A kinetic model for whey protein denaturation at different moisture contents and temperatures

The denaturation of whey protein samples that had previously undergone heat-treatment for different times at different temperatures and moisture contents was analysed by differential scanning calorimetry (DSC), using the DSC enthalpy as a measure of residual undenatured protein. Data were fitted to first order irreversible or reversible kinetic expressions, and the resulting rate constants were found to increase with both temperature and moisture content. The whole data set was then fitted as a function of time, temperature and moisture content, with rate constants varying according to either Arrhenius or Williams-Landel-Ferry (WLF) kinetics and with selected fit parameters made empirical functions of moisture content. The best fits were obtained using reversible WLF kinetics, which could be further slightly simplified without loss of accuracy. The model provides a platform for single- and multi-objective drying trajectory optimisation with respect to protein denaturation in dairy products.