鳄鱼皮酶解产物功能特性及抗氧化活性

为了解鳄鱼皮酶解产物功能特性和抗氧化活性,采用2种商业蛋白酶(木瓜蛋白酶、碱性蛋白酶)在各自最适反应条件下分别酶解鳄鱼皮,研究水解度(DH)、酶种类及pH值对酶解产物功能特性及抗氧化活性的影响.结果显示:随着酶解时间延长,鳄鱼皮水解度逐渐增加,鳄鱼皮在碱性蛋白酶酶解作用下水解度较高,水解4h时可达12％；木瓜蛋白酶酶解产物与碱性蛋白酶酶解产物的溶解性差异不显著(P＞0.05).相同水解度下,碱性蛋白酶酶解产物的热稳定性在pH4时优于木瓜蛋白酶酶解产物.酶解时间在1h之内,木瓜蛋白酶酶解物亚铁离子螯合力明显增强；随着时间延长,酶解产物亚铁离子螯合能力变化不显著(P＞0.05).酶解3h后碱性蛋白酶酶解产物亚铁离子螯合能力高于木瓜蛋白酶酶解产物,但木瓜蛋白酶酶解产物具有较强的清除DPPH自由基能力.综上表明,碱性蛋白酶水解作用的鳄鱼皮水解度较高,其酶解产物乳化活性和热稳定性优于木瓜蛋白酶酶解产物；鳄鱼皮酶解产物抗氧化能力较强,有较高的开发利用价值.

Functional Properties and Antioxidant Activity of Protein Hydrolysates from Crocodile Skin

This study explored functional properties and antioxidant activity of protein hydrolysates from crocodile skin.Two commercial proteases,papain and alcalase,were used to hydrolyze crocodile skin under optimum reaction conditions.The effects of protease type and hydrolysis time on degree of hydrolysis(DH),functional properties and antioxidant of protein hydrolysates were examined.For both proteases,DH increased with hydrolysis time up to 4 h,but a higher maximum DH value was obtained with alcalase.Protein hydrolysates obtained with both proteases did not show a significant difference in solubility(P>0.05).At the same DH,hydrolysis products with better heat stability at pH 4 were obtained with alcalase compared to papain.Ferrous ion-chelating capacity of protein hydrolysates prepared with papain considerably increased with increasing hydrolysis period up to 1 h and then reached a plateau without significant differences(P>0.05).After 3 h of hydrolysis,protein hydrolysates with higher ferrous ion-chelating capacity but weaker DPPH radical scavenging capacity were obtained with alcalase compared to papain.Collectively,the above findings suggest that alcalase is more effective in hydrolyzing crocodile skin and yields hydrolysis products with better emulsifying capacity and heat stability than papain.Protein hydrolysates from crocodile skin have potent antioxidant activity and thus have great potential for development and utilization.