Industrial & Engineering Chemistry Research, Vol.47, No.23, 9108-9114, 2008
Emulsion Texture and Stability: Role of Surfactant Micellar Interactions in the Presence of Proteins
This article presents the results of our recent research on the texture and stability of oil-in-water emulsions containing sucrose ester and proteins. We used both the direct microscopic imaging and nondestructive back-light scattering (Kossel diffraction) techniques to evaluate the emulsion texture and the energy barrier between droplets for two different emulsifier compositions with and without the proteins present. The microinterferometric method employing our capillary force balance was used to study the stability of the confined thin film (containing surfactant micelles and proteins) between two droplets. In addition to the film stability, we also measured the second virial coefficient of the micellar solutions with and without protein and assessed the intermicellar interaction and related it to the stabilities of the emulsions prepared using two different emulsifier compositions. The effect of protein on the oil-in-water emulsion stability was also assessed and was found to lead to the depletion attraction between droplets, resulting in a less stable emulsion. The results offer new insight into the understanding of how the micellar interactions in the presence of proteins affect emulsion texture and stability.