The glutenin fraction of wheat protein: The importance of genetic background on its quantity and quality

The influence of high-molecular-weight glutenin subunits on the properties of the gel-protein fraction of glutenin proteins in wheat was determined on 20 varieties grown in the 1989 UK Recommended List trials. Both the presence of subunit 1 (chromosome 1A) and the 1B/1R rye translocation were shown to influence gel-protein weight and breakdown rate during mixing. The gel-protein tests were correlated with CBP (Chorleywood Bread Process) loaf volume, but they did not add anything to the correlation between Glu-1 score and loaf volume. Both gel-protein tests indicated that phenotypic variation could be almost as large as genotypic variation. Breakdown rate was able to detect the abnormal properties of Pastiche (weak) and Fresco (extra-strong) that were not observed using established quality tests such as the sodium dodecylsulphate sedimentation volume.     

馒头加工过程中麦谷蛋白提取率变化研究

以3种小麦粉为原料,研究了在馒头加工过程中麦谷蛋白组分提取率的变化.结果表明:麦谷蛋白组分在馒头加工过程中均发生了有规律的变化.烟农19小麦样品SDS-可溶性麦谷蛋白提取率较低,残渣蛋白量多,很有可能是烟农19小麦样品通过-S-S-交联成的大分子麦谷蛋白含量高.3种小麦样品中GMP含量依次为烟农19＞豫麦47＞豫麦56.这说明GMP的含量和粒度分布是影响面粉烘焙品质性状的决定性因素.     

小麦谷蛋白溶涨指数与蛋白质组分关系的研究

谷蛋白溶涨指数是一种蛋白质品质测定方法，是一定量面粉在SDS乳酸溶液中溶涨、离心后的面粉重量与面粉原始重量的比值。为了研究小麦谷蛋白溶涨指数与蛋白质组分的关系，采用两种蛋白质组分分离方法提取测定了21个小麦品种(品系)的蛋白组分含量，并采用C．Wang的方法测定了不同溶涨时间(0min、5min、20min)的谷蛋白溶涨指数。简单相关分析结果表明：溶涨时间为5min、20min时的谷蛋白溶涨指数与球蛋白含量呈显著负相关，与总蛋白、醇溶蛋白、可溶性谷蛋白、不溶性谷蛋白含量呈极显著正相关；各蛋白质组分含量对SIG的通径分析结果为：谷蛋白含量对SIG值的影响最大，其中不溶性谷蛋白含量起主导作用。因此，谷蛋白溶涨指数法能间接预测不溶性谷蛋白的含量。     

高分子量谷蛋白亚基近等基因系面粉品质及其流变学特性的研究

分析了高分子量谷蛋白亚基近等基因系的高分子量谷蛋白亚基组成，并对该近等基因系进行了品质性状的分析，结果表明：Glu-D1位点的变化比Glu-B1位点的变化对面粉品质和流变学特性影响大；并且同时具有Glu-B1 14 15和Glu-D1 5 10的近等基因系2号无论是面粉品质还是流变学特性都优于其它两个近等基因系8号(null，7 9，5 10)和近等基因系13号(null，14 15，10)；而8号又优于13号，即Glu-B1 14 15的存在没有弥补Glu-D1 5亚基的缺失。     

Isolation and partial characterisation of two low molecular weight durum wheat (Triticum durum) glutenins

Two low molecular weight durum wheat (Triticum durum Desf) glutenins, DSG-1 and DSG-2 (durum-wheat sulphur-rich glutenin fractions) were isolated from two cultivars, Mondur of good technological quality and Kidur of poor technological quality. The glutenin fraction, composed mostly of DSG protein, was extracted using a low concentration of NA-tetradecanoate and then fractionted by by using molecular sieve chromatography (Bio-Gel P 30). The amino acid compositions and the N-terminal sequences of the pure DSG proteins were determined, and their hydrophobic characteristics, calculated on the basis of these data, showed that DSG-2 is more hydrophobic than DSG-1. The amino acid compositions of DSG-1 and DSG-2 were different. The N-terminal amino acids of DSG-1 and DSG-2 were also different but were identical for each of the two cultivars. In the case of DSG-1, in addition to the main chain a minor chain was found in which the first three amino acids of the main chain were missing. The minor chain represented about 30% int he DSG-1 of mondur and almost 50% in Kidur.     

