Modelização do tratamento térmico de madeira de carvalho português (Quercus Pyrenaica). Análise do comportamento dos compostos fenólicos de baixo peso molecular

Abstract

The heat treatment is of primary significance for the barrel quality. In the last fifteen years many papers have been focused on the effects of heat treatment on the phenolic composition of French and American oak woods, but the oak species grown in Portugal traditionally used in portuguese cooperage have never been studied. In this study we characterised the toasting levels with temperature and time by modelling, in laboratory, the heat treatment applied to barrels of a portuguese oak wood (Quercus pyrenaica) during coopering. The effect on some phenolic acids and aldehydes was acessed by HPLC. In all toasting levels and thoroughout the depth, it was found that the best curve to fit the data was given by a 5th degree polynomial equation. The analysis of phenolic composition indicates that optimization of this technological operation, in order to maximise the quality of the wood barrels, implies the control of both temperature and time. The results also show that the time has a secondary role in comparison with temperature. The phenolic fraction trends to increase with toasting temperature over time.