Quantitative analysis of digestion resistant ACE inhibitory dipeptides by small intestinal mucosa

The short chain peptides derived from sardines were incubated for 120 min with an extract of porcine small intestinal mucosa. Digestion-resistant dipeptides found in the digest, Val-Tyr, Val-Trp, Ile-Tyr and Ile-Trp, inhibited angiotensin I converting enzyme (ACE). Amounts of the four dipeptides isolated from the digest using a Sep-pak C-18 cartridge column and three steps of high-performance liquid chromatography, were 85.88, 21.87, 10.69 and 6.51 mg/100 g peptides, respectively, and the contribution of four peptides to total ACE inhibitory activity was 10.5%. It was confirmed that ACE inhibitory dipeptides were present in the digest of the short chain peptides.