Antioxidative activity of protein hydrolysate from round scad muscle using alcalase and flavourzyme

Antioxidative activity of hydrolysates from round scad (Decapterus maruadsi) muscle with degrees of hydrolysis (DH ) of 20, 40 and 60%, prepared using Alcalase (HA) or Flavourzyme (HF), was determined. At the same DH, HF exhibited a higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and reducing power, but a lower Fe2+ chelating ability than HA. HF from isopropanol-defatted muscle with 60% DH was extracted using different solvents, and hexane (E1), dichloromethane (E2), ethyl acetate (E3) and residual (R) fractions were obtained. Among all fractions, E2 and E3 exhibited the highest DPPH radical scavenging activity and reducing power. HF with 60% DH and E2 at 1,000 ppm exhibited antioxidant activity in linoleic oxidation and lecithin liposome systems, and the results were comparable to butylated hydroxytoluene (BHT) at 100 ppm. Therefore, type of proteinase, DH and defatting process prior to hydrolysis exerted an influence on the antioxidative activity of hydrolysates.