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H. M. HUDSON¹, C. R. Daubert, and E. A. Foegeding. (1) Department of Food Science, North Carolina State University, Campus Box 7624, Schaub Hall, Raleigh, NC 27695

Justification: Dairy ingredients able to mimic the thickening functionality of gelatin, hydrocolloids, and starches have been a focus of current research. Pregelatinized starch is often employed in dairy applications due to the instantaneous nature of thickening and the imparted stability. Proteins have been excluded as instantaneous thickeners due to the requisite thermal treatment required to produce structure. Therefore, a protein ingredient instantly gelling at ambient or refrigeration temperatures, while offering food processors a dairy-derived alternative to current viscosifiers would be advantageous for many food applications.

Objective: To describe a dairy protein thickening ingredient with similar or improved functionality to pregelatinized starch.

Methods: Gels from whey protein isolate and concentrate were thermally prepared under acidic conditions, subsequently freeze-dried, then ground into a powder. Once reconstituted in deionized water, solutions were evaluated and compared with the water holding and rheological attributes of pregelatinized starch. Rotational viscometry was performed at pH values between 3 and 8, temperatures of 5-90 °C, and shear rates between 1-100 s-1.

Results: Derivitized whey protein powders and pregelatinized starch exhibited pseudoplastic behavior under shear at all temperatures tested, with the derivitized whey powders exhibiting less shear dependence. Starch was characterized by significant temperature, pH, and time dependence at each concentration tested. WPC powders showed little temperature dependence at native and reduced pH, while WPI powders were essentially unchanged by varying pH, temperature or shear conditions.

Significance: A process has been developed to produce whey protein thickening ingredients which are stable over a wide range of typical food conditions and do not require heat or the addition of salts to function. This cold-set feature may impart a wide range of potential applications such as malted-milk beverages, protein drinks, and nutritious liquid formulations for athletes, infants, or the elderly.