Electrical stimulation, muscle tension and glycolysis in bovine Sternomandibularis

Electrical parameters previously employed to hasten the onset of rigor mortis in carcasses were derived empirically. Various parameters have been studied to determine their relationship to the two-stage fall of muscle pH resulting from stimulation. At any given stimulation period pulse frequency had a considerable effect on the magnitude of the pH fall that occurs during stimulation, the greatest falls, ∼ 0·7 pH units in a 120 sec period, being achieved with 5 to 16·6 pulses. sec(-1). The same total number of pulses delivered at differing frequencies did not produce pH falls of equal magnitude. Variation in pulse shape and polarity caused minor changes. Increased energy levels per pulse increases the magnitude of the pH fall during stimulation. All stimulation parameters tested resulted in the rate of pH fall after stimulation being one and a half times to twice that of non-stimulated muscle. The tension-time curves obtained with lower frequencies (< 10 pulses . sec(-1)) show incomplete summation of pulses with sustained tension. At higher frequencies a complete tetanus develops, while tension falls rapidly soon after achieving the peak tension. The relationship between the mechanical and biochemical responses and the implications for stimulation as a practical processing method are discussed.