However, EOs are sensitive and volatile compounds that can eas- ily evaporate and decompose under the action of oxygen, light and temperature [6,7]. However, an adequate formulation of EOs could protect them and provide a controlled release.
In recent years there has been increasing interest in develop- ing biodegradable particles from nano to micro scales as delivery systems to improve the biological activity of EOs. Alginate is one of the major polymeric matrices used in delivery systems because of its intrinsic biocompatibility and biodegradability, as well as the fact that it is readily available and affordable. It is an anionic biopolymer composed of randomly distributed units of 1,4-linked b-mannuronic and a-guluronic acid residues [8]. The common method of producing alginate nano or micro par- ticles compromise an oily compound is emulsification, followed by crosslinking using calcium chloride and solvent evaporation. The recent use of multiple emulsions as templates for produc- ing EO-loaded microparticles has attracted considerable interest because of their potential use with sensitive ingredients