Dynamic headspace extraction combined with thermal desorption and gas chromatography-olfactometry as a suitable tool for the investigation of odor profiles from wood by aroma extract dilution analysis for the creation of a database of wood odors

Odorous volatile organic compound (OVOC) emissions from wood materials can significantly impact air quality in indoor environments which in turn can influence human health and wellbeing. Increasing use of resin-rich softwoods, such as pine, for the purpose of furniture or indoor panel construction therefore brings challenges of odor management, and the need to understand and archive odorant activity across wood types and materials. Dynamic headspace extraction thermal desorption-gas chromatography-olfactometry (DHS-TD-GC-O) in combination with aroma extract dilution analysis (AEDA) was used for the determination of odorant activity expressed as flavor dilution factor (FD factor) from three different types of softwood ( Pinus sylvestris L., Pinus strobus L. and Pinus cembra L.). In combination with flame ionization detection (GC-FID) and mass spectrometry (GC-MS) analysis it was possible to identify over 25 individual odor compounds. By DHS-TD-GC-O 40 individual odor impressions could be reported. By variation of the split ratio, it was possible for the first time to obtain FD factors via the use of thermal desorption, spanning a wide range of 6 to 3072. Octanal, with a factor of 3072 and 2-nonenal with 1536, along with (E, Z)-2,6-nonadienal, 1-octen-3-on, α-pinene and hexanal with 768 were found to possess the highest odor activities for the Pinus sylvestris L. sample. Additionally, a panel of 20 testers revealed sensory profiles in good accordance with the findings by DHS-TD-GC-O, describing a musty-type aroma for Pinus sylvestris L. These findings demonstrate the usefulness of combining DHS-TD with GC-O for the quantitative detection of odorants and efficient determination of their FD factors by aroma extract dilution analysis (AEDA). This represents a big initial step towards the standardization of odor descriptors and FD factors assessment for the creation of a database for softwood odors.