Adsorption and shear rheology of β-lactoglobulin/SDS mixtures at water/hexane and water/MCT interfaces

The adsorption and shear rheological behavior is studied of β-lactoglobulin (BLG) alone and in mixtures with sodium dodecyl sulphate (SDS) at water/hexane and water/MCT interface. At a low ratio of SDS in the mixture, the adsorbed layer at the interface comprises mostly of protein–surfactant complexes while at a higher SDS/BLG mixing ratio the surfactant dominates at the interface and governs the interfacial properties. The adsorption and shear rheological behavior complement each other and confirm the stepwise replacement of BLG by SDS. The molecular scheme at the two studied interfaces is similar, but the quantitative properties differ due to the differences in the polarity of the oils.