Rheokinetic Analysis of Protein Films at the Air−Aqueous Subphase Interface. 2. Bovine Serum Albumin Adsorption from Sucrose Aqueous Solutions

In this paper surface dynamic properties (surface tension and surface dilational properties) of bovine serum albumin (BSA) films adsorbed on the air−aqueous sucrose solution interface are presented, as a function of adsorption time. The experiments were performed using a superficial, sinusoidal oscillatory rheometer (ring trough), at constant temperature (20 °C). The surface rheological parameters (i.e. surface dilational modulus, elastic and viscous component, and loss tangent angle) and the surface tension were measured as a function of sucrose concentration (0, 0.25, 0.5, and 1 M) and on a mixture of ethanol (1.0 M) and sucrose (0.5 M) in the aqueous phase. The films displayed a viscoelastic behavior, which was practically elastic. At low sucrose concentration (