Effects of Green Tea Polyphenols on Rigor Indexes and K Value of Yellowtail (Seriola quinqueradiata) during Ice Storage

Effects of green tea polyphenols (GTP), which contain (+) -catechin, (-) -epicatechin, (-) -gallocatechin, (-) -epigallocatechin, (-) -gallocatechin gallate, (-) -epicatechin gallate and (-) -epigallocatechin gallate, on rigor indexes of fish body and K values of meats in the cultured fish during round ice storage were investigated. The moist pellets supplemented with different concentrations of GTP (0, 0.02 and 0.2%) were fed to young yellowtails (Seriola quinqueradiata) of 0 (zero) -year fish. These fish were killed on the 2nd week after feeding of the moist pellets. The rigor indexes of fish body were not effected very much by GTP feeding during rigor mortis was perfected and kept up, but the decrease of them after starting of rigor resolution was slower than control group of GTP no feeding. However, the dose of supplemented GTP in the moist pellets did not show significant difference between test groups. On the changes in K values of fish meat during ice storage, there were no differences among three groups. Therefore, it was thought that the enzymatic reactions of ATP metabolism after killing fish might be not affected very much on either inhibition or acceleration by GTP feeding. Thus, it was concluded that GTP feeding would be useful for maintaining freshness of cultured fish during storage or delivery.