The study aimed to evaluate the extent of hydrolysis on the functional properties of fish protein hydrolysates from fish wastes. Fish protein hydrolysate (FPH) was prepared from the visceral waste of Rohu (Labeo rohita) using Alcalase®. Independent variables of the hydrolysis conditions, namely, time, temperature and enzyme-substrate ratio were optimized through response surface methodology using a completely randomized factorial design. Functional properties of FPH, such as antioxidant activity, metal chelating activity, emulsifying and foaming capacity were studied. Pre-heating of the raw viscera resulted 83% reduction of lipid content in the FPH. The DH was found to be significantly influenced by the hydrolysis conditions studied. The gel electrophoretic study showed that FPH contained peptides in the range of < 10-25 kDa. Optimum degree of hydrolysis (DH) was obtained as 34.7% at 87.5 min, 48.64 °C and enzyme concentration of 0.99%. The results demonstrated that the antioxidant and metal chelating properties of FPH increased with the increase of DH. The surface active properties like emulsifying and foaming capacity were found to be decreased with the increased levels of hydrolysis. These results suggest that hydrolysates from visceral waste of Rohu could find potential use as supplement in animal feed.
Keywords: Alcalase®; Antioxidant activity; Degree of hydrolysis; Fish protein hydrolysates; Fish visceral waste.
© Association of Food Scientists & Technologists (India) 2020.