Comparison of microwave-assisted distillation and conventional hydrodistillation in the essential oil extraction of flowers Rosa damascena Mill.

Abstract

Microwave-assisted distillation (MAD) is a combination of microwave heating and dry distillation at atmospheric pressure in which isolation and concentration of volatile compounds are carried out, simultaneously without solvent or water. The aim of this work is to evaluate the performance of MAD when isolating the essential oil of Rosa damascena Mill. For this purpose, first, two main parameters, namely extraction time and microwave power, which affect the efficiency of the extraction, were optimized. Then, to demonstrate the feasibility of the method, oil obtained under optimal conditions was compared quantitatively and qualitatively with that obtained by conventional hydrodistillation (HD) using an electric mantle heater. Considering the extraction yield, optimal extraction time and microwave power were obtained to be 15 minutes and 650 W, respectively. Extraction of essential oil from rose flowers with MAD offers important advantages over traditional HD in terms of energy saving, extraction time (15 minutes versus 3.5 hours) and extraction yield (0.037% versus 0.018%). However, there is a significant decrease in monoterpene alcohol percentages and increase in hydrocarbon percentages, which is a disadvantage from qualitative point of view.