Interfacial stabilization of aqueous foam based on soy protein-rhamnolipids interacting mixture

Abstract

The influence of rhamnolipids (RHA) on structure and foam characteristics of soy protein was evaluated to understand the potential of soy protein-biosurfactant complex as new foaming agents. The fluorescence spectra, circular dichroism and isothermal titration calorimetry showed that the soy protein combined with RHA in aqueous solution mainly through hydrophobic interaction, which may lead to the flexible conformation of protein. Compared to pure protein, the improvements in foaming properties and foam stability were observed for protein-RHA complex due to the enhancing capacity in surface tension reducing and ordered assembly on the air-water interface. The binding of RHA might facilitate the unfolding and adsorption of protein on the air-water interface, thus enhancing the protein-protein interfacial interactions. These findings are helpful for the application of protein-RHA complex as a natural foaming agent in the body wash and cosmetic industry.