Investigating the Storage Conditions of the Essential Oil Compounds of Garden Thyme

The changes in the compositions of essential oils (EOs) from the aerial parts of Thymus vulgaris (garden thyme) were determined at different temperatures and storage times. In this study, the effect of time and temperature on the quality of essential oils was investigated. The essential oil of air-dried samples was obtained by hydro-distillation and was analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Changes in essential oil compositions were detected during storage for three months in a refrigerator (4 ◦C), a freezer (−20 ◦C), and at room temperature. In thyme, the amount of the important thymol compound was stable until the first two months, but when entering the third month, a significant decrease was observed in all three temperature conditions. At the same time, a significant increase was observed in the amount of p-cymene in each of the temperature conditions. In the end, we can introduce the best temperature maintenance conditions for thyme at room temperature that can have a lower cost from an economic point of view than other conditions.