Production of collagen hydrolysate with antioxidant activity from pharaoh cuttlefish skin

The aim of this study was to produce collagen hydrolysate with antioxidant activity. Pepsin soluble collagen (PSC) isolated from the skin of Pharaoh cuttlefish (Sepia pharaonis) was used as a substrate for hydrolysis at 25°C and pH 7.5 by using collagenase from Clostridium histolyticum. The result showed that rapid hydrolysis was observed within the first 90 min with a degree of hydrolysis (DH) approaching 35%. Thereafter, a slower rate of hydrolysis was generally observed. An increase in DH was generally observed with increasing enzyme concentration. When log10 (collagenase concentration) versus DH (%) was plotted, a linear relationship was found with a coefficient of determination (R2) of 0.9863. Electrophoretic study of collagen hydrolysates with 10% DH, 20% DH, and 30% DH revealed that their major peptides had molecular weights (Mr) ranging from 6.5 to 10.3 kDa; and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activities. The ferric reducing activity power (FRAP) of collagen hydrolysates with 20% DH and 30% DH were similar (p > 0.05). Chelating activity of collagen hydrolysates with 20% DH was negligible and for 10% DH and 30% DH it was not detectable. Given these findings, Pharaoh cuttlefish skin, a byproduct of cuttlefish processing, is a promising source material for production of collagen hydrolysate with antioxidant activities.