FORMATION OF POSITIVELY CHARGED MICROCAPSULES BASED ON CHITOSAN-LECITHIN INTERACTIONS

The formation of microcapsules which contain rosemary oil, is herewith described. The process is based on two steps: (a) formation of oil-in -water emulsions, by using lecithin as emulsifier, thus imparting nega tive charges on the oil droplets; (b) addition of a cationic biopolyme r, chitosan, in conditions that favor the formation of an insoluble ch itosan-lecithin complex. Zeta potential measurements revealed that add ition of very low concentrations of chitosan to lecithin stabilized em ulsions, led to reversal of charge. At a suitable pH range the chitosa n precipitated around the oil droplets, forming positively charged mic rocapsules. The chitosan-lecithin insoluble complex is composed of a 1 :1 molar ratio of the chitosan monomeric unit and lecithin, as evaluat ed by elementary analysis and turbidity measurements.