Identification of angiotensin I-converting enzyme inhibitory peptides from koumiss, a traditional fermented mare's milk

The procedure of koumiss digestion by gastrointestinal protease and angiotensin I-converting enzyme (ACE) inhibitory activity determination.

Stability of angiotensin I-converting enzyme (ACE) inhibitory peptides P_I, P_K, P_M, and P_P derived from koumiss incubated at various temperatures, pH, and ACE treatments for 2h. The relative ACE inhibitory percentage was calculated as the ratio of ACE inhibitory activity between the control and the treatments (relative ACE inhibitory index=50% inhibitory concentration (IC₅₀) value of samples/IC₅₀ value of control × 100%). ^a–cMeans bearing different letters in the same row differ significantly compared with control samples (P<0.05).