Drying Peppermint Medicinal plant (Mentha piperita) using Combined Shade and Microwave Treatments –Part One: Investigating the Effects of Treatments on Drying Time, Amount and Components of Essential Oil

In order to investigate the effect of different drying methods on the drying time, the amount of essential oil and the essential components of peppermint medicinal plant, two experiments were carried out separately based on a completely randomized design with three repetitions. The results indicated a significant effect of different drying methods on the studied traits. In simple drying, the maximum drying time (570 minutes) was related to samples dried in a cabinet dryer, and the minimum drying time (5.03 minutes) was related to samples dried with 900 W microwave, while in combined drying, the maximum The drying time in the shade treatment was 520 minutes and the minimum time was 5.94 minutes for the 450W + shade microwave treatment. the maximum essential oil contente (2.6%) in simple drying obtained from cabinet dryer, while in the combined drying the maximum essential oil contente in the shade method with 2.4% and combined microwave 100W + shade treatment with 2.3%. in the simple drying method, the maximum amount of Menthol reach at microwave dried sample, while in this way a significant decrease was found Menthone, also in the combined drying, the maximum amount of Menthol reach at shade+ microwave 300 watts, but in this way, the amount of Mentone was significantly reduced. Therefore, it can be concluded that in simple drying, the cabinet dryer method and in combined drying, the shade method, are more favorable than other methods due to the preservation of essential oil.