胃蛋白酶水解大豆分离蛋白的研究

Enzymatic Hydrolysis of Soy Protein Extract with Pepsin

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 hydrol- ysis, the degree of hydrolysis values varied from 0% to 7.90% after 360 min of incubation. The molecular weight dis- tribution of soy protein hydrolysates prepared with Pepsin was determined by SE-HPLC and SDS-PAGE. The results showed that soy glyeinin （ 11 S） was selectively hydrolyzed by Pepsin. The molecular weight distribution of the hydrol- ysates 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 in- creased and then decreased, while the content of disulfide bonds had no obvious change. The results herein were help- ful for understanding the mechanism of soy protein hydrolysis with Pepsin, and could serve as a guide for the develop- ment of soy protein hydrolysate products.