide some useful information for the future researches on the development of cereal endosperm.

  1. Molecular order and functional properties of starches from three waxy wheat varieties grown in China.

    PubMed

    Wang, Shujun; Wang, Jinrong; Zhang, Wei; Li, Caili; Yu, Jinglin; Wang, Shuo

    2015-08-15

    Molecular order and functional properties of starch from three waxy wheat varieties grown in China were investigated by a combination of various technical analyses. The total starch content of the waxy wheat ranged between 54.1% and 55.0%, and the amylose content of the starch was between 0.71% and 1.63%. Average particle diameter of the three starches varied between 16.5 and 17.4 μm. Three waxy wheat starches presented the typical A-type X-ray diffraction pattern, with relative crystallinity between 38.7% and 40.0%. No significant differences were observed in relative crystallinity, IR ratios of 1047/1022 cm(-1) and 1022/995 cm(-1), and FWHH of the band at 480 cm(-1), indicating the similarity in long-range order of crystallites and short-range order of double helices of three starch granules. Small differences were observed in swelling power, gelatinization parameters, pasting viscosities, and in vitro enzymatic digestibility of three waxy wheat starches. Under the stored condition, no retrogradation occurred for three waxy wheat starches.

  2. Starch characterization in seven raw, boiled and roasted chestnuts (Castanea sativa Mill.) cultivars from Portugal.

    PubMed

    Silva, A P; Oliveira, I; Silva, M E; Guedes, C M; Borges, O; Magalhães, B; Gonçalves, B

    2016-01-01

    Changes occurring in seven chestnut (Castanea sativa sp.) cultivars, caused by boiling and roasting, on starch content, cell and starch granules dimension were evaluated, and morphological changes were characterized by scanning electron microscopy. Three clear patterns of variation were detected after processing, namely: i) decrease of starch content with processing; ii) starch increase with the applied treatments; iii) increase of starch with boiling and decrease with roasting. Starch granules of raw chestnuts presented round, oval or elliptical form, external smooth surface and eccentric hilum, with rather ellipsoid-shaped growth rings. Processing resulted in modifications of the granules, with fusion of individual granules, and gelatinization taking place with the formation of elongated clusters. The present results indicate that boiling and roasting, besides changing the starch content of chestnut, causes important modifications in the starch granules, which can affect the sensory, rheological and chemical characteristics of chestnuts.

  3. Structural and molecular basis of starch viscosity in hexaploid wheat.

    PubMed

    Ral, J-P; Cavanagh, C R; Larroque, O; Regina, A; Morell, M K

    2008-06-11

    Wheat starch is considered to have a low paste viscosity relative to other starches. Consequently, wheat starch is not preferred for many applications as compared to other high paste viscosity starches. Increasing the viscosity of wheat starch is expected to increase the functionality of a range of wheat flour-based products in which the texture is an important aspect of consumer acceptance (e.g., pasta, and instant and yellow alkaline noodles). To understand the molecular basis of starch viscosity, we have undertaken a comprehensive structural and rheological analysis of starches from a genetically diverse set of wheat genotypes, which revealed significant variation in starch traits including starch granule protein content, starch-associated lipid content and composition, phosphate content, and the structures of the amylose and amylopectin fractions. Statistical analysis highlighted the association between amylopectin chains of 18-25 glucose residues and starch pasting properties. Principal component analysis also identified an association between monoesterified phosphate and starch pasting properties in wheat despite the low starch-phosphate level in wheat as compared to tuber starches. We also found a strong negative correlation between the phosphate ester content and the starch content in flour. Previously observed associations between internal starch granule fatty acids and the swelling peak time and pasting temperature have been confirmed. This study has highlighted a range of parameters associated with increased starch viscosity that could be used in prebreeding/breeding programs to modify wheat starch pasting properties.

  4. Structural and functional properties of C-type starches.

    PubMed

    Cai, Jinwen; Cai, Canhui; Man, Jianmin; Zhou, Weidong; Wei, Cunxu

    2014-01-30

    This study investigated the structural and functional properties of C-type starches from pea seeds, faba bean seeds, yam rhizomes and water chestnut corms. These starches were mostly oval in shape with significantly different sizes and contents of amylose, damaged starch and phosphorus. Pea, faba bean and water chestnut starches had central hila, and yam starch had eccentric hilum. Water chestnut and yam starches had higher amylopectin short and long chain, respectively. Water chestnut and faba bean starches showed CA-type crystallinities, and pea and yam starches had C-type crystallinities. Water chestnut starch had the highest swelling power, granule swelling and pasting viscosity, lowest gelatinization temperatures and enthalpy. Faba bean starch had the lowest pasting viscosity, whereas yam starch had the highest gelatinization temperatures. Water chestnut and yam starches possessed significantly higher and lower susceptibility to acid and enzyme hydrolysis, the highest and lowest RDS contents, and the lowest and highest RS contents, respectively.

  5. Expression of an engineered granule-bound Escherichia coli maltose acetyltransferase in wild-type and amf potato plants.

    PubMed

    Nazarian Firouzabadi, Farhad; Vincken, Jean-Paul; Ji, Qin; Suurs, Luc C J M; Visser, Richard G F

    2007-01-01

    Starch is used in many industrial applications, but often requires chemical derivatization to enhance its properties before use. In particular, the stability of starch polymers in solution is improved by acetylation. A drawback of this treatment is the use of pollutant chemicals. A biological alternative to chemical derivatization was investigated by the expression of an amyloplast-targeted Escherichia coli maltose acetyltransferase (MAT) gene in tubers of wild-type (Kardal) and mutant amylose-free (amf) potato plants. MAT was expressed as such, or fused to the N- or C-terminus of a non-catalytic starch-binding domain (SBD) to target the starch granule. Starch granules derived from transgenic plants were found to contain acetyl groups, although their content was low, opening up an avenue to move away from the post-harvest chemical derivatization of starch. MAT inside starch granules was found to be active post-harvest when supplied with acetyl-coenzyme A and glucose or maltose, but it did not acetylate starch polymers in vitro. Starch granules from transformants in which MAT alone was expressed also showed MAT activity, indicating that MAT is accumulated in starch granules, and has affinity for starch by itself. Furthermore, starch granule morphology was altered, and fusion proteins containing MAT and SBD seemed to have a higher affinity for starch granules than two appended SBDs. These results are discussed against the background of the quaternary structure of MAT.

  6. Impact of amylose content on starch physicochemical properties in transgenic sweet potato.

    PubMed

    Zhou, Wenzhi; Yang, Jun; Hong, Yan; Liu, Guiling; Zheng, Jianli; Gu, Zhengbiao; Zhang, Peng

    2015-05-20

    The intrinsic relationship between amylose content and starch physicochemical properties was studied using six representative starch samples (amylose content 0-65%) produced from transgenic sweet potato (cultivar Xushu22). The transgenic lines (waxy and high-amylose) and wild-type (WT) sweet potatoes were analyzed for amylose content, particle size and chain length distribution, X-ray diffraction analysis, thermal characteristics, pasting and rheological property. Compared to the WT starch, the waxy and high-amylose starches showed larger average granule sizes and had fewer short chains and more medium and long chains. X-ray diffractogram analysis revealed that high-amylose starches show a type-B crystal form with a markedly decreased degree of crystallinity in contrast to the type-A crystal form of the WT and waxy starches. In the high-amylose sweet potato starches, the rise of setback value and the reduction of breakdown value led to the high shear resistance as indicated by the higher G', G", and tanδ from the oscillation test. ΔH was not found to be decreased with the reduction of crystallinity. The shear stress resistance of starch gel after gelatinization was also enhanced as amylose content increased. Principal component analysis also confirmed that the amylose content greatly influenced the starch structure and properties, e.g., storage modulus, setback value, and average chain length. Thus, our study not only shed light on how amylose content affects starch properties but also identified novel starches that are available for various applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Physicochemical properties of maca starch.

    PubMed

    Zhang, Ling; Li, Guantian; Wang, Sunan; Yao, Weirong; Zhu, Fan

    2017-03-01

    Maca (Lepidium meyenii Walpers) is gaining research attention due to its unique bioactive properties. Starch is a major component of maca roots, thus representing a novel starch source. In this study, the properties of three maca starches (yellow, purple and black) were compared with commercially maize, cassava, and potato starches. The starch granule sizes ranged from 9.0 to 9.6μm, and the granules were irregularly oval. All the maca starches presented B-type X-ray diffraction patterns, with the relative degree of crystallinity ranging from 22.2 to 24.3%. The apparent amylose contents ranged from 21.0 to 21.3%. The onset gelatinization temperatures ranged from 47.1 to 47.5°C as indicated by differential scanning calorimetry. Significant differences were observed in the pasting properties and textural parameters among all of the studied starches. These characteristics suggest the utility of native maca starch in products subjected to low temperatures during food processing and other industrial applications.

  8. Phosphoglucan phosphatase function sheds light on starch degradation.

    PubMed

    Silver, Dylan M; Kötting, Oliver; Moorhead, Greg B G

    2014-07-01

    Phosphoglucan phosphatases are novel enzymes that remove phosphates from complex carbohydrates. In plants, these proteins are vital components in the remobilization of leaf starch at night. Breakdown of starch is initiated through reversible glucan phosphorylation to disrupt the semi-crystalline starch structure at the granule surface. The phosphoglucan phosphatases starch excess 4 (SEX4) and like-SEX4 2 (LSF2) dephosphorylate glucans to provide access for amylases that release maltose and glucose from starch. Another phosphatase, LSF1, is a putative inactive scaffold protein that may act as regulator of starch degradative enzymes at the granule surface. Absence of these phosphatases disrupts starch breakdown, resulting in plants accumulating excess starch. Here, we describe recent advances in understanding the biochemical and structural properties of each of these starch phosphatases.

  9. Engineering Potato Starch with a Higher Phosphate Content

    PubMed Central

    Xu, Xuan; Huang, Xing-Feng; Visser, Richard G. F.

    2017-01-01

    Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a carbohydrate-binding module and a dual-specificity phosphatase domain, is involved in the dephosphorylation of glycogen. To modify phosphate content and better understand starch (de)phosphorylation in storage starch, laforin was engineered and introduced into potato (cultivar Kardal). Interestingly, expression of an (engineered) laforin in potato resulted in significantly higher phosphate content of starch, and this result was confirmed in amylose-free potato genetic background (amf). Modified starches exhibited altered granule morphology and size compared to the control. About 20–30% of the transgenic lines of each series showed red-staining granules upon incubation with iodine, and contained higher phosphate content than the blue-stained starch granules. Moreover, low amylose content and altered gelatinization properties were observed in these red-stained starches. Principle component and correlation analysis disclosed a complex correlation between starch composition and starch physico-chemical properties. Ultimately, the expression level of endogenous genes involved in starch metabolism was analysed, revealing a compensatory response to the decrease of phosphate content in potato starch. This study provides a new perspective for engineering starch phosphate content in planta by making use of the compensatory mechanism in the plant itself. PMID:28056069

  10. Engineering Potato Starch with a Higher Phosphate Content.

    PubMed

    Xu, Xuan; Huang, Xing-Feng; Visser, Richard G F; Trindade, Luisa M

    2017-01-01

    Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a carbohydrate-binding module and a dual-specificity phosphatase domain, is involved in the dephosphorylation of glycogen. To modify phosphate content and better understand starch (de)phosphorylation in storage starch, laforin was engineered and introduced into potato (cultivar Kardal). Interestingly, expression of an (engineered) laforin in potato resulted in significantly higher phosphate content of starch, and this result was confirmed in amylose-free potato genetic background (amf). Modified starches exhibited altered granule morphology and size compared to the control. About 20-30% of the transgenic lines of each series showed red-staining granules upon incubation with iodine, and contained higher phosphate content than the blue-stained starch granules. Moreover, low amylose content and altered gelatinization properties were observed in these red-stained starches. Principle component and correlation analysis disclosed a complex correlation between starch composition and starch physico-chemical properties. Ultimately, the expression level of endogenous genes involved in starch metabolism was analysed, revealing a compensatory response to the decrease of phosphate content in potato starch. This study provides a new perspective for engineering starch phosphate content in planta by making use of the compensatory mechanism in the plant itself.

  11. Effects of grain development on formation of resistant starch in rice.

    PubMed

    Shu, Xiaoli; Sun, Jian; Wu, Dianxing

    2014-12-01

    Three rice mutants with different contents of resistant starch (RS) were selected to investigate the effects of grain filling process on the formation of resistant starch. During grain development, the content of RS was increased with grain maturation and showed negative correlations with the grain weight and the starch molecular weight (Mn, Mw) and a positive correlation with the distribution of molecular mass (polydispersity, Pd). The morphologies of starch granules in high-RS rice were almost uniform in single starch granules and exhibited different proliferation modes from common rice. The lower activities of ADP-glucose pyrophosphorylase and starch branching enzyme and the higher activity of starch synthase and starch de-branching enzyme observed in high-RS rice might be responsible for the formation of small irregular starch granules with large spaces between them. In addition, the lower molecular weight and the broad distribution of molecular weights lead to differences in the physiochemical properties of starch.

  12. Structural and physicochemical characteristics of starch from sugar cane and sweet sorghum stalks.

    PubMed

    Alves, Fernanda Viginotti; Polesi, Luís Fernando; Aguiar, Cláudio Lima; Sarmento, Silene Bruder Silveira

    2014-10-13

    The starch present in sugar cane and sorghum juice has been considered a problem to the sugar industry. The objective of this work was to study the structural and physicochemical characteristics of the starch present in sugar cane and sweet sorghum. Sugar cane and sweet sorghum starches presented small granules (maximum 5.9 and 7.9 μm), A-type diffraction pattern, high degree of relative crystallinity (44.4 and 42.0%), and low amylose content (17.5 and 16.4%), respectively. Sugar cane starch presented more uniformity in granule shape and size, more homogeneity in amylose chain length, higher number of long lateral chains of amylopectin, and higher susceptibility to enzymatic digestion. Besides being in higher amount in the juice, sweet sorghum starch presented lower values for thermal properties of gelatinization, as well as higher swelling factor, which can cause more problems during processing. Additional studies are needed to evaluate the variety and maturity influence on these properties.

  13. Effect of acid concentration and treatment time on acid-alcohol modified jackfruit seed starch properties.

    PubMed

    Dutta, Himjyoti; Paul, Sanjib Kumar; Kalita, Dipankar; Mahanta, Charu Lata

    2011-09-15

    The properties of starch extracted from jackfruit (Artocarpus heterophyllus Lam.) seeds, collected from west Assam after acid-alcohol modification by short term treatment (ST) for 15-30min with concentrated hydrochloric acid and long term treatment (LT) for 1-15days with 1M hydrochloric acid, were investigated. Granule density, freeze thaw stability, solubility and light transmittance of the treated starches increased. A maximum decrease in the degree of polymerisation occurred in ST of 30min (2607.6). Jackfruit starch had 27.1±0.04% amylose content (db), which in ST initially decreased and then increased with the severity of treatment; in LT the effect was irregular. The pasting profile and granule morphology of the treated samples were severely modified. Native starch had the A-type crystalline pattern and crystalline structure increased on treatment. FTIR spectra revealed slight changes in bond stretching and bending. Colour measurement indicated that whiteness increased on treatment. Acid modified jackfruit seed starch can have applications in the food industry. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Influence of botanic origin and amylose content on the morphology of starch nanocrystals

    NASA Astrophysics Data System (ADS)

    LeCorre, Déborah; Bras, Julien; Dufresne, Alain

    2011-12-01

    Starch nanocrystals (SNC) are crystalline platelets resulting from the disruption of the semi-crystalline structure of starch granules by the acid hydrolysis of amorphous parts. The aim of this study was to assess the influence of botanic origin and amylose content of native starches on the morphology and properties of resulting nanoparticles. SNC were prepared from five different starches normal maize, high amylose maize, waxy maize, potato, and wheat; covering three botanic origins, two crystalline types, and three range of amylose content (0, 25, and 70%) for maize starch. Different types of nanocrystals were obtained with a thickness ranging between 4 and 8 nm and diameter from about 50 to 120 nm depending on the source. The comparison of their morphology, crystallinity, and rheological properties is proposed for the first time. For the same amylose content, maize, potato, and wheat resulted in rather similar size and crystallinity of SNC proving the limited influence of the botanic origin. For the same botanic origin (maize), differences in size were more important indicating the influence of the amylopectin content. Also, particles tended to show square shapes with increasing native starch's amylopectin content and A-type crystalinity. Thus, only high amylose content starches should be avoided to prepare SNC.

  15. Starch poisoning

    MedlinePlus

    Cooking starch poisoning; Laundry starch poisoning ... Cooking and laundry starch are both made from vegetable products, most commonly: Corn Potatoes Rice Wheat Both are usually considered nonpoisonous (nontoxic), but ...

  16. Transitory and storage starch metabolism: two sides of the same coin?

    PubMed

    Lloyd, James Richard; Kossmann, Jens

    2015-04-01

    The industrially important polymer, starch, is manufactured through a complex process involving multiple isoforms of several different enzymes. These contribute to alter the structure of starch which, in turn, affects its downstream industrial use. This review compares recent advances in our knowledge of starch metabolism in leaves and storage organs. Starch granule initiation and formation, enzyme complexes involved in starch metabolism and control of flux in starch synthesis and degradation are examined.

  17. Effect of the phytate and hydrogen peroxide chemical modifications on the physicochemical and functional properties of wheat starch.

    PubMed

    Sun, Fusheng; Liu, Jiannan; Liu, Xiyan; Wang, Yuesheng; Li, Kexiu; Chang, Junli; Yang, Guangxiao; He, Guangyuan

    2017-10-01

    To investigate the characteristics of chemically modified wheat starch, such as oxidized (OWS), cross-linked (CLWS) and dual-modified wheat starches, cross-linked oxidized (COWS) and oxidized cross-linked (OCWS) wheat starches were obtained by 12% hydrogen peroxide (H2O2) and 2% sodium phytate treatments, respectively. After modifications of wheat starch by cross-linking and oxidization, it was determined that native wheat starch was effectively modified with respect to the structure and physicochemical characteristics, as detected by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), Rapid Visco Analyzer (RVA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). DSC analysis demonstrated that peak temperature (Tp) 64.41°C of the COWS was the highest. The RVA viscosity indexes of CLWS were noticeably increased compared with the other four starches, of which three oxidized starch samples showed lower RVA profiles because of oxidation. The XRD result indicated that cross-linked phosphates from sodium phytate were primarily located in the amorphous regions of starch granules. After modifications by different treatments, the starch samples exhibited different morphological characteristics, including A-type and B-type wheat starch granules, which showed much closer contact with each other by the cross-linking reaction under SEM observations. The functional characteristics, including solubility, swelling power, light transmittance and freeze-thaw stability (FTS), of all five treated and untreated wheat starches demonstrated that COWS had the highest solubility at 0.57 and that CLWS showed the best swelling power at 12.63 (g/g). The paste clarity of COWS was improved to 47.72% higher than that of native starch (7.54%), and the water loss of COWS (21.62%) was the lowest, which is beneficial to the production of quick-frozen food. Our results showed that dual-modified starch by using sodium phytate and hydrogen peroxide

  18. Biogenesis and Degradation of Starch

    PubMed Central

    Ohad, Itzhak; Friedberg, Ilan; Ne'Eman, Zvi; Schramm, Michael

    1971-01-01

    Storage of mature or developing potato tubers (Solanum tuberosum “Up-to-Date” variety) at 4 C causes a reduction in the starch content and the elevation in the level of free sugars. This phenomenon is not observed when the tubers are stored at 25 C. Changes in the morphology of cells from developing or mature tubers after storage at 4 or 25 C have been followed by electron microscopy. During all stages of the tuber development the starch granules are surrounded by a membrane derived from the plastid envelope. Storage in the cold induces disintegration of this membrane. A membrane fraction isolated from starch granules of tubers stored at 4 C has a lower buoyant density, and the electrophoretic pattern of its proteins is different from that of a similar membrane fraction obtained from tubers stored at 25 C. It is suggested that the cold-induced changes in the starch and sugar content during storage of potato tubers might be correlated with damage to the membranes surrounding the starch granules and changes in their permeability to degradative enzymes and substrates. Images PMID:16657644

  19. Solvent effects on starch dissolution and gelatinization.

    PubMed

    Koganti, Nagamani; Mitchell, John R; Ibbett, Roger N; Foster, Tim J

    2011-08-08

    The disruption of starch granular structure during dissolution in varying concentrations of N-methyl morpholine N-oxide (NMMO) has been studied using three maize starches with varying ratios of amylose and amylopectin. Behavior in NMMO has been characterized by differential scanning calorimetry (DSC), microscopy, rapid viscosity analysis (RVA), and rheometry. Exothermic transitions were observed for the three starches in both 78 and 70% NMMO; the transition changed to an endotherm at 60 and 50% NMMO. Consistent with DSC, hot stage microscopy showed that starch granules dissolved at NMMO concentrations of 78 and 70%, whereas in 60 and 50% NMMO, gelatinization behavior similar to that found for starch in water was observed. Mechanical spectroscopy revealed the dominant viscous behavior (G″ > G') of starch at NMMO concentrations of 70 and 78% and more elastic behavior (G' > G″) at lower concentrations. Starch solutions in 78% NMMO obey the Cox-Merz rule, suggesting that the solutions are homogeneous on a molecular level.

  20. Native starch in tablet formulations: properties on compaction.

    PubMed

    Bos, C E; Bolhuis, G K; Van Doorne, H; Lerk, C F

    1987-10-16

    Maize, potato, rice and tapioca (cassava) starch were evaluated with respect to their properties on direct compression. Rice starch showed much better compactibility as compared to maize, potato and tapioca starch. Moreover, its binding capacity proved to be almost insensitive to mixing with magnesium stearate. This in contrast to the dramatic decrease in crushing strength of potato starch tablets containing the lubricant. The compactibility of the starches was found to be strongly affected by the equilibrium moisture content of the starches, which is dependent on the relative humidity of the atmosphere under which the powders were stored. All starches showed adequate capacity for water uptake to act as a disintegrant. Rice starch exhibited worst flowability, caused by its fine particle size as compared to the other starches. Granulation of rice starch changed it into a potential filler-binder in tablets prepared by direct compression.

  1. Model approach to starch functionality in bread making.

    PubMed

    Goesaert, Hans; Leman, Pedro; Delcour, Jan A

    2008-08-13

    We used modified wheat starches in gluten-starch flour models to study the role of starch in bread making. Incorporation of hydroxypropylated starch in the recipe reduced loaf volume and initial crumb firmness and increased crumb gas cell size. Firming rate and firmness after storage increased for loaves containing the least hydroxypropylated starch. Inclusion of cross-linked starch had little effect on loaf volume or crumb structure but increased crumb firmness. The firming rate was mostly similar to that of control samples. Presumably, the moment and extent of starch gelatinization and the concomitant water migration influence the structure formation during baking. Initial bread firmness seems determined by the rigidity of the gelatinized granules and leached amylose. Amylopectin retrogradation and strengthening of a long-range network by intensifying the inter- and intramolecular starch-starch and possibly also starch-gluten interactions (presumably because of water incorporation in retrograded amylopectin crystallites) play an important role in firming.

  2. Effect of gelatinization and starch-emulsifier interactions on aroma release from starch-rich model systems.

    PubMed

    Lopes Da Silva, J A; Castro, Sónia M; Delgadillo, Ivonne

    2002-03-27

    Release of selected volatile aldehyde compounds from starch-rich matrices was studied by headspace extraction, using solid-phase microextraction, and gas chromatography. Changes in the rheological properties of the starch-based matrices, due to starch concentration, gelatinization, and interactions with emulsifiers, were studied by steady shear and dynamic methods. The degree of volatile retention was found to depend on the compound properties, starch concentration, native structure of the granules, and presence of emulsifiers. The nongelatinized starch granules were more effective in lowering the volatile headspace quantities. Loss of the native structural integrity of the granules decreases the retention ability. For the nongelatinized starch dispersions, the more hydrophilic emulsifier showed a more pronounced effect on the matrix rheology and also on the aroma retention. A different behavior was observed for the gelatinized systems. Interpretation of the volatile release profiles was made on the basis of the matrix physical properties and interactions among components.

  3. Electron microscopy and composition of raw acorn starch in relation to in vivo starch digestibility.

    PubMed

    Cappai, Maria Grazia; Alesso, Giuseppe Andrea; Nieddu, Giuseppa; Sanna, Marina; Pinna, Walter

    2013-06-01

    The structure and composition of starch play an important role as co-factors affecting raw starch digestibility: such features were investigated in raw acorn starch from the most diffused oak trees in the Mediterranean basin. A total of 620 whole ripe acorns from Holm (Quercus ilex L., n = 198), Downy (Quercus pubescens Willd., n = 207) and Cork (Quercus suber L., n = 215) oaks sampled on the Sardinia Isle (40° 56' 0'' N; 9° 4' 0'' E; 545 m above the mean sea level) in the same geographical area, were analyzed for their chemical composition. The starch contents ranged between 51.2% and 53.5% of dry matter. The starch granules displayed a spheroid/ovoid and cylindrical shape; on scanning electron microscopic (SEM) analyses, a bimodal distribution of starch granule size was observed both for Holm and Cork oak acorns, whereas the starch granules of Downy oak acorns showed diameters between 10.2 and 13.8 μm. The specific amylose to amylopectin ratio of acorn starch was 25.8%, 19.5% and 34.0% in the Holm, Downy and Cork oaks, respectively. The (13)C Nuclear Magnetic Resonance (NMR) signal analysis displayed a pivotal spectrum for the identification of the amylose peaks in raw acorn starch, as a basis for the amylose to amylopectin ratio determination.

  4. Effects of starch synthase IIa gene dosage on grain, protein and starch in endosperm of wheat.

    PubMed

    Konik-Rose, Christine; Thistleton, Jenny; Chanvrier, Helene; Tan, Ihwa; Halley, Peter; Gidley, Michael; Kosar-Hashemi, Behjat; Wang, Hong; Larroque, Oscar; Ikea, Joseph; McMaugh, Steve; Regina, Ahmed; Rahman, Sadequr; Morell, Matthew; Li, Zhongyi

    2007-11-01

    Starch synthases (SS) are responsible for elongating the alpha-1,4 glucan chains of starch. A doubled haploid population was generated by crossing a line of wheat, which lacks functional ssIIa genes on each genome (abd), and an Australian wheat cultivar, Sunco, with wild type ssIIa alleles on each genome (ABD). Evidence has been presented previously indicating that the SGP-1 (starch granule protein-1) proteins present in the starch granule in wheat are products of the ssIIa genes. Analysis of 100 progeny lines demonstrated co-segregation of the ssIIa alleles from the three genomes with the SGP-1 proteins, providing further evidence that the SGP-1 proteins are the products of the ssIIa genes. From the progeny lines, 40 doubled haploid lines representing the eight possible genotypes for SSIIa (ABD, aBD, AbD, ABd, abD, aBd, Abd, abd) were characterized for their grain weight, protein content, total starch content and starch properties. For some properties (chain length distribution, pasting properties, swelling power, and gelatinization properties), a progressive change was observed across the four classes of genotypes (wild type, single nulls, double nulls and triple nulls). However, for other grain properties (seed weight and protein content) and starch properties (total starch content, granule morphology and crystallinity, granule size distribution, amylose content, amylose-lipid dissociation properties), a statistically significant change only occurred for the triple nulls, indicating that all three genes had to be missing or inactive for a change to occur. These results illustrate the importance of SSIIa in controlling grain and starch properties and the importance of amylopectin fine structure in controlling starch granule properties in wheat.

  5. Structural characteristics and crystalline properties of lotus seed resistant starch and its prebiotic effects.

    PubMed

    Zhang, Yi; Zeng, Hongliang; Wang, Ying; Zeng, Shaoxiao; Zheng, Baodong

    2014-07-15

    Lotus seed resistant starch (LRS) is a type of retrograded starch that is commonly known as resistant starch type 3 (RS3). The structural and crystalline properties of unpurified LRS (NP-LRS3), enzyme purified LRS after drying (GP-LRS3), and enzyme purified LRS (ZP-LRS3) were characterized. The result showed that the molecular weights of NP-LRS3, GP-LRS3, and ZP-LRS3 were 0.102 × 10(6), 0.014 × 10(6), and 0.025 × 10(6)Da, respectively. Compared with native starch and high amylose maize starch (HAMS), LRS lacked the polarization cross and the irregularly shaped LRS granules had a rougher surface, B-type crystal structure, and greater level of molecular order. The FT-IR measurements indicated no differences in the chemical groups. Analysis by (13)C NMR indicated an increased propensity for double helix formation and higher crystallinity in LRS than in the two other types of starch. Moreover, LRS was more effective than either glucose or HAMS in promoting the proliferation of bifidobacteria.

  6. Characterization of potato leaf starch.

    PubMed

    Santacruz, Stalin; Koch, Kristine; Andersson, Roger; Aman, Per

    2004-04-07

    The starch accumulation-degradation process as well as the structure of leaf starch are not completely understood. To study this, starch was isolated from potato leaves collected in the early morning and late afternoon in July and August, representing different starch accumulation rates. The starch content of potato leaves varied between 2.9 and 12.9% (dry matter basis) over the night and day in the middle of July and between 0.6 and 1.5% in August. Scanning electron microscopy analyses of the four isolated starch samples showed that the granules had either an oval or a round shape and did not exceed 5 microm in size. Starch was extracted by successive washing steps with dimethyl sulfoxide and precipitated with ethanol. An elution profile on Sepharose CL-6B of debranched starch showed the presence of a material with a chain length distribution between that generally found for amylose and amylopectin. Amylopectin unit chains of low molecular size were present in a higher amount in the afternoon than in the morning samples. What remains at the end of the night is depleted in specific chain lengths, mainly between DP 15 and 24 and above DP 35, relative to the end of the day.

  7. Structural and physicochemical characterisation of rye starch.

    PubMed

    Gomand, S V; Verwimp, T; Goesaert, H; Delcour, J A

    2011-12-13

    The gelatinisation, pasting and retrogradation properties of three rye starches isolated using a proteinase-based procedure were investigated and compared to those of wheat starch isolated in a comparable way. On an average, the rye starch granules were larger than those of wheat starch. The former had very comparable gelatinisation temperatures and enthalpies, but slightly lower gelatinisation temperatures than wheat starch. Under standardised conditions, they retrograded to a lesser extent than wheat starch. The lower gelatinisation temperatures and tendencies of the rye starches to retrograde originated probably from their higher levels of short amylopectin (AP) chains [degree of polymerisation (DP) 6-12] and their lower levels of longer chains (DP 13-24) than observed for wheat starch. The rapid visco analysis differences in peak and end viscosities between the rye starches as well as between rye and wheat starches were at least partly attributable to differences in the levels of AP short chains and in average amylose molecular weight. The AP average chain lengths and exterior chain lengths were slightly lower for rye starches, while the interior chain lengths were slightly higher than those for wheat starch.

