INFLUENCE OF SHEAR TREATMENTS ON CONSISTENCY AND GELLING PROPERTIES OF WHEY-PROTEIN ISOLATE SUSPENSIONS

Suspensions of whey protein isolate (WPI) subjected to controlled shearing by capillary extrusion, and rheologically tested after shearing, showed increasing consistency index as applied shear rate increased. Sheared suspensions gelled more rapidly than unsheared ones and produced stronger gels. SEM micrographs showed the development of a fine fibrous-like structure in the sheared suspensions, indicating numerous sites of protein-protein interaction. Sheared WPI suspensions, added as a replacement for fat in frankfurter formulations, showed excellent water-holding capacity, producing low-fat frankfruters with elastic moduli in the same order of magnitude as commercial frankfurters.