Phenolic composition of Bordeaux grapes 2009 vintage: comparison with 2006, 2007 and 2008 vintages

The cultivar with a greater oenological potential was ‘Monastel’, which showed overall better values than ‘Tempranillo’ in colour intensity, total polyphenol index, wine colour, total anthocyanins, resveratrol and gallic acid.

The aim of this work was the identification and quantification of polyphenols present in natural precipitate of a Sauvignon wine. Phenol analysis in wine precipitate was based on acid hydrolysis, CG- MS after derivatization, and LC-MS.

White wines are commonly stabilised by removing the heat unstable proteins through adsorption by bentonite, an effective but inefficient wine processing step. Alternative absorbents are thus sought and zirconium dioxide (zirconia) is recognised as a promising candidate.

A great variability in the amount of polysaccharides recovered at the end of fermentations carried out by pure cultures of 89 non-Saccharomyces yeasts was observed. The utilization of the best polysaccharides producers in mixed cultures with S. cerevisiae resulted in considerable increases in the final concentration of polysaccharides and showed a strain dependent effect on glycerol production as compared to pure culture of S. cerevisiae.

In this study for the first time, eight natural stilbenes (trans-resveratrol, trans-piceid, cis-piceid, trans-astringin, trans-piceatannol, (+)-trans-s-viniferin, pallidol and hopeaphenol) isolated and purified from Vitis vinifera, were simultaneously separated and analysed within 5 mn by ultra high pressure liquid chromatography coupled with photodiode array detection.