高温变性豆粕酶改性过程中蛋白质结构的变化

研究了高温变性豆粕(HDDSF)酶改性过程中蛋白质的结构变化,分析了高温变性豆粕蛋白质溶解性提高与结构的关系。在不同水解度(DH)下,检测酶改性处理前后的可溶性蛋白质的的表面巯基(SSH)、自由巯基(FSH)、总巯基(TSH)、二硫键(-S-S-)和表面疏水性(H0),通过SDS-PAGE图谱分析蛋白亚基变化。随着DH的提高,高温变性豆粕蛋白质溶解性增加,自由巯基和表面疏水性下降,总巯基和二硫键先上升后下降。经酶改性后蛋白质溶解性明显提高,酶解促使高温变性豆粕的不溶性蛋白质生成了以二硫键为主要化学键连接的可溶性聚合物,在酶继续作用下,生成的聚合物被最终酶解。

Effect of Enzymic Modification Treatment on Structural Characteristics of Commercial Highly Denatured Defatted Soy Flakes

The effects of enzymatic modification(EM) treatment on structural characteristics of highly denatured defatted commercial soy flakes(HDDSF) were investigated in order to analyze the relationship between its solubility and structure.Protein solubility,surface hydrophobicity(Ho),surface sulfhydryl(SSH) content,free sulfhydryl(FSH) content,total sulfhydryl(TSH) content and disulfide bond(-S-S-) content were evaluated.Protein subunits profiles for the hydrolysate were altered by the EM treatment and major changes were observed for the hydrolysate.With DH increasing,the solubility of HDDSF was increased significantly.The SSH content,FSH content and the TSH content were showed different changes,above all the-S-S-content of HDDSF was significantly increased after EM treatment at DH1 %,but was gradually decreased with further increase in DH.Analysis showed that the soluble aggregates were formed during EM treatment.Covalent interactions(i.e.disulfide bonds) was involved in the formation of soluble aggregates.The formation of soluble aggregates significantly improved the solubility of HDDSF,and the soluble aggregates were hydrolyzed by Alaclase thereafter.