Production And Characterization Of Multinuclcar Microcapsules Encapsulating Lavender Oil By Complex Coaccrvation

Microencapsulation of volatile essential oils by polymeric wall materials seems to be aneffective solution for increasing the stability of these compounds in order to improve theirefficiency and minimize environmental damage, thus providing them with a longer shelflife,which has been widely applied in food, cosmetics, textiles, pharmaceuticals and so on.Complex coacervation is the liquid-liquid phase separation phenomenon that occurswhen mixing two or more oppositely charged polyelectrolyte solutions. The complexcoacervation method principally consists of an emulsification step for making an oil-in-wateremulsion, a coacervation step for coating the oil droplet surface by adjusting the pH of thesolution, and a step for fixating the shell membrane through the gelation of the coacervates orby chemical crosslinking. Microcapsules prepared by complex coacervation possesses seriesof distinct strengths for its immobilization, protection, controlled release, structuration andfunctionalization.The gelatin (GE)-gum Arabic (GA) multinuclear microcapsules encapsulating Lavenderoil (LO) were prepared via complex coacervation. The LO loaded microcapsules werecharacterized with optical microscopy (OM), thermogravimetric analysis (TGA), scanningelectron microscopy (SEM), UV spectrophotometer (UV), fourier transformation infraredspectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS), respectively.Through some pre-tests and a series of single factor experiments, and then furtheroptimized by orthogonal experimental process, the optimal conditions for preparing sphericalmultinuclear microcapsules by complex coacervation were as follows: pH3.5, core/wall3:2,wall material concentration1%, stirring speed450rpm, homogenization rate25000rpm andglutaraldehyde as cross-linker.The OM and SEM has been employed to study the morphology of the preparedmicrocapsules. They displayed that the microcapsules were spherical and the average size wasfound to have110.3μm with a narrow size distribution. FTIR has been used to understand theinteraction between the polymers and oil, shown that there was only exist an electrostaticinteraction between GE and GA during the formation of complex but no significantinteraction between oil and gelatin-gum Arabic matrix. GC-MS and TGA indicated more than90%components of the LO could be encapsulated in gelatin-gum Arabic complex with nearly68.3%of the essential oil loading capacity. It also demonstrated that LO-loaded microcapsules had an enhanced thermo-stability and a better controlled-release comparedwith LO. The release profile of Lavender oil from the microcapsules could be well describedby Higuchi equation.