Effects of peptide fractions and amino acids on antioxidant properties of autolyzed tuna viscera protein hydrolysate

Abstract

Tuna viscera as a common waste product from the tuna processing industry contributes to environmental pollution. The effects were determined of peptide fractions and amino acids on the antioxidant properties of protein hydrolysate from tuna viscera. We converted this waste into protein hydrolysate, a high added-value product, using autolysis. Tuna protein hydrolysate was fractionated by ultrafiltration into four fractions (>10 kDa, 5–10 kDa, 1–5 kDa and <1 kDa) and each was examined for its antioxidant properties (DPPH, ABTS, FRAP and metal chelating) and amino acids composition. The MW and amino acids of the tuna protein hydrolysate peptide fractions were not directly correlated with DPPH radical scavenging activity and metal chelating. The ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) of the 1–5 kDa fraction were higher than for the other fractions. The tuna protein hydrolysate peptide fractions contributed to antioxidant activity and should be used to their full advantage by the nutritional and food industries