Effects of packaging method and temperature on the quality and lipid degradation of snakehead fish fillets during frozen storage

Temperature and packaging method are considered the main factors affecting the quality of fishery products during frozen storage. In the present study, snakehead fish fillets were air (AP) and vacuum (VP) packaged and stored at -20±2°C and -25±2°C for six months to investigate the effects of temperature and packaging method on the quality of snakehead fish fillets. Changes in the quality of snakehead fish fillets were assessed by determinations of lipid hydrolysis, lipid oxidation, and their resulting changes in colour, cooking yield (CY), and total volatile basic nitrogen (TVB-N) content. Storage temperature and packaging method showed strong preservative effects on the quality of snakehead fish fillets. Higher cooking yield and lower TVB-N content were observed in the VP samples stored at -25±2°C compared to the AP samples and stored at -20±2°C. Vacuum packaging and lower storage temperature (i.e. -25±2°C) significantly retarded lipid hydrolysis and lipid oxidation development. This resulted in lower free fatty acid (FFA), lipid hydroperoxides (PV), thiobarbituric acid-reactive substances (TBARS) values, and higher phospholipid content. Significant correlations between lipid oxidation products (PV and TBARS) and yellow discolouration (b* values) were found in this study. Based on these findings, it could be suggested that frozen snakehead fish fillets should be vacuum-packaged and stored at low temperatures to maintain their quality.