Low voltage electrical stimulation and post-mortem energy metabolism in beef

In the present study, the influence of low voltage electrical stimulation on glycolysis, concentrations of creatine phosphate and adenine nucleotides, as well as the relationship between metabolic activity and tenderness, was examined in bovine M. longissimus dorsi. During stimulation, about 50% of the creatine phosphate was consumed and the immediate pH drop was, on average, 0·21 units. The increased energy consumption resulted in a decrease in the halftime of ATP from 10 h in non-stimulated muscles to 5 h in electrically stimulated muscles. The total high energy phosphate turnover was found to be 2400 μmol/h/g during stimulation and 18 μmol/h/g immediately following stimulation compared with 9 μmol/h/g for the non-stimulated counterpart. No obvious abnormalities were found in the course of changes during energy metabolism following stimulation, besides the increased metabolic rate. Significant relationships were found between the degradation of several of the energy metabolites during stimulation and improvements in tenderness. It is concluded that, within the variation found in this study, the better the effect of electrical stimulation in increasing the metabolic rate, the better the resulting meat tenderness. Results also showed that the higher the shear force in the non-stimulated part, the better was the effect of electrical stimulation in improving the meat tenderness.