STUDIES ON MICROWAVE STEAM DISTILLATION PROCESS FOR EXTRACTION OF TULSI ESSENTIAL OIL

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.