Quality of Geranium Oils (Pelargonium Species): Case Studies in Southern and Eastern Africa

Abstract

As several sub-Saharan African countries are entering into the commercial production of geranium essential oils, this work sought to characterize the oil quality of Pelargonium sp. based on organoleptic, physicochemical and chemical properties from different Southern and East African countries to highlight the importance of germplasm selection in the commercial production of oils and to develop base-line yield information. In 2002, Rwanda began to rebuild their essential oil industry, and locally available Pelargonium cultivars were introduced into cultivation trials. The organoleptic evaluation and chemical profile (citronellol 13%, linalool 18% and geraniol 35%) showed that these oils were not suitable for international markets, but may have an important role in domestic markets. In an effort to upgrade the essential oil industry to higher standards, new geranium plantlets of the Bourbon type were obtained from South Africa and distributed to several sites in Southern and Eastern Africa. The newly introduced cultivar yielded essential oils with a suitable organoleptic and chemical profile (citronellol 31%, linalool 3% and geraniol 7%). In Zambia, a commercial grower was also producing geranium oils that were later deemed not suitable for international markets. While in Madagascar, a country with a long history of producing geranium in small land units by many small-scale commercial farmers, those samples analyzed in this study were found to produce high quality oil similar to the Bourbon type. These results clearly demonstrate that the selection and introduction of a specific strain or chemotype with the acceptable organoleptic and chemical profiles are among the key factors needed to obtain high quality essential oils that will meet international expectations and standards, prerequisites for the successful establishment and sustainability of an essential oil targeted for the global trade.