Antioxidant Properties of Tilapia Component Protein Hydrolysates and the Membrane Ultrafiltration Fractions

Abstract

In this study, three kinds of component proteins of tilapia were hydrolyzed with papain for 4h. The effect of hydrolysis and the antioxidant activities of the resulting hydrolysates were characterized. The results showed sarcoplasmic protein hydrolysate had significantly (p < 0.05) highest scavenging ability against hydroxyl, superoxide, DPPH radicals and the total reducing power. Stroma protein hydrolysate had the highest nitrogen recovery (NR) while myofibrillar protein hydrolysate had the highest degree of hydrolysis (DH). Sarcoplasmic protein hydrolysate with high radical scavenging ability was separated by membrane ultrafiltration into four molecular size fractions (<5, 5–10, 10–100, >100kDa). It was found that the antioxidant activities of the <5kDa fraction were higher than that of other fractions. Overall, sarcoplasmic protein is more efficient to obtain antioxidant properties when compared to other component proteins of tilapia.