Foaming properties of sweet whey solutions as modified by thermal treatment

The influence of thermal treatment on foaming properties of sweet whey solutions was studied. The tests were carried out on solutions of cheese sweet whey powder by a factorial experiment design of two variables, namely treatment temperature and time, at three levels, 75, 80 and 85 °C, and 300, 750 and 1200 s, respectively, with three central points. Selected responses were foam volume, liquid volume in foam, foam forming power and foam stability. The applied thermal treatments modified foam properties in such a way that the foam volume of thermally treated samples was always higher than that of the non-treated samples, with the exception of that treated at 85 °C for 750 s. Stability also behaved in the same way, except the sample treated at 75 °C for 300 s.