Influence of heat and pH on structure and conformation of whey proteins

The aim of this study was to understand the fundamental interactions responsible for aggregation of whey proteins (WPs) at pH 6 and 3 during heating at 140 °C for 30 s in the presence of different acidulants. The conformational changes in the various heat-treated WP dispersions were studied using chemical bond blockers and analysed using differential scanning calorimeter thermograms, polyacrylamide gel electrophoresis and turbidity measurements. Overall, the results indicated that WPs were denatured mainly by disruption of hydrophobic interactions, and that the extent of WP denaturation at pH 3 was affected by the type of acidulant used. The type of acidulant affected the extent of formation of additional high or medium molecular weight aggregates during heating at pH 3, while the types of interactions involved in the formation of such aggregates were affected by the pH at heating.