Antioxidant peptides derived from hydrolysates of red tilapia (Oreochromis sp.) scale

Processing red tilapia (Oreochromis sp.) yields a large quantity of scale, a byproduct of the aquaculture industry. This study focuses on evaluating the potential of red tilapia scales as a source of antioxidant peptides. Scales were ground and enzymatically hydrolyzed by Alcalase® 2.4 L. The hydrolysate obtained was fractionated to purify and identify the antioxidant peptides by membrane ultrafiltration and chromatographic technology guided by the antioxidant activity in rat vascular smooth muscle A7r5 cells. After ultrafiltration, the fraction with molecular weight of 3–10 kDa showed the highest activity and their chemical nature was hydrophilic. The sequence of twenty antioxidant peptides, containing 6–16 amino acids, was identified by liquid chromatography–tandem mass spectrometry. The results indicate that the red tilapia (Oreochromis sp.) scale could be a new natural source of antioxidant peptides.