  8. Functional and rheological properties of cold plasma treated rice starch.

    PubMed

    Thirumdas, Rohit; Trimukhe, A; Deshmukh, R R; Annapure, U S

    2017-02-10

    The present work deals with aimed to study the effect of cold plasma treatment on the functional and rheological properties of rice starch using two different power levels (40 and 60W). The changes in amylose content, turbidity, pH, water and fat absorption due to plasma treatment were evaluated. Where decrease in the turbidity and pH after the treatment was observed. Gel hydration properties and syneresis study revealed that there is an increase in leaching of amylose molecules after the treatment. Rapid Visco Analyzer examination showed an increase in pasting and final viscosities. From G' and G″ moduli determination we observed that there is decrease in retrogradation tendency of starch gels. XRD did not show any change in A-type pattern but decrease in the relative crystallinity was observed due to depolymerization caused by active plasma species. FTIR shows some of the additional functional groups after treatment. SEM showed formation of fissures on the surface of starch granules due to etching caused by the plasma species. Thus, plasma treatment can be one of the methods for physical modification of starch.

  9. Overcoming hydrolysis of raw corn starch under industrial conditions with Bacillus licheniformis ATCC 9945a α-amylase.

    PubMed

    Šokarda Slavić, Marinela; Pešić, Milja; Vujčić, Zoran; Božić, Nataša

    2016-03-01

    α-Amylase from Bacillus licheniformis ATCC 9945a (BliAmy) was proven to be very efficient in hydrolysis of granular starch below the temperature of gelatinization. By applying two-stage feeding strategy to achieve high-cell-density cultivation of Escherichia coli and extracellular production of BliAmy, total of 250.5 U/mL (i.e. 0.7 g/L) of enzyme was obtained. Thermostability of amylase was exploited to simplify purification. The hydrolysis of concentrated raw starch was optimized using response surface methodology. Regardless of raw starch concentration tested (20, 25, 30 %), BliAmy was very effective, achieving the final hydrolysis degree of 91 % for the hydrolysis of 30 % starch suspension after 24 h. The major A-type crystalline structure and amorphous domains of the starch granule were degraded at the same rates, while amylose-lipid complexes were not degraded. BliAmy presents interesting performances on highly concentrated solid starch and could be of value for starch-consuming industries while response surface methodology (RSM) could be efficiently applied for the optimization of the hydrolysis.

  10. Structural and physicochemical characterization of Sphenostylis stenocarpa (Hochst. ex A. Rich.) Harms tuber starch.

    PubMed

    Malumba, Paul; Bungu, Mulombo Denis; Katanga, Kabalevi Joseph; Doran, Lynn; Danthine, Sabine; Béra, François

    2016-12-01

    Several characteristics of African Yam Bean tuber starch (AYB) were studied and compared with that of a well-known native potato starch (P). The diameter of AYB granules ranged from 5.7μ to 49μ with a median at 19.5μ. During its pasting, AYB exhibited a low peak of viscosity in accordance with its low granules swelling and disintegration capacity. The gelatinization temperature of AYB was 75.2°C while that of P was 60.4°C. AYB was observed to be more stable during thermo-gravimetrical Analysis. Its degradation peak was observed at 308°C while that of P was 303°C. The X-ray diffraction analysis revealed that AYB belongs to the A-type crystalline group instead of C-type as claimed for several legumes starches. The stability of AYB and its capacity to structure starch-water systems make this resource an interesting ingredient for new food and non-food products.

  11. Characterization of starch from two ecotypes of andean achira roots (Canna edulis).

    PubMed

    Cisneros, Fausto H; Zevillanos, Roberto; Cisneros-Zevallos, Luis

    2009-08-26

    Starches from two ecotypes of achira roots (Canna edulis Ker-Gawler) were characterized and compared to commercial potato and corn starches. This included scanning electron microscopy (SEM) of starch granules and amylose content determination of starch. Starch solutions or gels were tested by rotational viscometry, Rapid Visco Analyzer (RVA), and texture analysis. Some starch samples were subjected to various treatments: pH reduction, autoclaving at high temperature, and high shear before testing by rotational viscometry. Achira starch showed some unusual properties, such as very large oblong granules (approximately 45-52 microm major axis and approximately 33-34 microm minor axis) and relatively high amylose content (approximately 33-39%). The San Gaban achira ecotype formed high-consistency gels upon cooling, both in RVA study (5% starch) and in texture analysis (8% starch), compared to other starch gels and also exhibited higher thermal resistance to viscosity breakdown.

  12. Structural features and thermal property of propionylated starches with different amylose/amylopectin ratio.

    PubMed

    Zhu, Jie; Zhang, Shuyan; Zhang, Binjia; Qiao, Dongling; Pu, Huayin; Liu, Siyuan; Li, Lin

    2017-04-01

    This work concerned the effects of amylose/amylopectin ratio on the structure and thermal stability of propionylated starches with high degree of substitution (DS). Four starches with different amylose content were used to obtain propionylated starches. Acylation partly disrupted granule morphology of native starches, and the imperfection and porous structures of starch granule were intensified along with the increased amylose content. It was noted that the crystalline structure of starch was destroyed and thus intense acylation occurred in both amorphous and crystalline regions. The acylated starch with high-amylose content displayed more ordered region compared to low-amylose starch. Acylation enhanced the thermal stability of starch, and this effect became more evident as the amylose content increased. Thus, the amylose/amylopectin ratio has been confirmed capable of affecting the structure and thermal behaviors of hydrophobic propionylated starch, which is of value for the design of starchy materials with tailored thermal stability.

  13. The Simultaneous Abolition of Three Starch Hydrolases Blocks Transient Starch Breakdown in Arabidopsis*

    PubMed Central

    Streb, Sebastian; Eicke, Simona; Zeeman, Samuel C.

    2012-01-01

    In this study, we investigated which enzymes are involved in debranching amylopectin during transient starch degradation. Previous studies identified two debranching enzymes, isoamylase 3 (ISA3) and limit dextrinase (LDA), involved in this process. However, plants lacking both enzymes still degrade substantial amounts of starch. Thus, other enzymes/mechanisms must contribute to starch breakdown. We show that the chloroplastic α-amylase 3 (AMY3) also participates in starch degradation and provide evidence that all three enzymes can act directly at the starch granule surface. The isa3 mutant has a starch excess phenotype, reflecting impaired starch breakdown. In contrast, removal of AMY3, LDA, or both enzymes together has no impact on starch degradation. However, removal of AMY3 or LDA in addition to ISA3 enhances the starch excess phenotype. In plants lacking all three enzymes, starch breakdown is effectively blocked, and starch accumulates to the highest levels observed so far. This provides indirect evidence that the heteromultimeric debranching enzyme ISA1-ISA2 is not involved in starch breakdown. However, we illustrate that ISA1-ISA2 can hydrolyze small soluble branched glucans that accumulate when ISA3 and LDA are missing, albeit at a slow rate. Starch accumulation in the mutants correlates inversely with plant growth. PMID:23019330

  14. Adhesion of Vibrio cholerae to granular starches.

    PubMed

    Gancz, Hanan; Niderman-Meyer, Orly; Broza, Meir; Kashi, Yechezkel; Shimoni, Eyal

    2005-08-01

    Cholera is a severe diarrheal disease caused by specific serogroups of Vibrio cholerae that are pathogenic to humans. Cholera can become epidemic and deadly without adequate medical care. Appropriate rehydration therapy can reduce the mortality rate from as much as 50% of the affected individuals to <1%. Thus, oral rehydration therapy (ORT) is an important measure in the treatment of this disease. To further reduce the symptoms associated with cholera, improvements in oral rehydration solution (ORS) by starch incorporation were suggested. Here, we report that V. cholerae adheres to starch granules incorporated in ORS. Adhesion of 98% of the cells was observed within 2 min when cornstarch granules were used. Other starches showed varied adhesion rates, indicating that starch source and composition play an important role in the interaction of V. cholerae and starch granules. Sugars metabolized by V. cholerae showed a repressive effect on the adhesion process. The possible mechanisms involved are discussed. Comparing V. cholerae adhesion with the adhesion of other pathogens suggests the involvement of starch degradation capabilities. This adhesion to granular starch can be used to improve ORT.

  15. Physicochemical properties and digestibility of hydrothermally treated waxy rice starch.

    PubMed

    Zeng, Feng; Ma, Fei; Kong, Fansheng; Gao, Qunyu; Yu, Shujuan

    2015-04-01

    Waxy rice starch was subjected to annealing (ANN) and heat-moisture treatment (HMT). These starches were also treated by a combination of ANN and HMT. The impact of single and dual modifications (ANN-HMT and HMT-ANN) on the molecular weight (M(w)), crystalline structure, thermal properties, and the digestibility were investigated. The relative crystallinity and short-range order on the granule surface increased on ANN, whereas decreased on HMT. All treated starches showed lower M(w) than that of the native starch. Gelatinization onset temperature, peak temperature and conclusion temperature increased for both single and dual treatments. Increased slowly digestible starch content was found on HMT and ANN-HMT. However, resistant starch levels decreased in all treated starches as compared with native starch. The results would imply that hydrothermal treatment induced structural changes in waxy rice starch significantly affected its digestibility.

  16. Structural investigations and morphology of tomato fruit starch.

    PubMed

    Luengwilai, Kietsuda; Beckles, Diane M

    2009-01-14

    The physicochemical properties of starch from tomato (Solanum lycopersicum L.) pericarp and columella of cv. Moneymaker fruit at 28 days post anthesis (DPA) were investigated, providing the first description of the composition and structure of tomato fruit starch. Starch granules from pericarp were mainly polygonal, 13.5-14.3 microm, and increased in size through development, being largest in ripening fruit. Amylopectin content was 81-83% and was of molecular weight 1.01 x 10(8) g/mol; the phosphorus content was 139 ppm, and starch showed a C-type pattern with crystallinity of 30%. Starch characteristics were similar in columella except granule size (16.8-17.8 microm) and crystallinity (40%), although 6-fold more starch accumulated in the pericarp. Solara, a high-sugar tomato cultivar, was also studied to determine if this affects starch granule architecture. There were few differences from Moneymaker, except that Solara columella starch crystallinity was lower (26%), and more starch granule-intrinsic proteins could be extracted by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

  17. Sedimentation field flow fractionation monitoring of bimodal wheat starch amylolysis.

    PubMed

    Salesse, C; Battu, S; Begaud-Grimaud, G; Cledat, D; Cook-Moreau, J; Cardot, P J P

    2006-10-06

    Enzymatic starch granule hydrolysis is one of the most important reactions in many industrial processes. In this study, we investigated the capacity of sedimentation field flow fractionation (SdFFF) to monitor the amylolysis of a bimodal starch population: native wheat starch. Results demonstrated a correlation between fractogram changes and enzymatic hydrolysis. Furthermore, SdFFF was used to sort sub-populations which enhanced the study of granule size distribution changes occurring during amylolysis. These results show the interest in coupling SdFFF with particle size measurement methods to study complex starch size/density modifications associated to hydrolysis. These results suggested different applications such as the association of SdFFF with structural investigations to better understand the specific mechanisms of amylolysis or starch granule structure.

  18. Effect of germination on the structures and physicochemical properties of starches from brown rice, oat, sorghum, and millet.

    PubMed

    Li, Cheng; Oh, Sea-Gwan; Lee, Dong-Hyun; Baik, Hyun-Wook; Chung, Hyun-Jung

    2017-07-22

    Four selected grains (brown rice, oat, sorghum, and millet) were subjected to germinate and changes in granule morphology, molecular structure, crystalline structure, and physicochemical properties of isolated starch were investigated. The germinated starches showed pits and holes on the surface of the starch granules and the particle size distributions shifted slightly to smaller size as the germination time increased. Germination led to decrease in amylose content, while molecular weights of the germinated starches showed no significant changes. The relative crystallinity of all selected grain starches decreased significantly during germination. Compared to the native starches, the germinated starches had lower retrogradation enthalpy. Brown rice and oat starches exhibited marginal increases in peak viscosities, whereas those of sorghum and millet starches decreased significantly during germination. Amylose leaching of brown rice and oat starches decreased after germination, whereas sorghum and millet starches showed an increase in amylose leaching. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Rheological behaviour of heated potato starch dispersions

    NASA Astrophysics Data System (ADS)

    Juszczak, L.; Witczak, M.; Ziêba, T.; Fortuna, T.

    2012-10-01

    The study was designed to investigate the rheological properties of heated potato starch dispersions. Water suspensions of starch were heated at 65, 80 or 95°C for 5, 15, 30 or 60 min. The dispersions obtained were examined for granule size distribution and rheology. It was found that the starch dispersions significantly differed in both respects. The mean diameters of starch granules were largest for the dispersion heated at 65°C and smallest for that heated at 95°C. As the heating temperature was raised, the yield stresses and consistency coefficients decreased, while the flow behaviour indexes and Casson plastic viscosities increased. There were also differences in the viscoelastic properties of the dispersions: for those heated at 65°C the storage and loss moduli increased with heating time whereas for those heated at 80°C both moduli decreased.

  20. Effect of amylose, particle size & morphology on the functionality of starches of traditional rice cultivars.

    PubMed

    Bhat, Farhan Mohiuddin; Riar, Charanjit Singh

    2016-11-01

    The research was carried out to investigate the effect of starch powder particle size, morphology, amylose content and varietal effect on physicochemical, X-ray diffraction pattern, thermal and pasting characteristics. The results indicated that starches isolated from seven traditional rice cultivars of temperate region of India have possessed higher yield (82.47-86.83%) with lower degree of granule damage and higher level of starch crystallinity (36.55-39.15%). The water and oil binding capacities were observed to correlate positively with amylose content. The bulk density and color parameters of starches were found to have linked with starch powder particle size coupled with arrangement and morphology of the starch granules. The rice cultivars having smaller starch powder particle size indicated lowest degree of crystallinity. Morphological studies revealed that the starches with tightly packed granules had greater mean granular width, while granules with openly spaced granular morphology depicted the higher values for mean granular length. The peak height index (PHI) among different starches ranged from 1.01 to 2.57 whereas the gelatinization range varied from 10.66 to 10.88. Concluding, the differences in distributional pattern of starch granule size and shape and powder particle size indicated a significant effect on the functional properties of starch. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Amylopectin small chain glucans form structure fingerprint that determines botanical origin of starch.

    PubMed

    Jaiswal, Sarita; Chibbar, Ravindra N

    2017-02-20

    Starch granule size, shape and structure of amylopectin are species specific and influence starch properties and end-use of starch. Amylopectin glucan chain structure was used to predict the starch botanical sources. Mathematical probability for accumulation of small glucan chains DP 6-10 reveal exponential fit curve with maximum R(2) in smallest granule size starches (Chlamydomonas, quinoa, buckwheat). Cereal and cassava showed R(2) of 0.81-0.96 while in pulses and tubers it was less than 0.7. The amylopectin small glucan chains form a unique 'finger print region' that identified starch botanical source. Differential amylopectin chain length distribution (APCLD) graphs between DP 6-80 of all species from Chlamydomonas starch distinguished five structural groups that clustered the 31 analyzed starches into four major patterns. APCLD analyses of amylopectin combined with characteristic pattern of small linear DP (6-9) glucan chains predicted the starch botanical source.

  2. Analysis of Cereal Starches by High Performance Size Exclusion Chromatography

    USDA-ARS?s Scientific Manuscript database

    Starch has unique physicochemical characteristics among carbohydrates. Most starch granules are a mixture of two sugar polymers: a highly branched polysaccharide named amylopectin, and a basically linear polysaccharide named amylose. The objective of this study was to develop a simple, one-step and ...

  3. A rapid method to determine starch damage in sorghum

    USDA-ARS?s Scientific Manuscript database

    As a major component of cereal grains including sorghum, starch plays an important role not only in grain development but also post-maturation processing and end-product quality. Because milling can result in the inadvertent disruption of starch granules, in turn negatively affecting dough rheology...

  4. Gelatinization and solubility of corn starch during heating in excess water: new insights.

    PubMed

    Ratnayake, Wajira S; Jackson, David S

    2006-05-17

    Starch gelatinization is associated with the disruption of granular structure causing starch molecules to disperse in water. This study was designed to examine starch granules as they were heated in water, and their resulting morphological, structural, and solubility traits. The results indicate that starch gelatinization is a more complex process than the previously suggested order-to-disorder transition. The energy absorbed by the granules facilitates the rearrangement or formation of new bonds among molecules prior to the temperatures normally associated with the melting of amylopectin crystallites during gelatinization. It is also evident that amylose plays an important role during the initial stages of corn starch gelatinization.

  5. Starch properties of the sago palm (Metroxylon sagu Rottb.) in different soils.

    PubMed

    Nozaki, K; Nuyim, T; Shinano, T; Hamada, S; Ito, H; Matsui, H; Osaki, M

    2004-01-01

    We investigated the relationships between starch concentrations and activities of starch synthetic enzymes in sago palms (Metroxylon sagu Rottb.) under acid sulfate and mineral soil conditions. Plants grown naturally that had reached their maturated stage were sampled. We found that the growth in acid sulfate soil is lower than that in mineral soil and that starch granules were larger and there was more amylase activity in acid sulfate soil than in mineral soil. Lower amylase activity in mineral soil could eliminate the degradation of starch, making the smaller granules suitable for storing large amounts of starch in a limited space inside cells.

  6. Effect of dry heat treatment with xanthan on waxy rice starch.

    PubMed

    Li, Yue; Zhang, Huien; Shoemaker, Charles F; Xu, Zhiting; Zhu, Song; Zhong, Fang

    2013-02-15

    Waxy rice starch was impregnated with xanthan and heat-treated in a dry state. The effects on the pasting and rheological properties of the treated starch-xanthan mixture were evaluated. Swelling of the granule was restricted, and a continuous rise of the viscosity during pasting was provided for the treated sample. After pasting, the gel forming ability of the treated starch was strengthened, as both storage and loss modulus increased and tan δ decreased. The paste also owned the highest zero order Newtonian viscosity and yield stress. An increase in starch particle size of the dry heated starch-xanthan mixture suggested a cross linking of the starch granules by the xanthan polymers. An increase of crystallinity was observed for the starch after dry heat treatment, but with the addition of xanthan the amorphous region of the granule became more resistant to dry-heating. The melting enthalpy was found to be correlated with the crystallinity.

  7. 'Green' crosslinking of native starches with malonic acid and their properties.

    PubMed

    Ghosh Dastidar, Trina; Netravali, Anil N

    2012-11-06

    Starch is a highly hydrophilic biomaterial with weak mechanical properties rendering it useless for commercial applications. A fully 'green' water based process is presented to crosslink corn (cereal) and potato (tuber) starch to enhance mechanical properties as well as lower hydrophilicity. In addition, malonic acid, a green, plant based water soluble and relatively inexpensive polycarboxylic acid, was used as the crosslinker. The reactivity of potato starch toward esterification and crosslinking was found to be higher than that of corn starch owing to the inherent differences in the granule morphology and internal structure of the two starches. It was observed that potato starch granules had a higher degree of substitution (DS) of 0.19 than corn starch granules (DS=0.1) under similar reaction conditions. Chemical, thermal and mechanical test results confirmed the crosslinking as well as reduced moisture sensitivity.

  8. Physicochemical properties and in vitro digestibility of sorghum starch altered by high hydrostatic pressure.

    PubMed

    Liu, Hang; Fan, Huanhuan; Cao, Rong; Blanchard, Christopher; Wang, Min

    2016-11-01

    A nonthermal processing technology, high hydrostatic pressure (HHP) treatment, was investigated to assess its influence on the physicochemical properties and in vitro digestibility of sorghum starch (SS). There was no change in the 'A'-type crystalline pattern of SS after the pressure treatments at 120-480MPa. However, treatment at 600MPa produced a pattern similar to 'B'-type crystalline. HHP treatment also resulted in SS granules with rough surfaces. Measured amylose content, water absorption capacity, alkaline water retention, pasting temperature and thermostability increased with increasing pressure levels, while the oil absorption capacity, swelling power, relative crystallinity and viscosity decreased. Compared with native starch, HHP-modified SS samples had lower in vitro hydrolysis, reduced amount of rapidly digestible starch, as well as increased levels of slowly digestible starch and resistant starch. These results indicate that HHP treatment is an effective modification method for altering in vitro digestibility and physicochemical properties of SS. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Synthesis, characterization and functional properties of low substituted acetylated corn starch.

    PubMed

    Han, Fei; Liu, Mingzhu; Gong, Honghong; Lü, Shaoyu; Ni, Boli; Zhang, Bing

    2012-05-01

    Acetylated corn starch (ACS) was synthesized by the reaction of native corn starch (NCS) with acetic anhydride (AA) in an aqueous medium in the presence of sodium hydroxide as a catalyst. The factors that could affect the degree of substitution (DS) and reaction efficiency (RE) of corn starch were investigated which included the reaction temperature and time, the mass ratio of AA to starch, the ratio of the water volume to starch mass and pH. The optimal DS of 0.071 and RE of 67.05% was obtained. FTIR spectrometry showed new bands at 1733, 1375 and 1252 cm(-1). The SEM of the ACS indicated some cavities on the granules which fused together, compared with NCS. Wide angle X-ray diffraction revealed that ACS had a similar profile as NCS (A type). However, the intensity of peaks were diminished. DSC thermograms exhibited that ACS had some lower gelatinization temperatures and enthalpies than NCS. The functional properties of ACS such as the swelling power, solubility, water absorption, clarity, freeze-thaw stability, retrogradation and viscosity were also studied. The results suggest that the ACS has much better functional properties than the NCS, and could be expected to have wide applications especially in food industry.

  10. Characterization of chemically modified waxy, partially waxy, and wild type tetraploid wheat starch

    USDA-ARS?s Scientific Manuscript database

    Durum wheats (Triticum turgidum L. var. durum) contain two Granule Bound Starch Synthase (GBSS) genes (wx-A1and wx-B1) controlling amylose synthesis; the other major starch polymer in durum wheat is amylopectin. Starches with little or no amylose are “waxy.” A GBSS null (non-producing) gene results ...

  11. The effect of high moisture heat-acid treatment on the structure and digestion property of normal maize starch.

    PubMed

    Liu, Huan; Liang, Rong; Antoniou, John; Liu, Fei; Shoemaker, Charles F; Li, Yue; Zhong, Fang

    2014-09-15

    The objective of this study was to analyze the influence of thermal-acid treatment on the formation of resistant starch (RS). The maximum RS content in citric acid-heat treated starches (CAHT) reached 36.55%, which was 7 times higher of that in native starch. According to HPSEC-MALLS-RI analysis, amylopectin was more susceptible to hydrolysis than amylose during citric acid-heat treatment (CAH). X-ray measurement revealed that even though the starch crystalline pattern was changed from A-type to a more resistant B-type after CAH, the fraction of crystalline region decreased from 21.16% to 8.37%. The hydroxyls on the starch chains were substituted by the citric acid anhydrides during CAH according to FT-IR analysis, which led to the formation of ester bond cross-linking structures in starch granules, and it could be the main contribution to the increase of RS content in CAHT samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Isolation and characterization of wheat bran starch and endosperm starch of selected soft wheats grown in Michigan and comparison of their physicochemical properties.

    PubMed

    Liu, Ya; Ng, Perry K W

    2015-06-01

    Three soft wheat varieties with relatively high crop yields and different levels of milling softness equivalence were studied to characterize bran starch properties compared with those of endosperm starch from the same wheat sample. Bran starch had more short chains than had endosperm starch, and was found to have a higher percentage of B-type granules, higher amylose content, higher crystallinity, broader gelatinization temperature range, higher enthalpy of gelatinization, lower retrogradation degree, and lower pasting peak and setback viscosities than had the counterpart endosperm starch. Bran starch of variety Aubrey had the highest crystallinity (21.75%) and gelatinization temperature (62.9°C), while bran starch of variety D8006 had the highest percentage of B-type granules and lowest retrogradation degree (21.7%). Results of this study provide a foundation for better utilization of bran starch during whole grain food processing. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. The impact of elevated CO2 concentration on the quality of algal starch as a potential biofuel feedstock.

    PubMed

    Tanadul, Orn-U-Ma; VanderGheynst, Jean S; Beckles, Diane M; Powell, Ann L T; Labavitch, John M

    2014-07-01

    Cultured microalgae are viewed as important producers of lipids and polysaccharides, both of which are precursor molecules for the production of biofuels. This study addressed the impact of elevated carbon dioxide (CO2) on Chlorella sorokiniana production of starch and on several properties of the starch produced. The production of C. sorokiniana biomass, lipid and starch were enhanced when cultures were supplied with 2% CO2. Starch granules from algae grown in ambient air and 2% CO2 were analyzed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The granules from algae grown in 2% CO2 were disk-shaped and contained mainly stromal starch; granules from cultures grown in ambient air were cup-shaped with primarily pyrenoid starch. The granules from cells grown in 2% CO2 had a higher proportion of the accumulated starch as the highly branched, amylopectin glucan than did granules from cells grown in air. The rate of hydrolysis of starch from 2% CO2-grown cells was 1.25 times greater than that from air-grown cells and 2-11 times higher than the rates of hydrolysis of starches from cereal grains. These data indicate that culturing C. sorokiniana in elevated CO2 not only increases biomass yield but also improves the structure and composition of starch granules for use in biofuel generation. These modifications in culture conditions increase the hydrolysis efficiency of the starch hydrolysis, thus providing potentially important gains for biofuel production.

  14. Chemical composition, mineral profile, and functional properties of Canna (Canna edulis) and Arrowroot (Maranta spp.) starches.

    PubMed

    Pérez, Elevina; Lares, Mary

    2005-09-01

    The aim of the present study was to evaluate some chemical and mineral characteristics and functional and rheological properties of Canna and Arrowroot starches produced in the Venezuelan Andes. Canna starch showed a higher (P < 0.05) moisture, ash, and crude protein content than arrowroot starch, while crude fiber, crude fat, and amylose content of this starch were higher (P < 0.05). Starches of both rhizomes own phosphorus, sodium, potassium, magnesium, iron, calcium, and zinc in their composition. Phosphorus, sodium, and potassium are the higher in both starches. Water absorption, swelling power, and solubility values revealed weak bonding forces in Canna starch granules; this explained the lower gelatinization temperature and the substantial viscosity development of Canna starch during heating. Arrowroot starch showed a higher gelatinization temperature measure by DSC, than Canna starch and exhibited a lower value of DeltaH. Both starches show negative syneresis. The apparent viscosity of Canna starch was higher (P < 0.05) than the Arrowroot starch values. The size (wide and large) of Canna starch granules was higher than arrowroot starch. From the previous results, it can be concluded that Canna and Arrowroot starches could become interesting alternatives for food developers, depending on their characteristics and functional properties.

  15. Twin screw granulation: steps in granule growth.

    PubMed

    Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2012-11-15

    The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying powder feed rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated. The granules became more spherical and their strength increased along the screw length. Tracer granules were also introduced in order to understand the role of kneading and conveying elements in the TSG. The kneading elements promoted consolidation and breakage while the conveying elements led to coalescence, breakage and some consolidation. The results presented here help to provide a qualitative and quantitative understanding of the twin screw granulation process.

  16. Granulation of coal fly ash by using different types of granule agents

    NASA Astrophysics Data System (ADS)

    Agusta, H.; Nisya, F. N.; Iman, R. N.; Bilad, D. B. C.

    2017-05-01

    The use of coal produces about 5% solid pollutant in the form of ash (fly ash and bottom ash). Of the total ash produced, about 10-20% is bottom ash and 80-90% is fly ash. This study was aimed at obtaining a type of adhesive which could be used as a fly granulation material for soil conditioner. The study was conducted at the pilot plant of Surfactant and Bioenergy Research Center (SBRC) LPPM IPB from April to August 2016. The fly ash used in this study was obtained from Kalimantan. A pan granulator was used in fly ash granule making process. Granule agent materials were diluted in the concentration of 5, 10, and 15%. Different types of granule agents, namely SBRC-M, SBRC-T, and SBRC-SC were used. The formed fly ash granules were then analyzed for their physical properties including particle density, fly ash granule pH, fly ash granule durability, and fly ash granule water holding capacity. Results showed that fly ash granules made from 15% of SBRC-M had the highest particle density (0.75 g/cm3). Fly ash granules made with SBRC-M had higher pH (10) than those made by using SBRC-SC adhesive (9.3) and SBRC-T (9). SBRC-T was found as the granule agent material which produced fly ash granules with the highest durability levels on average. In this study, the use of SBRC-M granule agent resulted in higher water holding capacity (WHC) (40.62%) than did SBRC-SC (38.79%) and SBRC-T (36.85%). As a granule agent, compared to SBRC-SC and SBRC-T, SBRC-M could produce fly ash granules with highest particle density, highest pH, good durability, and best water holding capacity.

  17. Starch nanoparticles formation via high power ultrasonication.

    PubMed

    Bel Haaj, Sihem; Magnin, Albert; Pétrier, Christian; Boufi, Sami

    2013-02-15

    Nano-sized starch particles (NSP) were prepared from starch granules using a purely physical method of high-intensity ultrasonication. Particle size distribution, Field Effect Scanning Electron Microscopy (FE-SEM), Raman spectroscopy, and Wide-Angle X-ray Diffraction (WAXD) were used to characterize the morphology and crystal structure of the ensuing nanoparticles. The results revealed that ultrasound treatment of the starch suspension in water and at low temperature for 75 min results in the formation of starch nanoparticles between 30 and 100 nm in size. An attempt to explain the generation of starch nanoparticles was made on the basis of WAXD, Raman analysis and FE-SEM observation. Compared to acid hydrolysis, which is the most commonly adopted process, the present approach has the advantage of being quite rapid, presenting a higher yield and not requiring any chemical treatment.

