Antioxidative Effect of Rainbow Sardine (Dussumieria acuta) Protein Hydrolysate on Lipid and Protein Oxidation in Black Pomfret (Parastromateus niger) Fillet by Glazing

The high polyunsaturated fatty acid content of oily fish such as black pomfret (Parastromateus niger) makes it particularly susceptible to oxidative degradation, and glazing of fillets protects them from the quality loss. This article describes the effects of glazing black pomfret fillets with rainbow sardine (Dussumieria acuta) protein hydrolysate (RSPH) as an antioxidant agent. Rancidity development and protein deterioration were measured by peroxide value (PV), thiobarbituric reactive substances (TBARS), free fatty acids (FFA), and carbonyl groups and compared with sensory analysis. Each fish was trimmed and glazed with different concentrations (0.05, 1, 2, and 4%) of RSPH. Iced-glazed fillets and fillets glazed with vitamin C (GVC) were compared with non-glazed fillets. All groups were frozen at -18 degrees C over a storage period of 6 months. When compared with control samples, RSPH 2 and 4%-treated samples showed a lower (p < 0.05) formation of lipid oxidation compounds and carbonyl groups that was corroborated by a longer (p < 0.05) shelf life. The samples glazed with RSPH 4% were the most preferred (p < 0.05) fillets, followed by the RSPH 2, 1, and 0.5% and GVC (p > 0.05). In conclusion, glazing with RSPH resulted in significant stability of biochemical characteristics and showed better sensory assessment.