b-casein introduction, even at moderate concentrations (0.5-2% in weight), had a significant impact on the ultimate interfacial shear modulus measured and significantly delayed the kinetics of the rise in moduli. Analysis of the frequency sweeps (Figures and) obtained after adsorption of corresponding mixed protein compositions clearly confirmed the trends observed from time sweeps (Figure ). The relatively broad linear viscoelastic region observed for BSA assemblies was significantly reduced upon the introduction of b-casein, above 5% by weight, with an increase in the slope of the frequency profiles and a reduction of the frequency at which breakdown of the waveform did not allow further quantification of associated moduli.