Abstract:In order to reduce the quality deterioration of perch fillets during freezing, the effects of air freezing (groups AF-7, AF-20, AF-40, AF-60), immersion freezing (groups IF-20, IF-40), and liquid nitrogen freezing on the quality of perch fillets were discussed. Quality-related indicators including ice crystal structure, microstructure, texture, thawing loss, moisture distribution, total volatile base nitrogen (TVB-N), K-value, and others were analyzed for samples subjected to different freezing methods. The results showed that as the freezing rate increased, the hardness and elasticity showed an upward trend, while the ice crystal equivalent diameter, TVB-N, and K-value tended to decrease. Although quality deterioration was observed across different treatment groups, the liquid nitrogen freezing group and the IF-40 group effectively preserved the quality characteristics of perch fillets, with the liquid nitrogen freezing group most closely resembling the fresh sample group. Under the same freezing temperature, immersion freezing achieved a faster freezing rate than air freezing, effectively inhibiting ice crystal growth and reducing changes in texture, TVB-N, and K-value. In comparison, liquid nitrogen freezing proved most effective in alleviating quality deterioration of perch fillets during freezing.
