Post-mortem biochemical changes in the muscle to tanner crab during storage

The changes in contents of glycogen, glycolytic metabolites, ATP-related compounds, free amino acids, polyamines, and volatile basic nitrogen (VBN) were investigated in the leg muscle of tanner crab during storage at 5, 0, and -1°C in relation to freshness. During storage, glycogen decomposed and lactate accumulated rapidly. Lactate reached its maximum level at the time when glycogen disappeared and later decreased at the stage of initial decomposition. As ATP decreased, inosine (HxR) together with IMP increased. The level of hypoxanthine (Hx) was low at the acceptable stage, but it increased rapidly at the stage of initial decomposition when both IMP and HxR degraded markedly. Ornithine (Orn) increased gradually during storage and formed noticeably as decomposition progressed. VBN also increased gradually during storage and reached a level of 24-28mg/100g at the stage of initial decomposition regardless of storage temperatures. Xanthine and cadaverine were absent at the acceptable stage and produced in small amounts at the stage of initial decomposition. From these results, Hx, Orn, and VBN seemed to be useful as potential indices for the fresh-ness of tanner crab.