The Pasting Characteristics of Various Sizes of Starch Granule from Wheat

Starches, of contrasted pasting properties from two bread wheat cultivars, were fractionated on the basis of granule size. Differences in starch hot-pasting characteristics were observed mainly between large A-granule fractions (diameter about 23 μm) of the two starches. Less pasting differences were seen between B-granules (diameter < 10 μm) of the two starches. Examination of immature starches suggested that pasting differences between A-granules were established during the period of A-granule early growth, within about 15 days of fertilization, rather than during the later period of grain filling and desiccation. Granule size distribution itself did not determine the differences observed.     

非晶颗粒态淀粉

本文介绍了非晶颗粒态淀粉的概念、性质及其主要的制备方法.制备方法包括物理方法和化学方法两大类.其中物理方法是通过控制淀粉颗粒粒度,化学方法是通过化学反应,破坏颗粒结晶区域.而且,本文对非晶化淀粉的发展作了展望.     

Starch Granule Size Strongly Determines Starch Noodle Processing and Noodle Quality

Chemical compositions, physical properties, and suitability for starch noodle making of different granule size fractions from potato and sweet potato starches were studied. The ash content, amylose content, phosphorus content, gel firmness, and freeze‐thaw stability of small‐size granule fractions(< 20 μm) were significantly different from those of the large‐size granule fractions. The processibility and the qualities evaluated by objective and subjective methods of both dried and cooked starch noodles made from small‐size granule fractions were significantly better than those made from their initial starch preparations and much better than those made from the large‐size granule fractions.     

变性淀粉浆料的定性鉴别和定量测定

根据各类变性淀粉浆料的结构特点和淀粉的物理化学性质，简明扼要地介绍了变性淀粉浆料的定性鉴别和定量测定方法。     

淀粉/蒙脱土纳米复合浆料的应用安全性

对蒙脱土和聚合物/蒙脱土纳米复合材料的使用与环境及人体健康的安全性进行了综述。蒙脱土是一种无毒的天然矿物性材料,已用于药物、美容产品、饲料等众多领域;由此推论淀粉/蒙脱土纳米复合浆料对环境和人体应不会有不良影响。     

蕨根淀粉颗粒形貌与糊化黏度特性

以马铃薯淀粉和红薯淀粉为对照,研究了蕨根淀粉的颗粒形貌及糊化黏度特性。蕨根淀粉颗粒多为圆形或椭圆形,少数呈棒状,颗粒表面光滑。颗粒大小差异较大,粒径为5~31μm。蕨根淀粉颗粒具有可见偏光十字,偏光十字位于颗粒一端,呈"Ⅹ"。蕨根淀粉的起糊温度明显低于红薯淀粉,与马铃薯淀粉相当。蕨根淀粉糊具有较好的热稳定性,较高的回生值,适宜加工粉丝类产品。蔗糖、NaCl、碱面和明矾的添加及pH值对蕨根淀粉糊化特性有影响。蔗糖使蕨根淀粉糊黏度增大;NaCl可提高蕨根淀粉糊的热稳定性,延缓体系老化;碱面、明矾的添加使蕨根淀粉糊的热稳定性下降;蕨根淀粉糊耐酸性差,在酸性条件下,蕨根淀粉发生明显水解作用,体系黏度降低。     

板栗淀粉颗粒特性研究

采用显微观察,ｘ－光衍射分析等手段对板栗淀粉颗粒特性了研究,结果表明,板栗淀粉颗粒形状多样,大小在１μｍ－２０μｍ之间;具有明显的偏光十字,呈“Ｘ”形,脐点位于颗粒中央;板栗淀粉颗粒有轮纹结构,大多呈不连续状态;颗粒的结晶结构属于Ｃ型。板栗淀粉的糊化温度为５５．５℃－６３．５℃。     

The Developing Starch Granule Part I. The Starch Content of Cereal Grains during their Development

When fertilization of developing cereal grains occurs, the pericarp (ovary wall) already contains starch granules. Hence the starch content of developing grains of wheat, triticale, rye, oats and barley commences at 30 or 40% of the dry weight. It increases only to 60 or 70% at ripeness when the pericarp has degenerated to bran layers and the endosperm is filled with stored starch granules and protein. All these cereals showed similar patterns of starch increase, with an inflexion at 40 to 50% starch due to degeneration of pericarp starch before endosperm deposition. In wheats and triticale there was a second inflexion at 50 to 60% starch caused by endosperm cells proliferating faster than they filled with starch granules. The rise and fall of rate of starch deposition coincided with the rise and fall of percentage of metabolic (non-storage) protein in the grain, calculated from total amino acid analyses. In the mature grain about 8% of the dry matter is not associated with starch and thus is non-endosperm tissues. About 70% of the remaining dry matter (endosperm) is starch. We suggest that fluctuations of metabolites and enzymes result from development or breakdown of groups of cells constituting distinct tissues in the grain.     

Distinctive Sorghum Starch Granule Morphologies Appear to Improve Raw Starch Digestibility

Various factors, including starch granule channels, have been suggested to contribute to the control of sorghum starch digestibility for animal feed. Isolated starch from two normal sorghum lines (P721N, IS6986) and one high protein digestibility (HPD) mutant line (111) that differed in starch granule morphology were selected to study the influence of these factors on starch digestibility. Scanning electron micrographs were taken of raw and digested starches. Microscopy results confirmed that in all three sorghum lines channels in starch granules are the main route of enzyme penetration and the central cavity area is the starting point of enzyme digestion. Channel density was more pronounced in the HPD sorghum mutant line than in normal lines, which may have been responsible for its relatively high digestibility. Micrographs of IS6986 showed unique starch granule morphology with a collapsed ”doughnut‐shaped” structure in a portion of the granules. These unusual granules were rapidly digested and, unlike normal spherical granules, totally disappeared after 30 min of digestion. Amylases appeared to have fast access to the collapsed‐appearing starch granules. Digestion profiles, following incubation with pepsin and α‐amylase, showed that IS6986 and the HPD mutant (111) had the highest initial rate of starch digestion, followed by P721N. These findings provide insight as to how new sorghum cultivars might be developed with high starch digestibility for animal feed use.     

