High post-mortem temperature combined with rapid glycolysis induces phosphorylase denaturation and produces pale and exudative characteristics in broiler Pectoralis major muscles

This study investigated the effect of early post-mortem temperature on broiler protein characteristics and meat quality. Muscles were kept at different temperatures (0, 20 and 40 °C) until 4. h post-mortem and then stored at 4 °C. Rapid degradation of ATP and glycogen, thus inducing a high rate of lactate formation and pH drop, were found in the 40 °C group during incubation. When extracting proteins, a lower protein content of the sarcoplasmic fraction and a higher protein content of the myofibrillar fraction were found in the 40 °C group at 24. h post-mortem; SDS-PAGE and western-blotting results revealed that phosphorylase was associated with the myofibrillar fraction. Furthermore, the 40 °C group had paler surfaces, higher drip loss and lower processing properties. These data suggest that elevated temperature during early post-mortem period, resulting in rapid glycolysis, induced phosphorylase denaturation and association with myofibrillar proteins thus generating pale and exudative characteristics. © 2011 Elsevier Ltd.