  18. Physicochemical and binder properties of starch obtained from Cyperus esculentus.

    PubMed

    Manek, Rahul V; Builders, Philip F; Kolling, William M; Emeje, Martins; Kunle, Olobayo O

    2012-06-01

    The purpose of this study was to isolate starch from the tubers of Cyperus esculentus L. and evaluate its physicochemical and binder properties. Extraction of starch using sodium metabisulfite yielded 37 g of starch per 100 g of the tubers. Scanning electron microscopy indicated that Cyperus starch consists of oval to elliptical particles with a smooth surface. Cyperus starch demonstrates a narrow particle size distribution with a mean of 8.25 μm. Cyperus starch conforms well to United States Pharmacopeia standards established for widely used starches like maize and potato. The X-ray powder diffraction pattern and moisture sorption profile of Cyperus starch were comparable to that of maize starch. Cyperus starch had lower swelling power than maize and potato starch, indicative of stronger associative forces within the granules. Carr's index and Hausner ratio indicate that Cyperus starch should have comparable flow properties with respect to maize and potato starch. Cyperus starch was employed as binder for the formulation of metronidazole tablets. Formulations containing 5%, 7.5%, and 10% Cyperus starch were compared with those containing 10% potato starch. At 10% binder concentration, the tablets containing Cyperus starch exhibited better hardness and negligible friability as compared with those with potato starch. Although the binder concentration had a significant effect on the disintegration time of the tablets, it did not seem to affect the dissolution profile. These results indicate that Cyperus starch provides excellent binding properties without compromising drug release characteristics and should be explored in pharmaceutical formulations.

  19. Preparation and characterization of acetylated starch nanoparticles as drug carrier: Ciprofloxacin as a model.

    PubMed

    Mahmoudi Najafi, Seyed Heydar; Baghaie, Maryam; Ashori, Alireza

    2016-06-01

    The objective of this study was to characterize in-vitro the potential of acetylated corn starch (ACS) particles as a matrix for the delivery of ciprofloxacin (CFx). ACS was successfully synthesized and optimized by the reaction of native corn starch using acetic anhydride and acetic acid with low and high degrees of substitution (DS). The nanoprecipitation method was applied for the formation of the ACS-based nanoparticles, by the dropwise addition of water to acetone solution of ACS under stirring. The effects of acetylation and nanoprecipitation on the morphology and granular structure of ACS samples were examined by the FT-IR, XRD, DSL and SEM techniques. The efficiency of CFx loading was also evaluated via encapsulation efficiency (EE) in ACS nanoparticles. The average degree of acetyl substitution per glucose residue of corn starch was 0.33, 2.00, and 2.66. The nanoparticles size of the ACS and ACS-loaded with CFx were measured and analyzed relative to the solvent:non-solvent ratio. Based on the results, ACS nanoparticles with DS of 2.00 and water:acetone of 3:1 had 312nm diameter. Increasing DS in starch acetate led to increase in the EE from 67.7 to 89.1% and with increasing ratio of water/acetone from 1:1 to 3:1, the EE raised from 48.5 to 89.1%. X-ray diffraction indicated that A-type pattern of native starch was completely transformed into the V-type pattern of acetylated starch. The scanning electron microscopy showed that the different sizes of pores formed on the acetylated starch granules were utterly converted into the uniform-sized spherical nanoparticles after the nanoprecipitation.

  20. Dual modification of starch via partial enzymatic hydrolysis in the granular state and subsequent hydroxypropylation.

    PubMed

    Karim, A A; Sufha, E H; Zaidul, I S M

    2008-11-26

    The effect of enzymatic pretreatment on the degree of corn and mung bean starch derivatization by propylene oxide was investigated. The starch was enzymatically treated in the granular state with a mixture of fungal alpha-amylase and glucoamylase at 35 degrees C for 16 h and then chemically modified to produce enzyme-hydrolyzed-hydroxypropyl (HP) starch. Partial enzyme hydrolysis of starch in the granular state appeared to enhance the subsequent hydroxypropylation, as judged from the significant increase in the molar substitution. A variable degree of granule modification was obtained after enzyme hydrolysis, and one of the determinants of the modification degree appeared to be the presence of natural pores in the granules. Enzyme-hydrolyzed-HP starch exhibited significantly different functional properties compared to hydroxypropyl starch prepared from untreated (native) starch. It is evident that the dual modification of starch using this approach provides a range of functional properties that can be customized for specific applications.

  1. Monitoring of barley starch amylolysis by gravitational field flow fractionation and MALDI-TOF MS.

    PubMed

    Mazanec, Karel; Dycka, Filip; Bobalova, Janette

    2011-12-01

    In barley, starch occurs in the form of granules with bimodal size distribution. Enzymatic hydrolysis of the starch granule is one of the most important reactions occurring during malting and mashing. Previous studies revealed the discrepancies in the assumption that barley varieties with better malting qualities should have a higher A/B (large/small starch granules) ratio. This led us to focus our attention on detailed analysis of two barley varieties, Jersey and Tolar, both with high malting quality but significantly differing in A/B (1.28 and 0.66, respectively), were chosen for more detailed analysis in the actual work. In this study, the capacity of gravitational field flow fractionation (GFFF) to monitor amylolysis of the starch granules was investigated. Isolated starch granules from these two barley cultivars were treated with amylases. The changes in starch granule size and bimodal distribution were studied by GFFF. Simultaneously, free sugars released during enzymatic digestion were observed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The changes in the fractogram and in the mass spectra reflect a correlation with the progress of enzymatic hydrolysis. The results show the interest in utilization of GFFF as a simple and cheap method for monitoring changes in the distribution of the starch granule size during amylolysis. Copyright © 2011 Society of Chemical Industry.

  2. Preparation of cassava starch grafted with polystyrene by suspension polymerization.

    PubMed

    Kaewtatip, Kaewta; Tanrattanakul, Varaporn

    2008-09-05

    Cassava starch grafted with polystyrene (PS-g-starch) copolymer was synthesized via free-radical polymerization of styrene by using suspension polymerization technique. Potassium persulfate (PPS) was used as an initiator and water was used as a medium. The graft copolymer was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction and scanning electron microscopy. The sub-micron spherical beads of PS were observed on the surface of starch granules. SEM micrographs showed porous patches of PS adhering on the starch granules after Soxhlet extraction. FTIR spectra also indicated the presence of PS-g-starch copolymer. XRD analysis exhibited insignificant changes in crystalline structure and degree of crystallinity. The effects of starch:styrene weight ratio, amount of PPS, reaction time and reaction temperature on the percentage of grafting - G (%), were investigated. G (%) increased with increasing starch content. Other variables showed their own individual optimal values. The optimum condition yielding 31.47% of G (%) was derived when the component ratio was 1:3 and reaction temperature and time were 50°C and 2h, respectively. Graft copolymerization did not change granular shape and crystallinity of starch. This study demonstrated the capability of polymerization of styrene monomer on the granular starch without emulsifier and the synthesis of graft copolymer without gelatinization of starch.

  3. Characterization of banana starches obtained from cultivars grown in Brazil.

    PubMed

    de Barros Mesquita, Camila; Leonel, Magali; Franco, Célia Maria Landi; Leonel, Sarita; Garcia, Emerson Loli; Dos Santos, Thaís Paes Rodrigues

    2016-08-01

    The starch market is constantly evolving and studies that provide information about the physical and rheological properties of native starches to meet the diverse demands of the sector are increasingly necessary. In this study starches obtained from five cultivars of banana were analyzed for size and shape of granules, crystallinity, chemical composition, resistant starch, swelling power, solubility, thermal and paste properties. The granules of starch were large (36.58-47.24μm), oval, showed crystallinity pattern type B and the index of crystallinity ranged from 31.94 to 34.06%. The phosphorus content ranged from 0.003 to 0.011%, the amylose ranged from 25.13 to 29.01% and the resistant starch ranged from 65.70 to 80.28%. The starches showed high peak viscosity and breakdown, especially those obtained from 'Nanicão' and 'Grand Naine'. Peak temperature of gelatinization was around 71°C, the enthalpy change (ΔH) ranged from 9.45 to 14.73Jg(-1). The starch from 'Grand Naine' showed higher swelling power (15.19gg(-1)) and the starch from 'Prata-Anã' higher solubility (11.61%). The starches studied are highlighted by their physical and chemical characteristics and may be used in several applications. Copyright © 2016. Published by Elsevier B.V.

  4. Expression of an (Engineered) 4,6-α-Glucanotransferase in Potato Results in Changes in Starch Characteristics

    PubMed Central

    Xu, Xuan; Dechesne, Annemarie; Visser, Richard G. F.; Trindade, Luisa M.

    2016-01-01

    Starch structure strongly influences starch physicochemical properties, determining the end uses of starch in various applications. To produce starches with novel structure and exploit the mechanism of starch granule formation, an (engineered) 4, 6-α-glucanotransferase (GTFB) from Lactobacillus reuteri 121 was introduced into two potato genetic backgrounds: amylose-containing line Kardal and amylose-free mutant amf. The resulting starches showed severe changes in granule morphology regardless of genetic backgrounds. Modified starches from amf background exhibited a significant increase in granule size and starch phosphate content relative to the control, while starches from Kardal background displayed a higher digestibility, but did not show changes in granule size and phosphate content. Transcriptome analysis revealed the existence of a mechanism to restore the regular packing of double helices in starch granules, which possibly resulted in the removal of novel glucose chains potentially introduced by the (engineered) GTFB. This amendment mechanics would also explain the difficulties to detect alterations in starch fine structure in the transgenic lines. PMID:27911907

  5. Physical characterisation of high amylose maize starch and acylated high amylose maize starches.

    PubMed

    Lim, Ya-Mei; Hoobin, Pamela; Ying, DanYang; Burgar, Iko; Gooley, Paul R; Augustin, Mary Ann

    2015-03-06

    The particle size, water sorption properties and molecular mobility of high amylose maize starch (HAMS) and high amylose maize starch acylated with acetate (HAMSA), propionate (HAMSP) and butyrate (HAMSB) were investigated. Acylation increased the mean particle size (D(4,3)) and lowered the specific gravity (G) of the starch granules with an inverse relationship between the length of the fatty acid chain and particle size. Acylation of HAMS with fatty acids lowered the monolayer moisture content with the trend being HAMSBstarch granules by NMR spectroscopy with Carr-Purcell-Meiboom-Gill (CMPG) experiments showed that T2 long was reduced in acylated starches and that drying and storage of the starch granules further reduced T2 long. Analysis of the Free Induction Decay (FID) focussing on the short components of T2 (correlated to the solid matrix), indicated that drying and subsequent storage resulted in alterations of starch at 0.33a(w) and that these changes were reduced with acylation. In vitro enzymatic digestibility of heated starch dispersions by bacterial α-amylase was increased by acylation (HAMSstarch. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. The diurnal metabolism of leaf starch.

    PubMed

    Zeeman, Samuel C; Smith, Steven M; Smith, Alison M

    2007-01-01

    Starch is a primary product of photosynthesis in leaves. In most plants, a large fraction of the carbon assimilated during the day is stored transiently in the chloroplast as starch for use during the subsequent night. Photosynthetic partitioning into starch is finely regulated, and the amount of carbohydrate stored is dependent on the environmental conditions, particularly day length. This regulation is applied at several levels to control the flux of carbon from the Calvin cycle into starch biosynthesis. Starch is composed primarily of branched glucans with an architecture that allows the formation of a semi-crystalline insoluble granule. Biosynthesis has been most intensively studied in non-photosynthetic starch-storing organs, such as developing seeds and tubers. Biosynthesis in leaves has received less attention, but recent reverse-genetic studies of Arabidopsis (thale cress) have produced data generally consistent with what is known for storage tissues. The pathway involves starch synthases, which elongate the glucan chains, and branching enzymes. Remarkably, enzymes that partially debranch glucans are also required for normal amylopectin synthesis. In the last decade, our understanding of starch breakdown in leaves has advanced considerably. Starch is hydrolysed to maltose and glucose at night via a pathway that requires recently discovered proteins in addition to well-known enzymes. These sugars are exported from the plastid to support sucrose synthesis, respiration and growth. In the present review we provide an overview of starch biosynthesis, starch structure and starch degradation in the leaves of plants. We focus on recent advances in each area and highlight outstanding questions.

  7. Effect of castor oil enrichment layer produced by reaction on the properties of PLA/HDI-g-starch blends.

    PubMed

    Xiong, Zhu; Zhang, Lisheng; Ma, Songqi; Yang, Yong; Zhang, Chuanzhi; Tang, Zhaobin; Zhu, Jin

    2013-04-15

    Blends of entirely bio-sourced polymers, namely polylactide (PLA) and starch, have been melt-compounded by lab-scale co-extruder with castor oil (CO) as a plasticizer. The enrichment of castor oil on starch had great effect on the properties of the blends. If the castor oil was mainly dispersed in PLA matrix, the properties of the blends were poor, but when the hexamethylenediisocyanate (HDI) was grafted on starch granules the ready reactions between the hydroxyl on CO and the isocyante on the HDI-grafted starch (HGSTs) brought CO molecules enriched on starch particles. DSC analysis shows that the CO layer on starch has a positive effect on the crystallization of PLA in the ternary blend. The accumulation of CO on starch greatly improves the toughness and impact strength of PLA/starch blends. The grafting content of HDI on the starch granules primarily determined the compatibility and properties of the resulted blends.

  8. Comparison of Morphology and Physicochemical Properties of Starch Among 3 Arrowhead Varieties.

    PubMed

    Li, Aimin; Zhang, Yunhong; Zhang, Yongji; Yu, Xurun; Xiong, Fei; Zhou, Rumei; Zhang, Yongtai

    2016-05-01

    Arrowhead (Sagittaria trifolia var. sinensis) is a source of starch worldwide, but arrowhead starch has been rarely studied. In this work, starch was separated from arrowhead corm. The morphology and physicochemical properties of starch were then investigated and compared among 3 different arrowhead varieties (Purple-corm, Hongta, and Japanese). Results showed that starches from the 3 varieties similarly featured an oval shape containing a visible polarization cross, a CA -type crystalline structure, and an ordered structure in the external granule region. However, starch content, granule size, crystal characteristics, and pasting properties differed among the 3 varieties. Japanese arrowhead exhibited the highest starch content and degree of ordered structure in the external granule region, as well as onset, peak, and final gelatinization temperature. Purple-corm arrowhead starch demonstrated the highest amylose content and relative degree of crystallinity, smallest granule size, and lowest swelling power and solubility. Purple-corm arrowhead starch also showed the highest gelatinization enthalpy, as well as peak, trough, final, and setback viscosities. This starch further presented the lowest breakdown viscosity and degree of hydrolysis by HCl and porcine pancreatic α-amylase. These findings can provide useful references for arrowhead variety selection in food and nonfood industries. © 2016 Institute of Food Technologists®

  9. Morphological, Thermal, and Rheological Properties of Starches from Maize Mutants Deficient in Starch Synthase III.

    PubMed

    Zhu, Fan; Bertoft, Eric; Li, Guantian

    2016-08-31

    Morphological, thermal, and rheological properties of starches from maize mutants deficient in starch synthase III (SSIII) with a common genetic background (W64A) were studied and compared with the wild type. SSIII deficiency reduced granule size of the starches from 16.7 to ∼11 μm (volume-weighted mean). Thermal analysis showed that SSIII deficiency decreased the enthalpy change of starch during gelatinization. Steady shear analysis showed that SSIII deficiency decreased the consistency coefficient and yield stress during steady shearing, whereas additional deficiency in granule-bound starch synthase (GBSS) increased these values. Dynamic oscillatory analysis showed that SSIII deficiency decreased G' at 90 °C during heating and increased it when the paste was cooled to 25 °C at 40 Hz during a frequency sweep. Additional GBSS deficiency further decreased the G'. Structural and compositional bases responsible for these changes in physical properties of the starches are discussed. This study highlighted the relationship between SSIII and some physicochemical properties of maize starch.

  10. Extrusion of starches from different sources and amylose contents: effect on extrudate structure and molecular changes in amylose and amylopectin

    USDA-ARS?s Scientific Manuscript database

    This study evaluated the effects of starch source and amylose content on expansion ratio, density and texture of expanded extrudates, as well as the structural and molecular changes that occurred in starch granules as a function of extrusion. Rice starches (8%, 20% and 32% amylose), carioca bean sta...

  11. Starches from A to C. Chlamydomonas reinhardtii as a model microbial system to investigate the biosynthesis of the plant amylopectin crystal.

    PubMed Central

    Buléon, A; Gallant, D J; Bouchet, B; Mouille, G; D'Hulst, C; Kossmann, J; Ball, S

    1997-01-01

    Wide-angle powder x-ray diffraction analysis was carried out on starch extracted from wild-type and mutant Chlamydomonas reinhardtii cells. Strains containing no defective starch synthases as well as mutants carrying a disrupted granule-bound starch synthase structural gene displayed the A type of diffraction pattern with a high degree of crystallinity. Mutants carrying a defect for the major soluble starch synthase (SSS), SSS II, were characterized by a switch to the B type of diffraction pattern with very low crystallinity. Mutant strains carrying SSS I as the only glucan elongation enzyme regained some of their crystallinity but switched to the C type of diffraction pattern. Differential scanning calorimetry analysis correlated tightly with the x-ray diffraction results. Together with the electron microscopy analyses, these results establish C. reinhardtii as a microbial model system displaying all aspects of cereal starch synthesis and structure. We further show that SSS II is the major enzyme involved in the synthesis of crystalline structures in starch and demonstrate that SSS I alone builds a new type of amylopectin structure. PMID:9390431

  12. Extrusion and characterization of thermoplastic starch sheets from "macho" banana.

    PubMed

    Alanís-López, P; Pérez-González, J; Rendón-Villalobos, R; Jiménez-Pérez, A; Solorza-Feria, J

    2011-08-01

    Starch isolated from macho banana was oxidized by using 2.5% and 3.5% (w/w) of sodium hypochlorite. Native and oxidized starches with glycerol were processed using a conical twin screw extruder to obtain thermoplastic laminates or sheets, which were partially characterized. Oxidized banana starches presented higher moisture and total starch but lower ash, protein, lipids, and apparent amylose content than the native starch. Micrographs of sheets from oxidized starches showed wrinkles and cavities presumably caused by the plasticizer, but with less free glycerol and unplasticized starch granules than those from native starch. Sheets from oxidized starch showed a notorious increase in all thermal parameters (To, Tp, and ΔH), mechanical properties (tensile strength, elongation at break, and elasticity), and solubility. Banana starch X-ray diffraction patterns corresponded to a mixture of the A- and B-type polymorphs, with apparently slightly higher crystallinity in oxidized specimens than in native starch. A similar trend was observed in the corresponding sheets. Due to the pollution problem caused by the conventional plastics, there has been a renewed interest in biodegradable sheets, because they may have the potential to replace conventional packaging materials. Banana starch might be an interesting raw material to be used as edible sheet, coating or in food packaging, and preservation, because it is biodegradable, cheap, innocuous, and abundant. © 2011 Institute of Food Technologists®

  13. Selective observation of starch in a water plant using optical sum-frequency microscopy

    NASA Astrophysics Data System (ADS)

    Miyauchi, Yoshihiro; Sano, Haruyuki; Mirzutani, Goro

    2006-07-01

    The photosynthesis, transfer, and storage of starch are the most important biogenic processes occurring in plants. In order to observe the colorless and transparent starch granules in a plant, a chemical pretreatment such as staining of the starch is currently required, which seriously damages the tissue cells in the plant. We demonstrate that nondestructive chemical analysis of starch granules in a plant can be performed by using optical second-harmonic and sum-frequency microscopy. These techniques for in vivo analysis will provide extremely useful information about saccharides in a plant and can be extended to the analysis of many other materials, from living tissue to semiconductors.

  14. Effect of different excipients on the physical characteristics of granules and tablets with carbamazepine prepared with polyethylene glycol 6000 by fluidized hot-melt granulation (FHMG).

    PubMed

    Kraciuk, Radosław; Sznitowska, Malgorzata

    2011-12-01

    The objective of this study was to investigate the properties of granules and tablets with carbamazepine which were prepared employing a fluidized hot-melt granulation (FHMG) technique. The FHMG process was carried out at 65°C. Macrogol 6000 (PEG 6000) was used as a binder at the content 10% (w/w) of the granulated mass. Granules containing up to 70% (w/w) of the drug and 20-90% (w/w) of a filler (lactose, mannitol, calcium hydrogen phosphate (Di-Cafos), pregelatinized starch, and microcrystalline cellulose (MCC)) were produced. When the drug content was 30% (w/w), the yield of the process was satisfying (>95%) and flowability of the granules was better than placebo granules or drug-loaded granules prepared by wet granulation. Type of a filler had strong impact on physical properties of granules, and size distribution of the particles was the most homogenous when lactose or Di-Cafos were used. The FHMG technique enabled preparation of granules with better compressability compared with the wet-granulated product or with non-granulated powders. Tablets with shorter disintegration time than 10 min were obtained with 2.0% crospovidone added as a disintegrant. In comparison to tablets prepared from the wet-granulated mass, employment of the FHMG method resulted in tablets with faster dissolution of carbamazepine (more than 80% of the drug released within 15 min). This was achieved with mannitol or lactose/MCC, as fillers.

  15. Morphologies and gelatinization behaviours of high-amylose maize starches during heat treatment.

    PubMed

    Chen, Xu; Du, Xianfeng; Chen, Peirong; Guo, Li; Xu, Yang; Zhou, Xiuhong

    2017-02-10

    The granule morphologies and gelatinization behaviours of high-amylose maize starches during heating treatment were investigated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Maltese crosses demonstrated that the high-amylose maize starches maintained a granular structure even at 120°C. The granules of high-amylose maize starches swelled slightly at 100°C and swelled remarkably at approximately 120°C. The destruction of the starch structure began at the centre and expanded rapidly to the periphery. The intense fluorescence of high-amylose maize starch granules gradually became feeble, and the darker region spread outward during heating at 130°C for 30min, indicating that the amylose component may have been damaged and shifted. The starch granules treated at 140°C were substantially destroyed, and the CLSM, normal light microscopy (NL) and SEM images displayed no discernible granules, which indicated that the original starch granules formed a continuous integrated matrix. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Isolation and partial characterization of starch from banana cultivars grown in Colombia.

    PubMed

    Chávez-Salazar, A; Bello-Pérez, L A; Agama-Acevedo, E; Castellanos-Galeano, F J; Álvarez-Barreto, C I; Pacheco-Vargas, G

    2017-05-01

    Banana starch is resistant to hydrolysis by digestive enzymes due to its structure and dietary fibre content. Starch was isolated from the following three cultivars of Colombian Musaceae: Gros Michel (dessert), Dominico Harton and FHIA 20 (cooking); also, the amylose and amylopectin contents, morphology of the granules, thermal properties, pasting, molecular characteristics and digestibility were determined. The total starch content, amylose content and digestibility (gelatinized starch) were higher in cooking varieties; the purity and gelatinization temperature were similar for the three varieties, but the enthalpy was higher in the dessert variety. The three varieties showed higher viscosities in the pasting profile compared to commercial maize starch in both acid and neutral conditions. Starch granules presented with heterogeneous sizes and shapes (elongated and ovals) that had birefringence. The Dominico Hartón variety showed the lowest rapidly digestible starch (RDS) value in the gelatinized sample that is in agreement with the greater proportion of long chains.

  17. Enhancement of photoassimilate utilization by manipulation of starch regulatory enzymes

    SciTech Connect

    Okita, Thomas W.

    2016-05-11

    ADPglucose pyrophosphorylase (AGPase) and the plastidial starch phosphorylase1 (Pho1) are two regulatory enzymes whose catalytic activities are essential for starch granule synthesis. Conversion of the pre-starch granule to the mature form is dependent on AGPase, which produces ADPglucose, the substrate used by starch synthases. The catalytic activity of AGPase is controlled by small effector molecules and a prime goal of this project was to decipher the role of the two subunit types that comprise the heterotetrameric enzyme structure. Extensive genetic and biochemical studies showed that catalysis was contributed mainly by the small subunit although the large subunit was required for maximum activity. Both subunits were needed for allosteric regulatory properties. We had also demonstrated that the AGPase catalyzed reaction limits the amount of starch accumulation in developing rice seeds and that carbon flux into rice seed starch can be increased by expression of a cytoplasmic-localized, up-regulated bacterial AGPase enzyme form. Results of subsequent physiological and metabolite studies showed that the AGPase reaction is no longer limiting in the AGPase transgenic rice lines and that one or more downstream processes prevent further increases in starch biosynthesis. Further studies showed that over-production of ADPglucose dramatically alters the gene program during rice seed development. Although the expression of nearly all of the genes are down-regulated, levels of a starch binding domain containing protein (SBDCP) are elevated. This SBDCP was found to bind to and inhibit the catalytic activity of starch synthase III and, thereby preventing maximum starch synthesis from occurring. Surprisingly, repression of SBDCP elevated expression of starch synthase III resulting in increasing rice grain weight. A second phase of this project examined the structure-function of Pho1, the enzyme required during the initial phase of pre-starch granule formation and its

  18. Formation of starch in plant cells.

    PubMed

    Pfister, Barbara; Zeeman, Samuel C

    2016-07-01

    Starch-rich crops form the basis of our nutrition, but plants have still to yield all their secrets as to how they make this vital substance. Great progress has been made by studying both crop and model systems, and we approach the point of knowing the enzymatic machinery responsible for creating the massive, insoluble starch granules found in plant tissues. Here, we summarize our current understanding of these biosynthetic enzymes, highlighting recent progress in elucidating their specific functions. Yet, in many ways we have only scratched the surface: much uncertainty remains about how these components function together and are controlled. We flag-up recent observations suggesting a significant degree of flexibility during the synthesis of starch and that previously unsuspected non-enzymatic proteins may have a role. We conclude that starch research is not yet a mature subject and that novel experimental and theoretical approaches will be important to advance the field.

  19. [Characterisation of Dioscorea bulbifera native starch].

    PubMed

    Araujo de Vizcarrondo, Consuelo; Rincón, Alicia Mariela; Padilla, Fanny

    2004-06-01

    A non conventional source of starch, bulbs of Dioscorea bulbifera, was evaluated. Giving a yield of 28.48 g/100 g on dry weight, chemical composition, physical, physico-chemical and morphological characteristics were assessed, as well as its rheological properties. Chemical analysis showed a amylose content of 29.37%. Micrographies showed that most of the starch granules were of irregular shape, similar to a pyramid with rounded vertices, and a smaller number were elongated with smooth surface. Dioscorea starch showed a gelatinization temperature of 70.8 degrees C and maximum viscosity at 88.6 degrees C of 435 Brabender units (BU). It presented a relatively stable consistency to the cooking process and a low tendency to retrogradation; which suggest the starch possible use in food products that need a fast viscosity and a gel with a stable consistency.

  20. Comparative Emulsifying Properties of Octenyl Succinic Anhydride (OSA)-Modified Starch: Granular Form vs Dissolved State

    PubMed Central

    Marefati, Ali; Gutiérrez, Gemma; Wahlgren, Marie; Rayner, Marilyn

    2016-01-01

    The emulsifying ability of OSA-modified and native starch in the granular form, in the dissolved state and a combination of both was compared. This study aims to understand mixed systems of particles and dissolved starch with respect to what species dominates at droplet interfaces and how stability is affected by addition of one of the species to already formed emulsions. It was possible to create emulsions with OSA-modified starch isolated from Quinoa as sole emulsifier. Similar droplet sizes were obtained with emulsions prepared at 7% (w/w) oil content using OSA-modified starch in the granular form or molecularly dissolved but large differences were observed regarding stability. Pickering emulsions kept their droplet size constant after one month while emulsions formulated with OSA-modified starch dissolved exhibited coalescence. All emulsions stabilized combining OSA-modified starch in granular form and in solution showed larger mean droplet sizes with no significant differences with respect to the order of addition. These emulsions were unstable due to coalescence regarding presence of free oil. Similar results were obtained when emulsions were prepared by combining OSA-modified granules with native starch in solution. The degree of surface coverage of starch granules was much lower in presence of starch in solution which indicates that OSA-starch is more surface active in the dissolved state than in granular form, although it led to unstable systems compared to starch granule stabilized Pickering emulsions, which demonstrated to be extremely stable. PMID:27479315

  1. Comparative Emulsifying Properties of Octenyl Succinic Anhydride (OSA)-Modified Starch: Granular Form vs Dissolved State.

    PubMed

    Matos, María; Marefati, Ali; Gutiérrez, Gemma; Wahlgren, Marie; Rayner, Marilyn

    2016-01-01

    The emulsifying ability of OSA-modified and native starch in the granular form, in the dissolved state and a combination of both was compared. This study aims to understand mixed systems of particles and dissolved starch with respect to what species dominates at droplet interfaces and how stability is affected by addition of one of the species to already formed emulsions. It was possible to create emulsions with OSA-modified starch isolated from Quinoa as sole emulsifier. Similar droplet sizes were obtained with emulsions prepared at 7% (w/w) oil content using OSA-modified starch in the granular form or molecularly dissolved but large differences were observed regarding stability. Pickering emulsions kept their droplet size constant after one month while emulsions formulated with OSA-modified starch dissolved exhibited coalescence. All emulsions stabilized combining OSA-modified starch in granular form and in solution showed larger mean droplet sizes with no significant differences with respect to the order of addition. These emulsions were unstable due to coalescence regarding presence of free oil. Similar results were obtained when emulsions were prepared by combining OSA-modified granules with native starch in solution. The degree of surface coverage of starch granules was much lower in presence of starch in solution which indicates that OSA-starch is more surface active in the dissolved state than in granular form, although it led to unstable systems compared to starch granule stabilized Pickering emulsions, which demonstrated to be extremely stable.

  2. Starch synthesis and programmed cell death during endosperm development in triticale (x Triticosecale Wittmack).

    PubMed

    Li, Chun-Yan; Li, Wei-Hua; Li, Cheng; Gaudet, Denis A; Laroche, André; Cao, Lian-Pu; Lu, Zhen-Xiang

    2010-07-01

    Triticale (x Triticosecale Wittmack) grains synthesize and accumulate starch as their main energy source. Starch accumulation rate and synthesis activities of ADP-glucose pyrophosphorylase, soluble starch synthases, granule-bound starch synthase and starch-branching enzyme showed similar pattern of unimodal curves during endosperm development. There was no significant difference in activity of the starch granule-bound protein isolated from total and separated starch granules at different developmental stages after anthesis in triticale. Evans Blue staining and analysis of DNA fragmentation indicated that cells of triticale endosperm undergo programmed cell death during its development. Dead cells within the endosperm were detected at 6 d post anthesis (DPA), and evidence of DNA fragmentation was first observed at 21 DPA. The period between initial detection of PCD to its rapid increase overlapped with the key stages of rapid starch accumulation during endosperm development. Cell death occurred stochastically throughout the whole endosperm, meanwhile, the activities of starch biosynthetic enzymes and the starch accumulation rate decreased in the late stages of grain filling. These results suggested that the timing and progression of PCD in triticale endosperm may interfere with starch synthesis and accumulation.

