Abstract
Curing skipjack meat in miso (called misodzuke-skipjack) is an effective method for preserving and improving the quality. Changes in the salt concentration and water activity value in skipjack meat were examined at different times during curing in miso. The numbers of general bacteria and psychrotrophic bacteria in the skipjack meat and miso used for curing were counted at different times during the curing period. The curing time for the most appropriate texture was determined. And the pro elonged preservation time and muscle condition of the cured skipjack were investigated by optical microscopy and a sensory test.
Misodzuke-skipjack cured for 10 days was evaluated to have the best condition from the parameters applied in the sensory test. There was no detectable increase in the numbers of general and psychrotrophic bacteria during 30 days of curing. To investigate further proelongation of the storage period, the miso was removed from the misodzuke-skipjack for 10 days, and the skipjack was frozen for 7 days at -20°C. The muscle of the frozen skipjack was then subjected to optical microscopy in comparison with the muscle of the misodzuke-skipjack for 10 days. The structure of the frozen muscle was preserved as well as the muscle of the misodzuke-skipjack. There were no notable differences in various aspects of the taste between the frozen and unfrozen misodzuke-skipjack. These results demonstrate that frozen storage after removing the miso from the misodzuke-skipjack for 10 days was effective for prolonging the preservation time.
