Optimization of the Supercritical Carbon Dioxide Separation of Bergapten from Bergamot Essential Oil

The possibility of following traditional cold-press extraction with the post process continuous separation of bergapten from bergamot essential oil was investigated. A fractionation tower was used in an experiment in which cold-pressed bergamot oil was extracted in a continuous countercurrent process by supercritical carbon dioxide under different conditions. Bergapten is fairly soluble in CO2 in its supercritical phase, in particular at a density of 277.90 kg.m(3), corresponding to a pressure of 8 MPa and temperature of 40 degrees C. Under these conditions, an extract with 0.198% bergapten was obtained, a figure slightly below the percentage of bergapten contained in cold-pressed oil (0.21%). However, at densities below 200 kg.m(-3), the amount of bergapten in the extracted oil was negligible. Of all tested conditions for separation, the best was found to be at a pressure of 8 MPa and temperature of 70 degrees C, conditions under which bergapten was not detected. The results of the experiment showed that bergapten, and the nonvolatile fraction in general, was extracted only in small quantities and was not extracted at all with at a CO2 pressure of 8 MPa.