Ge S J, Zhang L X
Department of Biology, Peking University, Beijing, China.
Appl Biochem Biotechnol. 1993 Dec;43(3):199-209. doi: 10.1007/BF02916453.
Soybean protein isolates of low soybean trypsin inhibitor (STI) residue were prepared by acidic precipitation of soybean flour water extracts (0.8-1.2%) at pH 5.0, followed by acidic washing at this pH and affinity adsorption of residual STI with immobilized trypsin on polystyrene anion-exchange resin GM 201. After heat treatment, soybean protein isolates were subjected to controlled hydrolysis with the immobilized trypsin. Then, the predigested soybean protein was prepared. The predigested soybean protein was free of STI activity, and its solubility at acidic pH range was greatly increased. Sedimentation test showed that it formed a much finer clot at pH 4.5 than that of untreated soybean protein. The pepsin digestibility index at pH 4.0 and chymotrypsin digestibility index at pH 8.0 were obviously improved. These results suggested that the predigested soybean protein prepared by this method may be used in infant formulas.
通过在pH 5.0条件下对大豆粉水提取物（0.8 - 1.2%）进行酸性沉淀，随后在此pH值下进行酸性洗涤，并使用固定在聚苯乙烯阴离子交换树脂GM 201上的胰蛋白酶对残留的大豆胰蛋白酶抑制剂（STI）进行亲和吸附，制备出低大豆胰蛋白酶抑制剂残留的大豆分离蛋白。热处理后，用固定化胰蛋白酶对大豆分离蛋白进行可控水解。然后，制备出预消化大豆蛋白。预消化大豆蛋白无STI活性，其在酸性pH范围内的溶解度大幅提高。沉降试验表明，在pH 4.5时，它形成的凝块比未处理的大豆蛋白细得多。在pH 4.0时的胃蛋白酶消化率指数和在pH 8.0时的胰凝乳蛋白酶消化率指数均有明显提高。这些结果表明，用该方法制备的预消化大豆蛋白可用于婴儿配方奶粉。
