Determination of the effects of different drying methods on the quality of some medicinal and aromatic plants

The selection of the appropriate drying method in medicinal and aromatic plants is one of the important steps in preserving the plants and extending the shelf life. In this study, three different drying methods such as drying in the shade, sun and oven were used for the determination of the quality characteristics of some medicinal and aromatic plants. Rosemary (Rosmarinus officinalis L.), Zahter (Thymbra spicata var. spicata), Oregano (Origanum onites), Lemon thyme (Thymus citriodorus L.), Lemongrass (Lippia citriodora), peppermint (Mentha piperita) and Spearmint (Mentha spicata) were used as research material. In the thesis, the color values of each plant were determined and the changes in the amount and composition of the active substance were examined. It was determined that L *, a * and b * values of the dried plants according to different drying methods differed according to drying applications. In Origanum onites, the highest essential oil content was obtained from shade drying and the highest carvacrol content was obtained from shade application with 71.0%. In Lippia citriodora L., the highest volatile oil content was obtained from sun drying application and the Limonene rate was high from oven drying application with 38.97%. Mentha spicata L. gave the highest volatile oil ratio in the shade drying method, while the highest carvone content was obtained from the sun application with 46.30%. The highest essential oil content was obtained from shade drying application, while Menthol content was obtained from oven drying application with the highest 38.63% in Mentha piperita L. Rosmarinus officinalis L. gave the highest volatile oil ratio in shade application, while the highest camphor content was obtained from sun application (28.83%). In Thymus citriodorus, the highest essential oil content was obtained from sun-drying, while the main component geraniol was obtained from shade-drying with a maximum of 38.41%. Thymbra spicata var. spicata L. had the highest essential oil ratio in the shade and the highest carvacrol content was obtained from the shadow application with 74.35%.