Protein adsorption isotherms studied by axisymmetric drop shape analysis

The pendant drop method is used to measure the interfacial tension isotherm s of solutions of the model proteins beta-casein, beta-lactoglobulin both f rom bovine milk, and human serum albumin. A recently developed theory of pr otein adsorption at fluid interfaces [V.B. Fainerman, R. Miller, R. Wustnec k, J. Colloid Interface Sci. 183 (1996) 26] is used to calculate the equili brium protein concentration at the interface and in the bulk. Comparison of the results with literature data obtained by plate and ring tensiometry sh ows that at low initial protein concentrations in a drop and a large surfac e area, the final protein concentration after the establishment of equilibr ium can be significantly decreased. However, this deficiency of the pendant drop method is turned into an advantage, as from the mass balance of the p rotein at low initial the adsorption can be calculated. (C) 1998 Elsevier S cience B.V. All rights reserved.