Production of rose geranium oil using supercritical fluid extraction

The present work aims to apply the supercritical fluid extraction (SFE) with carbon dioxide as a clean technology to extract the natural essential oil from a Portuguese-grown rose geranium (Pelargonium sp.). Geranium oil is an important ingredient in perfumery as middle note and is a natural resource with potential to be explored in Portugal, since this plant is well adapted to our climate and soil. A new SFE equipment was designed and constructed and it was used for the extraction of geranium. The obtained extracts were characterised by GC/MS and their organoleptic quality (colour and odour) was evaluated and compared with the materials obtained by the traditional techniques—hydrodistillation and organic solvent extraction. The best extraction conditions were: extraction time of 15–30 min, temperature of 40 °C, pressure of 90–100 bar, cut fresh plant and dynamic mode. The SFE yields varied between 0.019 and 0.22%. The CO2 geranium extract had a superior organoleptic quality, with very fresh natural floral–fruity character and a pale yellow colour, most suitable for the use in perfumery.