大米蛋白酶解物的ACE抑制活性研究

Angiotensin-converting Enzyme Inhibition By Rice Protein Hydrolysate

摘要:

为了考察大米四种蛋白经模拟体外消化后能否产生ACE抑制活性肽及其活性状况，本研究以大米为原料，Osborne法提取大米四种蛋白。体外模拟胃肠道消化过程，研究消化酶解ACE抑制活性肽产生情况及其活性大小，同时检测酶解产物的水解度和分子量分布。实验结果表明，大米四种蛋白经胃蛋白酶消化30 min，酶解产物的ACE抑制活性均达到较高水平，随后经过胰蛋白酶作用，酶解产物的ACE抑制活性下降。大米清蛋白，球蛋白，醇溶蛋白和谷蛋白的4 h消化产物半抑制浓度IC50值分别为1.45 mg/mL, 0.91 mg/mL, 1.19 mg/mL和0.75 mg/mL，分子量集中在1000 u以下，是易于被人体吸收的ACE抑制活性肽。同时，未经酶解的蛋白几乎没有ACE抑制活性。结果说明大米四种蛋白的体外消化酶解物具有不同大小的ACE抑制活性，其中大米谷蛋白消化产物的ACE抑制活性最高，人体正常食用大米蛋白，经胃肠消化可以产生被人体吸收的ACE抑制活性肽。

Abstract:

In this study, the production of peptides with angiotensin-converting enzyme (ACE) inhibition activity was investigated from simulated in vitro digestion of four rice proteins, namely albumin, globulin, prolamin, and glutelin. The proteins were extracted from rice using the Osborne method. Production and ACE inhibiting activity, the degree of hydrolysis, and the molecular weight distribution of the proteolysis products were investigated. The results revealed that ACE inhibition activity of individual products obtained after proteolysis of the proteins, was high after 30 min of pepsin digestion. The activity decreased upon subsequent digestion with trypsin. The hydrolysates of rice albumin, globulin, prolamin, and glutelin after 4-hour digestion showed half-inhibition concentration (IC50) of 1.45, 0.91, 1.19, and 0.75 mg/mL, respectively, and their molecular weight was < 1000 u, which means they can be easily absorbed by the human body. At the same time, undigested proteins had almost no ACE inhibition activity. The result also showed the products of in vitro protein proteolysis had different ACE inhibition activities and that rice glutelin proteolysis product showed the highest ACE inhibition activity. Therefore, the gastrointestinal digestion of regularly consumed rice can produce ACE-inhibiting peptides that can be absorbed by the human body.