Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 11, 2007
Publication Date: August 18, 2007
Citation: Tunick, M.H., Onwulata, C.I. 2007. Rheology of extruded whey protein isolate.(Abstract) American Chemical Society Book of Abstracts. AGFD171 Technical Abstract: Whey protein isolate (WPI), a high-quality protein used to fortify a number of foods, may be texturized with a twin-screw extruder. Since extrusion of food is commonly performed above 70°C, which causes whey protein to denature, cold extrusion below 70°C was investigated to determine the effects on native protein. The elastic modulus (G’) of WPI extruded at the lowest temperature tested was initially <1000 Pa and was lower than the G’ values of the other samples, which ranged up to 3200 Pa. Non-extruded controls exhibited values under 200 Pa. G’ of all samples decreased over several days of storage at room temperature. Reconstituting lyophilized samples produced two phases, a solid gum with G’ values as high as 56 kPa, and a liquid with values under 150 Pa. The rheology of cold-extruded WPI is dependent on temperature and post-extrusion treatment, which has implications for its use as a food ingredient.