Main chemical changes are the result of changes in composition due to water loss and salt penetration. The diffusion of water through the ham and its evaporation when reaching the surface is a slow and difficult process. Both rates must be equilibrated to achieve adequate drying and, in this sense, it is very important to have the water sorption isotherms to predict the required time for drying. Diffusion of salt is also very slow and is affected by many variables such as temperature, size of the ham, pH, amount of moisture, and intramuscular fat. It takes around 4 months to get full salt equalization through the entire piece, although the salt profile may change a little depending on the particular moisture content in each muscle. pH increases from initial values of around 5.6-5.8 to values near 6.4 toward the end of the process. PSE hams have a pH evolution similar to normal ones (8,23). This evolution constitutes a narrow range where all the enzymes and chemical reactions operate (24). However, even slight variation in pH might affect the action of muscle enzymes; for example, more intense proteolysis has been reported in low-pH hams (25).
Was this article helpful?