为了验证大豆多肽血管紧张素转换酶(ACE)抑制活性的生物可获得性，采用 Al-calase 蛋白酶催化大豆蛋白水解获得了 3 种水解程度不同的大豆多肽，再应用摸拟体外消化方法处理大豆蛋白及其水解产物，并进一步分析了摸拟消化前后大豆多肽结构、性质和 ACE 抑制活性的变化．结果显示:3 个大豆多肽的相对分子质量均小于 16000，且水解度越高，TCA 可溶性蛋白含量就越高;经过摸拟体外消化，大豆蛋白出现降解，其分子大小和性质与大豆多肽趋于一致，大豆多肽则进一步降解;3 种大豆多肽的 ACE 抑制活性在经过摸拟体外消化后显著下降， 大豆蛋白的 ACE 抑制活性则显著上升，两者之间没有显著差异，表明虽然 Alcalase 对大豆蛋白的酶促处理能够释放降血压肽，但经过模拟体外消化后其 ACE 抑制活性又会下降， 而直接口服大豆蛋白有可能获得同样的降血压效果．

In order to verify the bioavailability of ACE (Angiotensin Converting Enzyme) inhibitory activities ofsoybean peptides,3 kinds of soybean peptides with different hydrolysis degrees were prepared by using Alcalaseprotease to catalyze the hydrolysis of soybean protein,and the effects of simulated in- vitro digestion on the struc-ture,properties and ACE inhibitory activities of soybean protein isolates (SPI) and soybean peptides were ana-lyzed.The results show that (1) the relative molecular mass of the three kinds of soybean peptides are all less than16000,and the content of TCA soluble protein increases with the degree of hydrolysis; (2) after the simulated in-vitro digestion,SPI degrades,with its molecular size and properties tending to those of soybean peptides,and,atthe same time,soybean peptides further degrade; and (3) there is no significant difference between SPI and soy-bean peptides because the simulated in- vitro digestion results in a significant decrease of ACE inhibitory activities ofsoybean peptides and a remarkable increase of those of SPI.It is thus concluded that SPI is able to release antihy-pertensive peptides under the action of Alacalase protease,but the ACE inhibitory activities of soybean peptidesmay reduce after the simulated in- vitro digestion; and that SPI by oral administration may have the same effect oflowering blood pressure.