Changes in ATP-related compounds of beef and rabbit muscles and a new index of freshness of muscle.

Abstract

To establish an index of the freshness of meats, we examined the changes in amount of ATP-related compounds in beef and rabbit muscle kept in cold storage. We found an accumulation of hypoxanthine (Hx) and xanthine (X) in beef on the one hand and the accumulation of inosine (HxR) in rabbit muscle on the other. We inferred that this difference was caused by the outstandingly high level of activity in beef of nucleoside phosphorylase having HxR as substrate. The speed at which IMP decreased was greater in beef than in rabbit muscle.From these results we have come to the conclusion that such indexes of the freshness of fish meats as the K value, K1 value, IMP ratio, HxR ratio, and Hx ratio are not adequate to indicate the freshness of animal meats and that the K0 value, defined below, is the most effective. The distinctive merit of the K0 value is that it is applicable not only to animal meats and fish but also to marine invertebrates and crustaceans. K0 = (HxR + Hx + xanthine(X))/(ATP+ADP+AMP+IMP + adenosin...