麦谷蛋白与面条品质关系的研究

研究了酸可溶麦谷蛋白、酸不溶性麦谷蛋白、高相对分子质量麦谷蛋白亚基、低相对分子质量麦谷蛋白亚基对面条质构品质的影响.结果表明:酸不溶性麦谷蛋白能增强熟面条的硬度、粘结性、粘合性、咀嚼性、最大剪切应力和拉断力;低相对分子质量麦谷蛋白亚基能增强熟面条的硬度、粘合性、咀嚼性、回复性、拉断力和拉伸应变.     

兰州拉面专用粉对春小麦品质的要求——Ⅱ小麦籽粒面筋蛋白组成含量与品质的关系

共选用30份春小麦材料,参照Singh等[1]和Verbruggen等[2]方法,提取出不同材料的面筋蛋白、高分子量麦谷蛋白亚基(HMW-GS)和低分子量麦谷蛋白亚基(LMW-GS)。通过测定各蛋白组分的含量及比例,同时结合不同材料的理化品质、面团流变学特性以及拉面食用品质进行多元相关分析,结果表明:麦谷蛋白含量与小麦籽粒蛋白含量、湿面筋含量、面筋指数、干面筋含量呈显著正相关;与面团弹性、延伸性以及面团筋力也呈显著正相关;与拉面食用韧性、粘性以及总评分呈显著正相关。HMW-GS含量与小麦湿面筋和干面筋含量呈显著正相关;与面筋指数呈显著负相关。在面团品质方面,HMW-GS含量与面团韧性呈显著正相关,而与LMW-GS与面团延伸性和面团筋力为显著正相关。HMW-GS含量与拉面最终评分呈显著负相关,相反LMW-GS与拉面最终评分呈显著正相关。     

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。     

Wheat gluten: high molecular weight glutenin subunits--structure, genetics, and relation to dough elasticity

ABSTRACT:  Gluten proteins, representing the major protein fraction of the starchy endosperm, are predominantly responsible for the unique position of wheat amongst cereals. These form a continuous proteinaceous matrix in the cells of the mature dry grain and form a continuous viscoelastic network during the mixing process of dough development. These viscoelastic properties underline the utilization of wheat to prepare bread and other wheat flour based foodstuffs. One group of gluten proteins is glutenin, which consists of high molecular weight (HMW) and low molecular weight (LMW) subunits. The HMW glutenin subunits (HMW-GS) are particularly important for determining dough elasticity. The common wheat possesses 3 to 5 HMW subunits encoded at the Glu-1 loci on the long arms of group 1 chromosomes (1A, 1B, and 1D). The presence of certain HMW subunits is positively correlated with good bread-making quality. Glutamine-rich repetitive sequences that comprise the central part of the HMW subunits are actually responsible for the elastic properties due to extensive arrays of interchain hydrogen bonds. Genetic engineering can be used to manipulate the amount and composition of the HMW subunits, leading to either increased dough strength or more drastic changes in gluten structure and properties.     

馒头粉中高分子麦谷蛋白亚基组成及含量与面团流变性质的关系

目的：研究馒头粉中高分子麦谷蛋白亚基组成及含量与其面团流变性质关系。方法：采用十二烷基硫酸钠聚丙烯酰氨凝胶电泳及凝胶成像技术测定16 种馒头粉高分子质量谷蛋白亚基的组成及其含量,并采用布拉班德粉质和拉伸仪测定面团流变性质。结果：组成馒头粉高分子质量谷蛋白亚基的具有1、7＋8、2、7＋9、8、5＋10、2＋12亚基,并具有（1,7＋8,5＋10）、（7＋8,2,5＋10）、（1,7＋8,2,5＋10）、（7＋8,2＋12）、（7＋9,5＋10）、（1,7＋9,5＋10）、（1,7＋9,8,5＋10）、（1,7＋9,8,2,5＋10）8 种配组。其中5＋10、7＋8、7＋9亚基及其含量对面团粉质和拉伸特性作用大小顺序为5＋10＞7＋8＞7＋9;2＋12亚基及其含量与面团拉伸特性的正相关性最大;1、2、8亚基的存在,且2亚基与5＋10、8与7＋9亚基配组利于面团粉质和拉伸特性优化。结论：高分子质量谷蛋白亚基（high-molecular-weight glutenin subunits,LMW-GS）亚基的组成、含量以及它们的配组影响面粉面团的流变学特性。     

