Effect of Ice Storage on the Chemical Composition and Lipid Quality in Fat Greenling (Hexagrammos otakii) and Black Rockfish (Sebastes schlegelii)
The effect of ice storage on the chemical composition of fat greenling and black rockfish, especially their lipid quality were evaluated. Both physical and biochemical changes occurred during ice storage, resulting in increased moisture content, free fatty acid (FFA), acid values (AV), peroxide values (POV), thiobarbituric acid values (TBARS), and increased activities of lipases and lipoxygenase. Decreases in the ash, protein, phosphatidylcholine (PC), phosphatidyl ethanolamine (PE), triacylglycerol (TAG), and fatty acid contents were also observed. The decreased PC, PE, and TAG values, together with the increased amount of AV and each FFA as well as lipases activity indicated the hydrolysis of lipids induced by lipases. In addition, the increased POV and TBARS as well as lipoxygenase activities, together with the decrease in the fatty acid contents, point to the lipoxygenase-assisted oxidation of lipids. Based on the increase rate of the total volatile basic nitrogen and FFA as well as the decreased rate of the PC, PE, TAG, saturated, monounsaturated, and polyunsaturated fatty acids during ice storage, black rockfish was more prone to spoilage, less sensitive to hydrolysis, and more sensitive to oxidation compared to fat greenling.