  3. Starch-Branching Enzyme IIa Is Required for Proper Diurnal Cycling of Starch in Leaves of Maize1[OA

    PubMed Central

    Yandeau-Nelson, Marna D.; Laurens, Lieve; Shi, Zi; Xia, Huan; Smith, Alison M.; Guiltinan, Mark J.

    2011-01-01

    Starch-branching enzyme (SBE), a glucosyl transferase, is required for the highly regular pattern of α-1,6 bonds in the amylopectin component of starch. In the absence of SBEIIa, as shown previously in the sbe2a mutant of maize (Zea mays), leaf starch has drastically reduced branching and the leaves exhibit a severe senescence-like phenotype. Detailed characterization of the maize sbe2a mutant revealed that SBEIIa is the primary active branching enzyme in the leaf and that in its absence plant growth is affected. Both seedling and mature sbe2a mutant leaves do not properly degrade starch during the night, resulting in hyperaccumulation. In mature sbe2a leaves, starch hyperaccumulation is greatest in visibly senescing regions but also observed in green tissue and is correlated to a drastic reduction in photosynthesis within the leaf. Starch granules from sbe2a leaves observed via scanning electron microscopy and transmission electron microscopy analyses are larger, irregular, and amorphous as compared with the highly regular, discoid starch granules observed in wild-type leaves. This appears to trigger premature senescence, as shown by an increased expression of genes encoding proteins known to be involved in senescence and programmed cell death processes. Together, these results indicate that SBEIIa is required for the proper diurnal cycling of transitory starch within the leaf and suggest that SBEIIa is necessary in producing an amylopectin structure amenable to degradation by starch metabolism enzymes. PMID:21508184

  4. Starch-branching enzyme IIa is required for proper diurnal cycling of starch in leaves of maize.

    PubMed

    Yandeau-Nelson, Marna D; Laurens, Lieve; Shi, Zi; Xia, Huan; Smith, Alison M; Guiltinan, Mark J

    2011-06-01

    Starch-branching enzyme (SBE), a glucosyl transferase, is required for the highly regular pattern of α-1,6 bonds in the amylopectin component of starch. In the absence of SBEIIa, as shown previously in the sbe2a mutant of maize (Zea mays), leaf starch has drastically reduced branching and the leaves exhibit a severe senescence-like phenotype. Detailed characterization of the maize sbe2a mutant revealed that SBEIIa is the primary active branching enzyme in the leaf and that in its absence plant growth is affected. Both seedling and mature sbe2a mutant leaves do not properly degrade starch during the night, resulting in hyperaccumulation. In mature sbe2a leaves, starch hyperaccumulation is greatest in visibly senescing regions but also observed in green tissue and is correlated to a drastic reduction in photosynthesis within the leaf. Starch granules from sbe2a leaves observed via scanning electron microscopy and transmission electron microscopy analyses are larger, irregular, and amorphous as compared with the highly regular, discoid starch granules observed in wild-type leaves. This appears to trigger premature senescence, as shown by an increased expression of genes encoding proteins known to be involved in senescence and programmed cell death processes. Together, these results indicate that SBEIIa is required for the proper diurnal cycling of transitory starch within the leaf and suggest that SBEIIa is necessary in producing an amylopectin structure amenable to degradation by starch metabolism enzymes.

  5. Morphology, structural and physicochemical properties of starch from the root of Cynanchum auriculatum Royle ex Wight.

    PubMed

    Liu, Jun; Wang, Xingchi; Wen, Fanting; Zhang, Shurong; Shen, Ruru; Jiang, Wei; Kan, Juan; Jin, Changhai

    2016-12-01

    The root of Cynanchum auriculatum Royle ex Wight is a traditional Chinese herbal medicine and healthy food. Although C. auriculatum has already been processed into starch for human consumption in China, the structural characterizations of C. auriculatum starch is still unknown. Therefore, the morphology, structural and physicochemical properties of C. auriculatum starch were investigated in this study. C. auriculatum starch exhibited both spherical and polygonal shapes with granule size ranging from 2 to 12μm. Some void cavities and serpentine channels were observed in the inner of starch granules. X-ray powder diffraction pattern revealed that C. auriculatum starch was a CB-type with relative crystallinity of 25.19%. Small-angle X-ray scattering spectrum indicated C. auriculatum starch had a lamellar repeat distance of 9.21nm. The proportions of single helix, double helix and amorphous components in C. auriculatum starch were 3.42%, 27.11% and 69.47%, respectively. The amylose content of C. auriculatum starch was 28.0% with the gelatinization temperature ranging from 59.3 to 70.1°C. The maximum weight loss rate of C. auriculatum starch appeared at 309°C. In addition, C. auriculatum starch showed higher swelling power than other starches tested. Our results suggest C. auriculatum starch will have wide applications in food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. A quantitative assessment of the importance of barley seed alpha-amylase, beta-amylase, debranching enzyme, and alpha-glucosidase in starch degradation.

    PubMed

    Sun, Z T; Henson, C A

    1991-02-01

    Extracts of germinated barley (Hordeum vulgare L.) seeds of 41 different genotypes were analyzed for their activities of alpha-amylase, beta-amylase, alpha-glucosidase, and debranching enzyme and for their abilities to hydrolyze boiled soluble starch, nonboiled soluble starch, and starch granules extracted from barley seeds with water. Linear correlation analysis, used to quantitate the interactions between the seven parameters, revealed that boiled soluble starch was not a good substrate for predicting activities of enzymes functioning in in vivo starch hydrolysis as the extracts' abilities to hydrolyze boiled soluble starch was not correlated with their abilities to hydrolyze native starch granules. Activities of alpha-amylase and alpha-glucosidase were positively and significantly correlated with the seed extracts' abilities to hydrolyze all three starches. beta-Amylase was only significantly correlated with hydrolysis of boiled soluble starch. No significant correlations existed between debranching enzyme activity and hydrolysis of any of the three starches. Interactions between the four enzymes as they functioned together to hydrolyze the three types of starch were evaluated by path coefficient analysis. alpha-Amylase contributed to hydrolyses of all three starches primarily by its direct effect (noninteractive component). This direct contribution increased as the substrate progressed from the completely artificial boiled soluble starch, to the most physiologically significant substrate, native starch granules. alpha-Glucosidase contributed to the hydrolysis of boiled soluble starch primarily by its direct effect (noninteractive) yet contributed to starch granule hydrolysis primarily via its interaction with alpha-amylase (indirect effect). The contribution of beta-amylase to hydrolysis of boiled soluble starch was direct and it did not contribute significantly to hydrolysis of native starch granules.

  7. Impact of dry heating on physicochemical properties of corn starch and lysine mixture.

    PubMed

    Ji, Ying; Yu, Jicheng; Xu, Yongbin; Zhang, Yinghui

    2016-10-01

    Corn starch was modified with lysine by dry heat treatment and to investigate how they can affect the pasting and structural properties of the treated starches. Dry heating with lysine reduced the pasting temperature and resulting in viscosity increase. The particle size of heated starch-lysine mixture increased, suggesting that starch granules were cross-linked to lysine. After dry heating, the onset temperature, peak temperature and conclusion temperature of corn starch-lysine mixture were lower than those of other starches. The degree of crystallinity decreased for the starch after dry heat treatment while these heated starch samples still have the same X-ray diffraction types as the original starch. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. [Effect of acetylation and oxidation on some properties of breadfruit (Artocarpus altilis) seed starch].

    PubMed

    Rincón, Alicia Mariela; Bou Rached, Lizet; Aragoza, Luis E; Padilla, Fanny

    2007-09-01

    Starch extracted from seeds of Artocarpus altilis (Breadfruit) was chemically modified by acetylation and oxidation, and its functional properties were evaluated and compared with these of native starch. Analysis of the chemical composition showed that moisture content was higher for modified starches. Ash, protein, crude fiber and amylose contents were reduced by the modifications, but did not alter the native starch granules' irregularity, oval shape and smooth surface. Acetylation produced changes in water absorption, swelling power and soluble solids, these values were higher for acetylated starch, while values for native and oxidized starches were similar. Both modifications reduced pasting temperature; oxidation reduced maximum peak viscosity but it was increased by acetylation. Hot paste viscosity was reduced by both modifications, whereas cold paste viscosity was lower in the oxidized starch and higher in the acetylated starch. Breakdown was increased by acetylation and reduced with oxidation. Setback value was reduced after acetylation, indicating it could minimize retrogradation of the starch.

  9. Extrusion of Rice, Bean and Corn Starches: Extrudate Structure and Molecular Changes in Amylose and Amylopectin.

    PubMed

    Vanier, Nathan Levien; Vamadevan, Varatharajan; Bruni, Graziella Pinheiro; Ferreira, Cristiano Dietrich; Pinto, Vânia Zanella; Seetharaman, Koushik; Zavareze, Elessandra da Rosa; Elias, Moacir Cardoso; Berrios, Jose De J

    2016-12-01

    The objective of this study was to evaluate the effects of starch source and amylose content on the expansion ratio, density, and texture of expanded extrudates, as well as to investigate the structural and molecular changes that occur in starch granules as a function of extrusion. The starches employed were rice starches (8%, 20%, and 32% amylose), carioca bean starch (35% amylose), and Hylon V(®) corn starch (55% amylose). The extrudates from rice starches containing 20% and 32% amylose exhibited the highest expansion ratio, while, extrudates from Hylon V(®) corn starch containing 55% amylose exhibited the lowest expansion ratio. The hardness values of the extrudates with 55% amylose were twice those of the extrudates with 20%, 32%, and 35% amylose. An additional finding was that although the amylopectin promoted the expansion of the gelatinized starch matrix, it failed to strengthen and sustain the walls of the extrudate bubbles during expansion. © 2016 Institute of Food Technologists®.

  10. Milling of rice grains: effects of starch/flour structures on gelatinization and pasting properties.

    PubMed

    Hasjim, Jovin; Li, Enpeng; Dhital, Sushil

    2013-01-30

    Starch gelatinization and flour pasting properties were determined and correlated with four different levels of starch structures in rice flour, i.e. flour particle size, degree of damaged starch granules, whole molecular size, and molecular branching structure. Onset starch-gelatinization temperatures were not significantly different among all flour samples, but peak and conclusion starch-gelatinization temperatures were significantly different and were strongly correlated with the flour particle size, indicating that rice flour with larger particle size has a greater barrier for heat transfer. There were slight differences in the enthalpy of starch gelatinization, which are likely associated with the disruption of crystalline structure in starch granules by the milling processes. Flours with volume-median diameter ≥56 μm did not show a defined peak viscosity in the RVA viscogram, possibly due to the presence of native protein and/or cell-wall structure stabilizing the swollen starch granules against the rupture caused by shear during heating. Furthermore, RVA final viscosity of flour was strongly correlated with the degree of damage to starch granules, suggesting the contribution of granular structure, possibly in swollen form. The results from this study allow the improvement in the manufacture and the selection criteria of rice flour with desirable gelatinization and pasting properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Starch Flocculation by the Sweet Potato Sour Liquid Is Mediated by the Adhesion of Lactic Acid Bacteria to Starch.

    PubMed

    Zhang, Lili; Yu, Yang; Li, Xinhua; Li, Xiaona; Zhang, Huajiang; Zhang, Zhen; Xu, Yunhe

    2017-01-01

    In the current study, we focused on the mechanism underlying starch flocculation by the sweet potato sour liquid. The traditional microbial techniques and 16S rDNA sequencing revealed that Lactobacillus was dominant flocculating microorganism in sour liquid. In total, 86 bacteria, 20 yeasts, and 10 molds were isolated from the sour liquid and only eight Lactobacillus species exhibited flocculating activity. Lactobacillus paracasei subsp. paracasei L1 strain with a high flocculating activity was isolated and identified, and the mechanism of starch flocculation was examined. L. paracasei subsp. paracasei L1 cells formed chain-like structures on starch granules. Consequently, these cells connected the starch granules to one another, leading to formation of large flocs. The results of various treatments of L1 cells indicated that bacterial surface proteins play a role in flocculation and L1 cells adhered to the surface of starch granules via specific surface proteins. These surface starch-binding proteins were extracted using the guanidine hydrochloride method; 10 proteins were identified by mass spectrometry: three of these proteins were glycolytic enzymes; two were identified as the translation elongation factor Tu; one was a cell wall hydrolase; one was a surface antigen; one was lyzozyme M1; one was a glycoside hydrolase; and one was an uncharacterized proteins. This study will paves the way for future industrial application of the L1 isolate in starch processing and food manufacturing.

  12. Glycemic response to corn starch modified with cyclodextrin glycosyltransferase and its relationship to physical properties

    USDA-ARS?s Scientific Manuscript database

    Corn starch was modified with cyclodextrin glycosyltransferase (CGTase) below the gelatinization temperature. The porous, partially hydrolyzed, granules with or without CGTase hydrolysis products, cyclodextrins (CDs) and short chain maltodextrins, may be used as an alternative to modified corn starc...

  13. Processing of waxy starch/xanthan gum mixtures within the gelatinization temperature range.

    PubMed

    Heyman, Bart; Depypere, Frédéric; Van der Meeren, Paul; Dewettinck, Koen

    2013-07-25

    Pasting experiments of waxy potato and waxy maize starch systems were set up in which temperatures close to the gelatinization temperature were selected (67.5, 70 and 72.5°C). DSC measurements showed that under these conditions small fractions of the starches remained ungelatinized. During the pasting process two different shear rates were imposed (50s(-1) and 150s(-1)) to investigate the shear stability of the different starch containing systems. Swelling of the granules occurred in a more controlled manner and granule breakdown during pasting could be limited. As a result of these heating conditions more swollen granules are present, as confirmed by laser light diffraction. This positive effect was clearly noticeable in the flow curves of the cooled pastes. Xanthan gum addition could further reduce breakdown either by restricting the swelling or by stabilizing the granules. At higher starch contents the former is most likely dominating. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Proteomic analysis of the enzymes involved in the starch biosynthesis of maize with different endosperm type and characterization of the starch.

    PubMed

    Juárez-García, Erika; Agama-Acevedo, Edith; Gómez-Montiel, Noel Orlando; Pando-Robles, Victoria; Bello-Pérez, Luis Arturo

    2013-08-30

    The characterization of starch maize with different endosperm type and the proteomic analysis of its biosynthetic enzymes at 20 and 50 days after pollination (DAP) was carried out. There were differences between both endosperm types at 20 DAP, mainly in starch accumulation, amylose content, granule size and crystallinity percentage, whereas at 50 DAP the differences found were not relevant in the case of starch content, granule size, chain length distribution and thermal properties. SSSI, SBEIIb and GBSSI enzymes were identified; however, SBEIIb was only identified in two samples: floury endosperm at 20 DAP and vitreous at 50 DAP. Starch did not show differences in its morphological or structural characteristics in either endosperm on reaching maturity. Starch biosynthetic enzymes identified by matrix-assisted laser desorption/ionization-time of flight did not show a relationship to starch structure. © 2013 Society of Chemical Industry.

  15. Influence of growth conditions on barley starch properties.

    PubMed

    Tester, R F

    1997-08-01

    Air equilibrated barley starch comprises amylopectin, amylose, lipid and water. The structure of amylose and amylopectin, and the proportion of amylose in granules is under genetic control and is therefore subject to genotypic variation. The amount of lipid (which is essentially all lysophospholipid) is similarly under genetic control. Environment and especially environmental temperature do, however, have a regulatory effect on the size of starch granules, the amylose to amylopectin ratio and the amount of lipid (which is essentially all complexed with amylose) within barley starch. High growth temperatures probably facilitate amylopectin crystallisation and increase gelatinisation temperatures, (and to some extent the enthalpy of gelatinisation), but delay the onset and depress the extent of swelling of granules when heated in water.

  16. C-type starches and their derivatives: structure and function.

    PubMed

    Guo, Zebin; Jia, Xiangze; Zhao, Beibei; Zeng, Shaoxiao; Xiao, Jianbo; Zheng, Baodong

    2017-06-01

    The C-type starches are widely distributed in seeds or rhizomes of various legumes, medicinal plants, and crops. These carbohydrate polymers directly affect the application of starchy plant resources. The structural and crystal properties of starches are crucial parameters of starch granules, which significantly influence their physicochemical and mechanical properties. The unique crystal structure consisting of both A- and B-type polymorphs endows C-type starches with specific crystal adjustability. Furthermore, large proportions of resistant starches and slowly digestible starches are C-type starches, which contribute to benign glycemic response and proliferation of gut microflora. Here, we review the distribution of C-type starches in various plant sources, the structural models and crystal properties of C-type starches, and the behavior and functionality relevant to modified C-type starches. We outline recent advances, potential applications, and limitations of C-type starches in industry, aiming to provide a theoretical basis for further research and to broaden the prospects of its applications. © 2017 New York Academy of Sciences.

  17. Tuber starch amylose content is associated with cold-induced sweetening in potato.

    PubMed

    Jansky, Shelley H; Fajardo, Diego A

    2014-11-01

    Cold-induced sweetening (CIS) is the accumulation of reducing sugars in potato tubers at low storage temperatures. It is undesirable because it results in dark fry products. Our study evaluated the relationship between genetic resistance to CIS and two starch parameters, amylose content and starch granule size. We found that the amylose content in four CIS-resistant varieties was higher than that in five susceptible varieties. Amylose content was influenced not only by variety but also storage, production year, and field location. However, interactions between amylose content and environmental variables were not detected. In contrast, starch granule size was not associated with CIS resistance. No effect of storage on starch granule size was detected, and interactions among variety, production year, and field location were observed. Tuber starch amylose content should be considered a source of variability for CIS.

  18. Tuber starch amylose content is associated with cold-induced sweetening in potato

    PubMed Central

    Jansky, Shelley H; Fajardo, Diego A

    2014-01-01

    Cold-induced sweetening (CIS) is the accumulation of reducing sugars in potato tubers at low storage temperatures. It is undesirable because it results in dark fry products. Our study evaluated the relationship between genetic resistance to CIS and two starch parameters, amylose content and starch granule size. We found that the amylose content in four CIS-resistant varieties was higher than that in five susceptible varieties. Amylose content was influenced not only by variety but also storage, production year, and field location. However, interactions between amylose content and environmental variables were not detected. In contrast, starch granule size was not associated with CIS resistance. No effect of storage on starch granule size was detected, and interactions among variety, production year, and field location were observed. Tuber starch amylose content should be considered a source of variability for CIS. PMID:25493178

  19. Hydrolysis of native and heat-treated starches at sub-gelatinization temperature using granular starch hydrolyzing enzyme.

    PubMed

    Uthumporn, U; Shariffa, Y N; Karim, A A

    2012-03-01

    The effect of heat treatment below the gelatinization temperature on the susceptibility of corn, mung bean, sago, and potato starches towards granular starch hydrolysis (35°C) was investigated. Starches were hydrolyzed in granular state and after heat treatment (50°C for 30 min) by using granular starch hydrolyzing enzyme for 24 h. Hydrolyzed heat-treated starches showed a significant increase in the percentage of dextrose equivalent compared to native starches, respectively, with corn 53% to 56%, mung bean 36% to 47%, sago 15% to 26%, and potato 12% to 15%. Scanning electron microscopy micrographs showed the presence of more porous granules and surface erosion in heat-treated starch compared to native starch. X-ray analysis showed no changes but with sharper peaks for all the starches, suggested that hydrolysis occurred on the amorphous region. The amylose content and swelling power of heat-treated starches was markedly altered after hydrolysis. Evidently, this enzyme was able to hydrolyze granular starches and heat treatment before hydrolysis significantly increased the degree of hydrolysis.

  20. Granulation of fine powder

    DOEpatents

    Chen, Ching-Fong

    2016-08-09

    A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to form a dense compact with a higher density and more uniform pore size distribution.

  1. In situ observation of crystallinity disruption patterns during starch gelatinization.

    PubMed

    Cai, Canhui; Wei, Cunxu

    2013-01-30

    Twelve starches were isolated from the tuberous root of sweet potato, the rhizomes of lotus and yam, the tuber of potato, the corm of water chestnut, and the seeds of pea, bean, barley, wheat, lotus, water caltrop, and ginkgo. Their gelatinization processes were in situ viewed using a polarizing microscope in combination with a hot stage. Four patterns of crystallinity disruption during heating were proposed. The crystallinity disruption initially occurred on the proximal surface of the eccentric hilum, on the distal surface of the eccentric hilum, from the central hilum, or on the surface of the central hilum starch granule. The patterns of initial disruption on the distal surface of the eccentric hilum and on the surface of the central hilum starch were reported for the first time. The heterogeneous distribution of amylose in starch granule might partly explain the different patterns of crystallinity disruption and swelling during gelatinization. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Cecropia peltata Accumulates Starch or Soluble Glycogen by Differentially Regulating Starch Biosynthetic Genes[W][OA

    PubMed Central

    Bischof, Sylvain; Umhang, Martin; Eicke, Simona; Streb, Sebastian; Qi, Weihong; Zeeman, Samuel C.

    2013-01-01

    The branched glucans glycogen and starch are the most widespread storage carbohydrates in living organisms. The production of semicrystalline starch granules in plants is more complex than that of small, soluble glycogen particles in microbes and animals. However, the factors determining whether glycogen or starch is formed are not fully understood. The tropical tree Cecropia peltata is a rare example of an organism able to make either polymer type. Electron micrographs and quantitative measurements show that glycogen accumulates to very high levels in specialized myrmecophytic structures (Müllerian bodies), whereas starch accumulates in leaves. Compared with polymers comprising leaf starch, glycogen is more highly branched and has shorter branches—factors that prevent crystallization and explain its solubility. RNA sequencing and quantitative shotgun proteomics reveal that isoforms of all three classes of glucan biosynthetic enzyme (starch/glycogen synthases, branching enzymes, and debranching enzymes) are differentially expressed in Müllerian bodies and leaves, providing a system-wide view of the quantitative programming of storage carbohydrate metabolism. This work will prompt targeted analysis in model organisms and cross-species comparisons. Finally, as starch is the major carbohydrate used for food and industrial applications worldwide, these data provide a basis for manipulating starch biosynthesis in crops to synthesize tailor-made polyglucans. PMID:23632447

  3. Preparation and characterization of resistant starch III from elephant foot yam (Amorphophallus paeonifolius) starch.

    PubMed

    Reddy, Chagam Koteswara; Haripriya, Sundaramoorthy; Noor Mohamed, A; Suriya, M

    2014-07-15

    The purpose of this study was to assess the properties of resistant starch (RS) III prepared from elephant foot yam starch using pullulanase enzyme. Native and gelatinized starches were subjected to enzymatic hydrolysis (pullulanase, 40 U/g per 10h), autoclaved (121°C/30 min), stored under refrigeration (4°C/24h) and then lyophilized. After preparation of resistant starch III, the morphological, physical, chemical and functional properties were assessed. The enzymatic and retrogradation process increased the yield of resistant starch III from starch with a concomitant increase increase in its water absorption capacity and water solubility index. A decrease in swelling power was observed due to the hydrolysis and thermal process. Te reduced pasting properties and hardness of resistant starch III were associated with the disintegration of starch granules due to the thermal process. The viscosity was found to be inversely proportional to the RS content in the sample. The thermal properties of RS increased due to retrogradation and recrystallization (P<0.05). Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Cecropia peltata accumulates starch or soluble glycogen by differentially regulating starch biosynthetic genes.

    PubMed

    Bischof, Sylvain; Umhang, Martin; Eicke, Simona; Streb, Sebastian; Qi, Weihong; Zeeman, Samuel C

    2013-04-01

    The branched glucans glycogen and starch are the most widespread storage carbohydrates in living organisms. The production of semicrystalline starch granules in plants is more complex than that of small, soluble glycogen particles in microbes and animals. However, the factors determining whether glycogen or starch is formed are not fully understood. The tropical tree Cecropia peltata is a rare example of an organism able to make either polymer type. Electron micrographs and quantitative measurements show that glycogen accumulates to very high levels in specialized myrmecophytic structures (Müllerian bodies), whereas starch accumulates in leaves. Compared with polymers comprising leaf starch, glycogen is more highly branched and has shorter branches--factors that prevent crystallization and explain its solubility. RNA sequencing and quantitative shotgun proteomics reveal that isoforms of all three classes of glucan biosynthetic enzyme (starch/glycogen synthases, branching enzymes, and debranching enzymes) are differentially expressed in Müllerian bodies and leaves, providing a system-wide view of the quantitative programming of storage carbohydrate metabolism. This work will prompt targeted analysis in model organisms and cross-species comparisons. Finally, as starch is the major carbohydrate used for food and industrial applications worldwide, these data provide a basis for manipulating starch biosynthesis in crops to synthesize tailor-made polyglucans.

  5. Morphology and Physicochemical Properties of 3 Lilium Bulb Starches.

    PubMed

    Yu, Xurun; Zhang, Jing; Li, Aimin; Wang, Zhong; Xiong, Fei

    2015-08-01

    Lilium (Liliaceae) is an important wild plant and is used as food and traditional medicine worldwide. One Lilium cultivar (Lilium lancifolium) and 2 wild types (Lilium leucanthum and Lilium rosthornii) that are commonly distributed in Western China were investigated to completely utilize Lilium resources. The morphology of the flowers, bulbs, and scales and soluble sugar, total starch and amylose contents was remarkably different among the 3 Lilium species. Starches from the 3 Lilium species presented different granule size and shape. The starch of L. lancifolium exhibited higher swelling power and solubility than that of L. leucanthum and L. rosthornii. The starches from the 3 Lilium bulbs presented similar X-ray diffraction patterns and Fourier transform infrared spectroscopy. Among the 3 Lilium species, L. lancifolium showed the lowest crystallinity and the largest proportion of ordered structures in granule external region. Gelatinization temperatures and retrogradation percentage were significantly lower, but gelatinization enthalpy was significantly higher in L. lancifolium than those in L. leucanthum and L. rosthornii. Pasting properties of starch were different among the 3 Lilium species. Starch from L. lancifolium showed the highest degree of amylopectin branching, followed by L. leucanthum and L. rosthornii. Starches from L. leucanthum and L. rosthornii showed higher resistance to porcine pancreatic α-amylase hydrolysis compared to that of L. lancifolium. These results indicated that 3 Lilium bulbs exhibited remarkable differences in morphological, crystal, thermal, pasting, and hydrolysis properties of starches. © 2015 Institute of Food Technologists®

  6. Chemical and structural properties of sweet potato starch treated with organic and inorganic acid.

    PubMed

    Babu, A Surendra; Parimalavalli, R; Jagannadham, K; Rao, J Sudhakara

    2015-09-01

    In the present study sweet potato starch was treated with hydrochloric acid or citric acid at 1 or 5 % concentration and its properties were investigated. Citric acid treatment resulted higher starch yield. Water holding capacity and water absorption index was increased with increased acid concentration. Emulsion properties improved at 5 % acid concentration. The DE value of acid-thinned sweet potato starches was ranged between 1.93 and 3.76 %. Hydrochloric acid treated starches displayed a higher fraction of amylose. X-ray diffraction (XRD) study revealed that all the starches displayed C-type crystalline pattern with varied crystallinity. FT-IR spectra perceived a slight change in percentage intensity of C-H stretch of citric acid modified starches. Starch granules tended to appear less smooth than the native starch granules after acid treatment in Scanning Electron Micrographs (SEM) with granule size ranging between 8.00 and 8.90 μm. A drastic decrease in the pasting profile was noticed in hydrochloric acid (5 %) treated starch. While 5 % citric acid treated starch exhibited higher pasting profile. Differential Scanning Calorimeter (DSC) showed that peak and conclusion gelatinisation temperatures increased with increase in hydrochloric acid or citric acid concentration. Hence citric acid was found to mimic the hydrochloric acid with some variation which suggests that it may have promising scope in acid modification.

  7. Enzymatic degradation of granular potato starch by Microbacterium aurum strain B8.A.

    PubMed

    Sarian, Fean D; van der Kaaij, Rachel M; Kralj, Slavko; Wijbenga, Dirk-Jan; Binnema, Doede J; van der Maarel, Marc J E C; Dijkhuizen, Lubbert

    2012-01-01

    Microbacterium aurum strain B8.A was isolated from the sludge of a potato starch-processing factory on the basis of its ability to use granular starch as carbon- and energy source. Extracellular enzymes hydrolyzing granular starch were detected in the growth medium of M. aurum B8.A, while the type strain M. aurum DSMZ 8600 produced very little amylase activity, and hence was unable to degrade granular starch. The strain B8.A extracellular enzyme fraction degraded wheat, tapioca and potato starch at 37 °C, well below the gelatinization temperature of these starches. Starch granules of potato were hydrolyzed more slowly than of wheat and tapioca, probably due to structural differences and/or surface area effects. Partial hydrolysis of starch granules by extracellular enzymes of strain B8.A resulted in large holes of irregular sizes in case of wheat and tapioca and many smaller pores of relatively homogeneous size in case of potato. The strain B8.A extracellular amylolytic system produced mainly maltotriose and maltose from both granular and soluble starch substrates; also, larger maltooligosaccharides were formed after growth of strain B8.A in rich medium. Zymogram analysis confirmed that a different set of amylolytic enzymes was present depending on the growth conditions of M. aurum B8.A. Some of these enzymes could be partly purified by binding to starch granules.

  8. Adhesion of Bifidobacteria to Granular Starch and Its Implications in Probiotic Technologies

    PubMed Central

    Crittenden, R.; Laitila, A.; Forssell, P.; Mättö, J.; Saarela, M.; Mattila-Sandholm, T.; Myllärinen, P.

