A. Pedro Belchior

Influence of Botanical Species and Geographical Origin on the Content of Low Molecular Weight Phenolic Compounds of Woods Used in Portuguese Cooperage

Summary The influence of botanical species (Quercus and Castanea sativa) and geographical origin (Portugal—three different sites, France and North America) on the qualitative and quantitative content of some extractable low molecular weight phenolic compounds was assessed by HPLC. Chestnut wood had the highest total content of low molecular weight phenolic compounds, followed by the Portuguese oaks and the French oaks, whereas the American oak had the lowest content of these compounds. The contents of phenolic acids, phenolic aldehydes, scopoletin and umbelliferone were significantly different among the studied woods. Both the botanical species and the geographical origin affect the content of low molecular weight organic compounds of woods used in Portuguese cooperage. The results also show that the botanical species seem to be more important than the geographical origin to explain the difference in the wood phenolic composition. So, the separation of trees according to their origin is of considerable interest for coopers and winemakers to choose wisely the woods for the ageing of brandies.

Extraction/oxidation kinetics of low molecular weight compounds in wine brandy resulting from different ageing technologies

This study provides innovative information on the influence of new technologies of ageing (stainless steel tanks with wood staves or wood tablets of chestnut or Limousin oak), in comparison with traditional technology (oak wooden barrels), on the extraction/oxidation kinetics of low molecular weight compounds of wine brandy. The brandy was sampled and analysed by HPLC during the first year of ageing. The results show that most of the compounds tend to increase over the time, but their extraction/oxidation kinetics depend on the ageing technology. The wooden barrels promote greater enrichment in the majority of the compounds. However, gallic acid, ellagic acid and syringaldehyde, and vanillin and 5-methylfurfural, which are strong antioxidants and key-odourant compounds, respectively, present higher contents in the brandy aged with the alternative technologies. Chestnut proves to be a suitable alternative to Limousin oak for the ageing of brandy in all the studied technologies, inducing faster evolution and high quality.

Kinetics of odorant compounds in wine brandies aged in different systems.

The odorants compounds of aged wine brandies comprise compounds deriving from the wood, from the distillate and from the reactions that occur inside the barrel. The aim of this work was to study the kinetics of the odorant compounds of a wine brandy during two years of ageing in two ageing systems. The odorant compounds in the analysed brandies changed significantly over the time, but with different evolution patterns. The wood related compounds increased over time, with the highest increase in the first months of ageing. The kinetics of cis, trans-β-methyl-γ-octalactone, acetovanillone and of seven volatile phenols are established for the first time in brandies. Moreover, a significant effect of the ageing system was found on the kinetics of the wood related compounds. These results pointed out the interest of these compounds as a tool to discriminate different ageing technologies.