[Study of the process of essential oil extraction from rosemary plant by using steam distillation method]

ABSTRACT

Rosemary [Rosemarinus officinialis L.] is an aromatic, medicinal and condiment plant that belongs to the family labiatae, reaching a height of 1.5 meter. Essential oil of rosemary, known as rosemary oil, is extracted by hydrodistillation method from the fresh leaves and twigs. The yield ranges from 0.5 to 1.5% [w/w]. Improving the total yields, determining minimum steam to be passed through the packed bed, evaluating influence of used multi-stage column and trend to change into important component with time of distillation are the aims of this work. In this work, essential oil was extracted from rosemary plant by steam distillation method. For the extraction of essential oil by this method rosemary was exposed to the steam flow. The processes were done and the extraction yield was calculated. Then, the components of the essential oils analyzed by GC-MASS and GC instruments. Experiments that were conducted in multi-stage columns and decreased steam flow rate proved that an increase in the number of stages has a considerable effect upon the yield. Also analyses which were done on essential oils components during 5, 15, 30, 60 and 100 minutes intervals showed different extraction phenomena for three major components of the oil; a-pinene, 1, 8- cineol and camphor. This study showed a direct correlation between increase of contact time of steam and increase of the yield. Also barrier effect of cell wall and boiling point of components affect extraction phenomena of them