Preparation, characterization and the release kinetics of mentha-8-thiol-3-one-β-cyclodextrin inclusion complex

Mentha-8-thiol-3-one, with a characteristic black currant flavor, has been widely used in blending flavors and perfumes. To improve its shelf-life and stability, and control its release, mentha-8-thiol-3-one-beta-cyclodextrin inclusion complex was produced. The inclusion complex was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Kinetics and release characteristics of mentha-8-thiol-3-one from the inclusion complex were determined by thermogravimetric analysis. The results showed that mentha-8-thiol-3-one was successfully encapsulated in beta-cyclodextrin, and the loading capacity was about 13.5 %. The inclusion complex aggregates had many geometric shapes and the particle size was mostly in the range of 1-3 mu m. The distributions of S, C and O can be observed element maps of mentha-8-thiol-3-one-beta-CD inclusion complex. Mentha-8-thiol-3-one release from the inclusion complex mainly occurred in the first stage of pyrolysis. At 236.3 degrees C, the release rate of mentha-8-thiol-3-one attained the maximum value. The release reaction order was 1.5. The apparent activation energy and pre-exponential factor were 290.8 kJ/mol and 3.19 x 10(24), respectively.