1985 年 2 巻 1 号 p. 35-43
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).