17B-10 |
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J. D. FIREBAUGH and C. R. Daubert. Dept. of Food Science, North Carolina State Univ., Schaub Hall, Box 7624, Raleigh, NC 27695-7624 Whey protein was modified to produce powders capable of thickening, similar to pregelatinized starches. A basic understanding of foaming and emulsification properties of this all dairy ingredient will encourage incorporation into dairy foods. The investigation evaluated foaming and emulsification properties of derivatized whey protein powders. Whey protein isolate (WPI) solutions were modified through acid and thermal treatments, then spray dried into powders (dWPI). Samples were prepared by hydrating the derivatized powders in deionized water and, when needed, adjusting the sample pH from 3.35 to 6.80, with 6M NaOH. Yield stress, drainage, and overrun were measured for 6.5% WPI and dWPI foams. Emulsifying capacity was determined by measuring electrical resistance to determine the exact point of inversion from an oil-in-water emulsion to a water-in-oil emulsion. Creaming stability was determined through measurement of separated serum and emulsion layers after 7days storage at room temperature. Foaming ability of 6.5% protein (w/w) solutions of dWPI and WPI were compared at pH 3.35 and pH 6.80. The overrun of dWPI solutions was approximately 50% lower than WPI solutions at pH 3.35 and 6.80. Foams of the derivatized ingredient were significantly more stable than WPI foams. Whey protein isolate foams drained at least 80% after one hour, whereas dWPI foams drained less than 10% over an equivalent time. The derivatized ingredient displayed a similar emulsifying capacity to WPI at pH 3.35 and pH 7.00, 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.
Session 17B, Dairy Foods: General
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