Glu-1位点缺失对小麦麦谷蛋白聚合体粒度分布及面团特性的影响

以Glu-1位点正常和部分缺失的小麦品系为材料,探讨HMW-GS和LMW-GS组成与谷蛋白聚合体粒度分布和面团特性的关系,为利用HMW-GS缺失系改良小麦品质提供理论依据。在20个供试硬白冬麦品系中,1个品系为Glu-A1位点缺失,5个品系为Glu-D1缺失,3个品系为Glu-A1和Glu-D1双缺失。所有品系的蛋白质含量皆较高(13.39%~14.12%),品系间无显著差异,缺失系与非缺失系间也无显著差异。Glu-1位点缺失显著降低了高分子量谷蛋白/低分子量谷蛋白比(HMW/LMW)、不溶性谷蛋白大聚体的含量和百分比。谷蛋白/醇溶蛋白比(GLU/GLI)在基因型间变幅较小,且在缺失系和非缺失系间无显著差异。Glu-1位点缺失显著降低了面团弹性,但显著提高了面团的延展性。部分Glu-1位点缺失系仍具有较高的面团强度和突出的延展性,谷蛋白聚合体粒度分布和面团特性受谷蛋白亚基组成和表达量的共同影响。研究结果表明,利用Glu-1位点亚基缺失可能是改善面筋延展性,提高食品加工品质的方法之一。

Effects ofGlu-1Deletion on Size Distribution of Glutenin Polymeric Protein and Dough Properties in Common Wheat

The relationship between the HMW-GS and LMW-GS components and the size distribution of glutenin polymeric protein and dough properties were studied using Glu-1 normal and deletion lines, which provides a foundation for investigating the potential of Glu-1 deletion line in quality improvement of winter wheat. In the 20 hard white winter wheat lines tested, one was Glu-A1 deletion line, five were Glu-D1 deletion lines, and three were Glu-A1 and Glu-D1 double-deletion lines. Flour protein contents of the lines tested ranged from 13.39% to 14.12% with no significant difference between each other and between deletion and non-deletion groups. In Glu-1 deletion lines, the high molecular weight glutenin subunits/low molecular weight glutenin subunits ratio (HMW/LMW), content of SDS unextractable polymeric protein (UPP), and percentage of UPP (%UPP) were significantly lower than those in non-deletion lines. However, the glutenin/gliadin ratio (GLU/GLI) was similar in all genotypes, with no significant difference between deletion and non-deletion groups. Deletion at Glu-1 resulted in a significant decrease of dough elasticity and a significant increase of dough extensibility. Several Glu-1 deletion lines were characterized with medium gluten strength and excellent extensibility, suggesting that the size distribution of glutenin polymeric protein and dough properties were affected by both allelic composition and quantity of glutenin subunits. These results indicate that Glu-1 deletion lines can be used to improve dough extensibility and processing quality of common wheat.