Sensitivity of ultimate meat pH to initial metabolite
concentration when glycogen is not limiting
I. Vetharaniam and C.C. Daly
AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton,
New Zealand
Proceedings of the New Zealand Society of Animal Production.
2000 60: 120-123
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 pre-slaughter physical
exertions, while variation in muscle buffer concentration may be
genetically linked.
Keywords: NZSAPAB;
Meat ultimate pH, initial metabolite concentration, glycogen,
pre-slaughter stress
Last Updated 12-07-2000
