Impact of temperature fluctuations on fatty acid composition and nutritional quality of tilapia fillet (Oreochromis niloticus)

In this study, the muscle composition (approximate composition, amino acids, fatty acids) of frozen tilapia fillets undergoing temperature fluctuations (0, 1, 2, 3, 5, 7, 9 times) was simulated for nutritional evaluation using high performance liquid chromatography and gas chromatography. The results showed that moisture (79.5%similar to 81.0%), crude protein (15.8%similar to 18.0%), crude fat (3.2%similar to 4.0%) and ash (0.75%similar to 1.5%) in frozen tilapia fillets did not change significantly during temperature fluctuation (P > 0.05),the seven essential amino acids and polyunsaturated fatty acids decreased with the increase of the number of fluctuating cycles, monounsaturated fatty acids did not change significantly. Eicosapentaenoic and docosahexaenoic acids were decreased with increasing number of temperature fluctuations. It appeared that oxidation processes during temperature fluctuations contributed to the decline in quality of tilapia fillets. In conclusion, the nutritional quality of tilapia is decreased, but it is still a good source of high-quality protein and unsaturated fatty acids. The findings offer choices for consumers freezing food at home as well as a theoretical approach for the transportation and sales of tilapia industrial enterprises.