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。     

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.     

Functional properties of two low-molecular-weight glutenin subunits carrying additional cysteine residues from hybrid introgression line II-12 derived from Triticum aestivum and Agropyron elongatum

The functional properties of the various alleles of the low-molecular-weight glutenin subunits (LMW-GS) have not been widely addressed, even though they are important in the context of wheat end-use quality improvement. Two LMW-GS alleles introgressed into bread wheat from tall wheatgrass via asymmetric somatic hybridization differ from the norm by encoding either two or three additional cysteine residues. These genes were isolated and expressed heterologously in Escherichia coli to obtain sufficient product amounts for incorporation into the flour of a poor quality cultivar for the purpose of a micro-mixing test. Their effect was to decrease both the time to peak dough resistance and the peak width, while having no effect on either the 8 min curve width or the right of peak slope. Several effects on wheat dough properties were discussed in this paper.     

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.     

Proteomic Determination of Low-Molecular-Weight Glutenin Subunit Composition in Aroona Near-Isogenic Lines and Standard Wheat Cultivars

The low-molecular weight glutenin subunit (LMW-GS) composition of wheat (Triticum aestivum) flour has important effects on end-use quality. However, assessing the contributions of each LMW-GS to flour quality remains challenging because of the complex LMW-GS composition and allelic variation among wheat cultivars. Therefore, accurate and reliable determination of LMW-GS alleles in germplasm remains an important challenge for wheat breeding. In this study, we used an optimized reversed-phase HPLC method and proteomics approach comprising 2-D gels coupled with liquid chromatography–tandem mass spectrometry (MS/MS) to discriminate individual LMW-GSs corresponding to alleles encoded by the Glu-A3, Glu-B3, and Glu-D3 loci in the ‘Aroona’ cultivar and 12 ‘Aroona’ near-isogenic lines (ARILs), which contain unique LMW-GS alleles in the same genetic background. The LMW-GS separation patterns for ‘Aroona’ and ARILs on chromatograms and 2-D gels were consistent with those from a set of 10 standard wheat cultivars for Glu-3. Furthermore, 12 previously uncharacterized spots in ‘Aroona’ and ARILs were excised from 2-D gels, digested with chymotrypsin, and subjected to MS/MS. We identified their gene haplotypes and created a 2-D gel map of LMW-GS alleles in the germplasm for breeding and screening for desirable LMW-GS alleles for wheat quality improvement.     

具有5+12优质亚基节节麦的低分子量谷蛋白基因序列分析

根据低分子量谷蛋白亚基(LMW-GS)基因编码区保守序列设计引物,对具优质高分子量谷蛋白亚基(HMW-GS)5 12的节节麦材料AS63进行扩增,得到长度约为900bp和1000bp的DNA片段,克隆测序后获得3个LMW-GS基因序列LMWD-1(GenBank登录号AY841013)、LMWD-2(GenBank登录号AY841014)和LMWD-3(GenBank登录号AY841015)。它们具有小麦低分子量谷蛋白基因的典型结构特征。其中,LMWD-1和LMWD-2具有完整编码区,长度分别为1065bp和972bp,可分别编码333和302个氨基酸残基的成熟蛋白,且第一个半胱氨酸残基均出现在重复区第13位。在重复区,LMW-1的两个疏水单元为PIIIL和PVIIL,而LMWD-2的两个疏水单元为PIIIL和SVIIL。LMW-1的重复区中还存在一个连续13个Q组成的短肽。LMWD-3由于编码区内存在提前终止密码子,为不表达的假基因。氨基酸序列比较发现,LMW-GS基因的N-末端区序列具有位点特异性,且LMW-1和LMWD-2与普通小麦Gtu-D3位点的LMW-GS基因有很高的一致性。     

小麦醇溶蛋白和谷蛋白亚基的高效毛细管电泳分离研究

初步探讨了小麦醇溶蛋白和低分子量谷蛋白亚基（ＬＭＷ－ＧＳ）高效毛细管电泳（ＨＰＣＥ）分离的分辨芳及其重复性。结果显示：利用碱性硼酸钠缓冲液系统及一个改进的毛细管冲洗程序分离麦醇溶蛋白，可获得较高的分辨度和重要性。通常在３０ｍｉｎ内一个品种较易分离出４０个左右醇溶蛋白组分，而且重复分离之间峰迁移时间和峰高的平均相对标准偏差（ＲＳＤ）可分别保持在０．２％和４％左右。利用ｐＨ２．５酸性磷酸缓冲液（含２０