Identification of odorants in wood of Calocedrus decurrens (Torr.) Florin by aroma extract dilution analysis and two-dimensional gas chromatography–mass spectrometry/olfactometry
General emissions of volatile organic compounds from wood are well investigated, but only limited information is available on the odor-active substances contained therein. To close this gap, we aimed at specifically elucidating the odorous constituents of wood from incense cedar [Calocedrus decurrens (Torr.) Florin]; this material is commonly used for the production of a range of products such as pencils and interior accessories. Targeted odorant analysis requires specialized techniques combining modern odorant analytical tools with human-sensory evaluation. Following this concept, the odor profile of the wood sample was first evaluated by human-sensory analyses. Then, the most potent wood odorants were characterized by means of gas chromatography–olfactometry and ranked according to their odor potency via aroma extract dilution analysis. With use of this approach, more than 60 odorous substances were detected, and the 22 most potent odorants were successfully identified by gas chromatography–mass spectrometry/olfactometry and two-dimensional gas chromatography–mass spectrometry/olfactometry. Among the main odorants found were a series of terpenes, several degradation products of fatty acids, and a number of odorants with a phenolic core moiety. Five odorants are reported here for the first time as wood odorants, such as γ-octalactone and 3-phenylpropanoic acid; thymoquinone was demonstrated for the first time to have a pencil-like odor quality.
KeywordsAroma extract dilution analysis Gas chromatography–olfactometry Incense cedar 2-Isopropyl-5-methyl-1,4-benzoquinone Thymoquinone Octalactone
We are grateful to Alexander Vyhnal and Staedtler Mars GmbH & Co. KG for supplying the incense cedar wood as well as to the STAEDTLER Foundation for financial support of this study.
Compliance with ethical standards
The study was conducted in accordance with the principles of the Declaration of Helsinki. The study (registration number 180_16B) was approved by the Ethical Committee of the Medical Faculty, Friedrich-Alexander-Universität Erlangen-Nürnberg. Informed consent was obtained from all individuals participating in the study.
Conflict of interest
The authors declare that they have no conflict of interest.
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