Antioxidant Peptides from Dark Meat of Yellowfn Tuna (Thunnus albacares): Process Optimization and Characterization

Abstract

Tuna dark meat is a major edible by-product obtained from tuna cannery which is currently under-utilized or opted for the preparation of low-end products. Effective utilization of this marine biomass to bioactive peptides is a promising option facilitating numerous food and nutraceutical applications. Process optimisation studies for the extraction of antioxidant peptides from cooked dark meat of Thunnus albacares using RSM, indicated a papain based hydrolytic condition of 0.98% E/S, 240 min hydrolysis time as desirable under a pre-optimized temperature and pH of 60 °C and 6.5, respectively. Further detailed characterization viz., nutritional profle, molecular weight, surface morphology, thermal and spectral characteristics, physico-chemical properties, thermal/pH stability and in-vitro digestibility studies of the optimized antioxidant peptide was performed. Nutritional evaluation indicated its abundance in protein with balanced aminoacid profle and explored its richness in glutamic acid, aspartic acid, lysine and leucine. Molecular weight pattern indicated a major distribution of peptides in the size range of less than 3 kDa, 25% peptides between 10–30 kDa and 30%. Present study explores the application potential of tuna protein hydrolysate as a natural antioxidant in variety of food and nutraceutical systems.