Action of NaCl and polyphosphates in meat processing: Responses of myofibrils to concentrated salt solutions

When meat is treated with salt, some parts of the meat are exposed to very high salt concentrations which then fall during equilibration. To gain a better understanding of the consequences of this treatment, we have observed the swelling and extraction of isolated myofibrils treated with series of salt solutions designed to mimic conditions found in salt-treated meat. Myofibrils swelled most in 1m (5·8%) NaCl and hardly at all in 5m (29%) NaCl. Similar results were obtained when the concentration of NaCl was raised in steps to 5m. The pronounced extraction of the A-band that occurs in 1m NaCl was decreased if higher NaCl concentrations were used instead. Lowering the concentration from higher values to 1m caused some swelling and extraction of the A-band, but not as much as when 1m was used directly. Inclusion of pyrophosphate in the solutions had marked effects. There was little swelling in 1m NaCl and none in 5m. Lowering the NaCl concentration to 1m from higher concentrations gave more swelling than observed when 1m was used directly. Extraction of the A-band was greatest in 1m, and was strongly inhibited in 5m. Myofibrils treated with 5m NaCl lost the ability to respond to the presence of pyrophosphate in 1m NaCl. The behaviour of myofibrils in high concentrations of NaCl alone is similar to that of pieces of meat. However, the persistent swelling of meat when the NaCl concentration is slowly raised to 5m is not found with myofibrils, suggesting that significant water compartments exist outside the myofibrils in such meat.