Time-Temperature-Tolerance (T. T. T.) of On-Board Frozen Tuna During Subsequent On-Land Frozen Storage with Particular Reference to Commercial Scale Trial-II

-Esimation of T. T. T. of Frozen Tuna Meat Based on ATP-Breakdowns-

Abstract

As described in the preceding paper ¹⁾, there is a demand in the tuna industry from the view point of energy saving for setting up T. T. T. of on-board frozen tuna during on-land frozen storage. Three groups of tuna being composed of three different species, yellowfin (YF), southern bluefin (SB) and bigeye (BE) tuna which had been frozen on-board commercially were further stored experimentally at -40, - 30 and -20°C. K₁ value (one of freshness index for fish) and K₂ value (one of taste component index for fish meat) were used as quality index for T. T. T. decision.
Results are as follows :
Both values of three tunas examined did not change appreciably throughout storage at any temperature of -20, - 30 and -40°C. These findings indicated that T. T. T. of YF and SB was estimated to be 6 months^∗ at least, and that of BE to be 17 months^∗ at least as far as it was judged on bases of K¹⁾ and K₂ values. (Asterisks indicate merely the length of the experimental storage, ac tual T. T. T. therefore, must be longer).