Studies on prolongation of pre-rigor period of fish. I. Relation between rigor mortis of sea bream and storage temperatures.

Abstract

Influences of storage temperatures on the prolongation of pre-rigor period of sea bream Pagrus major were examined. The amounts of ATP in the muscle of sea bream decreased more rapidly and rigor mortis proceeded faster at 0°C than at 10°C. In the muscle stored at 10°C the onset of rigor mortis occurred seven hours later than at 0°C. The formation of lactic acid in the muscle of sea bream was parallel with the development of rigor mortis, i.e., the large amounts of ATP supplied through glycolysis were considered to be used as the contraction energy. K value as the index of freshness at 10°C was twice as high as at 0°C, however, after 48h of storage at 10°C it was below 10% which is thought to be very fresh. The production of inosinic acid during the storage at 0°C was more prompt than at 10°C. The decrease in ATP amounts was also examined in the muscle of plaice Paralichthys olivaceus stored at -3°C, 0°C, 5°C and 10°C. At -3°C and 0°C ATP decomposed very rapidly, followed by 5°C and most slowly at 10°C.