Characterization Of Starch Granules Research Articles

Development of an asymmetrical flow field-flow fractionation system for the size characterization of starch granules

淀粉颗粒粒径与分子尺寸分别在1~100 μm和20~250 nm之间,是影响淀粉功能特性的重要因素之一。非对称场流分离(AF4)是一种基于样品与外力场相互作用机制的分离技术,已应用于表征淀粉分子尺寸分布。商品化的AF4系统的粒径检测范围为1 nm~10 μm,对于淀粉颗粒粒径表征具有一定的局限性。该文研制了AF4分离系统;考察了其在微米尺度下对红薯、莲子和大米淀粉颗粒粒径表征的性能;采用微米尺寸的聚苯乙烯乳化球(PS)标准样品验证了构建的AF4系统的分离性能。实验结果显示,构建的AF4系统对PS混合样品(粒径2、6、12、20 μm)实现了基线分离,同商品化AF4相比提高了检测上线,具有分离表征淀粉颗粒的潜力。此外,该文研究了载液组成对淀粉颗粒分离表征的影响;通过光学显微镜验证了构建的AF4系统在微米尺度上对淀粉颗粒粒径分布的表征能力。最后,采用商品化的AF4系统串联多角度激光光散射检测器和示差折光检测器对3种淀粉分子进行了分离表征,考察了淀粉的溶解温度对其表征结果的影响。在摩尔质量10 6~108 g/mol范围内,红薯和莲子淀粉的回转半径和水合半径的比值(Rg/Rh)在0.9~1.1之间,大米淀粉的Rg/Rh在1.2~1.4之间。实验结果证明构建的AF4系统是一种快速、准确的淀粉颗粒粒径表征方法,与商品化的AF4系统结合可为研究淀粉尺寸分布与其功能性质之间的关系提供技术支持。

Studies on characterization of starch granules from botanicals using foldscope microscopy

Studies on characterization of starch granules from botanicals using foldscope microscopy

Fractionation and characterization of starch granules using field-flow fractionation (FFF) and differential scanning calorimetry (DSC)

Starch is one of the main carbohydrates in food; it is formed by two polysaccharides: amylose and amylopectin. The granule size of starch varies with different botanical origins and ranges from less than 1 μm to more than 100 μm. Some physicochemical and functional properties vary with the size of the granule, which makes it of great interest to find an efficient and accurate size-based separation method. In this study, the full-feed depletion mode of split-flow thin cell fractionation (FFD-SF) was employed for a size-based fractionation of two types of starch granules (corn and potato) on a large scale. The fractionation efficiency (FE) of fraction-a for corn and potato granules was 98.4 and 99.4%, respectively. The FFD-SF fractions were analyzed using optical microscopy (OM) and gravitational field-flow fractionation (GrFFF). The respective size distribution results were in close agreement for the corn starch fractions, while they were slightly different for the potato starch fractions. The thermal properties of FFD-SF fractions were analyzed, and the results for the potato starch showed that the peak temperature of gelatinization (Tp) slightly decreases as the size of the granules increases. Additionally, the enthalpy of gelatinization (ΔH) increases when the granule size increases and shows negative correlation with the gelatinization range (ΔT).

Characterization of Starch Granules in Rice Culms for Application of Rice Straw as a Feedstock for Saccharification

Rice plants are known to accumulate starch in leaf sheaths and culms, and in some cultivars significant amounts of starch are present at the mature stage. This can be considered as potential feedstock for the recovery of fermentable sugars. We isolated starches from the culms of cultivars Yumeaoba, Koshihikari, and Leafstar to investigate their structural and physical features. Yumeaoba culm starch contained 20.2% amylose, whereas Koshihikari and Leafstar contained 25.8% and 25.2%. Yumeaoba culm starch was found by chain-length distribution analysis to contain higher amounts of short chains, resulting in lower gelatinization temperature by 7 degrees C, as compared to Koshihikari and Leafstar. Consequently, the rate of enzymatic hydrolysis of Yumeaoba culm starches reached maximum at a lower temperature than Leafstar. Rice culm starch, with a lower gelatinization temperature, can provide an advantageous material for feedstock for bioethanol production in terms of energy conservation.

