FUNCTIONALITY OF WHEY AND CASEIN IN FERMENTATION AND IN BREADBAKING BY FIXED AND OPTIMIZED PROCEDURES

The effects of 4% dairy ingredients on dough absorption and mixing tim e, parameters of fermentation, loaf volume, and bread characteristics were determined. Dairy ingredients, generally, increased water absorpt ion and decreased mixing time. The decrease in mixing time was to some extent reversed by heat treatment (at 80 or 95 degrees C) of nonfat d ry milk (NFDM), casein, or whey. Dialysis of whey did not improve its poor mixing stability. Untreated dairy ingredients lowered the dough h eight at maximum development time (H-m, measured by the Rheofermentome ter). The drop was reversed by heat treatment or dialysis. H-m was pos itively correlated (r = 0.87) with time of H-m (T-1) and negatively co rrelated (r = -0.88) with drop in volume after 2 hr. Caseins drastical ly reduced the loaf volume of bread baked in the bread machine; heat t reatment of the caseins counteracted the loss. Heat-treated acid whey protein increased the loaf volume and lowered the rate of staling, as measured by universal testing machine (UTM) crumb firmness measurement s and differential scanning calorimetry enthalpy changes. In bread bak ed by the optimized procedure, heat treatment alone, or in combination with dialysis, counteracted the deleterious effects of adding nontrea ted whey protein, but not of caseins. Baking performance could be pred icted by the Rheofermentometer time of maximum gas formation. Heat-tre ated whey proteins lowered the rate of staling in optimally baked brea d as in bread baked by the fixed formula.