There has recently been an increasing demand to produce protein hydrolysates containing peptides with specific biological properties, which could be marketed as functional food ingredients. The objective of this study was to evaluate the in vitro angiotensin converting enzyme inhibitory activity of striped catfish skin hydrolysates and its corresponding fractionates. | Journal of Fisheries science and Technology - 2016 ACE-INHIBITORY ACTIVITY OF PROTEIN HYDROLYSATE FROM THE SKIN OF STRIPED CATFISH (Pangasius hypophthalmus) Hue Quoc Hoa1,2, Nguyen Xuan Duy3 Received: 21/7/2016; Revised: 09/8/2016; Accepted: 26/9/2016 ABSTRACT There has recently been an increasing demand to produce protein hydrolysates containing peptides with specific biological properties, which could be marketed as functional food ingredients. The objective of this study was to evaluate the in vitro angiotensin converting enzyme inhibitory activity of striped catfish skin hydrolysates and its corresponding fractionates. The striped catfish skin from fillet processing was extracted in an autoclave at 1210C for 30 minutes to obtain an extracted protein. Then it was further hydrolysed with Alcalase with the enzyme to substrate ratio of 20 units/gram protein at 50oC, pH 8 for 7h to obtain protein hydrolysate. The degree of hydrolysis (DH) increased with the increase of hydrolysis time and reached the highest DH of after 7h hydrolysis. The 5-h hydrolysate (DH= ) exhibited the highest ACE-inhibitory activity (IC50 = 831 µg/ml). Therefore, the 5-h hydrolysate sample was used as material for studying enrichment of ACE-inhibitory peptides by ultrafiltration using three different molecular weight cut-off membranes (10, 5, and 1 kDa). Six sample fractions obtained during ultrafiltration process (permeate and retentate) were tested for angiotensin converting enzyme inhibition activity. Permeate of 1 kDa membrane showed the highest activity. The obtained hydrolysates were fractioned using SephadexM G-15. Based on gel filtration chromatography results, angiotensin converting enzyme inhibitory peptides had molecular weight ranging of 307 Da to 429 Da. Our findings revealed the potential of using catfish skin as a promising material for retrieving angiotensin converting enzyme inhibitory substances. Keywords: Alcalase, ACE-inhibitory activity, hydrolysate, .
