A review of the kinetics of degradation of inosine monophosphate in some species of fish during chilled storage

A literature search was made for data on the concentrations of inosine monophosphate (IMP) and its degradation products, inosine (Ino) and hypoxanthine (Hx), in the flesh of vertebrate fish during storage in ice. Twenty-one publications containing data for forty-five species were selected for review. A mathematical model was developed for analysing the data by assuming that the kinetics of degradation of IMP could be modelled as consecutive first order reactions. The model was fitted to the data and in about half of the cases examined in the review the data suggested that IMP and degradation products were lost by leaching and the kinetic model was extended to allow for this loss. In all of the cases reviewed the mathematical model was a good fit to the experimental data and the reaction rates for the reactions are tabulated in the paper. In all species the concentration of IMP decreased as a first order reaction, but for thirteen of the species examined the enzyme model of IMP to Ino to Hx did not fit the data in that either Ino or Hx did not accumulate in the muscle. There were only a few examples of replications of storage trials within species and comparison of the outcomes of these replications suggested that season or, in the case of farmed fish, genetic stock or cultural practices might influence initial IMP concentrations or reaction rates.