Double emulsions stabilized with hybrids of natural polymers for entrapment and slow release of active matters.

The main focus and efforts for the next few years in the area of emulsion technology will be to improve stability and control the release of active matter in double emulsions (3rd World Congress on Emulsions, Lyon, France, September 2002). Almost any possible blends of low-molecular weight emulsifiers, oils, cosolvents and coemulsifiers have been already tested. Biopolymers, synthetic graft and comb co-polymers and polymerizable emulsifiers that impart steric or mechanical stabilization with improved stability and better controlled release were explored. Amphiphilic macromolecules, natural occurring or synthetic, that increase the viscosity of each of the phases, complex with the oil or the emulsifiers and form systems that will behave much like microcapsules, microspheres and/or mesophasic liquid crystals have been mentioned as possible new technologies for improved stability. This review will concentrate only on the most recent findings that can enhance stability of the double emulsions and/or will reduce droplets sizes for potential food applications. The attempts and achievements include: selection of food-grade blends of emulsifiers to enhance emulsion stability at both inner and outer interfaces and use of new polymeric amphiphiles (carriers, complexing agents, natural polymeric emulsifiers) to control and reduce the reverse micellar transport phenomena and to control the addenda transport.