Lipid class and fatty acid composition of oil extracted from Atlantic salmon by-products under different optimization parameters of enzymatic hydrolysis

Abstract Six operational parameters, including fish part, antioxidant use, water addition, enzyme types, enzyme concentration and hydrolysis time, were studied about their effect on nutritional composition of oil enzymatically extracted from farmed Atlantic salmon by-products. Compared to the oil extracted from salmon viscera, the oil extracted from mixture of salmon heads and frames had higher amounts of triacylglycerols (TAGs), omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and lower amounts of omega-6 PUFAs. The interaction between water and high levels of hydrolysis time (4 h) or enzyme concentration (1%) resulted in decreased TAG content, increased content of phospholipids (PLs) and increased omega-6 PUFA content. The addition of antioxidant significantly increased the average content of omega-6 PUFAs, but decreased EPA and DHA amounts in viscera oil due to the pro-antioxidant activity of ascorbic acid. The use of Alcalase, Flavourzyme or SEBPRo didn't result in any significant difference in oil composition under studied conditions. The negative correlation between amounts of TAG and free fatty acid (FFA) indicates that the increase of FFA content resulted in the decrease of TAG content, mainly due to the oxidation of TAG promoted by FFAs.