Emulsion-stabilizing effect of bacterial cellulose

The bacterial cellulose produced in an agitated culture (Ag-BC) showed the highest emulsion-stabilizing effect among the examined cellulosic materials, It was clarified that a mechanical barrier and a scaffolding structure composed of fine fibrils of bacterial cellulose interrupted the coalescence of oil droplets to stabilize the emulsion without reducing the interfacial tension as occurred with sorbitan monolaurate. Since Ag-BC consists of thinner fibrils and smaller flocs than any other cellulosic material, Ag-BC would cover a larger surface area of the oil droplet as a mechanical barrier. The emulsion containing Ag-BC was stable against the addition of salt, and changes in pH and temperature in comparison with xanthan gum and sorbitan monolaurate. This stability would have been due to the stability of the mechanical barrier and a scaffolding structure composed of stable crystalline cellulose. In contrast, instability in the conformation of xanthan gum and a reduction in the interfacial tension of the surfactant would lead to instability of the emulsion.