Abstract:
Essential oils are concentrated aromatic oily liquids distilled from different
parts of aromatic plants. Conventionally steam distillation has been widely used for
extraction but it have some disadvantages. Modern technologies have been
continuously developed to overcome the disadvantages of conventional methods.
Microwave steam distillation is based on the interaction between water in the plant
material and microwaves generated by the energy source. In this process, the steam
generated outside accelerates evaporating and carrying of the essential oil, from the
plant material, towards the condenser. In this study microwave steam distillation
was used for extracting tulsi essential oil in a system that was already developed in
the KCAET campus which is composed of microwave reactor, steam generator,
cartridge, extraction unit, supporting stand, energy meter and temperature sensor
and controller. In order to evaluate the developed system towards extraction of tulsi
essential oil, the effect of process parameters which would influence the essential
oil yield, microwave powers of 280, 420 and 560 W were studied. The physical
quality characteristics such as specific gravity, refractive index, solubility and
colour of essential oil were analysed. The optimised operating microwave power
and time of extraction for tulsi essential oil in microwave steam distillation were
found to be of 420 W and 35 min respectively. From the study it was concluded
that microwave steam distillation could be considered as an extraction technique
that results in the rapid production of high quality essential oil at shorter extraction
period with minimum energy consumption.
