Emulsifying and Foaming Properties of a Derivatized Whey Protein Ingredient

A derivatization procedure for the production of a cold gelling whey protein isolate (WPI) has been identified. The cold gelling derivatized whey protein isolate (dWPI) imparted greater viscosity and water holding ability when rehydrated at room temperature than unmodified whey powders. The objective of this study was to further characterize the foaming and emulsifying functionality of the derivatized ingredient. Samples were prepared by hydrating dWPI and WPI in deionized water and, when needed, adjusting the sample pH from 3.4 to 6.8, with 6M NaOH. Yield stress, drainage, and overrun were measured for 6.5% WPI and dWPI foams. Emulsifying capacity and creaming stability were determined for various WPI and dWPI emulsions. The overrun of dWPI foams was approximately 50% lower than WPI foams at pH 3.4 and 6.8. Foams of the derivatized ingredient were significantly more stable than WPI foams. The derivatized ingredient displayed a similar emulsifying capacity to WPI at pH 3.4 and pH 7.0, and differences were not observed in creaming of dWPI and WPI emulsions. Information on foaming and emulsifying ability of derivatized protein ingredients will expedite the development of applications with the novel dairy ingredient, particularly in those foods desiring an all-natural, or all dairy, food label.