Abstract:

A review with 57 refs. Multiple emulsions are complex systems of emulsion within an emulsion, where the droplets of the dispersed phase themselves contain even smaller dispersed droplets. The two major types are water-in-oil-in-water (W/O/W) and oil-in-water-in-oil (O/W/O) double emulsions. Double emulsions are unstable thermodn. systems, which tend to cream, flocculate and coalesce. Much effort has been made to develop methods of 'better sealing' in the inner and outer interfaces and to reduce the droplet size of the emulsions. Dissolved or dispersed compds. in the inner phase of double emulsions tend to be released to the outer phase primarily via a reverse micellar transport (which is diffusion-controlled) or through the thin lamellae of a surfactant phase migrating to the outer phase via the outer interface. It is difficult to control the release of the solutes unless macromols. are used to improve lamellar stabilization (steric stabilization) forming a rigid surfactant-polymer complex at the interfaces. The review describes recent achievements in the use of BSA, casein, gelatin and other naturally occurring macromols. together with monomeric-amphiphilic mols. for possible future applications in food systems. [on SciFinder(R)]