豆奶蛋白质中巯基含量的测定  

Determination of Sulfhydryl Content in Soymilk Protein

作　　者：欧仕益[1] 郭乾初[2] 包惠燕[1] 李爱军[1] 

机构地区：[1]暨南大学食品科学与工程系,广州510632 [2]香港理工大学应用生物与化学科技系

出　　处：《中国食品学报》2003年第2期59-62,共4页Journal of Chinese Institute Of Food Science and Technology

摘　　要：Ellman法是测定蛋白质中游离巯基和二硫键含量的快速、简便的方法,但该法用于测定豆奶等的巯基含量时,由于溶液高度混浊和巯基含量不高,给测定带来了困难。本实验先采用丙酮将豆奶中的蛋白质沉淀分离,再用含8mol/L尿素的Tris-甘氨酸缓冲溶液或不含尿素的Tris-甘氨酸缓冲溶液溶解,使蛋白质溶液的混浊度大大下降,从而能达到用分光度法准确测定豆奶蛋白质中巯基含量的目的。采用大豆分离蛋白作对照实验表明,丙酮处理不会影响蛋白质中的巯基含量,说明丙酮处理是测定高混浊度蛋白质溶液如牛奶、豆奶中的蛋白质巯基含量的一种有效方法。Ellman's method is a simple, rapid and brief method to determine the contents of SH and S-S groups in proteins. However, it met difficulties in directly determining SH and S-S-groups contents of soymilk because of its high turbidity and low content of SH group. In the experiment, acetone was used to separate the proteins from soymilk by precipitation, and the proteins were later dissolved in Tris-glycine buffer solution (pH = 8.0) containing or not containing 8mol/L urea, thus significantly decreased the turbidity of soymilk protein and made it accurately determine SH content in soymilk protein by spectra photometric method. Compare test of soy proteins isolate proved that the contents of SH and S-S-groups were not affected by acetone treatment. It can be concluded that acetone treatment is an effective method to determine the SH and S-S-groups content of proteins in high turbid solutions such as milk, soymilk etc.

关 键 词：豆奶 蛋白质 巯基含量 测定 丙酮处理 混浊度 

分 类 号：TS214.2[轻工技术与工程—粮食、油脂及植物蛋白工程]