Differences in the Extraction of Volatile Compounds from Oak Chips in Wine and Model Solutions

Abstract

Studies on the accumulation of oak-derived volatile compounds in wine and on the effects of different factors on the final concentration of these compounds are usually conducted with wine samples and with model solutions; the results obtained with model solutions are generally assumed to be comparable to results that would have been obtained with real wine. This present study was designed to test this assumption and to assess whether the studies with model solutions could be useful for explaining the behavior of these volatile compounds during aging. The evolution of the concentration of oak-derived volatile compounds (furfuryl and guaiacyl compounds, cis- and trans-β-methyl-γ-octalactone, and vanillin) was studied in wine and model solutions containing oak chips. Given that the physicochemical properties of the wine or the model solutions might also influence extraction, the model solutions were adjusted to three different titratable acidity values and three different alcohol percentages. The extraction rate and final quantities of guaiacyl derivates and lactones in model solutions were very similar to those observed in wines. However, the behavior of other compounds, such as furfuryl and vanillin, depended on the type of matrix in which the oak chips were soaked. The physicochemical properties of the matrix should also be taken into account when studying the extraction of oak-derived volatile compounds, because these properties can affect the accumulation of some compounds, such as lactones.