Interfacial properties of whey proteins at air/water and oil/water interfaces studied by dynamic drop tensiometry, ellipsometry and spreading kinetics

Abstract

Abstract The behaviour of different whey protein preparations at the air/aqueous and oil/aqueous interfaces have been investigated by surface tension measurements and ellipsometry, respectively. The results are discussed in relation to the composition of the different samples. For the ellipsometry measurement at the oil–aqueous interface, a new methodology has been developed and it will be discussed in relation to the experimental results. The surface viscoelastic properties of protein films formed at the air/aqueous interface have also been determined. Further information about the dynamics of the proteins at the interfaces was obtained by studying the kinetics of spreading of an oil droplet on the protein solutions.