Effect of pressure-drop rate on the isolation of cananga oil using instantaneous controlled pressure-drop process

The isolation of Indonesian cananga oil was carried out by a new process, instantaneous controlled pressure drop (DIC). Dry cananga flowers (Cananga odorata Hook. fil. et Thomson, forma macrophylla) were exposed for a short time to saturated steam and then the pressure was abruptly decreased to a vacuum level (about 5 kPa). This abrupt pressure drop provokes auto-vaporization of the superheated volatile compounds, expansion and breaking of the cell walls and instantaneous cooling. In this study, the effects of two parameters of DIC process namely pressure-drop rate and flowers moisture content on the yield of essential oil and its grouped compounds such as oxygenated monoterpenes, sesquiterpenes hydrocarbons, oxygenated sesquiterpenes and other light and heavy oxygenated compounds were studied. The oil composition was analyzed by GC coupled with MS. The availability of the volatile compounds in the residual flowers was analyzed using organic solvent extraction. The quantity of compounds obtained by DIC treatment increased with pressure-drop rate. At a rate of 1.43 MPa/s the total amount of compounds in the direct and residual oils was greater than in the reference oil obtained by chloroform extraction (2 h) from untreated flowers. The hydration of dry cananga flowers had no effect on the essential oil yield.