Quality attributes of horse mackerel (Trachurus japonicus) during frozen storage as affected by double-glazing combined with theaflavins

This study aims to investigate a new method of glazing for improving the storage quality of frozen horse mackerel. Specifically, this study explored the effect of double-glazing with theaflavins on the quality of horse mackerel stored at -20 degrees C for 28 weeks by comparing with unglazed and those single glazed with theaflavins. Chemical indicators were used to assess deterioration during storage, the water-holding capacity (WHC), weight loss, drip loss, and low-field nuclear magnetic resonance (LF-NMR) were used to analyze the water retention of fish and water migration in tissues. The water retention analysis results showed that double-glazing can maintain higher WHC, T-22 values and lower weight loss, drip loss, T-23 values at the end of storage. Chemical analysis results showed that double-glazing combined with theaflavins was highly effective in maintaining lower TVB-N, FAAs, MDA values, and higher SH, IFI values in frozen horse mackerel, especially theaflavins as inner layer glazed material, perhaps due to the synergistic effect of anti-crushing and antioxidant abilities. Therefore, the double-glazing with TF inner layer was more effective in controlling quality changes of frozen horse mackerel.