liquid interfaces, whereas the opposite leads to partial displacement of adsorbed BSA . To investigate such processes at Novec-PBS interfaces, we used our labelled proteins to form emulsions stabilised by single protein assemblies, followed by washing of the aqueous phase to remove excess free protein and injection of the second protein labelled with a different fluorophore. Microscopy images of the resulting emulsions, before and after injection of the second protein allowed the quantification of protein compositions at the corresponding interfaces (Figure ). Upon introduction of b-casein to BSA-stabilised emulsions, a significant decrease in BSA density was observed, correlating with a significant increase in b-casein surface density. In contrast, upon introduction of BSA to b-casein-stabilised emulsions, no significant changes in protein densities were observed, suggesting that b-casein is not displaced and that very limited levels of BSA adsorption occurs. interfaces between other globular proteins (including BSA and soy 11s) and b-casein, whereas bcasein and lysozyme were not found to readily exchange .