    2001-01-01

    Adhesion of 19 Bifidobacterium strains to native maize, potato, oat, and barley starch granules was examined to investigate links between adhesion and substrate utilization and to determine if adhesion to starch could be exploited in probiotic food technologies. Starch adhesion was not characteristic of all the bifidobacteria tested. Adherent bacteria bound similarly to the different types of starch, and the binding capacity of the starch (number of bacteria per gram) correlated to the surface area of the granules. Highly adherent strains were able to hydrolyze the granular starches, but not all amylolytic strains were adherent, indicating that starch adhesion is not a prerequisite for efficient substrate utilization for all bifidobacteria. Adhesion was mediated by a cell surface protein(s). For the model organisms tested (Bifidobacterium adolescentis VTT E-001561 and Bifidobacterium pseudolongum ATCC 25526), adhesion appeared to be specific for α-1,4-linked glucose sugars, since adhesion was inhibited by maltose, maltodextrin, amylose, and soluble starch but not by trehalose, cellobiose, or lactose. In an in vitro gastric model, adhesion was inhibited both by the action of protease and at pH values of ≤3. Adhesion was not affected by bile, but the binding capacity of the starch was reduced by exposure to pancreatin. It may be possible to exploit adhesion of probiotic bifidobacteria to starch granules in microencapsulation technology and for synbiotic food applications. PMID:11472921

  9. Adhesion of bifidobacteria to granular starch and its implications in probiotic technologies.

    PubMed

    Crittenden, R; Laitila, A; Forssell, P; Mättö, J; Saarela, M; Mattila-Sandholm, T; Myllärinen, P

    2001-08-01

    Adhesion of 19 Bifidobacterium strains to native maize, potato, oat, and barley starch granules was examined to investigate links between adhesion and substrate utilization and to determine if adhesion to starch could be exploited in probiotic food technologies. Starch adhesion was not characteristic of all the bifidobacteria tested. Adherent bacteria bound similarly to the different types of starch, and the binding capacity of the starch (number of bacteria per gram) correlated to the surface area of the granules. Highly adherent strains were able to hydrolyze the granular starches, but not all amylolytic strains were adherent, indicating that starch adhesion is not a prerequisite for efficient substrate utilization for all bifidobacteria. Adhesion was mediated by a cell surface protein(s). For the model organisms tested (Bifidobacterium adolescentis VTT E-001561 and Bifidobacterium pseudolongum ATCC 25526), adhesion appeared to be specific for alpha-1,4-linked glucose sugars, since adhesion was inhibited by maltose, maltodextrin, amylose, and soluble starch but not by trehalose, cellobiose, or lactose. In an in vitro gastric model, adhesion was inhibited both by the action of protease and at pH values of < or =3. Adhesion was not affected by bile, but the binding capacity of the starch was reduced by exposure to pancreatin. It may be possible to exploit adhesion of probiotic bifidobacteria to starch granules in microencapsulation technology and for synbiotic food applications.

  10. Physicochemical, morphological, thermal and IR spectral changes in the properties of waxy rice starch modified with vinyl acetate.

    PubMed

    Kalita, Dipankar; Kaushik, Neelima; Mahanta, Charu L

    2014-10-01

    Waxy rice starch was modified with vinyl acetate at levels of 4, 6, 8, and 10 % with degree of substitution of 0.021, 0.023, 0.032 and 0.056. The modified starches were studied for physicochemical, morphological, thermal and infra red spectral properties. Waxy starch acetates had high water holding capacity and did not sediment. Scanning electron microscopy revealed surface damage of the granules and their fusion. X ray diffractography showed that crystalline peak intensity had increased on acetylation. Differential scanning calorimetry studies showed changes in thermal properties. While gelatinization temperatures of modified starches were higher than the native starch, their transition enthalpies were lower than the native starch. IR spectra of the starch acetates did not show the peak typical for acetyl group. Thus, modification of waxy rice starch with vinyl acetate caused changes in the starch properties. The high water holding capacity of starch acetates can be exploited for specific applications.

  11. Starch Metabolism in the Leaf Sheaths and Culm of Rice 1

    PubMed Central

    Perez, Consuelo M.; Palmiano, Evelyn P.; Baun, Lyda C.; Juliano, Bienvenido O.

    1971-01-01

    The levels of starch and dextrin, free sugars, soluble protein, and enzymes involved in starch metabolism—α-amylase, β-amylase, phosphorylase, Q-enzyme, R-enzyme, and ADP-glucose starch synthetases—were assayed in the leaf sheaths and culm of the rice plant (Oryza sativa L., variety IR8) during growth. Starch accumulation in the leaf sheaths reached a maximum 10 to 11 weeks after transplanting, the time of development of the rice panicle. Maximal concentration of free sugars occurred earlier. Starch and sugars in the leaf sheaths and culm decreased rapidly during grain development. During starch accumulation, the starch granules of the leaf sheaths increased slightly in size and its gelatinization temperature decreased. The molecular size of amylose and amylopectin and amylose content of the starch were similar in both culm and leaf sheaths. Changes in the level of soluble protein paralleled changes in starch level in the leaf sheaths. Among the enzymes, only synthetase bound to the starch granule paralleled the level of starch in the leaf sheaths and in the culm. ADP-glucose, but not UDP-glucose, was utilized as a glucosyl donor by these starch synthetases. Zymograms of these extracts showed only one α-amylase band, one β-amylase band, two phosphorylase bands, and one Q-enzyme band. PMID:16657631

  12. Structural changes of waxy and normal maize starches modified by heat moisture treatment and their relationship with starch digestibility.

    PubMed

    Chen, Yongzhi; Yang, Qingyu; Xu, Xiaojuan; Qi, Liang; Dong, Zhihong; Luo, Zhigang; Lu, Xuanxuan; Peng, Xichun

    2017-12-01

    In the present study, the variations in structure of waxy and normal maize starches modified by heat-moisture treatment (HMT) for different treating time (3h and 9h) were investigated. HMT caused the destruction of starch granules. The (1)H NMR confirmed that glycosidic bonds were broken during HMT. The (13)C NMR result suggested that HMT caused the transformation of starch granules from double and single helical components into amorphous components. Heat-moisture treated starches exhibited higher gelatinization temperature (To, Tp and Tc), narrower gelatinization temperature range (Tc-To) and lower gelatinization enthalpy (ΔH). HMT caused the rearrangement of starch molecules, degeneration of double helices and formation of new single helix. In addition, in vitro digestibility assessment indicated that the contents of rapidly digestible starch (RDS) and slowly digestible starch (SDS) were improved and resistant starch (RS) was reduced after HMT, which was related to the decrease of single and double helical components. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Effects of heat pretreatment of starch on graft copolymerization reaction and performance of resulting starch-based wood adhesive.

    PubMed

    Zheng, Xianyu; Cheng, Li; Gu, Zhengbiao; Hong, Yan; Li, Zhaofeng; Li, Caiming

    2017-03-01

    In this study, effects of starch heat pretreatment at 70, 80 and 90°C on graft copolymerization reaction with vinyl acetate (VAc) and the performance of the resulting starch-based wood adhesive (SWA) were investigated. It was shown that SWA pretreated at 90°C achieved the best performance. At this temperature, the bonding capacity improved by 17.84% compared to the adhesive synthesized without heat pretreatment and the viscosity increased by 18.16% after 7 free-thaw cycles, much better than other samples. Scanning electron microscopy (SEM) and polarizing microscopy demonstrated that structures of starch granules were fully damaged after heat pretreatment at 90°C. The reaction took place not only on the surface of starch granules, but also internally, leading to improvement in the grafting amounts and grafting efficiency by 42.86% and 39.03%, respectively. This was further confirmed by Fourier transform infrared spectroscopy (FT-IR), Confocal Raman microscopy (CRM) and X-ray photoelectron spectroscopy (XPS), which also showed better reaction homogeneity both between different starch granules and from granule surface to its internal structure. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Granular size of potato starch affects structural properties, octenylsuccinic anhydride modification and flowability.

    PubMed

    Wang, Chan; Tang, Chuan-He; Fu, Xiong; Huang, Qiang; Zhang, Bin

    2016-12-01

    Native potato starch (PS) granules were separated into three size fractions: larger than 30μm (P-L), 15-30μm (P-M), and smaller than 15μm (P-S). The morphological and crystalline structure of fractionated potato starches were investigated by light and scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The P-L fraction showed ellipsoidal shape and B-type X-ray pattern, whereas the P-S fraction had spherical shape and A-type pattern. The fluorophore-assisted capillary electrophoresis data showed that the P-L fraction had more B2 chains and less short A and B1 chains than the P-S counterparts. Smaller granules with larger specific surface area had higher degree of substitution when reacted with octenylsuccinic anhydride (OSA), and showed more uniform distribution of octenylsuccinate substituents. Both OSA modified and unmodified P-S samples showed higher flowability compared with the P-L counterparts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Scale-up studies on high shear wet granulation process from mini-scale to commercial scale.

    PubMed

    Aikawa, Shouhei; Fujita, Naomi; Myojo, Hidetoshi; Hayashi, Takashi; Tanino, Tadatsugu

    2008-10-01

    A newly developed mini-scale high shear granulator was used for scale-up study of wet granulation process from 0.2 to 200 L scales. Under various operation conditions and granulation bowl sizes, powder mixture composed of anhydrous caffeine, D-mannitol, dibasic calcium phosphate, pregelatinized starch and corn starch was granulated by adding water. The granules were tabletted, and disintegration time and hardness of the tablets were evaluated to seek correlations of granulation conditions and tablet properties. As the granulation proceeded, disintegration time was prolonged and hardness decreased. When granulation processes were operated under the condition that agitator tip speed was the same, similar relationship between granulation time and tablet properties, such as disintegration time and hardness, between 0.2 L and 11 L scales were observed. Likewise, between 11 L and 200 L scales similar relationship was observed when operated under the condition that the force to the granulation mass was the same. From the above results, the mini-scale high shear granulator should be useful tool to predict operation conditions of large-scale granulation from its mini-scale operation conditions, where similar tablet properties should be obtained.

  16. Estimating Starch Content in Roots of Deciduous Trees--A Visual Technique

    Treesearch

    Philip M. Wargo; Philip M. Wargo

    1975-01-01

    A visual technique for determining starch content in roots of forest trees, based onz iodine-staining of starch granules, was compared with a chemical method. Although the chemical method was more precise, roots could be sorted with the visual method into groups that are probably biologically important. The visual technique is simple and can be adapted for use in the...

  17. Phase transitions of pea starch over a wide range of water content.

    PubMed

    Wang, Shujun; Copeland, Les

    2012-06-27

    The phase transitions of pea starch over a wide range of water content were investigated by differential scanning calorimetry (DSC). Swelling of starch granules increased progressively with increasing water content. The main endotherm G broadened progressively with increasing water content up to 94.5 wt % (water:starch ratio 15:1), above which it became too broad to define. The corresponding peak and conclusion temperatures and enthalpy change increased with increasing water content. Scanning electron microscopy (SEM) showed that, at a water:starch ratio of 2:1 (water content of 70.7 wt %), starch granules only swelled partially with discernible granular contours still clearly evident. The results of swelling power tests and SEM images revealed that the endotherm G obtained at a water:starch ratio of 2:1 represented only partial swelling of starch granules. The transition from a narrow to broad endotherm G was interpreted to reflect the thermal transition behavior progressing from limited swelling to maximum swelling and then partial dissolution and leaching of starch polymers from the granules.

  18. The potential of resistant starch as a prebiotic.

    PubMed

    Zaman, Siti A; Sarbini, Shahrul R

    2016-01-01

    Resistant starch is defined as the total amount of starch and the products of starch degradation that resists digestion in the small intestine. Starches that were able to resist the digestion will arrive at the colon where they will be fermented by the gut microbiota, producing a variety of products which include short chain fatty acids that can provide a range of physiological benefits. There are several factors that could affect the resistant starch content of a carbohydrate which includes the starch granule morphology, the amylose-amylopectin ratio and its association with other food component. One of the current interests on resistant starch is their potential to be used as a prebiotic, which is a non-digestible food ingredient that benefits the host by stimulating the growth or activity of one or a limited number of beneficial bacteria in the colon. A resistant starch must fulfill three criterions to be classified as a prebiotic; resistance to the upper gastrointestinal environment, fermentation by the intestinal microbiota and selective stimulation of the growth and/or activity of the beneficial bacteria. The market of prebiotic is expected to reach USD 198 million in 2014 led by the export of oligosaccharides. Realizing this, novel carbohydrates such as resistant starch from various starch sources can contribute to the advancement of the prebiotic industry.

  19. Structure, morphology and functionality of acetylated and oxidised barley starches.

    PubMed

    El Halal, Shanise Lisie Mello; Colussi, Rosana; Pinto, Vânia Zanella; Bartz, Josiane; Radunz, Marjana; Carreño, Neftali Lenin Villarreal; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2015-02-01

    Acetylation and oxidation are chemical modifications which alter the properties of starch. The degree of modification of acetylated and oxidized starches is dependent on the catalyst and active chlorine concentrations, respectively. The objective of this study was to evaluate the effect of acetylation and oxidation on the structural, morphological, physical-chemical, thermal and pasting properties of barley starch. Barley starches were acetylated at different catalyst levels (11%, 17%, and 23% of NaOH solution) and oxidized at different sodium hypochlorite concentrations (1.0%, 1.5%, and 2.0% of active chlorine). Fourier-transformed infrared spectroscopy (FTIR), X-ray diffractograms, thermal, morphological, and pasting properties, swelling power and solubility of starches were evaluated. The degree of substitution (DS) of the acetylated starches increased with the rise in catalyst concentration. The percentage of carbonyl (CO) and carboxyl (COOH) groups in oxidized starches also increased with the rise of active chlorine level. The presence of hydrophobic acetyl groups, carbonyl and carboxyl groups caused a partial disorganization and depolymerization of starch granules. The structural, morphological and functional changes in acetylated and oxidized starches varied according to reaction conditions. Acetylation makes barley starch more hydrophobic by the insertion of acetyl groups. Also the oxidation promotes low retrogradation and viscosity. All these characteristics are important for biodegradable film production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Zinc chloride aqueous solution as a solvent for starch.

    PubMed

    Lin, Meiying; Shang, Xiaoqin; Liu, Peng; Xie, Fengwei; Chen, Xiaodong; Sun, Yongyi; Wan, Junyan

    2016-01-20

    It is important to obtain starch-based homogeneous systems for starch modification. Regarding this, an important key point is to find cheap, low-cost and low-toxicity solvents to allow complete dissolution of starch and its easy regeneration. This study reveals that a ZnCl2 aqueous solution is a good non-derivatizing solvent for starch at 50 °C, and can completely dissolve starch granules. The possible formation of a "zinc-starch complex" might account for the dissolution; and the degradation of starch, which was caused by the H(+) inZnCl2 aqueous solution, could not contribute to full dissolution. From polarized light microscopic observation combined with the solution turbidity results, it was found that the lowest ZnCl2 concentration for full dissolution was 29.6 wt.% at 50 °C, with the dissolving time being 4h. Using Fourier-transform infrared (FTIR), solid state (13)C nuclear magnetic resonance (NMR), and X-ray diffraction (XRD), it was revealed that ZnCl2 solution had no chemical reaction with starch glucosides, but only weakened starch hydrogen bonding and converted the crystalline regions to amorphous regions. In addition, as shown by intrinsic viscosity and thermogravimetric analysis (TGA), ZnCl2 solution caused degradation of starch macromolecules, which was more serious with a higher concentration of ZnCl2 solution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Effect of Microwave Irradiation on the Physicochemical and Digestive Properties of Lotus Seed Starch.

    PubMed

    Zeng, Shaoxiao; Chen, Bingyan; Zeng, Hongliang; Guo, Zebin; Lu, Xu; Zhang, Yi; Zheng, Baodong

    2016-03-30

    The objective of this study is to investigate the effect of microwave irradiation on the physicochemical and digestive properties of lotus seed starch. The physicochemical properties of lotus seed starch were characterized by light microscopy, (1)H NMR, FT-IR spectroscopy, and HPSEC-MALLS-RI. The starch-water interaction and crystalline region increased due to the changed water distribution of starch granules and the increase of the double-helix structure. The swelling power, amylose leaching, molecular properties, and radius of gyration reduced with the increasing microwave power, which further affected the sensitivity of lotus seed starch to enzymatic degradation. Furthermore, the resistant starch and slowly digestible starch increased with the increasing microwave irradiation, which further resulted in their decreasing hydrolysis index and glycemic index. The digestive properties of lotus seed starch were mainly influenced by the reduced branching degree of amylopectin and the strong amylose-amylose interaction.

  2. Analysis of a preferential action of α-amylase from B. licheniformis towards amorphous regions of waxy maize starch.

    PubMed

    Foresti, María Laura; Williams, María del Pilar; Martínez-García, Ricardo; Vázquez, Analía

    2014-02-15

    Waxy maize starch was subjected to α-amylase (Bacillus licheniformis) hydrolysis in buffered medium to determine the evolution of reaction in quantitative terms and also in terms of the morphology and crystallinity of the partially hydrolyzed starch granules. Gathered data allowed studying the pattern of action of this α-amylase over waxy maize starch granules, with particular focus on a preferential hydrolysis of the amorphous regions of starch. Results showed that waxy maize starch hydrolysis followed a two-stage kinetic profile with an initial stage characterized by high reaction rate, followed by a slower second stage. The change of hydrolysis rate occurred at approximately 6h of reaction, a time for which X-ray diffraction data quantitatively analyzed by three different techniques showed a maximum of crystallinity in partially hydrolyzed granules. Scanning electron microscopy images illustrated the action of α-amylases which implied the exoerosion of the granules surface, the entry of α-amylases into the granules through radial channels, their endoerosion towards the granule exterior, and their fragmentation. Fragmentation of waxy maize starch granules revealed internal layered structures of starch which were interpreted as hydrolyzed/non-hydrolyzed growth rings. Under the conditions chosen, kinetic, electron microscopy and X-ray data all gave evidence of a preferential action of α-amylase from Bacillus licheniformis towards the less ordered regions of waxy maize starch. Results showed that, provided the proper hydrolysis time is chosen, starch granules with increased crystallinity can be obtained by a pure enzymatic treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Synchrotron X-ray Scattering Analysis of the Interaction Between Corn Starch and an Exogenous Lipid During Hydrothermal Treatment

    SciTech Connect

    E Hernandez-Hernandez; C Avila-Orta; B Hsiao; j Castro-Rosas; J Gallegos-Infante; J Morales-Castro; L Ochoa-Martinez; C Gomez-Aldapa

    2011-12-31

    Lipids have an important effect on starch physicochemical properties. There exist few reports about the effect of exogenous lipids on native corn starch structural properties. In this work, a study of the morphological, structural and thermal properties of native corn starch with L-alpha-lysophosphatidylcholine (LPC, the main phospholipid in corn) was performed under an excess of water. Synchrotron radiation, in the form of real-time small and wide-angle X-ray scattering (SAXS/WAXS), was used in order to track structural changes in corn starch, in the presence of LPC during a heating process from 30 to 85 C. When adding LCP, water absorption decreased within starch granule amorphous regions during gelatinization. This is explained by crystallization of the amylose-LPC inclusion complex during gelatinization, which promotes starch granule thermal stability at up to 95 C. Finally, a conceptual model is proposed for explaining the formation mechanism of the starch-LPC complex.

  4. Effect of gelatinization and hydrolysis conditions on the selectivity of starch hydrolysis with alpha-amylase from Bacillus licheniformis.

    PubMed

    Baks, Tim; Bruins, Marieke E; Matser, Ariette M; Janssen, Anja E M; Boom, Remko M

    2008-01-23

    Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on the hydrolyzate composition and reaction rate during wheat starch hydrolysis with alpha-amylase from Bacillus licheniformis were compared. Suspensions of native starch or starch gelatinized at different conditions either with or without enzyme were hydrolyzed. During hydrolysis, the oligosaccharide concentration, the dextrose equivalent, and the enzyme activity were determined. We found that the hydrolyzate composition was affected by the type of starch pretreatment and the enzyme addition point but that it was just minimally affected by the pressure applied during hydrolysis, as long as gelatinization was complete. The differences between hydrolysis of thermally gelatinized, high-pressure gelatinized, and native starch were explained by considering the granule structure and the specific surface area of the granules. These results show that the hydrolyzate composition can be influenced by choosing different process sequences and conditions.

  5. Acid hydrolysis of native and annealed starches and branch-structure of their Naegeli dextrins.

    PubMed

    Nakazawa, Yuta; Wang, Ya-Jane

    2003-11-21

    Eight commercial starches, including common corn, waxy corn, wheat, tapioca, potato, Hylon V, Hylon VII, and mung bean starch, were annealed by a multiple-step process, and their gelatinization characteristics were determined. Annealed starches had higher gelatinization temperatures, reduced gelatinization ranges, and increased gelatinization enthalpies than their native starches. The annealed starches with the highest gelatinization enthalpies were subjected to acid hydrolysis with 15.3% H2SO4, and Naegeli dextrins were prepared after 10 days' hydrolysis. Annealing increased the acid susceptibility of native starches in the first (rapid) and the second (slow) phases with potato starch showing the greatest and high amylose starches showing the least changes. Starches with a larger shift in onset gelatinization temperature also displayed a greater percent hydrolysis. The increase in susceptibility to acid hydrolysis was proposed to result from defective and porous structures that resulted after annealing. Although annealing perfected the crystalline structure, it also produced void space, which led to porous structures and possible starch granule defects. The molecular size distribution and chain length distribution of Naegeli dextrins of annealed and native starches were analyzed. The reorganization of the starch molecule during annealing occurred mainly within the crystalline lamellae. Imperfect double helices in the crystalline lamellae improved after annealing, and the branch linkages at the imperfect double helices became protected by the improved crystalline structure. Therefore, more long chains were observed in the Naegeli dextrins of annealed starches than in native starches.

  6. Stability and repeatability of a continuous twin screw granulation and drying system.

    PubMed

    Vercruysse, J; Delaet, U; Van Assche, I; Cappuyns, P; Arata, F; Caporicci, G; De Beer, T; Remon, J P; Vervaet, C

    2013-11-01

    The aim of this study was to investigate the process transfer of a commercially available product from the current batch fluid bed granulation and drying production method to an innovative continuously operating "from powder to tablet" production line using twin screw granulation as an intermediate granulation step. By monitoring process outcomes (torque, water temperature at the granulator jacket inlet, differential pressure over the dryer filters, and temperature mill screen) and granule and tablet quality in function of process time, the stability and repeatability during long production runs were determined. Three consecutive 5h "from powder to tablet" production runs were performed using the ConsiGma™-25 system (GEA Pharma Systems, Collette™, Wommelgem, Belgium). A premix of two active ingredients, powdered cellulose, maize starch, pregelatinized starch, and sodium starch glycolate was granulated with distilled water. After drying and milling (1000 μm and 800 rpm), granules were in-line blended with magnesium stearate and directly compressed using a Modul™ P tablet press (tablet weight: 430 mg, main compression force: 12 kN). Granule (loss on drying, particle size distribution, friability, flow) and tablet (weight uniformity, hardness, thickness, friability, content uniformity, disintegration time, and dissolution) quality was evaluated in function of process time. For each of the logged process outcomes, a stabilization period was needed to reach steady-state conditions. Slightly deviating particle size distribution and friability results for milled granules were observed during start-up due to initial layering of the mill screen. However, no deviating tablet quality was detected in function of process time. For multiple hours, granule and tablet quality was constant in function of process time. Furthermore, process data trends were highly repeatable. Consequently, the ConsiGma™-25 system can be considered as a stable and repeatable system for the

  7. Analysis of starch in food systems by high-performance size exclusion chromatography.

    PubMed

    Ovando-Martínez, Maribel; Whitney, Kristin; Simsek, Senay

    2013-02-01

    Starch has unique physicochemical characteristics among food carbohydrates. Starch contributes to the physicochemical attributes of food products made from roots, legumes, cereals, and fruits. It occurs naturally as distinct particles, called granules. Most starch granules are a mixture of 2 sugar polymers: a highly branched polysaccharide named amylopectin and a basically linear polysaccharide named amylose. The starch contained in food products undergoes changes during processing, which causes changes in the starch molecular weight and amylose to amylopectin ratio. The objective of this study was to develop a new, simple, 1-step, and accurate method for simultaneous determination of amylose and amylopectin ratio as well as weight-averaged molecular weights of starch in food products. Starch from bread flour, canned peas, corn flake cereal, snack crackers, canned kidney beans, pasta, potato chips, and white bread was extracted by dissolving in KOH, urea, and precipitation with ethanol. Starch samples were solubilized and analyzed on a high-performance size exclusion chromatography (HPSEC) system. To verify the identity of the peaks, fractions were collected and soluble starch and beta-glucan assays were performed additional to gas chromatography analysis. We found that all the fractions contain only glucose and soluble starch assay is correlated to the HPSEC fractionation. This new method can be used to determine amylose amylopectin ratio and weight-averaged molecular weight of starch from various food products using as low as 25 mg dry samples. © 2013 Institute of Food Technologists®

  8. Characterization of enzyme-resistant starch in maize amylose-extender mutant starches

    USDA-ARS?s Scientific Manuscript database

    In the human digestive system, a type of starch known as resistant starch (RS) can not be digested. RS is not absorbed in the small intestine, and is passed to the large intestine where it is fermented by bacteria to produce short-chain fatty acids, which have anti-cancer and anti-inflammatory prop...

  9. Evaluation of the Significance of Starch Surface Binding Sites on Human Pancreatic α-Amylase.

    PubMed

    Zhang, Xiaohua; Caner, Sami; Kwan, Emily; Li, Chunmin; Brayer, Gary D; Withers, Stephen G

    2016-11-01

    Starch provides the major source of caloric intake in many diets. Cleavage of starch into malto-oligosaccharides in the gut is catalyzed by pancreatic α-amylase. These oligosaccharides are then further cleaved by gut wall α-glucosidases to release glucose, which is absorbed into the bloodstream. Potential surface binding sites for starch on the pancreatic amylase, distinct from the active site of the amylase, have been identified through X-ray crystallographic analyses. The role of these sites in the degradation of both starch granules and soluble starch was probed by the generation of a series of surface variants modified at each site to disrupt binding. Kinetic analysis of the binding and/or cleavage of substrates ranging from simple maltotriosides to soluble starch and insoluble starch granules has allowed evaluation of the potential role of each such surface site. In this way, two key surface binding sites, on the same face as the active site, are identified. One site, containing a pair of aromatic residues, is responsible for attachment to starch granules, while a second site featuring a tryptophan residue around which a malto-oligosaccharide wraps is shown to heavily influence soluble starch binding and hydrolysis. These studies provide insights into the mechanisms by which enzymes tackle the degradation of largely insoluble polymers and also present some new approaches to the interrogation of the binding sites involved.

  10. Morphological, structural, thermal, and rheological characteristics of starches separated from apples of different cultivars.

    PubMed

    Singh, Narpinder; Inouchi, Naoyoshi; Nishinari, Katsuyoshi

    2005-12-28

    The starches were separated from unripe apples of five cultivars (Criterion, Ruspippum, Red Spur, Skyline Supreme, and Granny Smith) and evaluated using scanning electron microscopy (SEM), gel permeation chromatography (GPC), X-ray diffraction, differential scanning calorimetry (DSC), and dynamic viscoelasticity. SEM showed the presence of round granules as well as granules that had been partially degraded, probably by amylases. The starch granules in different apple starches ranged between 4.1 and 12.0 mum. Debranching of starch with isoamylase and subsequent fractionation of debranched materials by GPC revealed the presence of an apparent amylose, an intermediate fraction (mixture of amylose and amylopectin), long side chains of amylopectin, and short side chains of amylopectin in the range of 28-35.2, 3.6-4.4, 20-21.3, and 39.9-47.1%, respectively. The swelling power of starches ranged between 14.4 and 21.3 g/g. X-ray diffraction of apple starches showed a mixture of A- and B-type patterns. All apple starches showed peak intensities lower than that observed for normal corn and potato starch, indicating the lower crystallinity. The transition temperatures (onset temperature, T(o); peak temperature, T(p); and conclusion temperature, T(c)) and enthalpy of gelatinization (deltaH(gel)) determined using DSC ranged between 54.7 and 56.2 degrees C, between 57.1 and 59.1 degrees C, between 60.2 and 63.5 degrees C, and between 3.3 and 4.2 J/g, respectively. The viscoelastic properties of starch from different cultivars measured during heating and cooling using a rheometer differed significantly. Red Spur and Criterion starches with larger granule size showed higher G' and G' ' values, whereas those containing smaller size and amylolytically degraded granules showed lower G' and G' '.

  11. Starch: Structure, Properties, Chemistry, and Enzymology

    NASA Astrophysics Data System (ADS)

    Robyt, John F.

    Starch is a very important and widely distributed natural product, occurring in the leaves of green plants, seeds, fruits, stems, roots, and tubers. It serves as the chemical storage form of the energy of the sun and is the primary source of energy for the organisms on the Earth. Starch is composed of two kinds of polysaccharides, amylose and amylopectin, exclusively composed of D-glucose residues with α-(1→4) linkages in a linear amylose and α-(1→4) linkages and ˜5% α-(1→6) branch linkages in amylopectin, both combined in a water-insoluble granule that is partially crystalline and whose size, shape, and morphology are dependent on its biological source. The properties, isolation, fractionation, enzymatic degradation, biosynthesis, chemical modification, and specific methods of analysis of starch are presented.

  12. Rheological and biochemical properties of Solanum lycocarpum starch.

    PubMed

    Di-Medeiros, Maria Carolina B; Pascoal, Aline M; Batista, Karla A; Bassinello, Priscila Z; Lião, Luciano M; Leles, Maria Inês G; Fernandes, Kátia F

    2014-04-15

    This study was conducted to evaluate the rheological and physicochemical properties of Solanum lycocarpum starch. The thermogravimetric analysis of S. lycocarpum starch showed a typical three-step weight loss pattern. Microscopy revealed significant changes in the granule morphology after hydrothermal treatment. Samples hydrothermally treated at 50°C for 10 min lost 52% of their crystallinity, which was recovered after storage for 7 days at 4°C. However, samples hydrothermally treated at 65°C were totally amorphous. This treatment was sufficient to completely disrupt the starch granule, as evidenced by the absence of an endothermic peak in the DSC thermogram. The RVA of S. lycocarpum starch revealed 4440.7cP peak viscosity, 2660.5cP breakdown viscosity, 2414.1cP final viscosity, 834.3cP setback viscosity, and a pasting temperature of 49.6°C. The low content of resistant starch (10.25%) and high content of digestible starch (89.78%) in S. lycocarpum suggest that this starch may be a good source for the production of hydrolysates, such as glucose syrup and its derivatives.

  13. Nutrient composition and starch characteristics of Quercus glandulifera Bl. seeds from China.

    PubMed

    Li, Songnan; Zhou, Yibin; Liu, Mei; Zhang, Yang; Cao, Shengnan

    2015-10-15

    The chemical composition and starch characteristics of acorn (Quercus glandulifera Bl.) were studied. The moisture content of acorn seeds was 7.55%. The crude fat, crude protein, dietary fiber, total ash, and nitrogen-free extract contents of acorn seed were 4.20%, 10.16%, 2.95%, 0.03%, and 82.66%, respectively, on a dry weight basis. Linoleic, oleic, and palmitic were the most predominant fatty acids. UFA:SFA and SFA:MUFA:PUFA ratios were 2.6:1 and 1.25:1.34:1, respectively. The essential amino acid content from acorn seeds was low based on FAO reference values. Acorn seeds were a good source of Fe, Zn, and Mn. The contents of vitamins A and E were 1.40 mg RE/100g and 10.78 mg/100 g, respectively. Starch extracted from acorn seeds had round, triangle, and elliptical morphology with granule size of 3.3-126.2 μm. The ratio between amylose and amylopectin contents was 25.39:72.94. Acorn starch had a typical A-type crystal pattern with 23.53% relative crystallinity. The gelatinization temperature was 66.53 °C and the transition enthalpy was 4.33 J/g.

