Kinetics of the irreversible thermal denaturation and disulfide aggregation of α-lactalbumin in milk samples of various concentrations

alpha -lactalbumin denaturation was first order and was virtually unaffected by milk solids concentration, with a similar denaturation rate at all the concentrations for each temperature investigated. Similarly, disulfide aggregation of alpha -lactalbumin was first order and unaffected by milk solids concentration. Only about 70% of the denatured alpha -lactalbumin was involved in disulfide-aggregated complexes with other denatured whey proteins or with the casein micelles. Calculated thermodynamic parameters (activation energies, enthalpies of activation, entropies of activation and free energies of activation) for irreversible denaturation and for disulfide aggregation were similar for all milk concentrations.