Effect of Some Novel and Conventional Drying Methods on Quantitative and Qualitative Characteristics of Hyssop Essential Oil.

Hyssop (Hyssopus offisinalis L.) is a medicinal plant belonging to the Lamiaceae family. Hyssop essential oil has been used as antibacterial, antifungal and as a flavoring in the food industry. The essential oils from shade drying (20-25 °C), sun drying (under direct sunlight at 25-35°C,) oven drying (40, 50 and 60°C), microwave drying (300, 450 and 600 W) and infrared drying (40, 50 and 60°C) were isolated by hydrodistillation in a Clevenger apparatus and analyzed by GC and GC/MS. The results showed a significant effect of different drying methods on the drying time, essential oil content and composition. The lowest and highest of drying time was related to microwave drying at 600W and shade drying, respectively. Based on the results, 45 compounds were identified in the essential oil. The main compound was isopinocamphone (41.94-62.25 %) followed by (E) pinocamphone (4.67-16.56 %), β-pinene (3.93-13.62 %). Overall, it can be stated that the use of infrared treatment for hyssop drying, not only reducing the relative time and uniform drying of the herbal substance, but also preserved the quantity and quality of the essential oil components. [ABSTRACT FROM AUTHOR]