  14. Ultrastructural observation of mesophyll cells and temporal expression profiles of the genes involved in transitory starch metabolism in flag leaves of wheat after anthesis.

    PubMed

    Kang, Guozhang; Peng, Xiaoqi; Wang, Lina; Yang, Yingying; Shao, Ruixin; Xie, Yingxin; Ma, Dongyun; Wang, Chenyang; Guo, Tiancai; Zhu, Yunji

    2015-01-01

    Transitory starch in cereal plant leaves is synthesized during the day and remobilized at night to provide a carbon source for growth and grain filling, but its mechanistic basis is still poorly understood. The objective of this study is to explore the regulatory mechanism for starch biosynthesis and degradation in plant source organs. Using transmission electron microscopy, we observed that during the day after anthesis, starch granules in mesophyll cells of wheat flag leaves accumulated in chloroplasts and the number of starch granules gradually decreased with wheat leaf growth. During the night, starch granules synthesized in chloroplasts during the day were completely or partially degraded. The transcript levels of 26 starch synthesis-related genes and 16 starch breakdown-related genes were further measured using quantitative real-time reverse transcription polymerase chain reaction. Expression profile analysis revealed that starch metabolism genes were clustered into two groups based on their temporal expression patterns. The genes in the first group were highly expressed and presumed to play crucial roles in starch metabolism. The genes in the other group were not highly expressed in flag leaves and may have minor functions in starch metabolism in leaf tissue. The functions of most of these genes in leaves were further discussed. The starch metabolism-related genes that are predominantly expressed in wheat flag leaves differ from those expressed in wheat grain, indicating that two different pathways for starch metabolism operate in these tissues. This provides specific information on the molecular mechanisms of transitory starch metabolism in higher plants.

  15. Structural characterization of Peruvian carrot (Arracacia xanthorrhiza) starch and the effect of annealing on its semicrystalline structure.

    PubMed

    Rocha, Thais S; Cunha, Verena A G; Jane, Jay-Lin; Franco, Celia M L

    2011-04-27

    Structural characteristics of native and annealed Peruvian carrot (Arracacia xanthorrhiza) starches were determined and compared to those of cassava and potato starches. Peruvian carrot starch presented round and irregular shaped granules, low amylose content and B-type X-ray pattern. Amylopectin of this starch contained a large proportion of long (DP > 37) and short (DP 6-12) branched chains. These last ones may contribute to its low gelatinization temperature. After annealing, the gelatinization temperatures of all starches increased, but the ΔH and the crystallinity increased only in Peruvian carrot and potato starches. The annealing process promoted a higher exposure of Peruvian carrot amylose molecules, which were more quickly attacked by enzymes, whereas amylopectin molecules became more resistant to hydrolysis. Peruvian carrot starch had structural characteristics that differed from those of cassava and potato starches. Annealing affected the semicrystalline structure of this starch, enhancing its crystallinity, mainly due to a better interaction between amylopectin chains.

  16. A comparative study of annealing of waxy, normal and high-amylose maize starches: the role of amylose molecules.

    PubMed

    Wang, Shujun; Wang, Jinrong; Yu, Jinglin; Wang, Shuo

    2014-12-01

    The effect of annealing on starch structure and functionality of three maize starches (waxy, normal and high-amylose) was investigated, with the aim of understanding the role of amylose molecules during starch annealing. Amylose content, granular morphology and crystallinity of maize starches were little affected by annealing treatment. Annealing treatment did not alter the swelling power of waxy maize starch, but reduced the swelling power of normal and high-amylose maize starches. The thermal transition temperatures were increased, and the temperature range was decreased, but the enthalpy change was not affected greatly. The pasting viscosities of normal and waxy maize starches were decreased significantly, with the pasting temperature being little affected. The in vitro digestibility of three maize starches was not affected significantly by annealing treatment. Our results demonstrated that amylose molecules play an important role in the structural reorganization of starch granules during annealing treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Coexpression Analysis Identifies Rice Starch Regulator1, a Rice AP2/EREBP Family Transcription Factor, as a Novel Rice Starch Biosynthesis Regulator1[W][OA

    PubMed Central

    Fu, Fang-Fang; Xue, Hong-Wei

    2010-01-01

    Starch biosynthesis is important for plant development and is a critical factor in crop quality and nutrition. As a complex metabolic pathway, the regulation of starch biosynthesis is still poorly understood. We here present the identification of candidate regulators for starch biosynthesis by gene coexpression analysis in rice (Oryza sativa). Starch synthesis genes can be grouped into type I (in seeds; sink tissues) and type II (in vegetative tissues; source tissues), and 307 and 621 coexpressed genes are putatively involved in the regulation of starch biosynthesis in rice seeds and vegetative tissues, respectively. Among these genes, Rice Starch Regulator1 (RSR1), an APETALA2/ethylene-responsive element binding protein family transcription factor, was found to negatively regulate the expression of type I starch synthesis genes, and RSR1 deficiency results in the enhanced expression of starch synthesis genes in seeds. Seeds of the knockout mutant rsr1 consistently show the increased amylose content and altered fine structure of amylopectin and consequently form the round and loosely packed starch granules, resulting in decreased gelatinization temperature. In addition, rsr1 mutants have a larger seed size and increased seed mass and yield. In contrast, RSR1 overexpression suppresses the expression of starch synthesis genes, resulting in altered amylopectin structure and increased gelatinization temperature. Interestingly, a decreased proportion of A chains in rsr1 results in abnormal starch granules but reduced gelatinization temperature, whereas an increased proportion of A chains in RSR1-overexpressing plants leads to higher gelatinization temperatures, which is novel and different from previous reports, further indicating the complicated regulation of starch synthesis and determination of the physicochemical properties of starch. These results demonstrate the potential of coexpression analysis for studying rice starch biosynthesis and the regulation of a

  18. Effect of a small amount of sodium carbonate on konjac glucomannan-induced changes in thermal behavior of wheat starch.

    PubMed

    Zhou, Yun; Winkworth-Smith, Charles G; Wang, Yu; Liang, Jianfen; Foster, Tim J; Cheng, Yongqiang

    2014-12-19

    The effects of konjac glucomannan (KGM) on thermal behavior of wheat starch have been studied in the presence of low concentrations of Na2CO3 (0.1-0.2 wt% of starch). Confocal laser scanning microscopy (CLSM) allows the visualization of the starch gelatinization process and granule remnants in starch pastes. Heating the starch dispersion in KGM-Na2CO3 solution significantly delays granule swelling and inhibits amylose leaching, whereas Na2CO3 alone, at the same concentration, has little effect. Na2CO3 assists KGM in producing the extremely high viscosity of starch paste, attributing to a less remarkable breakdown of viscosity in subsequent heating, and protecting starch granules against crystallite melting. The distinct partially networked film around the surface of starch granules is evident in the CLSM images. We propose that Na2CO3 could trigger the formation of complexes between KGM and starch polymers, which exerts a protective effect on granular structure and modifying gelatinization characteristics of the mixtures.

  19. Effect of nitrogen and sulfur fertilization on accumulation characteristics and physicochemical properties of A- and B-wheat starch.

    PubMed

    Li, Wenhao; Shan, Yulin; Xiao, Xinlong; Zheng, Jianmei; Luo, Qingui; Ouyang, Shaohui; Zhang, Guoquan

    2013-03-13

    The effects of nitrogen (N) fertilization at the rates of 0 and 230 kg hm(-2) combined with selected sulfur (S) fertilization rates of 0, 46, 56, 77, and 115 kg hm(-2) on A- and B-wheat starch granule accumulation, composition, and thermal and pasting properties were investigated. Scanning electron micrographs revealed that A- and B-starch granules accumulation during grain filling can be influenced significantly by N and S fertilization, and B-granules tend to be more sensitive to S fertilization than A-starch granules. The doses of nitrogen and sulfur fertilization on starch properties were not positively correlated; higher concentration of fertilizers failed to cause a higher effects. N230S46 and N230S56 treatment resulted in the higher peak viscosity, trough viscosity, breakdown viscosity, final and setback viscosity, and gelatinization temperature (To, Tp, Tc) according to differential scanning calorimeter (DSC) and rapid visco analyzer (RVA), respectively.

  20. An investigation of the influence of process and formulation variables on mechanical properties of high shear granules using design of experiment.

    PubMed

    Mangwandi, Chirangano; Adams, Michael J; Hounslow, Michael J; Salman, Agba D

    2012-05-10

    Being able to predict the properties of granules from the knowledge of the process and formulation variables is what most industries are striving for. This research uses experimental design to investigate the effect of process variables and formulation variables on mechanical properties of pharmaceutical granules manufactured from a classical blend of lactose and starch using hydroxypropyl cellulose (HPC) as the binder. The process parameters investigated were granulation time and impeller speed whilst the formulation variables were starch-to-lactose ratio and HPC concentration. The granule properties investigated include granule packing coefficient and granule strength. The effect of some components of the formulation on mechanical properties would also depend on the process variables used in granulation process. This implies that by subjecting the same formulation to different process conditions results in products with different properties.

  1. Thermogravimetric study of water state in wheat starch gels obtained under high pressures.

    PubMed

    Orlowska, Marta; Utzig, Ewa; Randzio, Stanislaw L

    2010-02-01

    Wheat starch gels containing 56.0% of water were obtained during thermal gelatinization under isobaric conditions at different pressures ranging from 0.5 to 100 MPa. Thermogravimetric analysis allowed determination of pressure influence on water behavior in gel matrix. The vaporization rate indicated that water is released in two main steps. The first step corresponds to the diffusion of the water fraction (so-called nonbound water) from the porous structure of the amylose gel located between partially swollen starch granules. However, the second step that appears at higher temperature is related to the desorption of water molecules (bound water), included in the swollen granules. It was observed that the most important influence of pressure on water partitioning in the starch gel took place over a pressure range from 0.5 to 10 MPa. The results obtained indicate that pressure is a thermodynamical parameter, which stabilizes the native state of starch granules.

  2. Fast and controlled release of triamcinolone acetonide from extrusion-spheronization pellets based on mixtures of native starch with dextrin or waxy maize starch.

    PubMed

    Sergio, Almeida-Prieto; Isabel, de Sá Ferreira da Rocha Cristiana; José, Blanco-Méndez; Otero-Espinar, Francisco J

    2007-09-01

    Pellets composed chiefly of inexpensive starches allow modulation of the rate of release of the poorly soluble drug triamcinolone acetonide in media of pH 1.2-6.8. Wheat- or maize-starch-based pellets with 20% of white dextrin release the drug in vitro almost completely within 20 min, while maize-starch-based pellets with 5-35% of waxy maize starch sustain gradual release over periods of 9-12 hr or longer when prepared using appropriate amounts of granulation fluid.

  3. Effect of natural fibres on the mechanical properties of thermoplastic starch

    NASA Astrophysics Data System (ADS)

    Oniszczuk, Tomasz; Wójtowicz, Agnieszka; Moácicki, Leszek; Mitrus, Marcin; Kupryaniuk, Karol; Kusz, Andrzej; Bartnik, Grzegorz

    2016-04-01

    This paper presents the results covering the mechanical properties of thermoplastic potato starch granules with flax, cellulose fibre, and pine bark addition. A modified single screw extrusion-cooker TS-45 with L/D = 18 and an additional cooling section of the barrel was used as the processing unit. The establishment influence of the fibre addition, as well as the extrusion-cooker screw speed, on the mechanical properties of the thermoplastic starch granules was the main objective of the investigation. The maximum force during compression to 50% of the sample diameter, elastic modulus, and compression strength were evaluated. Significant differences were noted depending on the amount of fibre used, while only an insignificant influence of screw speed on the mechanical properties of the granulate was reported. An increased amount of fibres lowered the maximum force as well as the elastic modulus and compression strength of the thermoplastic starch granulates.

  4. Starch bioengineering affects cereal grain germination and seedling establishment

    PubMed Central

    Hebelstrup, Kim H.; Blennow, Andreas

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphosphorylated (HP) starch and more resistant amylose-only (AO) starch barley lines were used. The transgenics showed no severe phenotypes and the WT and HP lines degraded the starch similarly, having 30% residual starch after 12 d of germination. However, the AO line showed significant resistance to degradation, having 57% residual starch. Interestingly, protein and β-glucan (BG) degradation was stimulated for both HP and AO lines as compared with the WT. At late seedling establishment stages, specific sugars were rapidly consumed in the AO line. α-Amylase activity was distinctly suppressed in both the HP and the AO lines. Pre-germination β-amylase deposition was low in the AO grains and β-amylase was generally suppressed in both HP and AO lines throughout germination. As further supported by scanning electron microscopy and histochemical analyses on grain and seedlings, it was concluded that inadequate starch granule deposition in combination with the suppressed hydrolase activity leads to temporal and compensating re-direction of starch, sugar, and protein catabolism important to maintain metabolic dynamics during grain germination and seedling establishment. PMID:24642850

  5. Thermal and rheological properties of nixtamalized maize starch.

    PubMed

    Mendez-Montealvo, G; Sánchez-Rivera, M M; Paredes-López, O; Bello-Pérez, L A

    2006-12-15

    The effect of nixtamalization process on thermal and rheological characteristics of corn starch was studied. Starch of raw sample had higher gelatinization temperature than its raw counterpart, because, the Ca(2+) ions stabilize starch structure of nixtamalized sample; however, the enthalpy values were not different in both samples. The temperature of the phase transition of the retrograded starches (raw and nixtamalized) were not different at the storage times assessed, but the enthalpy values of the above mentioned transition was different, indicating a lower reorganization of the starch structure in the nixtamalized sample. The viscoamylographic profile showed differences between both starches, since raw starch had higher peak viscosity than the nixtamalized sample due to partial gelatinization of some granules during this heat treatment. Rheological test showed that at low temperature (25 degrees C) the raw and nixtamalized starches presented different behaviour; however, the elastic characteristic was more important in the starch gel structure. The nixtamalization process produced changes in thermal and rheological characteristics becoming important in those products elaborated from nixtamalized maize.

  6. Characterization of acetylated corn starch prepared under ultrahigh pressure (UHP).

    PubMed

    Kim, Hyun-Seok; Choi, Hyun-Shik; Kim, Byung-Yong; Baik, Moo-Yeol

    2010-03-24

    To investigate the impact of ultrahigh pressure (UHP) on the physicochemical properties of the UHP-assisted starch acetate, common corn starch was subjected to either conventional (0.1 MPa, 30 degrees C, 60 min) or UHP-assisted (400 MPa, 25 degrees C, 15 min) acetylation reactions at three levels (4, 8, or 12%) of acetic anhydride. Without significant changes in starch granule crystal structure, UHP-assisted reaction exhibited lower degree of substitution values than conventional reaction across reagent addition levels. An increase in reagent addition levels exhibited common trends in starch solubility/swelling power, gelatinization, and pasting properties for the conventional and UHP-assisted starch acetates relative to native starch. Within an equivalent derivatization level, however, the UHP-assisted (relative to conventional) starch acetates revealed restricted starch solubility/swelling power, reduced gelatinization temperatures, and lower pasting viscosities. Overall, this result suggested that UHP treatment in acetylation reaction might influence the physicochemical properties of starch acetate by facilitating the formation of lipid-complexed amylose or altering granular reaction patterns to acetic anhydride.

  7. Understanding size enlargement and hardening of granules on tabletability of unlubricated granules prepared by dry granulation.

    PubMed

    Patel, Sarsvatkumar; Dahiya, Sandeepkumar; Sun, Changquan Calvin; Bansal, Arvind Kumar

    2011-02-01

    The mechanism of loss of "reworkability" or tabletability of dry granulated microcrystalline cellulose (MCC) was investigated in relation to both granule size enlargement and granule hardness. Slugs of MCC were prepared under three pressures (12.5, 37.5, and 93.8 MPa) and tabletability (tensile strength vs. pressure) of respective granules (three different sizes) was determined. Nominal single granule fracture strength and granule friability were measured. The reduction in tabletability was profound for harder granules, which were obtained from higher slugging pressure. This is consistent with their ability to resist granule fragmentation during tableting. Variation in granule size exhibits negligible effect on tabletability for the lowest slugging pressure and only a small effect for the middle and highest slugging pressure. This observation is again related to different tendency to granule fragmentation during compaction. The results suggest that granule-hardening negatively affects tensile strength more than that of granule size enlargement for MCC.

  8. Effect of cultivar, location and year on total starch, amylose, phosphorus content and starch grain size of high starch potato cultivars for food and industrial processing.

    PubMed

    Šimková, Dagmar; Lachman, Jaromír; Hamouz, Karel; Vokál, Bohumil

    2013-12-15

    In recent time the interest of industry increases particularly in processing and use of potato high amylopectin (AMP) starches. Therefore the plant breeders effort to obtain "waxy" potato cultivars with low amylose (AMS) content. In this four-year study sixteen potato cultivars grown on five experimental locations were evaluated on the percentage of AMS/AMP by enzymatic method, starch content by the underwater weight method, phosphorus (P) content in starch digests spectrophotometrically, and starch granule size determined by laser diffraction method. Between enzymatic and iodine-potassium iodide method good correlation has been revealed (r=0.71). The correlation analysis between AMS and P levels showed a clear negative correlation. For all measured parameters (starch, AMS, P, starch granule size) significant impact of cultivar has been determined. Location and year have lower, but significant impact. No statistically significant effect of year on AMS has been found. The cultivar Amado distinguished with the highest AMP and P contents and the cultivar Westamyl showed all positive values interesting for growers and processors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Effects of alpha-amylase reaction mechanisms on analysis of resistant-starch contents.

    PubMed

    Moore, Samuel A; Ai, Yongfeng; Chang, Fengdan; Jane, Jay-lin

    2015-01-22

    This study aimed to understand differences in the resistant starch (RS) contents of native and modified starches obtained using two standard methods of RS content analysis: AOAC Method 991.43 and 2002.02. The largest differences were observed in native potato starch, cross-linked wheat distarch phosphate, and high-amylose corn starch stearic-acid complex (RS5) between using AOAC Method 991.43 with Bacillus licheniformis α-amylase (BL) and AOAC Method 2002.02 with porcine pancreatic α-amylase (PPA). To determine possible reasons for these differences, we hydrolyzed raw-starch granules with BL and PPA with equal activity at pH 6.9 and 37°C for up to 84 h and observed the starch granules displayed distinct morphological differences after the hydrolysis. Starches hydrolyzed by BL showed erosion on the surface of the granules; those hydrolyzed by PPA showed pitting on granule surfaces. These results suggested that enzyme reaction mechanisms, including the sizes of the binding sites and the reaction patterns of the two enzymes, contributed to the differences in the RS contents obtained using different methods of RS analysis.

  10. Calcium modified edible Canna (Canna edulis L) starch for controlled released matrix

    NASA Astrophysics Data System (ADS)

    Putri, A. P.; Ridwan, M.; Darmawan, T. A.; Darusman, F.; Gadri, A.

    2017-07-01

    Canna edulis L starch was modified with calcium chloride in order to form controlled released matrix. Present study aim to analyze modified starch characteristic. Four different formulation of ondansetron granules was used to provide dissolution profile of controlled released, two formula consisted of 15% and 30% modified starch, one formula utilized matrix reference standards and the last granules was negative control. Methocel-hydroxypropyl methyl cellulose was used as controlled released matrix reference standards in the third formula. Calcium starch was synthesized in the presence of sodium hydroxide to form gelatinized mass and calcium chloride as the cross linking agent. Physicochemical and dissolution properties of modified starch for controlled released application were investigated. Modified starch has higher swelling index, water solubility and compressibility index. Three of four different formulation of granules provide dissolution profile of controlled released. The profiles indicate granules which employed calcium Canna edulis L starch as matrix are able to resemble controlled drug released profile of matrix reference, however their bigger detain ability lead to lower bioavailability.

  11. Nature of the Periplastidial Pathway of Starch Synthesis in the Cryptophyte Guillardia theta

    PubMed Central

    Deschamps, Philippe; Haferkamp, Ilka; Dauvillée, David; Haebel, Sophie; Steup, Martin; Buléon, Alain; Putaux, Jean-Luc; Colleoni, Christophe; d'Hulst, Christophe; Plancke, Charlotte; Gould, Sven; Maier, Uwe; Neuhaus, H. Ekkehard; Ball, Steven

    2006-01-01

    The nature of the periplastidial pathway of starch biosynthesis was investigated with the model cryptophyte Guillardia theta. The storage polysaccharide granules were shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization very similar to those of starch from green algae and land plants. Most starch granules displayed a shape consistent with biosynthesis occurring around the pyrenoid through the rhodoplast membranes. A protein with significant similarity to the amylose-synthesizing granule-bound starch synthase 1 from green plants was found as the major polypeptide bound to the polysaccharide matrix. N-terminal sequencing of the mature protein proved that the precursor protein carries a nonfunctional transit peptide in its bipartite topogenic signal sequence which is cleaved without yielding transport of the enzyme across the two inner plastid membranes. The enzyme was shown to display similar affinities for ADP and UDP-glucose, while the Vmax measured with UDP-glucose was twofold higher. The granule-bound starch synthase from Guillardia theta was demonstrated to be responsible for the synthesis of long glucan chains and therefore to be the functional equivalent of the amylose-synthesizing enzyme of green plants. Preliminary characterization of the starch pathway suggests that Guillardia theta utilizes a UDP-glucose-based pathway to synthesize starch. PMID:16757743

  12. Structural and thermal transitions during the conversion from native to granular cold-water swelling maize starch.

    PubMed

    Dries, D M; Gomand, S V; Goderis, B; Delcour, J A

    2014-12-19

    Native maize starch was gradually converted into granular cold-water swelling starch (GCWSS) by aqueous ethanol treatments at elevated temperatures. At a treatment temperature of 95°C, decreasing ethanol concentrations from 68 to 48% (v/v) led to decreased post-treatment gelatinization enthalpies in excess water, reflecting remaining original A-type crystals. Concomitantly to native A-type crystal melting, VH-type crystals appeared. At an ethanol concentration of 48%, a granular cold-water swelling maize starch was successfully produced. All crystals in its intact granules were of the VH-type and appeared birefringent when studied in ethanol under polarized light. Removal of all residual solvent by high temperature drying did not influence swelling power, proving that a high temperature drying step is not necessary to induce cold-water swelling capacity. Based on in situ calorimetric measurements, the thermal requirements to produce GCWSS from different ethanol:water mixtures were elucidated. This work is the first to demonstrate that the amylose fraction contributes almost exclusively to VH-type crystal formation in GCWSS. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Tartary buckwheat (Fagopyrum tataricum Gaertn.) starch, a side product in functional food production, as a potential source of retrograded starch.

    PubMed

    Gao, Jinfeng; Kreft, Ivan; Chao, Guimei; Wang, Ying; Liu, Xiaojin; Wang, Li; Wang, Pengke; Gao, Xiaoli; Feng, Baili

    2016-01-01

    A starch rich fraction is a side product in Tartary buckwheat processing. This study investigated the fractions that are of technological and nutritional interest. Tartary buckwheat starch granules had a diameter of 3-14 μm, and presented a typical type "A" X-ray diffraction pattern. They contained nearly 39.0% amylose. The solubility of Tartary buckwheat starch was much lower at 70-90 °C (ranging within 9.9-10.4% at 90 °C) than that in maize (up to 49.3%) and potato (up to 85.0%) starch. The starch of one variety of Tartary buckwheat had significantly lower solubility at 70 °C and 80 °C than that of common buckwheat. The starch peak viscosity and breakdown were higher and pasting time was shorter in Tartary buckwheat than in that of the starch of common buckwheat. Tartary buckwheat starch had unique pasting and physicochemical properties, and is thereby capable of being exploited as a suitable raw material of retrograded starch in food processing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Characteristics of taro (Colocasia esculenta) starches planted in different seasons and their relations to the molecular structure of starch.

    PubMed

    Lu, Ting-Jang; Lin, Jheng-Hua; Chen, Jia-Ci; Chang, Yung-Ho

    2008-03-26

    Physico-chemical properties and molecular structure of starches from three cultivars (Dog hoof, Mein, and KS01) of taro tubers planted in summer, winter, and spring were investigated. The effects of the planting season on the physico-chemical properties and the molecular structure of starch were determined, and the relations between the physico-chemical properties and the molecular structure of starch are discussed. Results indicate that taro starches from tubers planted in summer had the largest granule size, a low uniformity of gelatinization, and a high tendency to swell and collapse when heated in water. Taro starch planted in summer also showed an elasticity during gelatinization that was higher than that of starches planted in the other seasons. In addition to the planting season and the variety, rheological and pasting properties of taro starches studied are influenced not only by the amylose content but also by the chain-length distribution of amylopectin, whereas swelling power and solubility only depend on the amylose content of starch. Taro starch with relatively high amylose content, high short-to-long-chain ratio, and long average chain length of long-chain fraction of amylopectin displayed high elasticity and strong gel during heating.

  15. Multigene engineering of starch biosynthesis in maize endosperm increases the total starch content and the proportion of amylose.

    PubMed

    Jiang, Lili; Yu, Xiaoming; Qi, Xin; Yu, Qian; Deng, Sen; Bai, Bing; Li, Ning; Zhang, Ai; Zhu, Changfu; Liu, Bao; Pang, Jinsong

    2013-12-01

    Maize (Zea mays spp. mays) is a staple crop for more than 900 million people. The seeds or kernels provide a rich source of calories because ~70% of the weight is carbohydrate, mostly in the form of starch. The content and composition of starch are complex traits controlled by many genes, offering multiple potential targets for intervention. We used a multigene engineering approach combining the overexpression of Bt2, Sh2, Sh1 and GbssIIa (to enhance the activity of sucrose synthase, AGPase and granule-bound starch synthase) with the suppression of SbeI and SbeIIb by RNA interference (to reduce the activity of starch branching enzyme). Maize plants expressing all six genes plus the selectable marker showed a 2.8-7.7% increase in the endosperm starch content and a 37.8-43.7% increase in the proportion of amylose, which was significant compared to untransformed control plants. We also observed improvements in other agronomic traits, such as a 20.1-34.7% increase in 100-grain weight, a 13.9-19.0% increase in ear weight, and larger kernels with a better appearance, presumably reflecting the modified starch structure within the kernels. Our results confirm that multigene engineering applied to the starch biosynthesis pathway can not only modulate the quality and quantity of starch but can also improve starch-dependent agronomic traits.

  16. Physicochemical properties and release characteristics of starches from seeds of Indian Shahi Litchi.

    PubMed

    Jaiswal, P; Kumar, K Jayaram

    2015-08-01

    Many conventional sources of starches are from staple foods. Non-conventional and cheap sources of starch are being explored. Starch was isolated from Shahi Litchi seeds using two extraction media; acidic (citric acid 0.3%, w/w; LC) and alkaline (NaOH 0.5%, w/w; LN). Each starch was investigated for various properties such as structural, morphological and functional. The percentage yield of LN and LC was 11% and 12.6%, respectively. Morphological properties of both starches show same structural makeup, but compound granules were in LN starch. Moisture content, amylose content was found to be higher LC starch than in LN starch, which indicates that extraction media affects the properties of starch. FTIR confirmed the carbohydrate nature of the both isolated starches. TGA data of both starches reveal slight difference in stability with temperature. In vitro release of both starches shows the release up to 58.95±0.04% and 67.184±0.07% in 5h for LN and LC, respectively, that indicates that these starches can be used in delayed drug delivery and targeting drugs to the colon. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Reduction of the plastidial phosphorylase in potato (Solanum tuberosum L.) reveals impact on storage starch structure during growth at low temperature.

    PubMed

    Orawetz, Tom; Malinova, Irina; Orzechowski, Slawomir; Fettke, Joerg

    2016-03-01

    Tubers of potato (Solanum tuberosum L.), one of the most important crops, are a prominent example for an efficient production of storage starch. Nevertheless, the synthesis of this storage starch is not completely understood. The plastidial phosphorylase (Pho1; EC 2.4.1.1) catalyzes the reversible transfer of glucosyl residues from glucose-1-phosphate to the non-reducing end of α-glucans with the release of orthophosphate. Thus, the enzyme is in principle able to act during starch synthesis. However, so far under normal growth conditions no alterations in tuber starch metabolism were observed. Based on analyses of other species and also from in vitro experiments with potato tuber slices it was supposed, that Pho1 has a stronger impact on starch metabolism, when plants grow under low temperature conditions. Therefore, we analyzed the starch content, granule size, as well as the internal structure of starch granules isolated from potato plants grown under low temperatures. Besides wild type, transgenic potato plants with a strong reduction in the Pho1 activity were analyzed. No significant alterations in starch content and granule size were detected. In contrast, when plants were cultivated at low temperatures the chain length distributions of the starch granules were altered. Thus, the granules contained more short glucan chains. That was not observed in the transgenic plants, revealing that Pho1 in wild type is involved in the formation of the short glucan chains, at least at low temperatures. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Improvement of the agitation granulation method to prepare granules containing a high content of a very hygroscopic drug.

    PubMed

    Hirai, Nobuaki; Ishikawa, Kazuyuki; Takahashi, Koichi

    2006-11-01

    This study describes a new approach to the preparation of a granulate with a high content of a very hygroscopic powder or drug, using the agitation granulation method, and the development of a tablet formulation using these granulates. A Chinese medicine extract, Hatimi-zio-gan, was used as the model of a very hygroscopic drug. Among the several excipients tested, only porous calcium silicate could be used to prepare granules, with a mixing ratio (extract to porous calcium silicate) from 2:1 to 20:1. With other excipients, very large lumps were formed during the granulation process. The best mixing ratio of extract to porous calcium silicate was 6:1. For preparation of the granules, water could be added to the mixed powder within a range of 1- to 4-times the amount of porous calcium silicate. From these results, it was concluded that the ability of porous calcium silicate to hold large amounts of water in its numerous pores may allow for the preparation of granulates with a high content of very hygroscopic drugs. Starch with partial alpha-links, carboxymethyl starch sodium salt and crospovidone were used for selection of the disintegration agent. When crospovidone was used as a disintegration agent, tablets containing about 70% of the Chinese medicine extract disintegrated in less than 7 min, with good dissolution rates. The same process was applied to extracts of Hotyu-ekki-to, Syo-seiryu-to, Boi-ogi-to and Bohu-tusyo-san. The absorption of paeoniflorin, a characteristic monoterpene glucoside contained in Hatimi-zio-gan extract, was evaluated in beagle dogs after oral administration of the Hatimi-zio-gan tablets prepared in this study. The values of C(max) and AUC obtained after administration of the tablets prepared in this study were significantly greater than those obtained for commercial tablets.

