SUPERCRITICAL FLUID EXTRACTION AND FRACTIONAL SEPARATION OF ESSENTIAL OILS

Supercritical fluid extraction of essential oils is one of the most widely discussed applications in the supercritical fluid literature. Peppermint leaf oil was isolated by a supercritical fluid extraction using CO2 in which the extraction was followed by a two-stage fractional separation. Chemical analysis revealed that oils extracted under different supercritical fluid extraction conditions possessed a widely different percentage composition. Oil obtained by hydrodistillation was also compared with the extracted oils. Although practically the same compounds were present in the hydrodistilled oil, its composition was similar to supercritical fluid extraction oil extracted under non-optimised conditions. The oil obtained at optimum supercritical fluid extraction conditions (p = 90 bar, T = 40°C) had a fragrance that better resembled that of the peppermint leaves used for the extraction of the oils