Antioxidative activities of hydrolysates from seabass skin prepared using protease from hepatopancreas of Pacific white shrimp

Antioxidative activities of hydrolysates from skin of seabass (Lates calcarifer) with different degrees of hydrolysis (DH: 10-40%) prepared using an ammonium sulphate precipitated fraction (ASPF) from Pacific white shrimp hepatopancreas and commercial Alcalase were compared. The hydrolysate prepared using ASPF or Alcalase had increases in 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidative power (FRAP) as DH increased (P < 0.05). When the hydrolysate prepared using ASPF with 40% DH was subjected to a gastrointestinal model system (GIMs), ABTS radical scavenging activity and chelating activity increased, especially in the duodenal condition. The hydrolysate (500-2000 mg/L) could inhibit lipid oxidation in a lecithin liposome system in a dose dependent manner. Based on gel filtration using a Sephadex™ G-15 column, peptide with a molecular weight of 364 Da showed the strongest ABTS radical scavenging activity. Therefore, the extract from hepatopancreas could be used to increase DH of hydrolysate from seabass skin.