Effect of Postmortem Storage on Cold-Shortened Bovine Muscle: Analysis by SDS-Polyacrylamide Gel Electrophoresis

Myofibrils were isolated from the longissimus (L) muscle of control (CON) and cold-shortened (CS) muscles after 0, 1, 3, 7, and 10 days of postmortem storage at 2°C. Isolated myofibrils were then examined by SDS-polyacrylamide gel electrophoresis to monitor the changes in the myofibrillar proteins during postmortem storage. The main changes in CS muscles were the gradual appearance of 110,000-, 95,000-, and 30,000d-dalton components and the disappearance of desmin and troponin-T components of myofibrils. In addition, there was a gradual increase in the intensity of a protein around 55,000-daltons. CON samples showed similar changes to those of CS samples. It appears that myofibrillar proteins of cold-shortened muscles are affected by postmortem aging in a manner similar to that of the normally chilled muscles.