Qualitative and quantitative changes in the essential oil of Laurus nobilis L. leaves as affected by different drying methods

The effect of six different drying methods on the content and chemical composition of the essential oil of Laurus nobilis L leaves was studied. The essential oils from fresh and dried samples were isolated by hydrodistillation in a Clevenger apparatus and analysed by gas chromatography-mass spectrometry (GC-MS). Results showed that air drying at ambient temperature and infrared drying at 45 degrees C increased significantly the essential oil content. Forty-seven components were determined in essential oils, which were mostly oxygenated monoterpenes. This class of compounds is not significantly affected by the method of drying except for air drying at ambient temperature. The main components 1,8-cineole, methyl eugenol, terpinen-4-ol, linalool and eugenol showed significant variations with drying methods. The concentrations of these compounds increased significantly in the case of air drying at ambient temperature. These results allowed considering this method of drying as the method that produced the best results in terms of essential oil and bioactive compounds contents. (C) 2010 Elsevier Ltd. All rights reserved.