本研究开发了一种通过中试规模制备大豆低聚肽的方法，制备出的大豆低聚肽具有较高的蛋白含量（91.45%）和较低的分子量（84.37%的分子量小于1000 u）。测定了大豆低聚肽的抗氧化和血管紧张素转化酶（ACE）抑制活性，然后利用反相高效液相色谱对其进行分离纯化，收集六个主要的液相组分，分别命名为组分1~6，利用质谱仪对这些组分进行肽段结构鉴定。共鉴定出41个肽段结构，选择15个肽段进行抗氧化和ACE抑制活性评价。结果表明，大豆低聚肽中有两个新型抗氧化肽段和四个ACE抑制肽段。抗氧化肽段分别为：Tyr-Glu，8.61±0.42 mmol Trolox等同物/g样品；Asp-Tyr-Arg，6.53±0.34 mmol Trolox等同物/g样品；ACE抑制肽段分别为：Leu-Val-Arg，IC50=51.75 μM；Leu-Tyr，IC50=305.76 μM；Asp-Tyr-Arg，IC50=1082.95 μM；Asp-Phe，IC50=1106.04 μM。这些肽段大多数是从大豆中新发现的抗氧化肽段和ACE抑制肽段。大豆低聚肽和这些活性肽段可作为抗氧化或降血压物质用于食品添加剂、营养物及医药制品中。

A pilot-scale production of soybean oligopeptides (SOPs) was developed in this study, and the SOPs had a high protein content (91.45%) and low molecular weight (84.37% of the product were less than 1000 u). The in vitro antioxidant activity and angiotensin I-converting enzyme (ACE) inhibitory activity of SOPs were analyzed. SOPs were then separated by reversed-phase high performance liquid chromatography, and six major fractions (numbered from 1?6) were collected and subjected to mass spectrometry to identify the active peptides. The sequences of 41 peptide fragments were identified, and 15 peptide fragments were selected to evaluate the antioxidative and ACE inhibitory activities using the aforementioned methods. The results showed that SOPs contained two novel potent antioxidative peptide fragments (Tyr-Glu, 8.61 ± 0.42 mmol Trolox equivalents/g sample; Asp-Tyr-Arg, 6.53 ± 0.34 mmol Trolox equivalents/g sample) and four potent ACE inhibitory peptide fragments (Leu-Val-Arg, IC50 = 51.75 μM; Leu-Tyr, IC50 = 305.76 μM; Asp-Tyr-Arg, IC50 = 1082.95 μM; Asp-Phe, IC50 = 1106.04 μM). Most of them were novel antioxidant or ACE inhibitory peptides derived from soybeans. This study suggested that SOPs and their active peptides might be used as antioxidative or hypotensive substances in food additives, dietary nutrients, and pharmaceutical agents.

National Key Technology Research and Development Program for the 13th five-year plan (2016YFD0400604); National High Technology Research and Development Program of China (863 Program) (2013AA102205-02)