The Effect of Different Drying Methods on the Content and Chemical Composition of Essential Oil of Lemon verbena (Lippia citriodora)

Abstract

The effect of different drying methods (room temperature, open air and oven drying at 30, 40 and 50°C) was studied on the content and chemical composition of essential oil of Lemon verbena (Lippia citriodora). The essential oils were isolated from aerial flowering parts of the plants by hydrodistillation method and then the oil subjected to GC and GC-MS analyses to determine the constituents. Fifty-four different components were identified in lemon verbena essential oil, which were mostly oxygenated monoterpenes. Geranial, Neral and limonene were the major components of essential oil. The highest content of essential oil and total monoterpens were obtained by oven drying under 30°C tratment. Moreover, neral and geranial were maximized in samples dried in oven 30°C. Increasing temperature of oven had a negative effect on oil content and monoterpenes like neral and geranial. Whereas, total sesquiterpenes and also some monoterpenes like limonene were enhanced as temperature increased. The method of oven drying at 30°C revealed to be the best drying method for keeping up the quality and quantity of essential oil in this study.