Variations in the quality and yield of the essential oil from Artemisia afra using different drying methods

The impact of drying methods, namely, air, sun and oven-drying on the quality and quantity of the essential oil of Artemisia afra was studied. The oil yields from the plant differed according to the drying methods; viz: 0. 18%,0.88%,1.54% and 1.88% for fresh, oven-dried, air-dried and sun-dried oils respectively. The essential oil from the plant contained mostly monoterpenoids (96.3% - 84.0%) and, to a small extent, sesquiterpenoids (2.6% - 0.1%). Compounds such as alpha- and beta-Thujone (52.1 - 39.8%), camphor (14.4 - 8.2%), 1, 8-cineole (21.8-13.1%) and borneol (7.8 - 2.7%) which are the major components responsible for the characteristic flavour of the herb, were present in significant amounts in the oils from the entire dried herb preparations. The fresh oil contained artemisia. ketone (6.9%), which was absent in the dried oils. Apart from the large quantitative difference in the yield of the hydrodistillates, there was no significant loss of volatile components, except in the sun-dried oil which were mainly sesquiterpenoids. Generally, the drying methods had no significant effect on the monoterpenoids composition of the essential oils from A. afra, however sun drying which has the lowest no of components (14) has the highest percentage oil yield and composition.