The Effect of Distillation Methods on the Chemical Composition of the Essential Oil from Pelargonium graveolens L' Heritier Cultivated in Selected Locations of Amathole District,Eastern Cape Province

Abstract

Pelargonium graveolens Lʹ Heritier is cultivated in different parts of the world for its essential oil production. In South Africa, small-holder farmers in the Eastern Cape province are cultivating P. graveolens to sustain the high demand for essential oil in the perfumery, toiletries, cosmetic, food, and pharmaceutical industries. The price of essential oil depends on the quality of the final product. Among other parameters, the ratio of major components (citronellol and geraniol) is used to determine the quality of the essential oil. The plant materials were collected and distilled (solvent free microwave distillation, hydro distillation and steam distillation) to obtain the essential oil. The essential oil was analyzed using a gas chromatography/mass spectrometer (GC/MS) configured to Wiley and National Institute of Standards and Technology (NIST) electronic library search for easy identification of the components. Regardless of the location, on average the essential oil yield in solvent free microwave distillation was higher (0.29%) compared to hydro distillation (0.10%) and steam distillation methods (0.09%). The results of the study showed variation in the ratio of citronellol to geraniol in essential oil obtained using different distillation methods. Nonetheless, the essential oils obtained at all cultivation sites were of higher quality, with citronellol to geraniol ratio of less than 3. This demonstrates that farmers in the Eastern Cape produce very good quality essential oil and may, thus, negotiate for better selling prices in the market.