Properties of Ovalbumin, Conalbumin, and Lysozyme at an Oil-Water Interface and in an Emulsion System1

ABSTRACT The interfacial adsorption properties of lysozyme, conalbumin, and ovalbumin at pH 6.5 were measured, using linear regression analyses of the interfacial tension responses with respect to protein concentration. After preparation of the oil-in-water emulsions, analyses were conducted to determine emulsion stabilities, mean dispersed globule diameters, and the concentration of irreversibly adsorbed protein per unit area of the dispersed phase. Lysozyme showed less total interfacial surface adsorption (1.94 mg per m2) than conalbumin (7.28 mg per m) or ovalbumin (9.37 mg per m2) when the interface was at saturation. However, both conalbumin and ovalbumin had less irreversibly adsorbed protein in the interfacial films of the emulsions (.74 mg per m2 and. 11 mg per m2, respectively) compared to lysozyme (1.15 mg per m2). A lower emulsion stability was provided by lysozyme than by the other proteins. The lower stability provided by lysozyme was related to its adsorption characteristics and the higher mean diameter of dispersed globules (34|i) within the emulsion, compared with the respective data for conalbumin and ovalbumin. Overall, the results obtained supported the concept that lysozyme possesses more surface hydrophobicity and less molecular flexibility for conformational alteration at the oil-water interface than conalbumin or ovalbumin