Effects of super-chilling storage on shelf-life and quality indicators of Coregonus peled based on proteomics analysis

The advantages of super-chilling storage at −2 °C for maintaining the quality of Coregonus peled muscle were investigated using the rigor-mortis index (RM), ATP-related compounds, K-value, muscle hardness, impedance measurement, and total viable count. The results indicated that the softening of fish muscle and increase in K-value were substantially suppressed following storage at −2 °C compared to that at 0 °C. In particular, the hardness of fish muscle stored for 6 days at −2 °C was much higher than that of the samples stored for 2 days at 0 °C. The K-value increased to 81% after 6 days at 0 °C, while increased to 57% at −2 °C. The impedance changed in a biphasic manner throughout the storage period. The initial increase accompanied by the progression of RM was followed by a gradual decrease. However, this decrease was much slower at −2 °C than 0 °C. Furthermore, proteomics analysis demonstrated that the mechanism of fish freshness changes between the two storage temperatures. Differentially abundant proteins between the samples stored at two temperatures were mainly involved in the cellular component and molecular function (GO pathway) as well as collagen digestion (KEGG pathway), which might be related to muscle textural properties. Therefore, super-chilling storage is a possible method for maintaining the freshness of Coregonus peled.