Solutions of a whey protein mixture were subjected to various time/temperature treatments, at pH 6.7. Kinetic and thermodynamic activation parameters for the rates of irreversible denaturation/aggregation of the principal whey protein component-beta-lactoglobulin (beta-1g) were followed by gel permeation. Fast Protein Liquid Chromatography (non-dissociating, non-reducing conditions) and by SDS-PAGE (dissociating, non-reducing conditions). The rate of loss of native beta-1g owing to the formation of disulphide linked protein aggregates (k(SDS-PAGE)) and the rate of formation of aggregates via both covalent and non-covalent bonds (k(GP-FPLC)) showed similar biphasic Arrhenius plots. However, the break of the plot occurred at different points. The k(GP-FPLC) Values were higher than values of k(SDS-PAGE) for all the temperatures examined. There was a similar trend for the thermodynamic activation parameters implying that not all of the beta-1g aggregates through thiol-disulphide interactions. Hydrophobically driven associations occur within the aggregates.
|Journal||International Journal of Food Science and Technology|
|Publication status||Published - Oct 1999|