Enzymatic Hydrolysis of Fish Waste as an Alternative to Produce High Value-Added Products

Abstract

Fish waste was studied as a raw material for the simultaneous production of protein hydrolysates, collagen and fish oil. Enzymatic hydrolysis was selected for recovering these by-products with high value-added. Alcalase 2.4 L was used to hydrolyze fish waste in a batch reactor under controlled conditions (180 min, 50 °C and pH 8). The influence of hydrolysis degree on by-products recovery was analyzed for different enzyme and substrate concentrations. Results suggested that the enzyme/substrate ratio was the main factor controlling the hydrolysis rate. Linear relationships were found between the degree of hydrolysis and the amount of each of the obtained by-products. From these relationships, the amounts of by-products with high added value can be predicted by only knowing the degree of hydrolysis reached. In optimal conditions (DH = 25%), 430 g of protein hydrolysate, 10 g of collagen and 350 g of oil could be obtained from 1000 g of fish waste. The use of fish waste as raw material for by-product fabrication resulted in a 79% reduction of waste disposed to landfill. Therefore, this study shows the enzymatic hydrolysis of fish waste as a feasible solution to obtain high value-added products and an alternative to landfilling disposal.