Hydrolysis and oxidation of lipids in mussel Mytilus edulis during cold storage

Change in quality of mussels (Mytilus edulis) meat when stored at 4 °C was evaluated by determining volatile basic nitrogen (TVB-N), peroxide value (POV), thiobarbituric acid reactive substance (TBARS), total oxidation (TOTOX), lipid class, fatty acid (FA), phosphatidylcholine (PC) and phosphatidylcholine (PE) content, and glycerophospholipid (GP) molecular species. After 4 days of storage, the percentages of triacylglycerol and polar lipid as well as the contents of PC, PE and major GP molecular species significantly decreased (P < 0.05), while the percentages of free FA and monoacylglycerol significantly increased (P < 0.05), indicating the hydrolysis of lipids. The increase in activities of phospholipase and lipase during storage suggests that they may contribute to the hydrolysis of lipids. The cold storage also resulted in significantly increased POV, TBARS and TOTOX as well as lipoxygenase activity (P < 0.05) but slightly decreased percentage of polyunsaturated FA (PUFA), indicating the occurrence of lipid oxidation.