Biotechnology of Wheat Quality

Wheat gluten proteins are largely responsible for the visco-elastic properties that allow doughs to be processed into bread and various other food products including cakes, biscuits (cookies), pasta and noodles. Detailed biochemical and biophysical studies are revealing details of the molecular structures and interactions of the individual gluten proteins, and their roles in determining the functional properties of gluten. In particular, one group of gluten proteins, the high molecular weight (HMW) subunits of glutenin, have been studied in detail because of their role in determining the strength (elasticity) of doughs. The development of robust transformation systems for bread wheat is now allowing the role of the HMW subunits to be explored experimentally, by manipulating their amount and composition in transgenic plants. Such studies should lead to improvement of the processing properties of wheat for traditional end uses and the development of novel end uses in food processing or as raw material for other industries. © 1997 SCI.     

谷朊粉应用概述

本文对谷朊粉的研究历史，组成和应用进行了综述。较全面的概述了谷朊粉中麦醇溶蛋白、麦谷蛋白的结构和性质，介绍了谷朊粉在工业和非工业领域的应用，提出了谷朊粉研究的方向，同时展望了谷朊粉在工业领域的发展前景。     

面粉加工中麦谷蛋白亚基分子结构变化及其品质关系

讨论了近年国内外在高分子质量麦谷蛋白亚基(HMW-GS)立体结构与面粉加工品质之间关系的相关解析技术,阐明了HMW-GS立体结构与面粉加工品质之间关系的分子机制,明确了HMW-GS中对加工品质功能起关键作用的功能域结构,为构建具有良好加工品质的小麦新品系提供分子和生物化学基础.     

Polymerization and Mechanical Degradation Kinetics of Gluten and Glutenin at Extruder Melt-Section Temperatures and Shear Rates

Thermal polymerization and mechanical degradation rates were measured for wheat gluten and glutenin at 25–30% moisture. Changes in soluble protein and disulfide bonds were measured at 85°C to 180°C, residence times of 2–60 set and shear rates of 10–275 sec^-l. Polyrnerization rates without shear were evaluated using isothermal analysis. An extrusion rheometer was used to simulate extruder conditions to determine the combined polymerization-degradation rates. Molecular weight distributions of soluble reaction products were determined using liquid size exclusion chromatography. Activation energies were 0.60–2.1 kcal/ mol, 2.0–8.2 kcal/mol, and 0.50–0.90 kcaVmo1 and reaction orders were 0.5–2.0, 0.8–1.5, and 0.6–0.7, respectively for polymerization without shear, polymerization with shear, and degradation.     

High‐molecular‐weight glutenin subunit composition of Pakistani hard white spring wheats grown at three locations for 2 years and its relationship with end‐use quality characteristics

Eleven Pakistani hard white spring wheat cultivars, along with one durum wheat and two hard white American‐grown wheat cultivars, were evaluated for their high‐molecular‐weight (HMW) glutenin subunit composition via sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE). The relationships among different quality characteristics and between these characteristics and HMW glutenin subunits were computed. Three to six HMW glutenin subunits were observed in Pakistani bread wheat cultivars. The presence of HMW glutenin subunits was not affected by growth locations or crop years. However, variations in intensities were observed. Correlations were noticed between certain HMW glutenin subunits and some quality attributes, such as protein, farinograph dough development time, farinograph water absorption, loaf volume and mixograph peak height. The presence of HMW glutenin subunit 20 in the older wheat cultivars C591 and C273, known for excellent chapati quality, indicated a possible relationship between this band and chapati quality. This observation will need to be confirmed by testing a larger number of wheat samples known to have characteristics for both good and poor chapati quality. © 2000 Society of Chemical Industry