The Effect of Air Drying and Extraction Methods on the Yield and Chemical Composition of Geranium ( Pelargonium graveolens L.'Hér) Essential Oils

Abstract

Geranium (Pelargonium graveolens) is an economical plant in Egypt, Three methods of extraction (steam distillation, solvent extraction, and hydrodistillation, respectively) were used to extract geranium essential oils from geranium herb. Three types of geranium essential oils (geranium oil, geranium absolute and geranium stripping oil) were extracted with the three different methods. The oil extracted with direct steam distillation is geranium oil was light green with a density of 0.889 g/ml, oil obtained from hydro distillation was geranium sreipping oil which was brownish with a density of 0.903 g/ml. while geranium stripping oil obtained with solvent extraction method was geranium absolute which was dark green with a density of 0.911 g/ml. Geranium herb were air dried for (0, 12, 24 and 48 h). All essential oils obtained were analyzed by Gas Chromatography/mass Spectrometry (GC-MS). Chromatographic analysis of the geranium essential oils demonstrated that citronellol is the main constituent, accounting 29.70%, 31.80% and 18.30% of geranium oil, geranium stripping oil and geranium absolute, respectively. Air drying had a significant effect on geranium oil and geranium stripping oil, for example for geranium oil citronellol percentages were 31.22, 21.20, 28.66 and 35.40 at 0, 12, 24 and 48 h. while geraniol percentages were 9.65, 5.28, 7.85 and 12.43 at same times. For geranium absolute oil air drying had no significant effect on the chemical composition of geranium absolute oil. Air drying had a significant effect on oil obtained from hydrodistillatin method, for example citronellol percentages were 26.44, 28.15, 31.85 and 29.92.