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。     

不同花生品种籽仁发育过程中蛋白质组分分析

采用蛋白质组分的连续累进提取法提取4个花生品种籽仁的清蛋白、球蛋白、醇溶蛋白和谷蛋白。利用聚丙烯酰胺凝胶电泳(SDS-PAGE)技术,对各蛋白组分的亚基组成进行分析。结果表明,花生籽仁发育过程中,清蛋白始终占绝对优势,占花生蛋白质总量的70%以上,最高达95%;球蛋白含量较低,仅占花生蛋白质总量的3%~5%,谷蛋白含量最低,其不足3%,醇溶蛋白痕量;在4种组分中,品种之间球蛋白含量差异最大。SDS-PAGE图谱显示,染色后清蛋白、球蛋白条带清晰可见,谷蛋白条带较为模糊,清蛋白含量高,清蛋白和球蛋白成分较丰富。花生蛋白亚基分子质量在14.4~97.4 ku之间,清蛋白有10~12个亚基,球蛋白有9~10个亚基。采用连续累进提取法可将花生蛋白组分分离,利用SDS-PAGE方法可以得到花生籽仁清蛋白、球蛋白的清晰条带且多态性高,而谷蛋白条带模糊。     

小麦籽粒蛋白质组分与面包烘焙品质性状关系的研究

利用３８个小麦种质材料,研究了小麦蛋白质组分与面包烘焙品质性状的关系。发现清蛋白或球蛋白与主要面包品质性状呈负相关,其中清蛋白含量与Ｚｅｌｅｎｙ沉降值呈显著负相关。醇溶蛋白或谷蛋白与面包品质性状呈正相关,谷蛋白与烘焙品质呈显著正相关。利用通径分析明确了不同蛋白组分对面包加工品质的直接作用和间接作用。据此提出改良面包加工品质及协调营养品质和面包加工品质的途径。     

粳稻粒位间蛋白质及其组分与品质性状间的相关性研究

为了研究不同粒位间籽粒总蛋白质及其4种组分含量与其他品质性状的关系,选用不同稳型粳稻为材料,按照穗部位置分为27个粒位,分析了它们之间的相关性。结果表明,粳稻穗内不同粒位间籽粒的总蛋白质及其4种组分含量与蒸煮食味品质、淀粉RVA谱特征、外观品质和碾米品质都有显著的关系。总蛋白质、醇溶蛋白和谷蛋白含量对食味有显著负面影响,而球蛋白含量对其则有显著正面影响;总蛋白质、清蛋白、醇溶蛋白和谷蛋白含量与直链淀粉含量和胶稠度有负相关性,与糊化温度有正相关性。总蛋白、清蛋白、醇溶蛋白和谷蛋白含量与峰值黏度、热浆黏度、崩解值、透明度和整精米率呈显著或极显著负相关,与消减值、垩白率、垩白度呈显著或极显著正相关;球蛋白表现规律则与之相反。粳稻不同粒位间籽粒的总蛋白质及其4种组分含量与RVA谱4个特征值、蒸煮食味品质和垩白性状的关系表现最为密切。     

小麦胚乳中蛋白质、淀粉组分分布及各性状关系的研究

以小麦品种为9023的各系统面粉样品为试验材料，测定各样品蛋白质及组分含量、湿面筋含量、面筋指数、淀粉及其组分含量．研究小麦胚乳中蛋白质与淀粉及组分分布情况，并对蛋白质和淀粉及各性状间的关系进行初步研究。结果表明：小麦胚乳由内向外．蛋白质含量及球蛋白、醇溶蛋白和谷蛋白含量呈现递增的分布趋势．而淀粉和直链淀粉含量则逐渐减小：球蛋白、醇溶蛋白和谷蛋白含量两两呈现显著或极显著正相关．且与粗蛋白含量显著正相关；湿面筋含量与蛋白质含量、醇溶蛋白和麦谷蛋白含量均呈现极显著正相关关系：直链淀粉含量与总淀粉含量显著正相关，与支链淀粉含量负相关：直链淀粉含量与粗蛋白含量、球蛋白和醇溶蛋白含量均呈显著负相关，支链淀粉含量与谷蛋白含量、湿面筋含量显著正相关。     

