Building phenomenological models that relate proteolysis in pork muscles to temperature, water and salt content

• Five different types of pork muscle were investigated: SM, BF, ST, RF and GM.
• We implemented response surface methodology coupled to a Doehlert design.
• Proteolysis index was correlated positively with temperature and water content.
• Proteolysis index (PI) was correlated negatively with salt content.
• We built phenomenological models relating PI to temperature, water and salt content.

Throughout dry-cured ham production, salt and water content, pH and temperature are key factors affecting proteolysis, one of the main biochemical processes influencing sensory properties and final quality of the product. The aim of this study was to quantify the effect of these variables (except pH) on the time course of proteolysis in laboratory-prepared pork meat samples. Based on a Doehlert design, samples of five different types of pork muscle were prepared, salted, dried and placed at different temperatures, and sampled at different times for quantification of proteolysis. Statistical analysis of the experimental results showed that the proteolysis index (PI) was correlated positively with temperature and water content, but negatively with salt content. Applying response surface methodology and multiple linear regressions enabled us to build phenomenological models relating PI to water and salt content, and to temperature. These models could then be integrated into a 3D numerical ham model, coupling salt and water transfers to proteolysis.