Thermal Degradation of Linalool-Chemotype Cinnamomum osmophloeum Leaf Essential Oil and Its Stabilization by Microencapsulation with ß-Cyclodextrin.

ABSTRACT

The thermal degradation of linalool-chemotype Cinnamomum osmophloeum leaf essential oil and the stability effect of microencapsulation of leaf essential oil with ß-cyclodextrin were studied. After thermal degradation of linalool-chemotype leaf essential oil, degraded compounds including ß-myrcene, cis-ocimene and trans-ocimene, were formed through the dehydroxylation of linalool; and ene cyclization also occurs to linalool and its dehydroxylated products to form the compounds such as limonene, terpinolene and α-terpinene. The optimal microencapsulation conditions of leaf essential oil microcapsules were at a leaf essential oil to the ß-cyclodextrin ratio of 1585 and with a solvent ratio (ethanol to water) of 15. The maximum yield of leaf essential oil microencapsulated with ß-cyclodextrin was 96.5%. According to results from the accelerated dry-heat aging test, ß-cyclodextrin was fairly stable at 105 °C, and microencapsulation with ß-cyclodextrin can efficiently slow down the emission of linalool-chemotype C. osmophloeum leaf essential oil.