302 The effect of whey protein isolate on mixing and viscosity building characteristics of wheat flour.

E. E. HOLTON and E. H. Asp. Dept. of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108.

The primary purpose of this research was to investigate the extent to which the addition of whey based ingredients affects the mixing properties of wheat flour. Currently, only about 2% of a dairy product such as non-fat dry milk or whey protein concentrate is added to some bread formulations. Whey protein ingredients are now added mainly to enhance color and nutrient content of baked products because other functional properties at increased usage levels have not yet been demonstrated. The results reported in the literature on the effects of whey proteins in baked products do not agree from study to study. Therefore, it is essential to understand how whey and bread systems are interacting in order to improve predictions about how a whey based ingredient will influence the final product characteristics of bread. Whey protein isolate (WPI) was used as the whey based ingredient for this project. Using a WPI allows for better study of the action of the protein and less interference by the minerals and lactose. Mixing experiments using a mixograph were performed to determine what higher levels of WPI can be used successfully in flour-water doughs and bread doughs and to study interactions between protein level and level of denaturation of the protein. The Rapid Visco Analyzer was used to determine how the interaction of the WPI and gluten affects the viscosity building characteristics of a flour and water system. Mixograph results show large changes in mixograms due to WPI additions. RVA curves indicate starch/whey protein interactions. These results maybe useful in determining how much whey can be added to bread formulations.