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

22 23 The aim of this study was to understand the fundamental interactions responsible for 24 aggregation of whey proteins (WPs) at pH 6 and 3 during heating at 140 oC for 30 s in the 25 presence of different acidulants. The conformational changes in the various heat-treated WP 26 dispersions were studied using chemical bond blockers and analysed using differential 27 scanning calorimeter thermograms, polyacrylamide gel electrophoresis and turbidity 28 measurements. Overall, the results indicated that WPs were denatured mainly by disruption 29 of hydrophobic interactions, and that the extent of WP denaturation at pH 3 was affected by 30 the type of acidulant used. The type of acidulant affected the extent of formation of additional 31 high or medium molecular weight aggregates during heating at pH 3, while the types of 32 interactions involved in the formation of such aggregates were affected by the pH at heating. 33 ___________________________________________________________________________ 34 M AN US CR IP T AC CE PT ED ACCEPTED MANUSCRIPT