低谷蛋白稻米组分蛋白提取工艺优化

为确定低谷蛋白稻米蛋白质组分的最优提取条件,以低谷蛋白水稻D105为材料,用连续提取法,在优化提取液浓度的基础上,采用响应面法 (RSM) 优化各组分蛋白的提取条件。结果表明,球蛋白提取最适提取氯化钠溶液浓度为0.6 mol/L、醇溶蛋白最适乙醇浓度为80%、谷蛋白的最适提取浓度为0.04 mol/L;基于单因素试验,选择料液比、提取时间、提取温度、提取次数为自变量,以各组分蛋白提取量为响应值,利用Box-Behnken (BB)中心组合设计4因素三水平试验,确定清蛋白最佳提取条件为：料液比1:22、提取温度31.6 ℃、提取时间43 min、提取3次;球蛋白最佳提取条件为：料液比1:20、提取温度33.1 ℃、提取时间22 min、提取3次;醇溶蛋白最佳提取条件为：料液比1:21、提取温度34.6 ℃、提取时间40 min、提取2次;谷蛋白最佳提取条件为：料液比1:16、提取温度34.7 ℃、提取时间22 min、提取3次。在此条件下稻米各组分蛋白的提取量分别为：清蛋白4.26 mg/g、球蛋白9.76 mg/g、醇溶蛋白2.27 mg/g、谷蛋白23.60 mg/g,与预测值的相对误差分别为 0.0187、0.0563、0.0308、0.014,表明响应面法优化所得提取工艺条件较好,具有应用价值。     

甜荞蛋白质组分的物化特性研究

研究甜荞不同蛋白组分的物化特性.采用分步提取法分离收集甜荞清蛋白、球蛋白、醇溶蛋白和谷蛋白.结果表明甜荞清蛋白、球蛋白、醇溶蛋白和谷蛋白的含量分别占总蛋白的21.91%、19.36%、2.26%和19.95%,等电点分别为pH4.40、5.00、4.80和4.60,变性温度分别为79.39℃、70.36℃、80.04℃和83.09℃,前三种蛋白白色略偏黄,而谷蛋白偏红色.甜荞清蛋白、球蛋白和谷蛋白的必需氨基酸含量丰富.甜荞清蛋白含铁量高,醇溶蛋白含锌量高,球蛋白含镁量高,而铅、锡、砷在各蛋白质组分中的含量均很低.     

小麦籽粒淀粉品质与蛋白质品质关系的初步研究

通过测定32个小麦品种籽粒的11个淀粉品质性状及10个蛋白质品质性状，分析了各性状之间的简单相关关系。结果表明：直链淀粉含量与清蛋白含量显著正相关，与支链淀粉含量、膨胀势、高峰粘度、衰减值、粗蛋白含量、醇溶蛋白含量、谷蛋白大聚合体含量、沉降值显著负相关；支链淀粉含量与糊化温度显著负相关，与沉降值、面筋指数显著正相关；膨胀势、高峰粘度、低谷粘度、最后粘度两两间极显著正相关；衰减值与醇溶蛋白含量、谷蛋白大聚合体含量、沉降值，糊化温度与球蛋白含量呈显著正相关；回生值与面筋含量，峰值时间与沉降值显著负相关。文章还分析了淀粉品质和蛋白质品质与蒸煮类食品品质的关系。     

萌发大麦种子蛋白组分含量变化研究

采用蛋白质组分连续累进提取分析法，检测了垦啤8号、甘啤4号、Harrington、Es．terel四个品种大麦种子萌发前后各蛋白组分的含量变化。结果表明：大麦种子中清蛋白含量较低，占总蛋白含量的3％～5％，种子萌发后，清蛋白含量迅速升高，发芽第四天达到最大值，含量占10％左右，绿麦芽焙焦后，含量略有下降；球蛋白含量变化较为复杂，在种子发芽2天后达到最大值，由3％升至6％左右；醇溶蛋白在种子萌发过程中明显减少，Esterel品种变化最大，减少了总蛋白质的7．14％，其它三个品种减少了4到6个百分点；谷蛋白含量在萌发过程中略呈升高趋势，但变化不大。     

