采用胃蛋白酶对大豆分离蛋白进行酶法水解,随着酶解时间的延长,蛋白质的水解度逐渐增大,水解6h,DH为7.90%。采用分子筛凝胶过滤色谱(SE-HPLC)和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)对不同的酶解时间下大豆分离蛋白酶解物的分子结构进行表征,结果表明,胃蛋白酶选择性地酶解大豆11 S球蛋白。大豆分离蛋白经胃蛋白酶水解6 h后,分子量大于10 ku的部分占21.34%,其中主要是7 S球蛋白;分子量小于5 ku的部分所占比例为68.30%。对酶解物中的游离巯基和二硫键含量测定结果表明,随着酶解的进行,游离巯基的含量呈现先增大后减小的趋势,二硫键的含量总体变化不大。该研究旨在更好地了解胃蛋白酶水解大豆分离蛋白的机理,并为开发大豆分离蛋白酶解物产品提供理论依据。

Soy protein extract was enzymatically hydrolyzed with Pepsin.With the increase of soy protein hydrolysis,the degree of hydrolysis values varied from 0% to 7.90% after 360 min of incubation.The molecular weight distribution of soy protein hydrolysates prepared with Pepsin was determined by SE-HPLC and SDS-PAGE.The results showed that soy glycinin(11S) was selectively hydrolyzed by Pepsin.The molecular weight distribution of the hydrolysates obtained after 6 h of incubation were as follows:21.34 % were above 10 ku and 68.30 % were below 5 kDa.Soy conglycinin played a big role on the MW above 10 kDa.With the hydrolysis,free sulfhydryl content first increased and then decreased,while the content of disulfide bonds had no obvious change.The results herein were helpful for understanding the mechanism of soy protein hydrolysis with Pepsin,and could serve as a guide for the development of soy protein hydrolysate products.