EVALUATION AND COMPARISON OF COMPOSITION AND BIOLOGICAL ACTIVITIES OF PEPTIDES OBTAINED FROM RAINBOW TROUT (Oncorhynchus mykiss) AND CHLORELLA (Chlorella sorokiniana)

Abstract

This study compared protein hydrolysates generated from Rainbow Trout (Oncorhynchus mykiss) by-products and Chlorella (Chlorella sorokiniana), for their functional properties as bioactive peptides. The Trout hydrolysate was derived via a fermentative hydrolysis method, while Chlorella hydrolysate was obtained by sequential microwave treatment and enzymatic hydrolysis. Both hydrolysates were fractionated using Ultrafiltration membranes. Lyophilized crude hydrolysate and different molecular weight fractions were analyzed for antioxidant and Angiotensin converting enzyme (ACE) inhibitory capacities. Despite similar protein content (30% dw) in Chlorella biomass, the hydrolysate's soluble protein was 4.96 mg/mL, nearly 90% lower than the soluble protein content of fish hydrolysate. Nevertheless, Chlorella hydrolysate fractions showed significantly higher antioxidant capacities compared to fish hydrolysates, while no difference was observed for ACE inhibition activity. Protein extraction from Chlorella could be enhanced and optimized to increase yield. Supplementation of trout hydrolysate with Chlorella hydrolysates was identified as potentially providing a unique high-value bioactive peptide blend for combined activities.