ABSTRACT
Enzyme activity has been used extensively as an indicator for quality changes in fish and fishery products. Most enzyme indicators are endogenous (i.e., inher ently present in the fish). Postmortem changes, preprocessing and processing methods, particularly freezing, icing, and thawing, can all lead to tissue damage and disruption of such cellular organelles as mitochondria and lysosomes, releas ing several enzymes bound to these structures into the cellular fluid. Thus, cell disruption will increase or decrease the activity of enzymes. The measurement of the rate of change of this enzyme activity is usually done by the estimation of the reaction product(s). Of the various enzymes, ATPase (EC 36.1.8, ATP pyrophospho hydrolase) and lactic dehydrogenase (LDH, L-lactate: NAD oxydo-reductase, EC 1.1.1.27) of the glycolytic pathway and associated ATP breakdown and rigor mortis have been extensively investigated (1).
