漁獲物の生きの保持に関する研究 ＩＩＩ 二，三海産魚における死後硬直の進行と貯蔵温度の影響

Abstract

Yellowtail, bartailed flathead and Japanese striped knifejaw were spiked at the brain, and stored at O°and 10°C. Yellowtail set in rigor-mortis after 2h, irrespective of storage temperature, attaining the full-rigor state after 7h at O°C and 15h at 10°C. Rigor-mortis of bartailed flathead started after 10h at O°C and 13h at 10°C. This species reached the full-rigor state after 20h at O°C and 40h at 10°C. In the case of Japanese striped knifejaw, rigor-mortis began to appear immediately after killing at O°C whereas after 4h at 10°C. The full-rigor state was attained with this fish after 13 and 20h, respectively, in the above order of storage temperature. Therefore, rigor-mortis proceeded roughly two times slower at 10°C than at O°C, regardless of fish species. In accordance with rigor-mortis progress, the muscle of each species showed a 2-3 times slower decrease of ATP concentration when stored at 10°C than when stored at O°C. Disappearance of creatine phosphate preceded that of ATP while lactate accumulation was nearly maximal when ATP disappeared, irrespective of fish species and storage temperature. No marked differences in initial ATP concentration were observed among the fish species examined. The highest lactate level was encountered in yellowtail which exhibited the fastest progress of rigor-mortis at either storage temperature. Japanese striped knifejaw showed a much lower accumulation of lactate than yellowtail, the accumulation of which was even lower than that in bartailed flathead. On the other hand, rigormortis progress of Japanese striped knifejaw was comparable to that of yellowtail and somewhat faster than that of bartailed flathead.