Rheological behaviour in the interaction of lecithin and guar gum for oil-in-water emulsions

Abstract

The effects of guar gum and lecithin concentrations (1, 0.75, and 0.5%wt) on the stability of oil in water emulsion were investigated. All emulsions can be stabilized at the studied concentrations of stabilizers. The samples tested by steady shear flow and dynamic viscoelasticity tests were carried out to characterize the rheological behaviour of emulsions as influenced by concentration. Emulsions presented a non-Newtonian behaviour type with shear thinning and flow curves that could be described by the Carreau model. The dynamic viscoelastic properties characterized by an oscillatory frequency sweep under small deformation conditions showed fluid-like viscoelastic behaviour. The interaction of the stabilizers in the mixture with each other at the interface appears to play a decisive role for the stabilization of emulsions.