Optimisation of pressurised liquid extraction for the determination of monosaccharides and polyalcohols in woods used in wine aging

BACKGROUND: The carbohydrate profile of woods used to age wines and spirits is largely unstudied in spite of its possible influence on the quality of aged beverages. This experiment evaluated the feasibility of employing pressurised liquid extraction to isolate monosaccharides and polyalcohols from woods used in aging, yielding a reliable analytical extraction method for characterising these compounds. Various solvents were tested and the extraction procedure was optimised by a three-level factorial experimental design based on two main factors: extraction temperature and extraction time. The total extraction yield of target compounds was taken as response variable, and model parameters were estimated by multiple linear regression. RESULTS: Methanol was best at extracting the target compounds and hence was selected as solvent. Temperature was the most important factor in the extraction process, and the optimal extraction conditions were 90 degrees C for 15 min. CONCLUSION: Pressurised liquid extraction proved to be a highly suitable and powerful technique for extracting the monosaccharides and polyalcohols from wood samples. Analysis of the carbohydrate profile of the woods revealed differences among samples of different species and types of wood. (C) 2009 Society of Chemical Industry