固定化蛋白酶法制备低苦味蛋白质水解物的研究

Study on Preparation of Weak, Bitter-tasting Protein Hydrolysate by Immobilized Protease

目的用固定化蛋白酶制备低苦味蛋白质水解物。方法将中性蛋白酶(neutral protease,NP)和复合蛋白酶(protamex,PM)共价固定到经戊二醛预处理的壳聚糖上,所得固定化蛋白酶于50℃催化酪蛋白分解。结果固定化中性蛋白酶(INP)和固定化复合蛋白酶(IPM)的活性回收率分别为59.9%和35.0%;重复使用10次(10 h/次)后,INP和IPM的酶活性仍分别保存70.0%和79.8%。用IPM和INP制备的蛋白质水解物的水解度分别达到9.4%和26.5%,苦味值分别为4级和2级。用INP制备的蛋白质水解物与用游离PM制备的蛋白质水解物的水解度和苦味值基本相同。结论使用固定化蛋白酶制备低苦味蛋白质水解物的水解度和苦味值都能达到食品蛋白质水解物的质量要求。

Objective To prepare weak,bitter-tasting protein hydrolysate by immobilized protease.Methods The neutral protease（NP） and Protamex（PM） were covalently immobilized on glutaraldehyde-pretreated chitosan.The immobilized protease was used to catalyze the hydrolysis of casein at 50 ℃.Results The activity recovery for the immobilized neutral protease（INP） and the immobilized Protamex（IPM） was 59.9 % and 35.0 %,respectively.The activity of INP and IPM remained 70.0 % and 79.8 % respectively after repeated usage for 10 times（10 h/time）.The degree of hydrolysis（DH） for the IPM-catalyzed hydrolysate and the INP-catalyzed hydrolysate was 9.4 % and 26.5 %,with the bitterness degree of 4 and 2,respectively.The DH and the bitterness degree for the INP-catalyzed hydrolysate were as high as those for the free PM-catalyzed hydrolysate.Conclusion The degree of hydrolysis and the bitterness degree of the weak,bitter-tasting protein hydrolysate prepared by immobilized protease can be good enough to fulfill the quality requirement for the food protein hydrolysate.