Abstract

The causes of variations in the ultimate pH of meat under conditions in which glycogen is in excess are considered using a model of energy metabolism in the post-mortem period. A key component of the model attributes the inhibition and ultimate cessation of glycolysis to the accumulation of lactate (which inhibits the regeneration of NAD+ via the lactate dehydrogenase reaction) rather than acidosis. The initial concentrations (concentrations at slaughter) of creatine phosphate, ATP, lactate, and also the buffering capacity of the muscle tissue are shown to affect the ultimate pH. The ultimate pH was particularly sensitive to initial lactate concentration and muscle buffer concentration such that increases in either resulted in an increase in ultimate pH. Variations in the initial conditions of muscle metabolites are attributed primarily to preslaughter physical exertions, while variation in muscle buffer concentration may be genetically linked.

I, Vetharaniam, and CC Daly

Proceedings of the New Zealand Society of Animal Production, Volume 60, Hamilton, 120-123, 2000