Effect of Different Drying Methods on Some Quantitative and Qualitative Traits of Mint (Mentha sativa L.)

To investigate the effect of different drying methods on some quantitative and qualitative properties of mint, an experiment was performed in a completely randomized design with three replicates. Treatments included drying in shadow, drying in the sun and drying in the oven at 45 °C, 55 °C and 65 °C. Results showed that the drying method had significant effects on the drying time, essential oil content, microbial level and the colour of dried plant samples, however, it did not have any significant impact on the content of phenolic compounds, mineral elements and components of essential oil. The highest content of oil and the best colour were belonged to the methods of drying in shadow and in the oven at 45 °C; while the best results for the drying time and the microbial levels were obtained from treatments at high temperatures in the oven. Also, the results of the essential oil analysis by gas chromatography indicated that the major components of the mint essential oil are limonene and carvone, which comprise more than 80 percent of the total essential oil in mint.