Impact of toasting and botanical origin on oak wood (Q. sp.) volatilome using untargeted GCxGC-ToFMS analysis
Many works have been carried out to identify the key aroma volatile compounds of oak wood (e.g., whisky-lactone, furfural, maltol, eugenol, guaiacol, vanillin) using conventional gas chromatography coupled with olfactometry and mass spectrometry (GC-O-MS). Inspired by recent untargeted approaches in the field of food “omics”, this work aims to extend our knowledge on the impact of cooperage process on the volatile composition of oak wood using two-dimensional comprehensive gas chromatography coupled with time of flight mass spectrometry (GCxGC-ToFMS).
In a first experiment, five levels of toasting intensity were selected and applied to Q. sessilis oak wood samples (control, 160 °C, 180 °C, 200 °C and 220 °C, 30 min, n=3). Organic extracts were prepared (CH2Cl2, 50 g/L) and analyzed by GCxGC-ToFMS on a combination of conventional nonpolar/midpolar columns (DB-5ms/Rxi-17Sil). Data processing was as follows: mass spectra (TIC) were deconvoluted (ChromaTOF software) and compared to spectra from a database for a tentative peak identification and some “filters” were applied to reduce the number of processed peaks. Using an R script, we identified 77 molecular markers associated with toasting intensity. Some of them were sensory active and well known in oak wood, such as guaiacol, creosol and isoeugenol, while others were identified for the first time, such as 2-methylbenzofuran (burnt), 3-methylcyclohexane-1,2-dione (coffee) and 2-hydroxy-2-cyclopenten-1-one (caramel). Their sensory impact was assessed by GC-MS and sensory analysis. Applying the same methodology through the previously developed R script, additional results were discussed on the ability of GCxGC-ToFMS to distinguish the botanical origins of oak wood (Q. sessilis, Q. robur, Q. alba).
Issue: ICGWS 2023
1Univ. Bordeaux, Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, F-33140 Villenave d’Ornon, France
2Bordeaux Sciences Agro, Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, F-33170 Gradignan, France
3Tonnellerie Seguin Moreau, Merpins, France
4ENSCBP, Bordeaux INP, 33600, Pessac, France