PHYSICAL PROPERTY OF CARP MUSCLE DURING RIGOR TENSION GENERATION

The effects of rigor tension generation on the postmortem tenderization process of fish muscle was investigated by measuring the breaking strength, creep and recovery properties. The postmortem time range of the sharp decrease in breaking strength of stressed and unstressed carp muscle coincided with the time required for a rigor tension peak to occur. The temporary increase of breaking strength and the minimum compliance were detected at the onset of tension generation, and these values in stressed fish muscle were similar to those in unstressed muscle, irrespective of their widely different peak tensions detected later than the onset of tension generation. In stressed fish muscle, the breaking strength decreased more sharply with postmortem time and reached a minimum value lower than that of the unstressed muscle. The stressed fish muscle generated rigor tension at a much earlier postmortem time, and the tension was twice that generated by the unstressed. It was supposed that the physical restraint of muscle structure opposed the tension but that the structure could not remain intact as the tension increased. The structure of stressed fish muscle was partially broken down and weakened significantly due to larger tension.