INVESTIGATION OF THE VARIATION OF THE MASS RATIOS FOR LARGE AND SMALL STARCH GRANULES WITH THE pH AND IONIC STRENGTH OF THE DISPERSING MEDIUM BY SEDIMENTATION/STERIC FIELD-FLOW FRACTIONATION

ABSTRACT The relatively new technique of Sedimentation/Steric Field-Flow Fractionation (Sd/St FFF) is a simple, fast, and accurate method for the size separation and characterization of starch granules. In the present work, the Sd/St FFF technique was used for the calculation of the mass ratios of the A-large and B-small granules from barley and wheat starch samples. The mass ratios were obtained from the distribution curves of the starch samples at various pH and ionic strength of the suspending medium, in the presence or the absence of the surfactant FL-70. The influence of the suspension pH and ionic strength on the mass ratios of A- and B-granules is discussed in relation to the zeta potentials of the particles, which were measured by a microelectrophoresis apparatus.

STUDY OF THE INFLUENCE OF IONIC STRENGTH AND pH OF THE SUSPENDING MEDIUM ON THE SIZE OF WHEAT STARCH GRANULES, MEASURED BY SEDIMENTATION/STERIC FIELD-FLOW FRACTIONATION

The sedimentation/steric field-flow fractionation (Sd/StFFF) technique has been approved as a simple and accurate method for the size separation and characterization of starch granules. In the present work, we further investigate this application by studying the influence of the ionic strength and the pH of the suspending medium on the size of the wheat starch granules measured by Sd/StFFF. A bimodal size distribution curve was found by Sd/StFFF for the starch granules, in accordance with the results obtained by scanning electron microscopy (SEM). The number and weight average diameters for the large (A-type) and small (B-type) starch granules are independent of the presence of the indifferent electrolyte KNO3 in the suspending medium, indicating that disintegration or aggregation phenomena of the starch particles are absent. The later was also verified by SEM. The fact that the suspension pH does not influence the number and weight average diameters of the starch granules is discussed, in relation to the zeta potentials of the particles, which were measured by a microelectrophoresis apparatus.

Characterization of Starch Granules in Maize Using Microspectrophotometry

AbstractStarch granule‐associated proteins and protein aggregates not associated with starch granules were visualized by staining with acid fuchsin. Based on fluorescence intensity, it was observed that non‐granule‐associated proteins could be removed from starch granule preparations by treatment with a modification of the Osborne‐Mendel fractionation method without affecting the apparent level of granule‐associated proteins. Moreover, fluorescence microscopy with direct spectrophotometric measurement of the proteins confirmed the presence of major subpopulations of granules differing in size and acid fuchsin‐induced fluorescence. Treatment of stained granules with 1.0% SDS dramatically reduced fluorescence intensity, indicating the removal of granule‐associated proteins.

Characterization of Starch Granules from Waxy, Nonwaxy, and Hybrid Seeds ofAmaranthus hypochondriacusL.

Perisperm starch granules of the dicotyledonous plant Amaranthus hypochondriacus L. were prepared from two homozygous lines (WxWx and wxwx) and their hybrid (Wxwx). The hybrid line was obtained by natural hybridization. By Sephadex G-75 column chromatography of isoamylase-debranched starches, the amylose content of WxWx starch was 16.9%, that of Wxwx was 10.7, and wxwx was zero. SDS-polyacrylamide gel electrophoresis showed that starch granules from two genotypes (WxWx and Wxwx) contained a Wx protein (MW = 68,000) which was supposed to be a starch granule-bound starch synthase and was associated with amylose synthesis, as observed in nonwaxy maize. The intensities of the stained protein bands were apparently correlated with the number of the Wx alleles. The Wx protein was not detected in the wxwx starch. These findings suggest that the Wx allele produces the Wx protein and amylose in the perisperm of A. hypochondriacus, with incomplete dominance over the wx allele. The Wx allele did not affect the fine structure of amylopectin and had little if any effect on susceptibility to glucoamylase and pasting properties of starch granules from these genotypes.

Characterization of starch granules from waxy, nonwaxy, and hybrid seeds of Amaranthus hypochondriacus L.

Perisperm starch granules of the dicotyledonous plant Amaranthus hypochondriacus L. were prepared from two homozygous lines (WxWx and wxwx) and their hybrid (Wxwx). The hybrid line was obtained by natural hybridization. By Sephadex G-75 column chromatography of isoamylase-debranched starches, the amylose content of WxWx starch was 16.9%, that of Wxwx was 10.7, and wxwx was zero. SDS-polyacrylamide gel electrophoresis showed that starch granules from two genotypes (WxWx and Wxwx) contained a Wx protein (MW = 68,000) which was supposed to be a starch granule-bound starch synthase and was associated with amylose synthesis, as observed in nonwaxy maize. The intensities of the stained protein bands were apparently correlated with the number of the Wx alleles. The Wx protein was not detected in the wxwx starch. These findings suggest that the Wx allele produces the Wx protein and amylose in the perisperm of A. hypochondriacus, with incomplete dominance over the wx allele. The Wx allele did not affect the fine s...