Yield, physicochemical, and antioxidant properties of Atlantic salmon visceral hydrolysate: Comparison of lactic acid bacterial fermentation with Flavourzyme proteolysis and formic acid treatment

Abstract

This study compares a cost‐effective microbial method, involving lactic acid (LA) fermentation, with the conventional formic acid (FA) treatment and Flavourzyme (FL) enzymatic hydrolysis for valorizing Atlantic salmon processing waste (Viscera). LA and FA processing approaches relied on production (LA) or addition (FA) of organic acids to lower the pH and activate the inherent proteases in these tissues, whereas FL processing was carried out at the optimum conditions for Flavourzyme (37 °C, pH 7.0). Highest protein hydrolysate fraction recovery (∼57%) was seen in LA fermentation, while FA processing resulted in the highest protein levels (∼87%) in the recovered hydrolysate fraction and lowest residual fraction (∼4%). In general, FL processing demonstrated higher Fe(II) chelation (73%) and ferric reducing capacity (27 mM glutathione equivalent) whereas LA‐hydrolysates showed enhanced sacrificial antioxidant properties. Findings from this study would have implications on the application and production of salmon‐based protein hydrolysates, especially, from the perspective of their functionality.