Sun Chongzhen, Shan Yangwei, Tang Xin, Han Duo, Wu Xiyang, Wu Hui, Hosseininezhad Marzieh
Department of Food Science and Engineering Jinan University Guangzhou China.
College of Food Science and Engineering South China University of Technology Guangzhou China.
Food Sci Nutr. 2021 Aug 25;9(10):5379-5390. doi: 10.1002/fsn3.2474. eCollection 2021 Oct.
To improve the antioxidant efficiency of mulberry leaf protein (MLP), alcalase, protamex, papain, flavourzyme, neutrase, and trypsin were used to hydrolyze MLP. The yield of soluble peptides, secondary structures, molecular weight distributions, and antioxidant activities of MLP hydrolysates (MLPHs) were investigated. Results showed that the native MLP was rich in the fraction above 6.5 kDa and was mainly composed of β-sheets, while MLPHs were abundant in the fractions of 0.3-0.6 kDa and 0.6-6.5 kDa and were mainly composed of disordered coils and β-folds. Limited hydrolysis of MLP could lead to better antioxidant activity than extensive hydrolysis. After enzymatic hydrolysis, the content of total sugar and total phenol in MLP increased significantly. MLP hydrolysates prepared with neutrase, alcalase, and protamex were preferable to other enzymes. Meanwhile, an enzyme to substrate level of 1% and a hydrolysis time of 2 hr were the optimum conditions to obtain higher antioxidant hydrolysates using neutrase.
为提高桑叶蛋白（MLP）的抗氧化效率，使用碱性蛋白酶、中性蛋白酶、木瓜蛋白酶、风味酶、中性淀粉酶和胰蛋白酶对MLP进行水解。研究了MLP水解产物（MLPHs）的可溶性肽产率、二级结构、分子量分布和抗氧化活性。结果表明，天然MLP富含分子量大于6.5 kDa的部分，主要由β-折叠组成，而MLPHs在0.3 - 0.6 kDa和0.6 - 6.5 kDa的部分含量丰富，主要由无规卷曲和β-折叠组成。与过度水解相比，对MLP进行有限水解可产生更好的抗氧化活性。酶解后，MLP中的总糖和总酚含量显著增加。用中性淀粉酶、碱性蛋白酶和中性蛋白酶制备的MLP水解产物优于其他酶。同时，酶与底物水平为1%且水解时间为2小时是使用中性淀粉酶获得更高抗氧化水解产物的最佳条件。
