Novel angiotensin I-converting enzyme inhibitory peptides derived from soya milk

Inhibitors of angiotensin I-converting enzyme (ACE) are useful in treating hypertension, and many have been derived from food products, including soybeans. Using the industrial protease PROTIN SD-NY10, we developed a processed soya milk (PSM) with enhanced ACE inhibitory activity. The ACE inhibitory activity of PSM (IC50 = 0.26 μg/ml) was greater than that of regular soya milk (IC50 = 8.75 μg/ml). Eight novel ACE inhibitory peptides were purified from PSM by reversed-phase chromatography: FFYY (IC50,1.9 μM), WHP (4.8 μM), FVP (10.1 μM), LHPGDAQR (10.3 μM), IAV (27.0 μM), VNP (32.5 μM), LEPP (100.1 μM), and WNPR (880.0 μM). The IC50 values of these peptides are comparable to those reported for other ACE inhibitory peptides derived from wheat, chicken, bonito, wine, etc. Due to the relatively low IC50 values of several peptides identified in this study, they may serve as ideal base components of food supplements for patients with hypertension.