Comments on viscosity enhancement and depletion flocculation by polysaccharides

Polysaccharides are added to oil-in-water emulsions to enhance the viscosity of the aqueous phase, which modifies their texture and retards droplet creaming. Nevertheless, at certain concentrations polysaccharides have been shown to accelerate creaming instability by promoting droplet flocculation through a depletion mechanism. This paper examines the relationship between the molecular structure of polysaccharides and their ability to enhance the viscosity of aqueous phases and to induce depletion flocculation in emulsions. A theoretical phase diagram is developed to relate the creaming instability caused by polysaccharides to their molecular structure and concentration.