脱除不同溶解性内源蛋白质对早籼米粉理化性质的影响

为通过利用内源蛋白质调控早籼米粉理化性质提高其制品品质，本文研究脱除不同溶解性内源蛋白质（清蛋白、球蛋白、醇溶蛋白和谷蛋白）对早籼米粉溶解度、膨胀度、成糊特性及其糊化后水分结合状态、流变学特性和冻融稳定性的影响。结果表明，脱除球蛋白和谷蛋白可提高早籼米粉的溶解度，而脱除醇溶蛋白和谷蛋白均可在高温下提高其膨胀度。脱除清蛋白使早籼米粉成糊的峰值粘度、终值粘度、崩解值和回生值分别降低16%、21%、50%和43%；脱除球蛋白可提高其糊化温度并降低其峰值粘度，脱除醇溶蛋白则相反；脱除谷蛋白使其峰值粘度和终值粘度分别降低22%和12%，并使其崩解值和回生值分别提高49%和53%。脱除谷蛋白使早籼米粉糊化后的弱结合水含量降低14%；脱除球蛋白和谷蛋白均可提高其糊化后与水结合的强度，脱除醇溶蛋白则相反。脱除醇溶蛋白使早籼米粉糊化后的似固状态增强20%；脱除球蛋白和谷蛋白均可降低其糊化后的弹性，脱除醇溶蛋白则相反。脱除球蛋白和谷蛋白使早籼米粉糊化后的冻融稳定性分别降低121%和56%。该研究工作为利用不同溶解性内源蛋白质提高早籼米粉制品品质提供了重要的参考依据。     

Quantification of monomeric and polymeric wheat proteins and the relationship of protein fractions to wheat quality

Wheat protein composition is important for understanding the biochemical basis of wheat quality. The objective of this study was to design a simple protein fractionation protocol with low cross‐contamination and to show that these protein fractions were associated with wheat quality. The protocol consists of three sequential extractions from 100 mg of flour with 7.5% propan‐1‐ol and 0.3 M sodium iodide (monomeric‐rich protein), 50% propan‐1‐ol (soluble glutenin‐rich protein) and 40% propan‐1‐ol and 0.2% dithiothreitol (insoluble glutenin‐rich protein). Nitrogen content of protein solubility groups was determined from dry residues using an automated combustion nitrogen analyser. About 90% of the total protein in the flour was solubilised. Cross‐contamination of protein fractions was evaluated by SDS‐PAGE, SE‐HPLC and RP‐HPLC. Variation in nitrogen content of the protein solubility fractions was lowest for monomeric‐rich protein (<2%) and insoluble glutenin‐rich protein (<4%). Three wheats with similar high‐molecular‐weight (HMW) glutenin subunit composition, Alpha 16, Glenlea and Roblin, varied significantly (P ≤ 0.05) in the proportion of monomeric‐rich and insoluble glutenin‐rich protein in the flour. Dough rheological properties were directly related to the proportion of insoluble glutenin‐rich protein and inversely related to the proportion of monomeric‐rich protein. The protocol was validated using an expanded set of 11 wheats which also showed that inter‐cultivar differences in the proportion of monomeric‐rich, insoluble glutenin‐rich protein and glutenin‐to‐gliadin ratio in the flour governed dough rheological properties such as mixograph, farinograph and microextension tests. The protocol has merit for quality screening in wheat‐breeding programmes when the sample size is too small or when time constraints limit the ability to perform traditional rheological tests. For the Department of Agriculture and Agri‐Food, Government of Canada, Copyright © Minister of Public Works and Government Services Canada 2003. Published for SCI by John Wiley & Sons, Ltd.     

Quantitative assessment of protein fractions of Chinese wheat flours and their contribution to white salted noodle quality

Protein quantity and quality play a significant contribution to white salted noodle processing. The objective of this study was to determine the contribution of different protein fractions to 25 Chinese varieties on wheat based noodle quality. The results showed: the average ratio of monomeric protein, soluble glutenin and insoluble glutenin in Chinese Huanghuai winter wheat was 3.7:1.0:1.8. Compared with Canadian wheat varieties, the ratio was 4.4:1.0:2.0. The monomeric protein and insoluble glutenin were lower in the Chinese varieties, the soluble glutenin content was higher; while the dough character was lower than Canadian hard wheat, but most Chinese wheat can make good quality noodles. This may be the defining difference between noodle wheat and bread wheat. The monomeric protein content was significant positive correlated with fresh noodle maximum resistance, and high significant positive with extension distance and area. The soluble and insoluble glutenin were mainly responsible in fresh noodle maximum resistance, extension distance and using a texture analyzer, but were high negative correlated with fresh noodle sheet length (Table 2). For cooked noodles, the soluble glutenin content demonstrated a high significant positive relationship to cutting firmness, and a significant negative correlation to cooking loss. The insoluble glutenin content was high significant positive correlated with cooked noodle thickness, hardness and cutting firmness (Table 3). The results suggested that the monomeric protein is less important than that of the glutenin for fresh noodle resistance. The soluble glutenin content is the most important property for noodle wheat, and soluble glutenin content can be used in the early generations to identity Chinese noodle wheat.     