  19. Structural properties and digestibility of pulsed electric field treated waxy rice starch.

    PubMed

    Zeng, Feng; Gao, Qun-Yu; Han, Zhong; Zeng, Xin-An; Yu, Shu-Juan

    2016-03-01

    Waxy rice starch was subjected to pulsed electric field (PEF) treatment at intensity of 30, 40 and 50kVcm(-1). The impact of PEF treatment on the granular morphology, molecular weight, semi-crystalline structure, thermal properties, and digestibility were investigated. The micrographs suggested that electric energy could act on the granule structure of starch granule, especially at high intensity of 50kVcm(-1). Gelatinization onset temperature, peak temperature, conclusion temperature and enthalpy value of PEF treated starches were lower than that of native starch. The 9nm lamellar peak of PEF treated starches decreased as revealed by small angle X-ray scattering. The relative crystallinity of treated starches decreased as the increase of electric field intensity. Increased rapidly digestible starch level and decreased slowly digestible starch level was found on PEF treated starches. These results would imply that PEF treatment induced structural changes in waxy rice starch significantly affected its digestibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Effect of alcohol-acid modification on physicochemical, rheological and morphological properties of glutinous rice starch.

    PubMed

    Gope, Sangeeta; Samyor, Duyi; Paul, Atanu Kumar; Das, Amit Baran

    2016-12-01

    In the present study chemical modification of glutinous rice starch was carried out using 1-Buatnol-hydrochloric acid with varying time and temperature. The changes in physico-chemical, dynamic rheological and morphological properties of starch during hydrolysis was investigated. There was a significant increase in water solubility of starch due to modification; however, swelling and sedimentation value decrease after modification. The peak, hold and final viscosity of modified starches were decreased significantly as compared to native starch. Thermal properties and dynamic rheological properties of rice starch were changed with the change in time and temperature during modification. The storage (G') modulus, loss (G″) modulus, dynamic viscosity (η') and complex viscosity (η*) of modified starches were varied significantly. Analysis of microstructure revealed that the hydrolysis altered morphology of starch granules. The hydrolysis was affected the surface properties and granule size of rice starch. These results suggested that 1-butanol-HCl hydrolysis of glutinous rice starch can be a preferred way of modification. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Effect of γ-irradiation on structure and physico-chemical properties of Amorphophallus paeoniifolius starch.

    PubMed

    Reddy, Chagam Koteswara; Suriya, M; Vidya, P V; Vijina, K; Haripriya, Sundaramoorthy

    2015-08-01

    Gamma irradiation is one of the effective techniques able to alter structure and its properties of starch. In this research, the effect of modification in terms of molecular structure and physico-chemical properties of Amorphophallus paeoniifolius starch by γ-irradiation using (60)Co as γ-source at doses of 5, 10, 15, 20 and 25 kGy with dose rate 2 kGy/h was studied. Morphology of native and irradiated starches under scanning electron microscope revealed that granules are round, elliptical and polygonal in shape with smooth surfaces; no cracking or roughness was noted on irradiated starches. Amylose content, pH, swelling power of the starches and syneresis of the gelatinized starch were significantly decreased by irradiation; while carboxyl content, solubility, light transmittance and water absorption capacity of the starch granules were raised with increased dose of irradiation. Reduced pasting parameters and changes in FTIR spectrum significantly differed from each other. XRD pattern of irradiated starches showed C-type pattern with intermediate peaks of 2θ at 16.92° and 18.12°, strong peaks of 2θ at 23.05° and weak peaks of 2θ at 14.7°, displaying slight decreased in the intensity of peaks in irradiated starches. Irradiation of starches increased gelatinization temperatures and enthalpy value was measured using DSC.

  2. Characterisation, in vitro digestibility and expected glycemic index of commercial starches as uncooked ingredients.

    PubMed

    Romano, Annalisa; Mackie, Alan; Farina, Federica; Aponte, Maria; Sarghini, Fabrizio; Masi, Paolo

    2016-12-01

    In this study native starches as ingredients (corn, rice, wheat, tapioca and potato) were characterized for microstructure, physicochemical, functional and thermal properties, in vitro digestibility and glycemic index. There was a significant variation in the granule shape and size distribution of the starches. Particle size monomodal (corn, tapioca, potato) and bimodal (rice, wheat) distribution was observed amongst the starches. The potato starch showed the biggest size granules while the rice showed the smallest. The examined properties and nutritional characteristics of starches were significantly different. Thermal properties were studied using Differential Scanning Calorimeter (DSC). DSC results showed that the transition temperatures (58.8-78.7 °C) and enthalpies of gelatinization (2.3-8.2 J/g) of the starches appeared to be greatly influenced by microstructure and chemical composition (e.g. resistant starch). Nutritional properties such as slowly digestible starch and expected glycemic index values followed the order: rice > wheat > tapioca > corn > potato. In particular, the highest resistant starch was recorded for potato starch.

  3. Toward underlying reasons for rice starches having low viscosity and high amylose: physiochemical and structural characteristics.

    PubMed

    Zhang, Changquan; Zhu, Lijia; Shao, Ke; Gu, Minghong; Liu, Qiaoquan

    2013-05-01

    To understand the reasons for low starch viscosity in rice variety Q11 (Qing-lu-zhan 11), the physiochemical and structural characteristics of flours and starches were investigated and compared with another rice cultivar with similar high amylose but normal viscosity. Our results showed that residual α-amylase activity and proteins were not the major causes of low starch viscosity in Q11 rice. Homogeneous small granule size and lower swelling power of high-amylose Q11 rice starches was one reason for the low swelling volume and thus the low pasting property. Q11 starch paste contained some partially swollen granules, which could increase the fluidity and thus cause the low paste viscosity. The small gelatinization enthalpy might be due to the lower crystallinity in Q11 starches. Moreover, Q11 starches consisted of more amylose with short chains, but also amylopectin with fewer short chains (DP 11-21) and more long chains (DP 22-54), which might be other important factors contributing to the low viscosity of Q11 starches. These data can add to our understanding of the relationships between low viscosity and physiochemical properties, and will be helpful in elucidating the underlying mechanism of formation of low starch viscosity, as well as applications for low-viscosity rice starches. © 2012 Society of Chemical Industry.

  4. Starch-related cytosolic heteroglycans in roots from Arabidopsis thaliana.

    PubMed

    Malinova, Irina; Steup, Martin; Fettke, Joerg

    2011-08-15

    Both photoautotrophic and heterotrophic plant cells are capable of accumulating starch inside the plastid. However, depending on the metabolic state of the respective cell the starch-related carbon fluxes are different. The vast majority of the transitory starch biosynthesis relies on the hexose phosphate pools derived from the reductive pentose phosphate cycle and, therefore, is restricted to ongoing photosynthesis. Transitory starch is usually degraded in the subsequent dark period and mainly results in the formation of neutral sugars, such as glucose and maltose, that both are exported into the cytosol. The cytosolic metabolism of the two carbohydrates includes reversible glucosyl transfer reactions to a heteroglycan that are mediated by two glucosyl transferases, DPE2 and PHS2 (or, in all other species, Pho2). In heterotrophic cells, accumulation of starch mostly depends on the long distance transport of reduced carbon compounds from source to sink organs and, therefore, includes as an essential step the import of carbohydrates from the cytosol into the starch forming plastids. In this communication, we focus on starch metabolism in heterotrophic tissues from Arabidopsis thaliana wild type plants (and in various starch-related mutants as well). By using hydroponically grown A. thaliana plants, we were able to analyse starch-related biochemical processes in leaves and roots from the same plants. Within the roots we determined starch levels and the morphology of native starch granules. Cytosolic and apoplastic heteroglycans were analysed in roots and compared with those from leaves of the same plants. A. thaliana mutants lacking functional enzymes either inside the plastid (such as phosphoglucomutase) or in the cytosol (disproportionating isoenzyme 2 or the phosphorylase isozyme, PHS2) were included in this study. In roots and leaves from the three mutants (and from the respective wild type organ as well), starch and heteroglycans as well as enzyme patterns were

  5. Investigating starch gelatinization through Stokes vector resolved second harmonic generation microscopy

    PubMed Central

    Mazumder, Nirmal; Xiang, Lu Yun; Qiu, Jianjun; Kao, Fu-Jen

    2017-01-01

    The changes of the morphology during heating and the degree of crystallinity of dry and hydrated starch granules are investigated using second harmonic generation (SHG) based Stokes polarimetry. A spatial distribution of various polarization parameters, such as the degree of polarization (DOP), the degree of linear polarization (DOLP), and the degree of circular polarization (DOCP) are extracted and compared with the two dimensional second harmonic (SH) Stokes images of starch granules. The SH signal from hydrated and dry starch on heating differed significantly in DOLP and DOCP values, indicating that hydrated starch has a greater degree of ultrastructural amylopectin disorder. The detail of denaturation and the phase transition of hydrated starch demonstrate the significant influence of thermal processing. PMID:28383522

  6. Investigating starch gelatinization through Stokes vector resolved second harmonic generation microscopy

    NASA Astrophysics Data System (ADS)

    Mazumder, Nirmal; Xiang, Lu Yun; Qiu, Jianjun; Kao, Fu-Jen

    2017-04-01

    The changes of the morphology during heating and the degree of crystallinity of dry and hydrated starch granules are investigated using second harmonic generation (SHG) based Stokes polarimetry. A spatial distribution of various polarization parameters, such as the degree of polarization (DOP), the degree of linear polarization (DOLP), and the degree of circular polarization (DOCP) are extracted and compared with the two dimensional second harmonic (SH) Stokes images of starch granules. The SH signal from hydrated and dry starch on heating differed significantly in DOLP and DOCP values, indicating that hydrated starch has a greater degree of ultrastructural amylopectin disorder. The detail of denaturation and the phase transition of hydrated starch demonstrate the significant influence of thermal processing.

  7. Investigating starch gelatinization through Stokes vector resolved second harmonic generation microscopy.

    PubMed

    Mazumder, Nirmal; Xiang, Lu Yun; Qiu, Jianjun; Kao, Fu-Jen

    2017-04-06

    The changes of the morphology during heating and the degree of crystallinity of dry and hydrated starch granules are investigated using second harmonic generation (SHG) based Stokes polarimetry. A spatial distribution of various polarization parameters, such as the degree of polarization (DOP), the degree of linear polarization (DOLP), and the degree of circular polarization (DOCP) are extracted and compared with the two dimensional second harmonic (SH) Stokes images of starch granules. The SH signal from hydrated and dry starch on heating differed significantly in DOLP and DOCP values, indicating that hydrated starch has a greater degree of ultrastructural amylopectin disorder. The detail of denaturation and the phase transition of hydrated starch demonstrate the significant influence of thermal processing.

  8. A photographic approach to the possible mechanism of retrogradation of sweet potato starch.

    PubMed

    Lian, Xijun; Zhao, Shuyi; Liu, Qinsheng; Zhang, Xu

    2011-01-01

    Although the subject of starch retrogradation has been studied for about 20 years, the mechanism of starch retrogradation seems not yet to be completely established. In this paper, the possible retrogradation mechanism of sweet potato starch was postulated from four optical micrographs at the stages of melting of the starch granules, autoclaving treatment and aging. The possible process of retrogradation consists of three stages. Firstly, starch granules was swelled and melted with loss of X-ray crystallinity and formation of both crystalline and amorphous lamellae; secondly, in crystalline lamellae, amylopectin began to form nucleation when they were autoclaved; finally, the nucleus grew up to great rod-like crystals as the result of congregating of amylose on plates which were composed of and prolongated by amylopectin.

  9. Molecular and supra-molecular structure of waxy starches developed from cassava (Manihot esculenta Crantz).

    PubMed

    Rolland-Sabaté, Agnès; Sanchez, Teresa; Buléon, Alain; Colonna, Paul; Ceballos, Hernan; Zhao, Shan-Shan; Zhang, Peng; Dufour, Dominique

    2013-02-15

    The aim of this work was to characterize the amylopectin of low amylose content cassava starches obtained from transgenesis comparatively with a natural waxy cassava starch (WXN) discovered recently in CIAT (International Center for Tropical Agriculture). Macromolecular features, starch granule morphology, crystallinity and thermal properties of these starches were determined. M¯(w) of amylopectin from the transgenic varieties are lower than WXN. Branched and debranched chain distributions analyses revealed slight differences in the branching degree and structure of these amylopectins, principally on DP 6-9 and DP>37. For the first time, a deep structural characterization of a series of transgenic lines of waxy cassava was carried out and the link between structural features and the mutated gene expression approached. The transgenesis allows to silenced partially or totally the GBSSI, without changing deeply the starch granule ultrastructure and allows to produce clones with similar amylopectin as parental cassava clone.

  10. Effects of waterlogging after pollination on the physicochemical properties of starch from waxy maize.

    PubMed

    Lu, Dalei; Cai, Xuemei; Shi, Yaxing; Zhao, Jiuran; Lu, Weiping

    2015-07-15

    Waterlogging frequently occurs in Southern China in summer and significantly affects waxy maize growth. This study investigated the physicochemical properties of starch from six waxy maize varieties exposed to waterlogging for 1-7 days after pollination. Waterlogging decreased the starch granule size. Starch maximum absorption wavelength, iodine-binding capacity, crystallinity, and peak intensities in response to waterlogging depended on varieties. Swelling power and solubility in response to waterlogging increased in Wannuo5 and decreased in the other five varieties. Gelatinization and pasting temperatures were only slightly affected by waterlogging. Gelatinization enthalpy was unaffected in Nongkeyu301, increased in Guangbainuo5, and decreased in the other four varieties. Peak and breakdown viscosities decreased and retrogradation percentage increased when plants were subjected to waterlogging after pollination. In conclusion, waterlogging decreased starch granule size, crystallinity, swelling power, and solubility, resulting in deteriorated starch quality (i.e., low swelling, less sticky and easy to retrograde). Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Characterization and Prebiotic Effect of the Resistant Starch from Purple Sweet Potato.

    PubMed

    Zheng, Yafeng; Wang, Qi; Li, Baoyu; Lin, Liangmei; Tundis, Rosa; Loizzo, Monica R; Zheng, Baodong; Xiao, Jianbo

    2016-07-19

    Purple sweet potato starch is a potential resource for resistant starch production. The effects of heat-moisture treatment (HMT) and enzyme debranching combined heat-moisture treatment (EHMT) on the morphological, crystallinity and thermal properties of PSP starches were investigated. The results indicated that, after HMT or EHMT treatments, native starch granules with smooth surface was destroyed to form a more compact, irregular and sheet-like structure. The crystalline pattern was transformed from C-type to B-type with decreasing relative crystallinity. Due to stronger crystallites formed in modified starches, the swelling power and solubility of HMT and EHMT starch were decreased, while the transition temperatures and gelatinization enthalpy were significantly increased. In addition, HMT and EHMT exhibited greater effects on the proliferation of bifidobacteria compared with either glucose or high amylose maize starch.

  12. Arabidopsis thaliana FAR-RED ELONGATED HYPOCOTYLS3 (FHY3) and FAR-RED-IMPAIRED RESPONSE1 (FAR1) modulate starch synthesis in response to light and sugar.

    PubMed

    Ma, Lin; Xue, Na; Fu, Xiaoyu; Zhang, Haisen; Li, Gang

    2017-03-01

    In living organisms, daily light/dark cycles profoundly affect cellular processes. In plants, optimal growth and development, and adaptation to daily light-dark cycles, require starch synthesis and turnover. However, the underlying molecular mechanisms coordinating daily starch metabolism remain poorly understood. To explore the roles of Arabidopsis thaliana light signal transduction proteins FAR-RED ELONGATED HYPOCOTYLS3 (FHY3) and FAR-RED-IMPAIRED RESPONSE1 (FAR1) in starch metabolism, the contents of starch and water-soluble polysaccharides, and the structure of starch granules were investigated in fhy3, far1 and fhy3 far1 mutant plants. Disruption of FHY3 or FAR1 reduced starch accumulation and altered starch granule structure in the fhy3-4, far1-2, and fhy3-4 far1-2 mutant plants. Furthermore, molecular and genetic evidence revealed that the gene encoding the starch-debranching enzyme ISOAMYLASE2 (ISA2) is a direct target of FHY3 and FAR1, and functions in light-induced starch synthesis. Our data establish the first molecular link between light signal transduction and starch synthesis, suggesting that the light-signaling proteins FHY3 and FAR1 influence starch synthesis and starch granule formation through transcriptional activation of ISA2.

  13. A comparison of artificial solar granules with real solar granules

    NASA Technical Reports Server (NTRS)

    Woehl, H.; Nordlund, A.

    1985-01-01

    The properties of computer-generated images of solar granules were compared with data from the literature and with observations of granules from 1975 and 1979. The lifetimes, shapes, and dimensions of the granules were estimated, and the results are discussed. No significant differences were found between the artificial images and the observed granules. The ratios of width to length among the artificial granules are given in a table.

  14. Robust and biodegradable elastomers based on corn starch and polydimethylsiloxane (PDMS).

    PubMed

    Ceseracciu, Luca; Heredia-Guerrero, José Alejandro; Dante, Silvia; Athanassiou, Athanassia; Bayer, Ilker S

    2015-02-18

    Designing starch-based biopolymers and biodegradable composites with durable mechanical properties and good resistance to water is still a challenging task. Although thermoplastic (destructured) starch has emerged as an alternative to petroleum-based polymers, its poor dimensional stability under humid and dry conditions extensively hinders its use as the biopolymer of choice in many applications. Unmodified starch granules, on the other hand, suffer from incompatibility, poor dispersion, and phase separation issues when compounded into other thermoplastics above a concentration level of 5%. Herein, we present a facile biodegradable elastomer preparation method by incorporating large amounts of unmodified corn starch, exceeding 80% by volume, in acetoxy-polyorganosiloxane thermosets to produce mechanically robust, hydrophobic bioelastomers. The naturally adsorbed moisture on the surface of starch enables autocatalytic rapid hydrolysis of polyorganosiloxane to form Si-O-Si networks. Depending on the amount of starch granules, the mechanical properties of the bioelastomers can be easily tuned with high elastic recovery rates. Moreover, starch granules considerably lowered the surface friction coefficient of the polyorganosiloxane network. Stress relaxation measurements indicated that the bioelastomers have strain energy dissipation factors that are lower than those of conventional rubbers, rendering them as promising green substitutes for plastic mechanical energy dampeners. Corn starch granules also have excellent compatibility with addition-cured polysiloxane chemistry that is used extensively in microfabrication. Regardless of the starch concentration, all of the developed bioelastomers have hydrophobic surfaces with lower friction coefficients and much less water uptake capacity than those of thermoplastic starch. The bioelastomers are biocompatible and are estimated to biodegrade in Mediterranean seawater within three to six years.

  15. In vitro Biochemical Characterization of All Barley Endosperm Starch Synthases

    PubMed Central

    Cuesta-Seijo, Jose A.; Nielsen, Morten M.; Ruzanski, Christian; Krucewicz, Katarzyna; Beeren, Sophie R.; Rydhal, Maja G.; Yoshimura, Yayoi; Striebeck, Alexander; Motawia, Mohammed S.; Willats, William G. T.; Palcic, Monica M.

    2016-01-01

    Starch is the main storage polysaccharide in cereals and the major source of calories in the human diet. It is synthesized by a panel of enzymes including five classes of starch synthases (SSs). While the overall starch synthase (SS) reaction is known, the functional differences between the five SS classes are poorly understood. Much of our knowledge comes from analyzing mutant plants with altered SS activities, but the resulting data are often difficult to interpret as a result of pleitropic effects, competition between enzymes, overlaps in enzyme activity and disruption of multi-enzyme complexes. Here we provide a detailed biochemical study of the activity of all five classes of SSs in barley endosperm. Each enzyme was produced recombinantly in E. coli and the properties and modes of action in vitro were studied in isolation from other SSs and other substrate modifying activities. Our results define the mode of action of each SS class in unprecedented detail; we analyze their substrate selection, temperature dependence and stability, substrate affinity and temporal abundance during barley development. Our results are at variance with some generally accepted ideas about starch biosynthesis and might lead to the reinterpretation of results obtained in planta. In particular, they indicate that granule bound SS is capable of processive action even in the absence of a starch matrix, that SSI has no elongation limit, and that SSIV, believed to be critical for the initiation of starch granules, has maltoligosaccharides and not polysaccharides as its preferred substrates. PMID:26858729

  16. Application of ultra high pressure (UHP) in starch chemistry.

    PubMed

    Kim, Hyun-Seok; Kim, Byung-Yong; Baik, Moo-Yeol

    2012-01-01

    Ultra high pressure (UHP) processing is an attractive non-thermal technique for food treatment and preservation at room temperature, with the potential to achieve interesting functional effects. The majority of UHP process applications in food systems have focused on shelf-life extension associated with non-thermal sterilization and a reduction or increase in enzymatic activity. Only a few studies have investigated modifications of structural characteristics and/or protein functionalities. Despite the rapid expansion of UHP applications in food systems, limited information is available on the effects of UHP on the structural and physicochemical properties of starch and/or its chemical derivatives included in most processed foods as major ingredients or minor additives. Starch and its chemical derivatives are responsible for textural and physical properties of food systems, impacting their end-use quality and/or shelf-life. This article reviews UHP processes for native (unmodified) starch granules and their effects on the physicochemical properties of UHP-treated starch. Furthermore, functional roles of UHP in acid-hydrolysis, hydroxypropylation, acetylation, and cross-linking reactions of starch granules, as well as the physicochemical properties of UHP-assisted starch chemical derivatives, are discussed.

  17. Factors affecting the disintegration and dissolution of chloroquine phosphate/starch tablets.

    PubMed

    Pilpel, N; Otuyemi, S O; Kurup, T R

    1978-04-01

    A study has been made of the effects produced on the disintegration and dissolution times of chloroquine phosphate tablets by varying their moisture and starch contents and the distribution of the starch in the formulation. 3 to 5% w/w of moisture produces a maximum in the disintegration and dissolution times. Starch added externally as a powder acts only as a disintegrating agent for the tablets, but starch added internally as a paste during granulation acts both as a binding agent and a disintegrant.

  18. Multiphoton imaging to distinguish grana and starch inside an intact leaf

    NASA Astrophysics Data System (ADS)

    Chen, Mei-Yu; Zhuo, Guan-Yu; Chen, Po-Fu; Wu, Pei-Chun; Liu, Tzu-Ming; Chu, Shi-Wei

    2013-02-01

    We have demonstrated a straightforward and noninvasive method to identify the distribution of grana and starch within an intact leaf. Grana and starch are the major functional structures for photosynthesis and energy storage of plant, respectively. Both exhibit highly ordered molecular structures and appear as micrometer-sized granules inside chloroplasts. In order to distinguish grana and starch, we used multiphoton microscopy, with simultaneous acquisition of two photon fluorescence (2PF) and second harmonic generation (SHG) signals. Consequently, SHG is found on both grana and starch while 2PF from chlorophyll indicates the identity of grana.

  19. Properties of amylose-oleic acid inclusion complexes from corn starch grafted with poly(methyl acrylate)

    USDA-ARS?s Scientific Manuscript database

    Corn starch granules have been previously investigated as fillers in polymers. In this study, much smaller particles in the form of spherulites produced by steam jet-cooking high-amylose corn starch and oleic acid to form amylose inclusion complexes were graft polymerized with methyl acrylate, both ...

  20. Starch chain interactions within the amorphous and crystalline domains of pulse starches during heat-moisture treatment at different temperatures and their impact on physicochemical properties.

    PubMed

    Ambigaipalan, P; Hoover, R; Donner, E; Liu, Q

    2014-01-15

    Pulse (faba bean [FB], black bean [BB] and pinto bean [PB]) starches were heat-moisture treated (HMT) at 80, 100 and 120°C for 12h at a moisture content of ∼23%. Structural changes on HMT were monitored by microscopy, HPAEC-PAD, ATR-FTIR, WAXS, DSC and susceptibility towards acid and enzyme hydrolysis. Amylopectin chain length distribution remained unchanged in all starches on HMT. In all starches, HMT increased crystallinity and gelatinisation temperatures. The gelatinization enthalpy remained unchanged in some starches, whereas it decreased slightly in other starches on HMT. Slowly digestible starch content decreased at all temperatures of HMT, whereas resistant starch content increased at HMT80 and HMT100 (HMT80>HMT100), but decreased at HMT120. Birefringence, B-type crystallites and acid hydrolysis decreased on HMT. The extent of the above changes varied amongst starch sources and genotypes. HMT altered the X-ray pattern from A+B→A. The results of this study showed that structural reorganisation of starch chains during HMT temperature was influenced by starch chain flexibility, starch chain interactions and crystalline stability of the native granules.

  1. Structure and digestibility of debranched and repeatedly crystallized waxy rice starch.

    PubMed

    Zeng, Feng; Chen, Fuquan; Kong, Fansheng; Gao, Qunyu; Aadil, Rana Muhammad; Yu, Shujuan

    2015-11-15

    Debranched waxy rice starch was subjected to repeated crystallization (RC) treatment, and its physicochemical properties and digestion pattern were investigated. The A-type crystalline pattern of native starch was crystallized to a complex of B- and V-type patterns by debranching and RC treatment. Among the treated starches, the relative crystallinity of debranched starch reached its maximum (29.6%) after eight repetitions of crystallization. Changes in weight-average molar mass among treated starch samples were not significantly different. The repeated-crystallized starches showed higher thermal transition temperatures and melting enthalpy than that of debranched starch. As a result, slowly digestible starch (SDS) content of repeated-crystallized starches reached a very high level (57.8%). Results showed that RC treatment induced structural changes of waxy rice starch result in a great amount of SDS.

  2. Dual modification of taro starch by microwave and other heat moisture treatments.

    PubMed

    Deka, Dhritiman; Sit, Nandan

    2016-11-01

    Effect of heat moisture treatment on the physicochemical properties of taro starch with 25% moisture (w/w) modified by single treatments of microwave (HMT1), autoclave (HMT2) and hot air oven (HMT3), and dual treatments of microwave followed by autoclave (HMT4) and microwave followed by hot air oven (HMT5) were investigated. Amylose contents of the modified starches increased except for HMT3. A loss of physical integrity of the starch granules were observed for dual modified starches. The swelling and solubility of all the modified starches increased. The peak viscosities of starches modified by HMT1 and HMT5 were found to be higher whereas for other modified starches it was lower than that of native starch. The holding and final viscosities of all the modified starches except HMT4 were higher than native starch. The freeze-thaw stabilities of the modified starches were also found to be better than that of native starch. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Effects of acetic acid and lactic acid on physicochemical characteristics of native and cross-linked wheat starches.

    PubMed

    Majzoobi, Mahsa; Beparva, Paniz

    2014-03-15

    The effects of two common organic acids; lactic and acetic acids (150 mg/kg) on physicochemical properties of native and cross-linked wheat starches were investigated prior and after gelatinization. These acids caused formation of some cracks and spots on the granules. The intrinsic viscosity of both starches decreased in the presence of the acids particularly after gelatinization. Water solubility increased while water absorption reduced after addition of the acids. The acids caused reduction in gelatinization temperature and enthalpy of gelatinization of both starches. The starch gels became softer, less cohesive, elastic and gummy when acids were added. These changes may indicate the degradation of the starch molecules by the acids. Cross-linked wheat starch was more resistant to the acids. However, both starches became more susceptible to the acids after gelatinization. The effect of lactic acid on physicochemical properties of both starches before and after gelatinization was greater than acetic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Effect of succinylation on functional and morphological properties of starches from broken kernels of Pakistani Basmati and Irri rice cultivars.

    PubMed

    Moin, Abeera; Ali, Tahira Mohsin; Hasnain, Abid

    2016-01-15

    Starch extracted from broken kernels of Basmati and Irri rice varieties of Pakistani rice were subjected to modification by addition of succinic anhydride at levels of 2%, 4% and 5% based on dried weight of starch. The succinyl content of Irri rice starch increased with the concentration of succinic anhydride. Scanning electron micrographs revealed presence of dents and fusion of rice starch granules. Swelling power and water retention capacity (WRC) significantly improved after succinylation while on refrigerated storage percent decline in paste clarity of modified rice starches was stable as compared to native Basmati (BC) and Irri (IC) rice starches. Succinylation also reduced solubility, pasting temperature (PT) and gel hardness of starch gels. Improvement was observed in cold storage stability of rice starch succinates as evident from textural profile analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Simultaneous utilization of non-starch polysaccharides and starch and viscosity reduction for bioethanol fermentation from fresh Canna edulis Ker. tubers.

    PubMed

    Huang, Yuhong; Jin, Yanling; Fang, Yang; Li, Yuhao; Zhao, Hai

    2013-01-01

    Viscosity reduction and the effect of cell-wall degrading enzymes (CWDEs) were investigated using Canna edulis Ker. for bioethanol fermentation. The fermentation mash treated with CWDEs was much thinner (2.12 Pas) than the control mash (8.42 Pas), the fermentation efficiency was increased from 90.46% to 96.11%. HPLC analysis revealed that after treated with CWDEs, glucose and total sugar were increased by 28.07% and 7.60%, respectively. Changes in the starch granules were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and confocal laser scanning microscopy (CLSM). The results suggested that the reduction in viscosity was caused by changes in saccharide composition and physical changes of the starch granules. This present study is of significance that non-starch polysaccharides and starch can be simultaneously utilized for bioethanol production using roots and tubers as feedstock.

  6. Effects of regular and modified starches on cooked pale, soft, and exudative; normal; and dry, firm, and dark breast meat batters.

    PubMed

    Zhang, L; Barbut, S

    2005-05-01

    The effects of potato and tapioca starches (regular and modified) on the texture, yield, and microstructure of pale, soft, and exudative (PSE); normal; and dark, firm, and dry (DFD) chicken breast meats were studied. Cook yield and fracture force were higher in DFD than in normal and PSE meat. All starches significantly improved yield with modified tapioca showing the best results. Light microscopy showed even distribution and gelatinization of large potato starch granules and small tapioca granules. Addition of starches to the normal meat (46 < L* < 53, 5.9 < pH < 6.1) resulted in higher modulus of rigidity (G') values above 60 degrees C. During cooling, this trend continued as all starches provided significantly higher G' values compared with the control; regular and modified potato resulted in higher G' values than the tapioca starches. Overall, starch addition can compensate for part of the meat protein functionality lost in PSE meat.

