Angiotensin I‐converting enzyme inhibitory activity of protein hydrolysates prepared from three freshwater carps ( Catla catla , Labeo rohita and Cirrhinus mrigala ) using Flavorzyme

Summary Fish protein hydrolysates from three freshwater carps, C atla catla, L abeo rohita and C irrhinus mrigala with different degree of hydrolysis ( DH ) (5%, 10%, 15% and 20%), were prepared using Flavorzyme enzyme and designated as HCF , HRF and HMF , respectively. The angiotensin I ‐converting enzyme ( ACE ) inhibitory activity of hydrolysates was found to vary from 43 ± 2% to 71 ± 3%. Based on ACE inhibitory activity, HRF with DH ‐15% was taken up for further study. The mode of ACE activity inhibition by HRF ‐ DH 15% was mixed type as revealed by Lineweaver–Burk plot. Sequential digestion of HRF ‐ DH 15% using pepsin and pancreatin decreased the ACE inhibitory activity from 76% to 63%. Partial purification of HRF ‐ DH 15% by size exclusion chromatography gave three different fractions designated as F ‐1, F ‐2 and F ‐3 with the molecular mass in the range of 6456–407 Da. Fraction 2 had significantly higher ACE inhibitory activity than the other fractions.