优质小麦体细胞杂种中一种新的HMW麦谷蛋白亚基基因cDNA的克隆和测序

研究了在小麦(Triticun acetivum L．)与高冰草(Agropyron elngatum(Host)Neviski)不对称体细胞杂种优质株系Ⅱ-1．3中出现的迁移率与优质小麦高分子量麦谷蛋白亚基(HMW-GS)一致的1B16亚基,通过Westem blot杂交证明了该亚基与普通小麦的1By16亚基有很强的杂交信号。依据Ⅱ-1-3中类似16亚基N端15个氨基酸序列设计简并引物,通过RT．PCR扩增Ⅱ-1—3 F4中未成熟胚种子总RNA,得到三条特异带(2．3、2．2、2．11kb),对其中分子量最大的一条2．3kb带谱进行了克隆、测序。该序列(p16BL-1,测序编号为473)长2298bp,包括2137bp的编码区和161bp的3’非编码区。同源性分析发现,该片段与普通小麦HMW Glu-IR、Glu1BY9同源性较高。利用RNA二级结构预测软件对该片段、GlulR和GlulBy9进行预测表明,所分离的基因片段为一新的HMW-麦谷蛋白基因。该片段所编码的氨基酸序列中,N端的99个氨基酸和C端的42个氨基酸均为典型的HMW麦谷蛋白保守区。中间重复区中6肽重复22个,9肽重复7个。通过对其蛋白质二级结构的预测发现,在460～470氨基酸附近比GlulR和GlulBy9多一个α螺旋区和一个转角。该片段在Genbank中的编号为AY249141,所翻译的蛋白序列编号为AA074630。本文揭示了体细胞杂交引起小麦基因序列变化及与体细胞杂种小麦优良品质的相关性,为小麦品质育种研究提供了新途径。     

高分子量蛋白亚基组成及其对小麦粉品质的影响

对山东省优选的12个小麦品种的高分子量蛋白亚基(HMW GS)组成及其对小麦粉品质的影响作用进行了研究,为小麦品质的改良提供理论依据。     

Genetic Variation in Glutenin Protein Composition of Aestivum and Durum Wheat Cultivars and Its Relationship with Dough Quality

Genetic variability of high molecular weight glutenin subunits and low molecular weight glutenin subunits composition at the Glu-1 loci in Triticum aestivum L., and T. durum L., wheat was studied using sodium dodecyl sulfate polyacrylamide gel electrophoresis and polymerase chain reaction based markers. The end use quality of wheat is mainly influenced by the composition of glutenin protein. Aestivum cultivar GW-273 showed highest gluten index (94.4%) and sedimentation value (61 mL). GW-273 and GW-322 showed highest Glu-1 score of 10 out of 10, indicating superior dough quality for bread making. Results from glutenin protein separation using electrophoresis revealed that selected Indian wheat cultivars were abundant in high molecular weight glutenin subunits AxNull allele, which is responsible for poor quality. Gene specific polymerase chain reaction using high molecular weight glutenin subunits and low molecular weight glutenin subunits primers showed Dx5 and Dy10 in only two cultivars GW-273 and GW-322, which is responsible for good dough quality. Sequencing of high molecular weight glutenin subunits Dx5 gene fragment showed four cysteine at the N-terminal end. Cysteine residues are helpful in intermolecular disulfide bond formation among different glutenin and gliadins proteins leading to good elasticity of dough.     

Effects of a cross-linking enzyme on the protein composition,mechanical properties,and microstructure of Chinese-style noodles

Flours, representing the three major classes of Canadian wheat used for the production of noodles, were processed into fresh, Chinese-style, yellow alkaline noodles (YAN) with and without (1 w/w, fwb) the cross-linking enzyme transglutaminase (TG). The flours, YAN-TG and YAN + TG were sequentially extracted to remove albumins and globulins, followed by a series of 50% propanol extractions (±4% DTT) and 50% propanol +4% DTT +1% acetic acid to ensure removal of all extractable gliadin and glutenin components. Reverse-phase (RP) HPLC analyses of all propanol extracts were performed and the change in protein composition and distribution reported. Raw YAN, ±TG, were simultaneously evaluated for their fundamental rheological characteristics using ultrasound and stress relaxation testing. Significant changes in the distribution of protein within the various propanol extracts were observed when the flours were processed into YAN ± TG. The amount of unextractable protein increased by as much as ∼3-fold in YAN + TG, and ∼2-fold in YAN-TG, relative to that present in their respective source flour. Significant differences were observed within and between the YAN variety samples for the longitudinal modulus and the tan delta, when processed ±TG. Significant correlations (p = 0.05) were observed between protein composition, ultrasonic and stress relaxation parameters.     

High-Molecular-Weight Glutenin Subunits: Genetics,Structures, and Relation to End Use Qualities

High-molecular-weight glutenin subunits (HMW-GSs) are storage proteins present in the starchy endosperm cells of wheat grain. Encoding the synthesis of HMW-GS, the Glu-1 loci located on the long arms of group 1 chromosomes of the hexaploid wheat (1A, 1B, and 1D) present multiple allelism. In hexaploid wheat cultivars, almost all of them express 3 to 5 HMW-GSs and the 1Ay gene is always silent. Though HMW-GSs are the minor components in gluten, they are crucial for dough properties, and certain HMW-GSs make more positive contributions than others. The HMW-GS acts as a “chain extender” and provides a disulfide-bonded backbone in gluten network. Hydrogen bonds mediated by glutamine side chains are also crucial for stabilizing the gluten structure. In most cases, HMW-GSs with additional or less cysteines are related to the formation of relatively more or less interchain disulfide bonds and HMW-GSs also affect the gluten secondary structures, which in turn impact the end use qualities of dough.