2019 Volume 7 Issue 1 Pages 31-37
To clarify whether bovine cardiac muscle tenderizes during aging of meat in the same manner as skeletal muscle, we investigate the textural changes and the changes of myofibrillar proteins during postmortem aging. The shear force values and storage modulus became the hardest at 6 to 12 hours postmortem, after which bovine cardiac muscle tended to be tendered at 1 day postmortem. At 6 hours postmortem, sarcomere lengths of bovine cardiac muscle were shortened to 1.69 μm, and then recovered to 1.89 μm at 24 hours postmortem. From the results of rheological and structural data, we consider that bovine cardiac muscle reaches completion of rigor mortis at 6-12 hours postmortem and then resolves the rigor shortening at 24 hours postmortem. The degree of myofibrillar fragmentation index (MFI) in the bovine cardiac muscle increased to 0.3 at 2 days postmortem; this degree was lower compared with that in skeletal muscle. SDS-PAGE analysis and western blotting analysis showed that troponin-T, which is a marker of meat tenderization, was not degraded among the myofibrillar proteins during postmortem storage. We conclude that postmortem change in bovine cardiac muscle was induced, but such change was different from that in skeletal muscle.
