Antimicrobial activity of microencapsulated lemongrass essential oil and the effect of experimental parameters on microcapsules size and morphology

Lemongrass (Cymbopogom citratus) essential oil, known due to its broad-spectrum antimicrobial activity, was microencapsulated by simple coacervation. Poly(vinyl alcohol) (PVA, 78,000 Da and 88 mol% degree of hydrolysis) crosslinked with glutaraldehyde was used as wall-forming polymer. The influence of stirring rate and oil volume fraction on the microcapsule size distribution were evaluated. Sodium dodecil sulphate (SDS) and Poly(vinyl pirrolidone) were tested in order to avoid microcapsules agglomeration during the process. Depending on the experimental conditions, microcapsules in the range of 10 μm to 250 μm were obtained. Microcapsules presenting no agglomeration were obtained when SDS at 0.03 wt.% was used. The composition and the antimicrobial properties of the encapsulated oil were determined, demonstrating that the process of microencapsulation did not deteriorate the encapsulated essential oil.