Effect of Temperature Fluctuation on Chemical Index and Water Holding Capacity of Salmon in Frozen Storage

In the short-term frozen storage, in order to improve the frozen storage temperature of salmon, reduce the energy consumption and operation cost of frozen storage. The effects of temperature fluctuation on TVB-N value, TBARS value, K value and water holding capacity of salmon were studied under the frozen storage environment at −18 ℃ during the frozen storage period (6 months), and compared with the frozen storage quality at (−50±0.1) ℃. The results showed that: the initial values of TVB-N, TBARS, K value and water holding capacity of salmon were 6.21 mg N/100 g, 0.11 mg MDA/kg, 9.87% and 86.31%, respectively. The TVB-N values increased to 19.06, 23.25 and 25.91 mg N/100 g, TBARS values increased to 1.65, 1.89, 1.96 mg MDA/kg, K values increased to 43.28%, 55.38%, 63.54%, and water holding capacity decreased to 57.16%, 53.49% and 51.67%, respectively after frozen for 6 months at (−18±0.5), (−18±1) and (−18±2) ℃, which indicates that the greater the temperature fluctuation, the more significant the increase in chemical indicators, and the more obvious the drop in water holding capacity. By reducing the temperature fluctuation to ± 0.5 ℃, the frozen storage temperature of salmon can be effectively increased to −18 ℃ within 3 months, and the TVB-N value, TBARS value, K value and water holding capacity of salmon can be ensured to be equivalent to those of salmon frozen at (−50±0.1) ℃ for 6 months, so as to save cost and reduce energy consumption. Taking the frozen storage time and temperature fluctuation as independent variables and water holding capacity as dependent variables, a multiple linear regression fitting equation was established to provide a basis for shelf life prediction.