In this thesis, the composition and stability of the hydrolates of lavender (Lavandula angustifolia) and rosemary (Salvia rosmarinus) were studied using gas chromatography coupled to mass spectrometry (GC-MS).
Essential oils and hydrolates were obtained from freshly harvested plants through the distillation process. The hydrolates were stored under different conditions for five months to monitor their stability. The storage conditions included: glass packaging in a refrigerator, glass packaging stored at 40 °C, glass packaging at 20–25 °C (room temperature) in the dark, glass packaging at 20–25 °C exposed to light, HDPE packaging at 20–25 °C in the dark, metal packaging at 20–25 °C in the dark, and PE packaging at 20–25 °C. At monthly intervals, the stored hydrolates were analyzed using GC-MS to track changes in the content of volatile compounds, and the concentrations of the main volatile compounds were determined using standard solutions of known concentrations.
The composition analysis confirmed the relationship between hydrolate stability and storage conditions. Hydrolates stored in a refrigerator exhibited the least changes in chemical composition over time. In contrast, hydrolates stored at elevated temperatures (40 °C) or exposed to light showed more pronounced changes in the number and concentration of key volatile compounds. The packaging material also influenced stability; glass containers provided better protection compared to plastic or metal packaging.
Based on the results, we concluded that to optimally preserve the chemical composition and quality of lavender and rosemary hydrolates, storage in glass containers in a refrigerator or at least in the dark at room temperature (20–25 °C) is recommended. These findings are essential for proper storage and determining the shelf life of hydrolates used in cosmetics, aromatherapy, food, and other fields.
|
