Encapsulation of nutraceutical monoterpenes in beta-cyclodextrin and modified starch.

The encapsulation of thymol and geraniol in beta-cyclodextrin (beta-CD) and modified starch (MS) by spray- and freeze-drying was studied. The formation of thymol/beta-CD and geraniol/beta-CD inclusion complexes was confirmed by differential scanning calorimetry (DSC). Oxidative DSC revealed that the monoterpenes enclosed in the beta-CD cavity were protected against oxidation, remaining intact in temperatures at which free monoterpenes were oxidized. Phase solubility studies showed that the inclusion complexes of thymol and geraniol with beta-CD are more soluble in water than the free molecules themselves. Furthermore, in order to evaluate the fraction of monoterpenes that can be released from their complexes with MS in aqueous media, a series of release experiments were conducted.