Kinetics of Thermal Denaturation of Protein in Cured Pork Meat

Abstract

Thermal denaturation of protein in cured pork meat that contains different amounts of sodium chloride (NaCl) was analyzed using differential scanning calorimetry (DSC). Three endothermic peaks that correspond to myosin, sarcoplasmic proteins and collagen, and actin were affected by the curing process. Denaturation of actin occurred at a lower temperature in line with the increase in the amount of NaCl in the meat sample. In addition, the endothermic peak of myosin disappeared when the NaCl level exceeded 20 mg/g. The influence of the NaCl level on the kinetic constant of protein denaturation and temperature dependency were studied using the DSC dynamic method. As the level of NaCl in the meat increased, the thermal-denaturation rate constant of each protein increased. Especially, the rate constant for actin increased remarkably, e.g. rate constant at 70℃ increased from 0.1 min⁻¹(2 mg/g of NaCl) to 1.75 min⁻¹(40 mg/g of NaCl). Using both the averaged activation energy of each protein (Myosin: 2.41×10² kJ/mol, Sarcoplasmic proteins and Collagen: 3.26×10² kJ/mol, Actin: 2.50×10² kJ/mol) and the empirical equations that represent NaCl dependency of pre-exponential factor in Arrhenius equation, denaturation rate constant at arbitrary temperature was able to be obtained.