Effects of different reheating methods on lipid oxidation in frozen silver carp fish cakes

This study investigated the effect of five different reheating methods (boiling water, steaming, low-heat microwave at 120 W, medium-heat microwave at 400 W, high-heat microwave at 800 W) on lipid oxidation of silver carp fish cake. The changes of lipid content, thiobarbituric acid (TBA) value, acid value (AV), peroxide value (POV), volatile flavour components and fatty acid composition were detected. The results indicated that products reheated with medium-heat microwave had higher lipid content, lower TBA, AV and POV value. The medium-heat and high-heat microwave reheated group had larger variety of volatile flavour substances. Moreover, the relative content of hexanal and heptanal related to unpleasant “overcooked taste” was less, and the relative content of 2-heptanone, which contributed to the reduction of fishy odour, was more in medium-heated microwave group. The content of monounsaturated fatty acids in the medium-heat microwave group was higher than other reheating methods, so as the ratio of unsaturated to saturated fatty acids. Considering all indicators, medium-heat microwave reheating is more recommended due to its inhibition of fat oxidation.