Delia A. Sorgentini

Comparative study of foaming properties of whey and isolate soybean proteins

Abstract Whey soy proteins (WSP) is obtained from the soluble fraction separated in the isoelectric precipitation of the major components of native soy isolate (NSI), the 7S and 11S fractions. WSP is composed mainly by Kunitz Trypsin Inhibitor and Lectin. Water solubility of WSP was less affected by pH than that of NSI. Therefore, WSP has good foaming capacity in all pH range (pH 2–10). According to the rate of liquid incorporation into the foam, WSPs have higher tensioctive behavior, and in consequence, they are rapidly adsorbed into the water–air interface. At extreme pHs, with low or high ionic strength, good foams were obtained with WSP and NSI. Mixtures of both in different relations, showed better stabilization and foam formation than that expected for the simple additivity of both preparations. This effect was more evident at high ionic strength. These results indicate that there is a synergistic effect between these proteins in relation to foaming properties.