OSCILLATORY RHEOLOGICAL COMPARISON OF THE GELLING CHARACTERISTICS OF EGG-WHITE, WHEY-PROTEIN CONCENTRATES, WHEY-PROTEIN ISOLATE, AND BETA-LACTOGLOBULIN

A Bohlin rheometer was used in the oscillatory mode to compare the gel ation characteristics of egg white, two commercially available whey pr otein concentrates, a commercially available whey protein isolate, and beta-lactoglobulin. At a given protein concentration egg white had a lower gelation temperature, a higher initial gelation rate, a higher g el stiffness (G'), and, at concentrations less than or equal to 16% pr otein, a higher value of the ratio G'(80 degrees C)/G'(20 degrees C) t han had the three commercial whey protein products. Furthermore, egg w hite had a much lower minimum protein concentration for gelation. Whey protein concentrate and isolate preparations with increased salt cont ents could match egg white in terms of gel stiffness and could almost match egg white in terms of initial gelation rate. However, further de velopment work is needed to produce whey protein products that match e gg white in terms of the other three properties mentioned above. Catio ns tested all increased G' of whey protein isolate gels in the order M g2+ > Fe3+ > Ca2+ > K+ > Na