To investigate the assembly of b-casein at liquid-liquid interfaces, interfacial shear rheology was selected. Indeed, this technique enables shearing of liquid-liquid and air-liquid interfaces without inducing significant changes in surface area, and therefore enables to dissociate contributions from interfacial shear mechanics from surface tension effects . Oscillatory dilatational rheology typically reflects both changes in surface tension and in plane shear mechanical properties of the interfaces characterised. Similarly, force probe microscopy allows the quantification of interfacial mechanics, but the indentation moduli obtained reflect a combination of interfacial mechanics and disjoining pressure (combining contributions from surface tension, as well as coulombic and van der Waals surface-probe interactions). As a result, force probe microscopy is relatively weakly sensitive to interfacial shear mechanics, with surface tension/disjoining pressure dominating indentation profiles at interfacial shear moduli near 10-100 mN/m, and only becoming significant in the range of 100 mN/m and above .