GC-MS analysis of essential oil of some commercial Fennel teas

Fennel teas were prepared by classical infusion or microwave decoction of unbroken and crushed fruits, three pre-packaged teabags and two instant teas. Their volatile constituents were obtained by extraction with n-hexane and analysed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS), using two columns with stationary phases of different polarity. Of the constituents 85-95% were identified on the basis of their GC retention times and their mass spectra in relation to authentic compounds. No volatile constituents were detected in one sample of instant tea. Conventional teas from crushed fruits and teas prepared from the other instant tea showed the highest levels of volatile constituents. Anethole (30-90%) and/or anisaldehyde (0.7-51%) were the main constituents of all the samples. Methychavicol (0.8-4.1%), eugenol (1.5-11.3%) and fenchone (0.5-47%) were detected in most samples. Carvone (2.1-6.1%) was presenting only some teabags and camphor (2.3-2.6%) in others. The volatile constituents of only one instant tea included limonene (1.4%) and alpha-terpineol (0.4%). (C) 2002 Elsevier Science Ltd. All rights reserved.