Structural changes in beef muscle during ageing

The ageing of beef muscle set in rigor mortis while restrained at twice its resting, excised length has been examined. Ageing leads to opening of gaps between the A and I bands of the sarcomere. With the shrinkage of both bands during cooking, the gaps become the major feature of the sarcomere and develop within the tenderising time‐scale. As such they represent the most distinct structural change yet encountered to explain the phenomenon of ageing. A possible reconciling of the contradictory views of ageing—splitting at the A–I junctions and decay of Z lines—is discussed.