酶解虾壳蛋白制备ACE 抑制剂的工艺优化

以虾壳粉为原料，以水解度和ACE抑制率为指标，利用中性蛋白酶、碱性蛋白酶、菠萝蛋白酶和木瓜蛋白酶进行酶解，其中中性蛋白酶和碱性蛋白酶有较高的ACE抑制活性，因此对碱性蛋白酶和中性蛋白酶的工艺条件进一步优化。结果表明：碱性蛋白酶酶解工艺优化条件为：温度60℃、pH9.5、底物质量浓度2.5g/100mL、加酶量4000U/g、酶解时间2.5h，在此条件下ACE抑制率最高，为67.70%，水解度为69.79%；中性蛋白酶酶解工艺优化条件为：温度50℃、pH7.0、底物质量浓度2.5g/100mL、加酶量2000U/g、酶解时间2h，在此条件下ACE抑制率最高，为84.04%，水解度为26.76%。提示中性蛋白酶酶解能够产生更多的ACE抑制肽，是酶解虾壳蛋白制备ACE抑制肽的较优酶。

Enzymatic Preparation of Angiotensin I-Converting Enzyme Inhibitory Peptides from Shrimp Shell

In order to find the appropriate proteases for enzymatic preparation of angiotensin Ⅰ-converting enzyme(ACE) inhibitory peptides from shrimp shell,neutral protease,alkaline protease,bromelin and papain were evaluated for their effectiveness in hydrolyzing shrimp shell based on hydrolysis degree and ACE-inhibitory activity.It was found that both neutral protease and alkaline protease were more suitable for the preparation of ACE-inhibitory peptides from shrimp shell.The process conditions for hydrolyzing shrimp shell with neutral protease or alkaline protease were optimized by orthogonal array design method.The optimized alkaline protease hydrolysis conditions were hydrolysis temperature of 60 ℃,hydrolysis pH of 9.5,substrate concentration of 2.5 g/100 mL,enzyme concentration of 4000 U/g and hydrolysis time of 2.5 h,resulting in an ACE-inhibitory rate of 67.70% and a hydrolysis degree of 69.79%.The optimized neutral protease hydrolysis conditions were hydrolysis temperature of 50℃,hydrolysis pH of 7.0,substrate concentration of 2.5 g/100 mL,enzyme concentration of 2000 U/g and hydrolysis time of 2 h,resulting in an ACE-inhibitory rate of 84.04% and a hydrolysis degree of 26.76%.In conclusion,neutral protease is a superior protease over alkaline protease for the preparation of ACE-inhibitory peptides from shrimp shell.