中文摘要：

为提高沙蜇肽的降血压和抗氧化活性,通过plastein反应修饰沙蜇蛋白酶解物。根据单因素试验优化得出plastein反应最佳条件：温度20℃、底物质量分数35%、加酶量2.5kU/g。在此条件下反应6h,游离氨基减少量为83.09μmol/g,plastein反应产物的体外ACE抑制率为83.15%（产物质量浓度为15mg/mL）,比沙蜇蛋白酶解物的ACE抑制率提高了10.45%;反应4h,游离氨基减少量为107.52μmol/g,plastein反应产物的体外DPPH的IC50为24.68 mg/mL,比沙蜇蛋白酶解物的DPPH清除力提高了39.63%。plastein反应可提高沙蜇肽的ACE抑制活性和DPPH清除能力。

英文摘要：

The hydrolysate of jellyfish was modified by plastein reaction to improve its antihypertensive and antioxidant activity.The optimal conditions of plastein reaction were obtained by single factor experiments as follows：reaction temperature of 20 ℃,concentration of jellyfish hydrolysates of 35%and enzyme amount of 2.5kU/g.Under the conditions,the maximal decrease of free amino groups in reaction mixture of 83.09μmol/g was obtained.The angiotensin converting enzyme inhibitory activity of the product was 83.15%（the concentration of product was 15 mg/mL）after reaction for 6h,which increased by 10.45%compared with the unmodified hydrolysate.The maximal decrease of free amino groups in reaction mixture of 107.52μmol/g was obtained after reaction for 4h,and the product exhibited IC50 of DPPH was 24.68 mg/mL,which increased by 39.63% compared with the unmodified hydrolysate.The plastein reaction could improve ACE inhibitory activity and DPPH radical scavenging activity of hydrolysate obtained from jellyfish.