Chemical compounds released from five different woods used to make barrels for aging wines and spirits: volatile compounds and polyphenols

Aging wine and spirits in wooden barrels is an industrial process used to stabilize color and improve limpidity; many compounds are released from the wood and enrich the sensorial characteristics of the product. The main wood species used for making barrels is oak, but in particular cases also acacia, chestnut, cherry and mulberry. In this work, polyphenols contained in the extracts of these wood species obtained by solutions of 50% hydroalcohol as well as a model wine were studied and compared with the extracts from oak. The hydroalcoholic extracts of chestnut and mulberry had higher total polyphenols, followed by cherry, acacia and oak, respectively. The oak model wine extract had the highest percentage of polyphenols extractable by the wine, followed by chestnut, acacia, cherry and mulberry, respectively. Chestnut extracts had the highest percentage of oxidizable compounds, followed by acacia, oak, mulberry and cherry. The GC/MS-EI profile of 50% hydroalcoholic extracts revealed as principal volatiles several benzene compounds containing a guaiacol residue, and high contents of C-6-C-18 fatty acids. To our knowledge, this is the first study reporting on polyphenolic and complete volatile compounds characterization of these woods for oenological purposes.