Encapsulation of Citral Isomers in Extracted Lemongrass Oil with Cyclodextrins: Molecular Modeling and Physicochemical Characterizations

The complexation between two isomers of citral in lemongrass oil and varying types of cyclodextrins (CDs), alpha-CD, beta-CD, and HP-beta-CD, were studied by molecular modeling and physicochemical characterization. The results obtained revealed that the most favorable complex formation governing between citrals in lemongrass oil and CDs were found at a 1:2 mole ratio for all CDs. Complex formation between E-citral and CD was more favorable than between Z-citral and CD. The thermal stability of the inclusion complex was observed compared to the citral in the lemongrass oil. The release time course of citral from the inclusion complex was the diffusion control, and it correlated well with Avrami's equation. The release rate constants of the E- and Z-citral inclusion complexes at 50 degrees C, 50% RH were observed at 1.32 x 10(-2) h(-1) and 1.43 x 10(-2) h(-1) respectively.