Freshness changes of ready-to-eat raw tuna fillets at different cold storage temperatures

The changes of cooling storage quality of thawing raw-eaten yellowfin tuna steaks in 0, 2, 4, 6 and 8℃were systematically studied. The raw-eaten endpoint of every cooling storage temperature was taken as 20% (K value) . In the process of cooling storage, the K value and p H were tested to evaluate the quality to achieve the law of quality change. In the cooling storage of yellowfin tuna sashimi, the content of ATP decreased quickly, ADP and AMP decreased slowly, IMP had a trend of accumulation, the accumulation of Hx R was large and the yellowfin tuna was a fingerling producing Hx R. There were no significant differences of p H in the cooling storage, and p H was not suitable to judge the small changes of freshness when the raw- eaten yellowfin tuna steaks had a very high quality. The dynamic model of ready-to-eat raw tuna fillets cooling storage on the K value with time was built. The model was according to the first kinetics equation. The influences of cooling storage temperature on reaction rate constant were described by Arrhenius equation, which had a higher fitting precision.