Characterization of hydrolysates derived from enzymatic hydrolysis of wheat gluten

ABSTRACT:  The aim of this study is to investigate the characteristics of wheat gluten hydrolysates. Enzymatic hydrolysis was performed using a papain (food-grade enzyme) in the present study. The gluten proteins were hydrolyzed for 8 h. During enzymatic hydrolysis, average peptide chain length in the hydrolysate decreased rapidly. Increasing proteolysis resulted in the increase in the contents of the soluble forms of nitrogen. However, the content of peptide nitrogen increased within the 1st 6 h, and then began to decrease. The percentage of the released peptides with molecular weight (MW) of over 15 kD decreased with extending enzymatic hydrolysis, while those with MW below 5 kD increased significantly ( P < 0.05). The peptides with MW 10 to 15 kD and those having the MW 5 to 10 kD had different changes. The polymeric glutenin and monomeric gliadin in gluten complex showed different behavior after enzymatic hydrolysis. The monomeric protein (gliadin) and soluble glutenin were prone to enzymatic hydrolysis, while insoluble glutenin was resistance to enzymatic hydrolysis.     

Protein composition of some Croatian and German wheat varieties and their influence on the loaf volume

Ten Croatian and five German wheat varieties were tested. Wheat protein composition was analysed according to a modified Osborne fractionation. They were extracted in four fractions: NaCl fraction, ethanol fraction, acetic acid fraction and insoluble fraction. The influence of protein and protein composition on the loaf volume was investigated. In protein composition a difference between the Croatian and German wheat varieties were found. Protein content, glutenin content and insoluble glutenin content showed influences on the loaf volume.     

麦谷蛋白聚合体含量与小麦粉质量性状相关性研究

利用9个小麦高世代品系(F7),含118个株系为研究材料,研究了蛋白质组分及谷蛋白聚合体(GMP)含量与微量SDS沉降值及面筋指数的相关性.结果表明:清球蛋白含量与微量SDS沉降值无相关性,谷蛋白含量与微量SDS沉降值及面筋指数均呈极显著正相关;GMP含量、GMP/TPP、GMP/CP、GMP/SGP以及TPP/CP对微量SDS沉降值有极显著的正向作用,其中GMP的贡献最大;GMP含量、GMP/TPP、GMP/CP与面筋指数呈显著或极显著正相关,其中GMP/TPP与面筋指数的相关性最高.偏相关分析表明:微量SDS沉降值变异平方和的60.58%可由其与TPP%、GMP%和GMP/SGP的线性关系来说明;通径分析结果显示:GMP含量与微量SDS沉降值的相关性主要是由其直接效应提供,GMP含量是影响微量SDS沉降值的第一因素.研究结果指出,西南麦区小麦品质改良中GMP含量,面筋指数可作为优质面条、馒头小麦的早代选择指标.     

Glutenin structure

The fall in viscosity of dispersions of gluten when treated with excess of mercaptoethanol does not exhibit an initial induction period. This finding appears to rule out the idea that glutenin is highly crosslinked in a branching mode. It is compatible with a linear model in which one SS bond, not two, joins adjacent chains, or a model with low levels of branching. However, it is unnecessary to postulate branching crosslinks to explain glutenin properties in the present state of knowledge. The insoluble residue fraction of wheat flour protein is believed to be mainly linear glutenin of high molecular weight. A linear hypothesis can account for the Orth and Bushuk effect, in which baking quality is positively and negatively correlated with insoluble and soluble protein, respectively. It is suggested that gliadin may act as a plasticiser and aid to dispersion of glutenin.     

Wheat protein composition and properties of wheat glutenin in relation to breadmaking functionality

The unique breadmaking properties of wheat are generally ascribed to the visco-elastic properties of its gluten proteins. While monomeric gluten proteins (gliadin) show viscous behavior, polymeric gluten proteins (glutenin) are elastic. The unique elasticity of glutenin results to a large extent from its polymeric nature. Glutenin is a highly heterogeneous mixture of polymers consisting of a number of different high- and low-molecular-weight glutenin subunits linked by disulfide bonds. Although glutenin obviously is the major polymeric protein in wheat, other polymeric proteins occur as well. Their importance in breadmaking may be underestimated. Nevertheless, variations in both quantity and quality of glutenin strongly determine variations in breadmaking performance. Structural features of different classes of glutenin subunits are described. Variations in glutenin quality may result from variations in its (1) structure, (2) size distribution, and (3) subunit composition. Some hypotheses on glutenin structure and current insights into the role of glutenin size distribution are evaluated. Finally, different ways in which variation in glutenin composition may directly or indirectly (by affecting glutenin structure and/or size distribution) influence glutenin quality are discussed.