Relationship between the translocation of paratropomyosin and the restoration of rigor-shortened sarcomeres during post-mortem ageing of meat—A molecular mechanism of meat tenderization

The weakening effect of paratropomyosin on rigor linkages formed between actin and myosin was determined by measuring the restoration of rigor-shortened sarcomeres of chicken, pork and beef. We observed the rate of the post-mortem translocation of paratropomyosin from the A-I junction region of sarcomeres onto the thin filaments in the A-band, where rigor linkages had been formed; this agreed well with the rate of increase in length of rigor-shortened sarcomeres. The sarcomere lengths were found to be maximum at 1, 7 and 10 days post-mortem in chicken, pork and beef, respectively. Thus, translocated paratropomyosin weakens rigor linkages and brings about the recovery in the length of rigor-shortened sarcomeres. Paratropomyosin stimulates the resolution of rigor mortis, and is a key factor in meat tenderization during post-rigor ageing. These results powerfully support the ‘Calcium theory of meat tenderization’ which we have proposed.