耦合Plastein反应的大豆蛋白降压肽酶法制备技术

利用碱性蛋白酶酶解大豆分离蛋白，制备出水解度为16.6% 的大豆蛋白水解物，随后对水解物进行Plastein反应修饰。利用响应面分析优化修饰反应条件，得到适宜参数：底物质量分数45%、酶添加量275U/g 蛋白质、反应时间3～4h、温度30℃。制备修饰反应程度不同的9 种修饰产物并评价其体外ACE 抑制活性，发现修饰产物的IC50 值为0.64～1.30mg/mL，均小于大豆蛋白水解物IC50 值(1.45mg/mL)。排阻色谱分析结果确认，修饰产物中有更多的高分子质量肽段存在。结果显示，大豆蛋白的酶解以及耦合Plastein 反应修饰，是一种制备高ACE抑制活性大豆蛋白降压肽的新技术。

Preparation of ACE Inhibitory Peptides from Soybean Protein Isolate by Enzymatic Hydrolysis Coupled with Optimized Plastein Reaction

Soybean protein hydrolysates (SPHs) with a degree of hydrolysis of 16.6% were prepared by 4 h hydrolysis with alcalase, and then subjected to plastein reaction for modification. Response surface analysis was applied to optimize the conditions for plastein reaction, and the optimal conditions obtained were as following: substrate concentration 45%, enzyme loading 275 U/g proteins, reaction time 3 to 4 h and reaction temperature 30 ℃. Nine modified products were prepared, and their ACE inhibitory activities were evaluated in vitro. It was found that the IC50 values of the modified products were in the range of 0.64 to 1.30 mg/mL, lower than that of SPHs (1.45 mg/mL). The analytical results from size exclusion chromatography confirmed that more large peptides with higher molecular weight were generated in the modified products. This study suggests that enzymatic hydrolysis coupled with plastein reaction might be served as a new approach to prepare ACE inhibitory peptides with higher activity from soybean protein isolate.