卷土重来的美国纺织投资热

新年伊始,日本东丽株式会社宣布,将向美国南卡州投资10亿美元,开发新型碳纤维材料.截至今日,成百亿上千亿的资金引发了美国纺织投资热.美国纺织权威比尔＆#183;史密斯先生深感诧异.他说,美国固然是世界上最大的纺织品贸易市场,又何以引发大量亚洲公司蜂拥而入？     

The Lipids of Various Sizes of Wheat Starch Granules

Starches have been prepared from two wheat cultivars having contrasted hot-pasting characteristics. The granules have been separated by successive sedimendations into several size classes and their lipid compositions determined. In agreement with previous work, the lipid is mainly lysophosphatidylcholines of palmitic and linoleic acids in nearly equal quantities. The saturated acid predominates in the smallest granules. The amounts of lipid per granule tend to be proportional to the granule surface areas of the larger granules but proportional to the volumes of the smaller granules. There was no distinction between contents or types of lipid in the two cultivars, suggesting that their contrasted pasting qualities were not a function of lipid composition.     

The Developing Starch Granule Part IV. Sucrose Synthase,Sucrase, and Starch Synthesis in Developing Wheat Grains

Developing wheat grains of three cultivars have been serially harvested and analyses made for sucrose synthase, sucrase, and amylase, and rate of starch deposition. The sucrose synthase and sucrase are demonstrated to be separate reactions but of similar activity through most of development. However, the sucrase of very early development stages appears to be another enzyme, of much higher activity. The synthase utilizes UDP⁽¹⁾-glucose more effectively than ADP⁽¹⁾-glucose. The time relationship between the synthase and an amylase with respect to starch synthesis has been determined.     

两种氧化-交联淀粉上浆性能比较

用酯交联淀粉和醚交联淀粉对棉和涤／棉上浆，就浆纱强力，浆纱伸度，毛羽下降率，上浆率进行了试验结果表明：自制的酯交联淀粉浆料在浆纱强度，毛羽下降方面性能更优。     

非晶化淀粉研究进展

淀粉是一种天然多晶聚合物,随着对淀粉结晶结构研究的深入,人们发现了淀粉颗粒在某些条件下淀粉结构的有序性被破坏,具有非晶化现象.非晶化的淀粉颗粒称为非晶颗粒态淀粉,其颗粒结构发生较大的变化,具有较高的酶降解性、反应活性等,更加适于改性和深加工.对非晶颗粒态淀粉的研究概况、结构、性质等作相关阐述,并对其今后的研究作相关展望.     

小红栲淀粉颗粒特性研究

采用显微观察，X－射线衍射和碘电位滴定法等对小红栲淀粉颗粒特性进行了研究。结果表明：小红材淀粉颗粒的形状比较规则，具有明显的偏光黑十字，大小在5.4-34.5μm范围内，颗粒的晶体结构属于C型，小红栲淀粉的糊化温度65.5-79.5℃，直链分含量为22．83％。小红栲淀粉颗粒的溶解度和膨胀度较小。     

小麦淀粉颗粒的微观结构研究

利用差示扫描量热仪和扫描电子显微镜并结合SPSS软件探讨了小麦中A型和B型淀粉颗粒直径的大小及颗粒形态对其糊化特性的影响,定性地分析了小麦淀粉颗粒形态特征对其热力学行为的影响,并在此基础上研究了小麦淀粉结合蛋白含量与淀粉颗粒大小的相关性。结果表明：品种间A型淀粉颗粒直径越大,B型淀粉颗粒直径则越小;A型淀粉颗粒直径越大,淀粉则越难糊化;B型淀粉颗粒直径越大,淀粉则越易糊化;热力学参数顶点温度与热焓值间存在着显著的正相关性;淀粉结合蛋白的含量与B型淀粉直径大小的呈显著的负相关性,而与A型淀粉直径大小呈相关系数较小的负相关。     

淀粉颗粒粒径对淀粉交联程度影响的研究

本文通过改变淀粉颗粒的粒径来研究淀粉的交联。交联程度高的淀粉,溶胀度低,在同温度下黏度低。通过测定交联淀粉的黏度与溶胀度发现:淀粉的交联难易程度的大小随着淀粉颗粒粒径的变化而变化,在一定范围内,淀粉颗粒粒径越大,淀粉越易发生交联反应,同一交联条件下越易形成交联程度高的淀粉。     

Scanning Electron Microscopy of Wheat Starch. III. Granule Development in the Endosperm

Study of A type starch granules from immature wheat endosperm with the scanning electron microscope has led to a developmental sequence being suggested. Evidence is provided which indicates that the initial minute spherical granule becomes a “nucleus” which is progressively surrounded in the equatorial plane by a continually enlarging structure which resembles two lips with a furrow between them. When the lips have completely surrounded the “nucleus” the thickness and diameter of the granule continue to increase in such a way that the furrow becomes shallower and is present in the mature biconvex structure only as a shallow score.