Effect of pasteurisation and foaming temperature on the physicochemical and foaming properties of nano-filtered mineral acid whey

Foaming can pose a major challenge during processing of acid whey (AW). In this study, nano-filtered mineral AW was collected from a commercial plant before (AW(0)) and after pasteurisation (AW(past); 75 degrees C, 15 s). Both AW samples were foamed at 21 degrees C and in addition, AW(past) was foamed at 61 degrees C, corresponding to the temperature of in-plant foaming. Physicochemical, foaming, and surface properties of AW samples were compared. Foaming at 21 degrees C resulted in less pronounced foam characteristics for AW(past) compared with AW(0). Pasteurisation was found not to significantly affect physicochemical properties; however, interfacial kinetics during foaming were altered, which affected foaming behaviour. Foaming of AW(past) at 61 degrees C produced more stable, "dry" foams. FTIR spectra confirmed the influence of protein unfolding at elevated temperatures on foaming, which was reversible upon cooling. This is significant as it gives processors a mean of controlling foaming through temperature control, where possible. (C) 2022 Elsevier Ltd. All rights reserved.