The use of simultaneous 1H & 31P magic angle spinning nuclear magnetic resonance measurements to characterize energy metabolism during the conversion of muscle to meat

In order to investigate the potential of magic angle spinning nuclear magnetic resonance (MAS NMR) in the elucidation of post-mortem metabolism in muscle biopsies, simultaneous 1H and 31P MAS NMR measurements were made continuously on post-mortem (20 min to 24 h) muscle longissimus samples from rabbits. The animals had either been or not been given adrenaline (0.5 mg kg^-1 4 h pre-slaughter) to deplete stores of muscle glycogen. The intracellular pH was calculated from 1H spectra, and the post-mortem rate of formation of lactate was followed and quantified. Comparison of measurements made on muscle samples from rabbits treated with adrenaline with measurements made on muscle samples from untreated rabbits revealed significant effects of adrenaline treatment on both pH (pH24 h = 6.42 vs. pH24 h = 5.60) and formation of lactate (16 mmol g^-1 vs. 65 mmol g^-1). The 31P NMR spectra were used to follow the rate of degradation of ATP and phosphocreatine. The present study clearly shows that MAS NMR has potential for the study of post-mortem energy metabolism.