Foaming properties of white wheat flour-yoghurt mixture as affected by fermentation

Effect of fermentation on the foam stability (FS) and overrun (O) of a whit e wheat hour-yoghurt mixture was investigated using response surface method ology with concentration (0.5-1.5%, w/v) and whipping time (30-120 s) being the independent variables. Regression equations for predicting the FS and O were developed. Results suggest that concentration had the most pronounce d effect on the overrun while concentration and whipping time were both eff ective on foam stability. Response surface plots suggest that fermentation causes a decrease in the overrun, possibly resulting from the change in the structure of protein due to breaking down of molecules into small nitrogen ous molecules as a result of fermentation. Fermented sample has a better fo am stability (i.e., 8.0 +/- 0.1 min) than unfermented control sample (i.e., 5.0 +/- 0.1 min) at the same concentration and whipping time. (C) 1999 Aca demic Press.