Nowadays, oak wood chips play a significant role in winemaking and do have a profound effect on the flavor of the finished wine. Aging systems using oak chip treatment can replace maturation in barrels thus, generating wines in a faster way but with similar results in flavor signatures. Besides species and geographic origin, in particular the toasting process of the oak wood is the key step in the formation of aroma-active components.However, although several studies were already conducted on the identification of the complex set of volatiles in oak wood before and after toasting, a systematic approach clarifying the contribution of each volatile to the overall aroma of wine has scarcely been performed. As knowledge on the key odorants present in oak chips is the prerequisite for further studies on the impact on wine aroma, in this study hydro-alcoholic extracts from French oak chips of different toasting degrees (untoasted, medium and heavy) were investigated by means of the Sensomics concept.In total 40 compounds were identified as the most odor-active constituents and were subsequently quantitated by stable isotope dilution assays. In untoasted oak, only 6 odorants exceeded their odor thresholds in ethanol/water, such as trans- and cis-oak lactone, eugenol and trans-2-nonenal. But, in the heavily toasted oak, 14 aroma compounds showed high OAVs and indicated that particularly vanillin, trans-isoeugenol and 2-methoxyphenol were newly formed during thermal processing. Finally, the analytical data were confirmed by preparing aroma recombinates in water/ethanol using the quantitated compounds in their natural concentrations.

Influence of the toasting process on the formation of key aroma compounds in French oak (<i>Q.</i> <i>robur</i>)

248th National Meeting (2014)

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Influence of the toasting process on the formation of key aroma compounds in French oak (Q. robur)