This paper describes the physic-chemical principles underlying the functional role of hydrocolloids in oil-in-water emulsions. Basic terms such as emulsifier and stabilizer are defined, and the origins of electrostatic and steric interaction potentials arc explained. The paper discusses the main factors controlling flocculation, creaming, coalescence and Ostwald ripening, distinguishing between the differing effects of adsorbing and no adsorbing hydrocolloids. The attention is specifically directed towards new understanding concerning the rheological and microstructural control of emulsion stability by non-adsorbing hydrocolloids, and the great potential of electrostatic protein-polysaccharide interactions at the oil-water interface for enhancing emulsion properties.
