Evaluation of the Effect of different microwave dryer power on the Qualitative and Quantitative properties of Essential oil of Bakhtiari Savory

Drying is one of the most important post-harvest stages of medical plants which has a significant effect on the quality and quantity of the effective compounds. In order to promote the objectives of the study, microwave power was selected as an independent variable so that power variable microwave was designed and constructed. After collection and drying the savory samples in the shade, the essential oil at different treatments was extracted in three levels of 400, 600 and 800 W. The volatile oil was analyzed using GC/MS method. Results of experiments showed that increase in the power from 400 W to 600 and 800 W caused a reduction in drying time. The most yield of essential oil was obtained in the shade drying method with the essence value of 2.41%. It was also revealed that with increasing the microwave power, the amount of essence decreased, so that the microwave power of 800 W had the lowest essence value. The highest values of thymol and carvacrol and sum of them that show the quality of essential oil was obtained in drying methods with microwave power of 800 W (56.83%). Overall, when the quality of essence is important, the common method of shade drying is suggested, while considering the speed and quality, the microwave drying is recommended.