Physicochemical Properties and Angiotensin I Converting Enzyme Inhibitory Peptides of Freshwater Fish Skin Collagens

Abstract

ABSTRACT The objectives of this study were to characterize physicochemical properties of two collagens, tilapia skin (TS) and hybrid catfish skin (HS). Angiotensin-converting enzyme (ACE) inhibitory peptides from extracted TS and HS collagen using pepsin were also determined. HS collagen had a higher amount of imino acid than TS collagen, while TS contained higher amounts of tyrosine (Tyr) and lysine (Lys). Fourier-transform infrared spectra of both collagens showed predominant helix structure. The HS collagen hydrolysate prepared by pepsin was fractionated using sequential ultrafiltration membranes, and the fraction with molecular weight (MW) <5 kDa showed the highest ACE inhibitory activity (p < .05). After cation exchange and two steps size exclusion chromatography, peptides showed ACE inhibitory activity of 72.06%. This study revealed that ACE inhibitory peptides derived from HS collagen could be developed as a functional food with potential antihypertensive properties.