  7. Internal structure and physicochemical properties of corn starches as revealed by chemical surface gelatinization.

    PubMed

    Kuakpetoon, Daris; Wang, Ya-Jane

    2007-11-05

    The organization of amylose and amylopectin within starch granules is still not well elucidated. This study investigates the radial distribution of amylose and amylopectin in different corn starches varying in amylose content (waxy corn starch (WC), common corn starch (CC), and 50% and 70% amylose corn starches (AMC)). Corn starches were surface gelatinized by 13 M LiCl at room temperature to different extents (approximately 10%, 20%, 30%, and 40%). The gelatinized surface starch and remaining granules were characterized for amylose content, amylopectin chain-length distribution, thermal properties, swelling power (SP), and water solubility index (WSI). Except for the outmost 10% layer, the amylose content in CC increased slightly with increasing surface removal. In contrast, amylose was more concentrated at the periphery than at the core for 50% and 70% AMC. The proportion of amylopectin A chains generally decreased while that of B1 chains generally increased with increasing surface removal for all corn starches. The gelatinization enthalpy usually decreased, except for 70% AMC, whereas the retrogradation enthalpy relatively remained unchanged for CC but increased for WC, 50% and 70% AMC with increasing surface removal. The SP and WSI increased with increasing surface removal for all corn starches, with WC showing a significant increase in SP after the removal of the outmost 10% layer. The results of this study indicated that there were similarities and differences in the distribution of amylose and amylopectin chains along the radial location of corn starch granules with varying amylose contents. More amylose-lipid complex and amylopectin long chains were present at the periphery than at the core for amylose-containing corn starches.

  8. A review of starch-branching enzymes and their role in amylopectin biosynthesis.

    PubMed

    Tetlow, Ian J; Emes, Michael J

    2014-08-01

    Starch-branching enzymes (SBEs) are one of the four major enzyme classes involved in starch biosynthesis in plants and algae, and their activities play a crucial role in determining the structure and physical properties of starch granules. SBEs generate α-1,6-branch linkages in α-glucans through cleavage of internal α-1,4 bonds and transfer of the released reducing ends to C-6 hydroxyls. Starch biosynthesis in plants and algae requires multiple isoforms of SBEs and is distinct from glycogen biosynthesis in both prokaryotes and eukaryotes which uses a single branching enzyme (BE) isoform. One of the unique characteristics of starch structure is the grouping of α-1,6-branch points in clusters within amylopectin. This is a feature of SBEs and their interplay with other starch biosynthetic enzymes, thus facilitating formation of the compact water-insoluble semicrystalline starch granule. In this respect, the activity of SBE isoforms is pivotal in starch granule assembly. SBEs are structurally related to the α-amylase superfamily of enzymes, sharing three domains of secondary structure with prokaryotic Bes: the central (β/α)8 -barrel catalytic domain, an NH2 -terminal domain involved in determining the size of α-glucan chain transferred, and the C-terminal domain responsible for catalytic capacity and substrate preference. In addition, SBEs have conserved plant-specific domains, including phosphorylation sites which are thought to be involved in regulating starch metabolism. SBEs form heteromeric protein complexes with other SBE isoforms as well as other enzymes involved in starch synthesis, and assembly of these protein complexes is regulated by protein phosphorylation. Phosphorylated SBEIIb is found in multienzyme complexes with isoforms of glucan-elongating starch synthases, and these protein complexes are implicated in amylopectin cluster formation. This review presents a comparative overview of plant SBEs and includes a review of their properties

  9. Potato starch oxidation induced by sodium hypochlorite and its effect on functional properties and digestibility.

    PubMed

    Zhou, Fengchao; Liu, Qian; Zhang, Hongwei; Chen, Qian; Kong, Baohua

    2016-03-01

    The effects of different concentrations of sodium hypochlorite (active chlorine content at 0.1, 0.2, 1.0, 2.0, 3.0, and 4.0 g/100 g) on the properties of potato starch (PS) were investigated by determining the morphological, physicochemical, crystallinity, pasting, gel texture and digestive properties. The starch granules of PS oxidized with high oxidant concentrations caused cracks and pores, and oxidation mainly acts on the amorphous regions of the starch granules. As the sodium hypochlorite concentration increases, the carbonyl content, carboxyl content, solubility, and pasting temperature of PS increased, as measured using a Rapid Visco Analyser (RVA). The swelling power, breakdown, setback, and peak and final viscosities decreased according to the RVA (P<0.05). The gel strength increased under low-intensity oxidative treatments and decreased under high-intensity oxidative treatments. Oxidative treatment decreased the digestibility of gelatinized potato starch. The slowly digestible starch and resistant starch contents increased significantly, while the rapidly digestible starch content decreased after the oxidation modification (P<0.05). Overall, PS oxidation with sodium hypochlorite improved the functional characteristics of starch and decreased starch digestibility. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Gel characteristics and microstructure of fish myofibrillar protein/cassava starch composites.

    PubMed

    Fan, Mingcong; Hu, Ting; Zhao, Siming; Xiong, Shanbai; Xie, Jing; Huang, Qilin

    2017-03-01

    The changes in fish myofibrillar protein/cassava starch composites in the starch fraction range from 0 to 1, with their total content maintained at 60mg/mL, were investigated in terms of textural properties, rheological behaviours, morphology, spatial distribution and protein molecular structure. The results revealed that the starch fraction of 0.5 was a critical point for the conversion of the protein matrix to starch matrix and conversion of the gel from elastic to weak. Moreover, the protein-starch synergistic effect on the storage modulus was strongest at fractions of 0.5 and 0.6, due to the formation of a semi-interpenetrating network, with more amylose from the melted starch granules interpenetrated with the protein molecules, and the absorption of water by the starch granules to concentrate the protein matrix. Additionally, no covalent interaction between the protein and starch occurred with increasing starch fraction, thus having no significant influence on the protein secondary structure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Influence of lysophosphatidylcholine on the gelation of diluted wheat starch suspensions.

    PubMed

    Ahmadi-Abhari, S; Woortman, A J J; Hamer, R J; Oudhuis, A A C M; Loos, K

    2013-03-01

    Starch is an omnipresent constituent which is used for its nutritional and structuring properties. Recently concerns have been raised since starch is a source of readily available glucose which is tightly correlated with diabetes type II and obesity. For this reason, the possibilities for modulating the digestibility of starch while preserving its functional properties were investigated; therefore the focus of this paper is on starch gelatinization and the effect of lysophosphatidylcholine (LPC) on the structuring properties of wheat starch. The effect of LPC on thermal properties and viscosity behavior of starch suspensions was studied using DSC and RVA, respectively. The influence on granular structure was observed by light microscopy. The RVA profile demonstrated no viscosity increase at high LPC concentrations which proves intact granular structure after gelatinization. LPC in intermediate concentrations resulted in a notable delay of pasting; however the peak and end viscosities were influenced as well. Lower LPC concentrations demonstrated a higher peak viscosity as compared with pure starch suspensions. DSC results imply that inclusion complexes of amylose-LPC might be formed during pasting time. Since the viscosity profiles are changed by LPC addition, swelling power and solubility of starch granules are influenced as well. LPC hinders swelling power and solubility of starch granules which are stimulated by heating.

  12. Pasting properties of heat-moisture treated canna starches using different plasticizers during treatment.

    PubMed

    Juansang, Juraluck; Puttanlek, Chureerat; Rungsardthong, Vilai; Puncha-Arnon, Santhanee; Jiranuntakul, Wittawat; Uttapap, Dudsadee

    2015-05-20

    Different plasticizers (propanol, propylene glycol, glycerol, erythritol, xylitol and sorbitol) were used for plasticizing canna starch during heat-moisture treatment (HMT). Pasting properties of the modified starches were determined and compared with those of native starch and of HMT starch using water as a plasticizer. Canna starch was soaked in 5% (w/w) plasticizer solutions and adjusted to 25% moisture content before heating at 100 °C for 1h. The least change in paste viscosity was found when water was used as a plasticizer. Viscosity of the modified starches decreased as the molecular weight of plasticizers decreased. Plasticizer content in starch granules increased with decreasing molecular weight of the plasticizer, as well as with increased soaking time (from 10 min to 4 and 24h). However, pasting profiles of HMT starches prepared by soaking for 4h were comparable to those soaked for 24h, indicating that there was an effective limit of plasticizers. The plasticizer content in starch granules played a greater role in HMT than the number of hydroxyl groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Biosynthesis and Regulation of Wheat Amylose and Amylopectin from Proteomic and Phosphoproteomic Characterization of Granule-binding Proteins

    PubMed Central

    Chen, Guan-Xing; Zhou, Jian-Wen; Liu, Yan-Lin; Lu, Xiao-Bing; Han, Cai-Xia; Zhang, Wen-Ying; Xu, Yan-Hao; Yan, Yue-Ming

    2016-01-01

    Waxy starch has an important influence on the qualities of breads. Generally, grain weight and yield in waxy wheat (Triticum aestivum L.) are significantly lower than in bread wheat. In this study, we performed the first proteomic and phosphoproteomic analyses of starch granule-binding proteins by comparing the waxy wheat cultivar Shannong 119 and the bread wheat cultivar Nongda 5181. These results indicate that reduced amylose content does not affect amylopectin synthesis, but it causes significant reduction of total starch biosynthesis, grain size, weight and grain yield. Two-dimensional differential in-gel electrophoresis identified 40 differentially expressed protein (DEP) spots in waxy and non-waxy wheats, which belonged mainly to starch synthase (SS) I, SS IIa and granule-bound SS I. Most DEPs involved in amylopectin synthesis showed a similar expression pattern during grain development, suggesting relatively independent amylose and amylopectin synthesis pathways. Phosphoproteome analysis of starch granule-binding proteins, using TiO2 microcolumns and LC-MS/MS, showed that the total number of phosphoproteins and their phosphorylation levels in ND5181 were significantly higher than in SN119, but proteins controlling amylopectin synthesis had similar phosphorylation levels. Our results revealed the lack of amylose did not affect the expression and phosphorylation of the starch granule-binding proteins involved in amylopectin biosynthesis. PMID:27604546

  14. Inferred properties of stellar granulation

    SciTech Connect

    Gray, D.F.; Toner, C.G.

    1985-06-01

    Apparent characteristics of stellar granulation in F and G main-sequence stars are inferred directly from observed spectral-line asymmetries and from comparisons of numerical simulations with the observations: (1) the apparent granulation velocity increases with effective temperature, (2) the dispersion of granule velocities about their mean velocity of rise increases with the apparent granulation velocity, (3) the mean velocity of rise of granules must be less than the total line broadening, (4) the apparent velocity difference between granules and dark lanes corresponds to the granulation velocity deduced from stellar line bisectors, (5) the dark lanes show velocities of fall approximately twice as large as the granule rise velocities, (6) the light contributed to the stellar flux by the granules is four to ten times more than the light from the dark lanes. Stellar rotation is predicted to produce distortions in the line bisectors which may give information on the absolute velocity displacements of the line bisectors. 37 references.

  15. Physicochemical, thermal and functional properties of gamma irradiated chickpea starch.

    PubMed

    Bashir, Khalid; Aggarwal, Manjeet

    2017-04-01

    The study was conducted to evaluate the effect of gamma irradiation (0, 0.5, 1, 2.5, 5 and 10kGy) on physicochemical, functional and thermal properties of chickpea starch. Results revealed that the pasting properties showed a significant (p≤0.05) decrease in peak viscosity, final viscosity, setback viscosity, trough viscosity and pasting temperature in dose dependent manner. Swelling, solubility index, oil absorption capacity and water absorption capacity increased significantly with dose, while as syneresis decreased with dose. Gelatinization temperatures To, Tp and Tc decreased significantly with dose. X-ray diffraction showed a characteristic C type pattern of the starches and the crystallinity decreased with dose. Scanning electron microscopy revealed small oval shaped starch granules and slight surface fissures were seen in the irradiated starch treated with 5 and 10kGy. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Properties of starch from potatoes differing in glycemic index.

    PubMed

    Lin Ek, Kai; Wang, Shujun; Brand-Miller, Jennie; Copeland, Les

    2014-10-01

    Potatoes are a popular source of dietary carbohydrate worldwide and are generally considered to be a high glycemic index (GI) food. Potato starch characteristics play a key role in determining their rate of digestion and resulting glycemic response. Starches isolated from seven potato cultivars with different GI values, including a low GI cultivar (Carisma), were examined for relative crystallinity, granule size distribution, amylopectin chain length, and thermal and pasting properties. Starch from the Carisma cultivar was more thermally stable and more resistant to gelatinization, with significantly higher (p < 0.05) pasting temperature and differential scanning calorimetry (DSC) gelatinization onset, peak and conclusion temperatures, compared to the other cultivars. Differences between the potatoes in the other properties measured did not align with the GI ranking. Thermal analysis and starch pasting properties may be useful indicators for preliminary identification of potato cultivars that are digested slowly and have a lower GI.

  17. Two- and multi-step annealing of cereal starches in relation to gelatinization.

    PubMed

    Shi, Yong-Cheng

    2008-02-13

    Two- and multi-step annealing experiments were designed to determine how much gelatinization temperature of waxy rice, waxy barley, and wheat starches could be increased without causing a decrease in gelatinization enthalpy or a decline in X-ray crystallinity. A mixture of starch and excess water was heated in a differential scanning calorimeter (DSC) pan to a specific temperature and maintained there for 0.5-48 h. The experimental approach was first to anneal a starch at a low temperature so that the gelatinization temperature of the starch was increased without causing a decrease in gelatinization enthalpy. The annealing temperature was then raised, but still was kept below the onset gelatinization temperature of the previously annealed starch. When a second- or third-step annealing temperature was high enough, it caused a decrease in crystallinity, even though the holding temperature remained below the onset gelatinization temperature of the previously annealed starch. These results support that gelatinization is a nonequilibrium process and that dissociation of double helices is driven by the swelling of amorphous regions. Small-scale starch slurry annealing was also performed and confirmed the annealing results conducted in DSC pans. A three-phase model of a starch granule, a mobile amorphous phase, a rigid amorphous phase, and a crystalline phase, was used to interpret the annealing results. Annealing seems to be an interplay between a more efficient packing of crystallites in starch granules and swelling of plasticized amorphous regions. There is always a temperature ceiling that can be used to anneal a starch without causing a decrease in crystallinity. That temperature ceiling is starch-specific, dependent on the structure of a starch, and is lower than the original onset gelatinization of a starch.

  18. Characterization of Modified Tapioca Starch in Atmospheric Argon Plasma under Diverse Humidity by FTIR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Deeyai, P.; Suphantharika, M.; Wongsagonsup, R.; Dangtip, S.

    2013-01-01

    Tapioca is economical crop grown in Thailand and continues to be one of the major sources of starch. Nowadays, tapioca starch has been widely used in industrial applications, however the native form of starch has limited the applications. Thus scientists try to modify the properties of starch for increasing the stability of the granules, pastes to low pH, heat, and shear during the food process. We modify the tapioca starch by plasma treatment under an argon atmosphere. The degree of modification is determined by following water content in the starch granules. The tablet samples of native starch are also prepared and compared with the plasma treated starch. Before plasma treatment, the starch tablets are stored under three different relative humilities (RH) including 11%, 68%, and 78%RH, respectively. The samples are characterized using FTIR spectroscopy associated with the degree of cross-linking. The results show that the water molecules are engulfed into the starch structure in two ways, a tight bond and a weak absorption of water molecules which is represented at two wave number of 1630 cm-1 and 3272 cm-1, respectively. The degree of cross-linking can be identified from the relative intensity of these two peaks with the C—O—H peak at 993 cm-1. The results show that the degree of cross-linking increase in the plasma treated starch. The degree of cross-linking of the treated starch with high relative humidity is less than that of the treated starch with low relative humidity.

  19. Physicochemical characteristics and in vitro digestibility of potato and cassava starches under organic acid and heat-moisture treatments.

    PubMed

    Van Hung, Pham; Huong, Nguyen Thi Mai; Phi, Nguyen Thi Lan; Tien, Nguyen Ngoc Thanh

    2017-02-01

    A combination of acid (citric acid or lactic acid) and heat-moisture treatment was used to modify cassava and potato starches in this study. Changes in physicochemical properties and in vitro digestibility of the treated starches were investigated. The cassava starch contained 17.0% amylose and possessed A-type crystallinity, whereas the potato starch had 27.4% amylose and possessed B-type crystallinity. After acid and heat-moisture treatment, the crystalline structure of the cassava starch remained unchanged (A type), while the crystalline structure of the potato starch changed from B type to the C (B+A) type. The acid and heat-moisture treatment increased gelatinization temperature, peak and final viscosities of cassava starch but reduced peak and breakdown viscosities of the potato starch. After acid and heat-moisture treatment, rapid digestible starch contents of the treated cassava and potato starches were significantly reduced. However, resistant starch (RS) contents of the treated starches significantly increased as compared to the native starches. Citric acid was found to have high impact on formation of RS in starches. The RS contents of cassava and potato starches obtained under the citric acid and heat-moisture treatment were 40.2% and 39.0%, respectively, two times higher than those of the native starches.

  20. Investigation of glycerol concentration on corn starch morphologies and gelatinization behaviours during heat treatment.

    PubMed

    Chen, Xu; Guo, Li; Du, Xianfeng; Chen, Peirong; Ji, Yishun; Hao, Huili; Xu, Xiaonan

    2017-11-15

    The effects of various glycerol concentrations (0%, 5%, 10%, 20%, and 50%, w/w) on the morphologies and gelatinization behaviours of corn starch were evaluated by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and rapid visco-analyzer (RVA). When corn starch granules with no added glycerol were treated at 65°C, the granules of corn starch were almost completely broken and tightly connected, and the characteristic birefringence of the starch granules disappeared. Various microscopic techniques revealed that starch gelatinization was delayed to higher temperatures as the glycerol concentration increased. In the presence of glycerol-water systems (5%, 10%, 20%, and 50%, w/w), the peak temperatures of corn starch increased by 1.6°C, 7.4°C, 10.7°C, and 19.7°C, respectively, compared to corn starch in water. The RVA pasting profiles showed that the gelatinization temperature increased as the glycerol concentration increased, which was consistent with polarized light microscope observations and DSC tests. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Allelic variants of the amylose extender mutation of maize demonstrate phenotypic variation in starch structure resulting from modified protein–protein interactions

    PubMed Central

    Liu, Fushan; Ahmed, Zaheer; Lee, Elizabeth A.; Donner, Elizabeth; Liu, Qiang; Ahmed, Regina; Morell, Matthew K.; Emes, Michael J.; Tetlow, Ian J.

    2012-01-01

    amylose extender (ae−) starches characteristically have modified starch granule morphology resulting from amylopectin with reduced branch frequency and longer glucan chains in clusters, caused by the loss of activity of the major starch branching enzyme (SBE), which in maize endosperm is SBEIIb. A recent study with ae− maize lacking the SBEIIb protein (termed ae1.1 herein) showed that novel protein–protein interactions between enzymes of starch biosynthesis in the amyloplast could explain the starch phenotype of the ae1.1 mutant. The present study examined an allelic variant of the ae− mutation, ae1.2, which expresses a catalytically inactive form of SBEIIb. The catalytically inactive SBEIIb in ae1.2 lacks a 28 amino acid peptide (Val272–Pro299) and is unable to bind to amylopectin. Analysis of starch from ae1.2 revealed altered granule morphology and physicochemical characteristics distinct from those of the ae1.1 mutant as well as the wild-type, including altered apparent amylose content and gelatinization properties. Starch from ae1.2 had fewer intermediate length glucan chains (degree of polymerization 16–20) than ae1.1. Biochemical analysis of ae1.2 showed that there were differences in the organization and assembly of protein complexes of starch biosynthetic enzymes in comparison with ae1.1 (and wild-type) amyloplasts, which were also reflected in the composition of starch granule-bound proteins. The formation of stromal protein complexes in the wild-type and ae1.2 was strongly enhanced by ATP, and broken by phosphatase treatment, indicating a role for protein phosphorylation in their assembly. Labelling experiments with [γ-32P]ATP showed that the inactive form of SBEIIb in ae1.2 was phosphorylated, both in the monomeric form and in association with starch synthase isoforms. Although the inactive SBEIIb was unable to bind starch directly, it was strongly associated with the starch granule, reinforcing the conclusion that its presence in the

  2. mRNP granules

    PubMed Central

    Buchan, J Ross

    2014-01-01

    Messenger ribonucleoprotein (mRNP) granules are dynamic, self-assembling structures that harbor non-translating mRNAs bound by various proteins that regulate mRNA translation, localization, and turnover. Their importance in gene expression regulation is far reaching, ranging from precise spatial-temporal control of mRNAs that drive developmental programs in oocytes and embryos, to similarly exquisite control of mRNAs in neurons that underpin synaptic plasticity, and thus, memory formation. Analysis of mRNP granules in their various contexts has revealed common themes of assembly, disassembly, and modes of mRNA regulation, yet new studies continue to reveal unexpected and important findings, such as links between aberrant mRNP granule assembly and neurodegenerative disease. Continued study of these enigmatic structures thus promises fascinating new insights into cellular function, and may also suggest novel therapeutic strategies in various disease states. PMID:25531407

  3. Polarization Second Harmonic Generation Discriminates Between Fresh and Aged Starch-Based Adhesives Used in Cultural Heritage.

    PubMed

    Psilodimitrakopoulos, Sotiris; Gavgiotaki, Evaggelia; Melessanaki, Kristallia; Tsafas, Vassilis; Filippidis, George

    2016-10-01

    In this work, we report that polarization second harmonic generation (PSHG) microscopy, commonly used in biomedical imaging, can quantitatively discriminate naturally aged from fresh starch-based glues used for conservation or restoration of paintings, works of art on paper, and books. Several samples of fresh and aged (7 years) flour and starch pastes were investigated by use of PSHG. In these types of adhesives, widely used in cultural heritage conservation, second harmonic generation (SHG) contrast originates primarily from the starch granules. It was found that in aged glues, the starch SHG effective orientation (SHG angle, θ) shifts to significantly higher values in comparison to the fresh granules. This shift is attributed to the different degree of granule hydration between fresh and aged adhesives. Thus noninvasive high-resolution nonlinear scattering can be employed to detect and quantify the degree of deterioration of restoration adhesives and to provide guidance toward future conservation treatments.

  4. Pasting investigation, SEM observation and the possible interaction study on rice starch-pullulan combination.

    PubMed

    Chen, Long; Ren, Fei; Yu, Xueping; Zhang, Zipei; Xu, Dejun; Tong, Qunyi

    2015-02-01

    The pasting properties of rice starch (RS) with high concentration (10%, w/w) were investigated in the presence or absence of pullulan (PUL) using a rapid visco-analyzer (RVA). Addition of pullulan resulted in the reduction of peak viscosity, trough viscosity, final viscosity, and setback value of RS. Furthermore, an interesting phenomenon, i.e. a small viscosity peak appeared in the RVA curves of RS-PUL mixtures, was observed. It indicated that addition of pullulan might suppress the gelatinization of starch granules by maintaining the integration of some granules. The scanning electron microscope (SEM) observation of samples suggested that starch granules could be wrapped by a thin membrane composed of pullulan and/or pullulan-amylose associations. The coating ability of pullulan and/or the possible molecular interactions between pullulan and amylose could be responsible for these results.

  5. The relationship between translucency of rice grain and gelatinization of starch in the grain during cooking.

    PubMed

    He, G; Suzuki, H

    1987-08-01

    The soaked and nonsoaked rice grains were cooked by the excess water method and the steamer method, and subjected to Ranghino's test, X-ray diffraction, and microscopic observation. The starch granules in the nonsoaked rice were gelatinized at the same time as the grains became translucent during cooking. However, when the grains of medium amylose varieties and waxy rice were presoaked, the starch granules were not fully gelatinized in the translucent grains cooked for Ranghino's cooking time. The gelatinization of starch granules proceeded faster in the soaked rice and by the excess water method than that in the nonsoaked rice and by the steamer method. The cooking time and gelatinization time correlated negatively with the water content after soaking, and positively with the amylose content in the rice grains. The japonica rices were gelatinized fully in less than 20 min when the amount of water added for cooking was adequate.

  6. Polymorphism of starch pathway genes in cassava.

    PubMed

    Vasconcelos, L M; Brito, A C; Carmo, C D; Oliveira, E J

    2016-12-02

    The distribution and frequency of single nucleotide polymorphisms (SNPs) can help to understand changes associated with characteristics of interest. We aimed to evaluate nucleotide diversity in six genes involved in starch biosynthesis in cassava using a panel of 96 unrelated accessions. The genes were sequenced, aligned, and used to obtain values for nucleotide diversity (π), segregating sites (θ), Tajima's D test, and neighbor-joining (NJ) clustering. On average, one SNP per 147 and 171 bp was identified in exon and intron regions, respectively. Thirteen heterozygous loci were found. Three of seven SNPs in the exon region resulted in non-synonymous replacement or four synonymous substitutions. However, no associations were noted between SNPs and root dry-matter content. The parameter π ranged from 0.0001 (granule bound starch synthase I) to 0.0033 (α-amylase), averaging 0.0011, while θ ranged from 0.00014 (starch branching enzyme) to 0.00584 (starch synthase I), averaging 0.002353. The θ diversity value was typically double that of the π. Results of the D test did not suggest any evidence of deviance of neutrality in these genes. Among the evaluated accession, 82/96 were clustered using the NJ method but without a clear separation of the root dry-matter content, root pulp coloration, and classification of the cyanogenic compound content. High variation in genes of the starch biosynthetic pathway can be used to identify associations with the functional properties of starch for the use of polymorphisms for selection purposes.

  7. Performance of high amylose starch-composited gelatin films influenced by gelatinization and concentration.

    PubMed

    Wang, Wenhang; Wang, Kun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana; Liu, Anjun

    2017-01-01

    In order to study the impact of starch in film performance, high amylose corn starch was composited in gelatin films under different gelatinization conditions and, in high and low concentrations (10 and 50wt.%). It was found that hot water gelatinized starch (Gel-Shw) increased film mechanical strength and was dependent upon the starch concentration. The addition of an alkali component to the starch significantly enhanced the swelling of the starch granules and expedited the gelatinization process. Incorporation of starch, especially the alkalized starch (Sha), into the gelatin films decreased film solubility which improved its water resistance and water vapor permeability (WVP). Multiple techniques (DSC, TGA, FT-IR, and XRD) were used to characterize the process and results, including the crosslinking of the dissolved starch molecules and the particles formed from gelatinized starch during retrogradation process, which played an important role in improving the thermal stability of the composited gelatin films. Overall, the starch-gelatin composition provides a potential approach to improve gelatin film performance and benefit its applications in the food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Effect of chemical modification on molecular structure and functional properties of Musa AAB starch.

    PubMed

    Koteswara Reddy, Chagam; Vidya, P V; Haripriya, Sundaramoorthy

    2015-11-01

    Starch extracted from Musa AAB (poovan banana) was subjected to acetylation, acid-thinning and oxidation. The effect of the treatments on molecular structure and functional properties of starch were analysed. Chemical composition revealed that non-starch components were reduced after chemical treatment. Amylose content of starch decreased on acetylation from 24.16% to 20.90%, whereas it increased to 24.50% and 25.5% on oxidation and acid-thinning, respectively. X-ray diffraction pattern of modified starches showed B-type crystalline structure with peaks at 2θ=5.5°, 15.0°, 17.1° and 23.5°; which were parallel with the pattern observed in case of native starch. Swelling capacity of starch granules was found to reduce by acid-thinning and oxidation but acetylation induced to increase it. The percentage of colour (L*, a* and b*), solubility and water absorption capacities varied significantly from native starch after chemical modification. Changes in gelatinisation temperatures and enthalpy value of starches were observed in modified starches and it is varied according to reaction conditions. Pasting properties of the starches was increased by acetylation and oxidation while acid-thinning reduced it (P<0.05).

  9. Characterization of cationic starch flocculants synthesized by dry process with ball milling activating method.

    PubMed

    Su, Yuting; Du, Hongying; Huo, Yinqiang; Xu, Yongliang; Wang, Jie; Wang, Liying; Zhao, Siming; Xiong, Shanbai

    2016-06-01

    The cationic starch flocculants were synthesized by the reaction of maize starch which was activated by a ball-milling treatment with 2,3-epoxypropyl trimethyl ammonium chlorides (ETMAC) using the dry method. The cationic starches were characterized by several approaches including scanning electron microscope (SEM), degree of substitution (DS), infrared spectrum (IR), X-ray diffraction (XRD), flocculating activity, electron spin resonance (ESR), and solid-state nuclear magnetic resonance (NMR). The effect of mechanical activation on starch etherifying modification was investigated. The mechanical activation cracked starch granules and destructed their crystal structures. This resulted in enhancements to the reaction activity and reaction efficiency, which was approved by ESR and solid state NMR. The starch flocculants, synthesized by the reaction of mechanically activated starches at 90°C for 2.5h with ETMAC at molar ratio of 0.40:1.00, showed good flocculation activity. The substitution degree (0.300) and reaction efficiency (75.06%) of starch flocculants synthesized with mechanically activated starches were significantly greater than those of starch flocculants with native starches (P<0.05).

  10. Chemical, morphological and functional properties of Brazilian jackfruit (Artocarpus heterophyllus L.) seeds starch.

    PubMed

    Madruga, Marta Suely; de Albuquerque, Fabíola Samara Medeiros; Silva, Izis Rafaela Alves; do Amaral, Deborah Silva; Magnani, Marciane; Queiroga Neto, Vicente

    2014-01-15

    Starches used in food industry are extracted from roots, tubers and cereals. Seeds of jackfruit are abundant and contain high amounts of starch. They are discarded during the fruit processing or consumption and can be an alternative source of starch. The starch was extract from the jackfruit seeds and characterised to chemical, morphological and functional properties. Soft and hard jackfruit seeds showed starch content of 92.8% and 94.5%, respectively. Starch granules showed round and bell shape and some irregular cuts on their surface with type-A crystallinity pattern, similar to cereals starches. The swelling power and solubility of jackfruit starch increased with increasing temperature, showing opaque pastes. The soft seeds starch showed initial and final gelatinisation temperature of 36°C and 56°C, respectively; while hard seeds starch presented initial gelatinisation at 40°C and final at 61°C. These results suggest that the Brazilian jackfruit seeds starches could be used in food products. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Identification of three proteins up-regulated by raw starch in Cytophaga sp.

    PubMed

    Shiau, Rong-Jen; Wen, Yu-Der; Jeang, Chii-Ling

    2008-12-01

    Raw starch-digesting amylases (RSDAs) in many microorganisms convert starch granules into maltodextrins and simple sugars. We cloned and sequenced from Cytophaga sp. an RSDA with an excellent raw st