Effect of freezing and thawing on the flesh quality of cultured carp（Cyprinus carpio）during storage in ice

摘要

To elucidate the effect of freezing and thawing on the flesh quality of the cultured carp (Cyprinus carpio) during storage in ice, we examined the changes in ATP related compounds (K values %), expressible water (%), breaking strength (N/cm2) and histological observation. During storage in ice, the increasing speed of K value in the freeze-thawing group was 1.6-fold higher than the unfrozen group. In addition, the rate of expressible water in the freeze-thawing group was higher than the unfrozen group through the storage period, implying that the ice crystals produced by frozen were melted and effluxed to extracellular space. The breaking strength after freezing and thawing was lower than that of the unfrozen. Although the breaking strength of the unfrozen group was decreased with storage in ice, the breaking strength of the freeze-thawing group remained at low level until the end of storage period. These results suggest that the freezing and thawing processes deteriorate the flesh quality through the increase in the incresing ratio of K value and expressible water, and a decrease in breaking strength.