小麦麦谷蛋白与面粉品质

从麦谷蛋白聚合体特性上考虑小麦品质的差异。通过不同溶剂麦谷蛋白的提取率测定,麦谷蛋白的氨基酸组成分析,Sepharose 4 B凝胶层析分析还原前后麦谷蛋白的分子量分布,麦谷蛋白中游离-SH、-S-S-含量测定,-S-S-断裂动力学研究,SDS—PAGE分析麦谷蛋白亚基组成,发现品质好的小麦面粉相对于品质差的有下列特点:通过-S-S-交联成的大分子麦谷蛋白聚集体比例大,在宏观物理特性上表现为面团流变学特性好;麦谷蛋白分子中的游离-SH、-S-S-含量和其它氨基酸组成与小麦品质无明显关系;面团流变学特性和烘焙品质较好的小麦的麦谷蛋白中的-S-S-不易断裂,在面团揉和过程中分子解聚慢,揉和稳定性好。这可能是不同品质小麦麦谷蛋白亚基组成的不同导致上述差异。

Wheat Glutenin Protein and Their Flour Quality

By analysing wheat glutenin extraction rate in various solvcnis, amino acid composition, Sepharose 4B gel filtration before and after reduction, the free -SH groups and -S-S- bonds content, the splitting dynamics of -S S- bonds, SDS-PAGE of subunits composition, four wheat culiivars glulenin of different dough performance were studied. The results showed that the glutenin aggregates play an important role in their dough characteristics. Evidence is presented that the wheat cultivars of better dough characteristics possess more high molecular weight (HMW) aggregated glutenin stabilised by -S-S bonds. There did not appear to be any relationship between the dough characteristics and the free -SH content, -S S-bonas content, amino acid composition of glutenin. However, the -S-S- bonds contained in glutenin of better dough characteristics are less accessible for splitting, The HMW glutenin subunits composition are discussed in relation to flour quality.