Valorization of Tilapia (Oreochromis niloticus) Wastes (Skin, Head and Viscera) Using Green Processes

Abstract

In the fishery industry, the consumption of residue and fish waste allows effective uses of the potential fish wastes as food additives, such as Omega-3 fatty acids. Oil extraction from tilapia wastes and by-products were carried out by SC-CO2 at 45°C, 250bar for 3h and n-hexane at 45°C, 250rpm for 16h. Hydrolyzing of deoiled tilapia residues were done by subcritical water at 160°C and 190°C. The overall oil yield from SC-CO2 was 34% and 63.5% from n-hexane extraction. A higher proportion of total saturated fatty acids (SFAs) than monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids ( PUFAs) was found in tilapia by-products. The acid content of SC-CO2 for the skin, head and viscera was 5.46, 3.35, 7.19 mgKOH/g and the peroxide value were 1.77, 1.34 and 4.48 meq/kg. The FFA SC-CO2 yields 3.62% skin, 1.79% head, and 4.29% viscera, from n-hexane 3.19% skin, 1.69% head, and 4.44% viscera within a reasonable 1-7%. Hydrolysate values ranged from 2.04±0.01 to 7.44±0.01% of samples. The highest and lowest protein and total sugar content were, 4.42±0.79, 31.28±0.92mg/g and 30.06±4.07, 28.51±0.83mg/g respectively. SC-CO2 and n-hexane are the favored techniques in the valorization of tilapia waste containing substantial bioactive compounds that are essential for human and animal health.