Recovery of Bioactive Peptide Fractions from Rainbow Trout (Oncorhynchus mykiss) Processing Waste Hydrolysate

Aims: Bioactive peptides with antioxidant properties derived from fish by-products and wastes by enzymatic hydrolysis have become a topic of great interest for pharmaceutical, health food, and processing/preservation industries.
Materials & Methods This study aimed to characterize peptide fractions with antioxidative activity recovered from rainbow trout gelatin hydrolysate. Four peptide fractions (30 kDa) were obtained from gelatin hydrolysate by subjecting them to centrifugal ultrafiltration using successively a 30 kDa, 10 kDa, and a 3 kDa membrane. The 10–30 kDa fraction was characterized in terms of amino acid composition. The antioxidant activity of all fractions was monitored by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radical scavenging as well as reducing power activity.
Findings: The free amino acids in 10–30 kDa fraction were dominated by Gly, Pro, Ala, and Hyp; the total hydrophobic amino acid of 10–30 kDa fraction was also 61.5%. All hydrolysate and peptidic fractions demonstrated high antioxidant activities. Moreover, 10–30 kDa fraction exhibited the highest DPPH and ABTS radical scavenging activity (2, 5, and 10 mg ml−1) and reducing power (10 mg ml−1) compared to other fractions (p These results revealed the potential of peptide fractions recovered from rainbow trout skin gelatin as source of natural antioxidants for use in food products.