知识与财富的链接
该研究旨在探讨蛋白血管紧张素转换酶（angiotensin I-convening enzyme,ACE）抑制肽及抗氧化肽的酶解制备方法。选取3种蛋白酶（碱性蛋白酶、中性蛋白酶及芽孢杆菌蛋白酶）酶解制备桑叶功能活性多肽,以ACE抑制活性为主要指标并辅以水解度（degree of hydrolysis,DH）评价ACE抑制活性,以DPPH自由基清除能力和总抗氧化能力（total antioxidant capacity,T-AOC）为指标评价其抗氧化性能。运用单因素逐级优化法对酶解反应的酶解pH值、底物浓度、加酶量、酶解温度和酶解时间进行参数优化。结果表明,3种蛋白酶的酶解产物均具有ACE抑制活性,中性蛋白酶酶解产物效果最佳,酶解工艺条件为底物浓度20 g/L、加酶量7.5%、酶解时间50 min、酶解温度55℃、pH7.0时,酶解产物的ACE抑制活性为81.23%,DH为21.41%。在不同蛋白酶优化条件下测定3种酶解产物的抗氧化能力,中性蛋白酶DPPH自由基清除率和总抗氧化能力均为最高,分别为80.702%和4.717 mmol/g。
The enzymatic hydrolysis methods for preparing angiotensin I-converting enzyme（ACE）inhibitory peptides and antioxidant peptides were studied.Three proteases（alkaline protease,neutral protease,and Bacillus subtilis protease）were selected for enzymatic hydrolysis to prepare functional active peptides from mulberry leaves.The ACE inhibition activity was evaluated with ACE inhibition rate and degree of hydrolysis（DH）as the indicators.The antioxidant performance was evaluated based on the scavenging activity against DPPH free radicals and total antioxidant capacity（T-AOC）.The single factor method was employed to optimize the enzymatic hydrolysis conditions including enzymatic hydrolysis pH,substrate concentration,enzyme addition amount,enzymatic hydrolysis temperature,and enzymatic hydrolysis time.The results showed that the enzymatic hydrolysates of three proteases all exhibit ACE inhibitory activity,and the neutral protease hydrolysates had the best effect.The enzymatic hydrolysis conditions were optimized as substrate concentration of 20 g/L,enzyme addition of 7.5%,enzymatic hydrolysis at 55 ℃for 50 min,and pH 7.0.The hydrolysates obtained under these conditions showed the ACE inhibition rate of 81.23% and DH of 21.41%.Measure the antioxidant capacity of three enzymatic hydrolysis products under different protease optimization conditions,the neutral protease hydrolysates showed the highest DPPH free radical scavenging rate（80.702%）and total antioxidant capacity（4.717 mmol/g）.
