Release of Thyme Oil from Polylactide Microcapsules

Microencapsulation reveals numerous advantages over conventional applications of flavors or fragrances. Thus, the goal of this work was to study the release rate of thyme oil through the polylactide (PLA) microcapsules prepared by coacervation. Microcapsules have spherical shape and a mean particle size of 36 μm. The results show that the release of thymol is faster in the first hour and remains almost constant in the next days. Moreover, it was observed that the release of the polar compounds of thyme oil is faster than the apolar ones. The diffusion coefficient in the first hour of release was 1.39 × 10–15 m2/s for thymol and 5.21 × 10–17 m2/s for p-cymene. For a period of 5 days, diffusion coefficients of 3.81 × 10–17 m2/s for thymol and 1.43 × 10–18 m2/s for cymene were determined. The diffusion of thyme oil from the PLA cross-linked membrane was dependent on the microcapsules morphological characteristics.