Analysis of non-coloured phenolics in red wine: Effect of Dekkera bruxellensis yeast

The non-coloured phenolic composition of red wine obtained from Touriga Nacional grapes growing in the Dão region (Portugal) was determined by HPLC/DAD and 16 compounds were identified and quantified. The effect of nine different Dekkera bruxellensis strains on the levels of phenolic acids and flavonoids of the wine were also evaluated. In all samples (inoculated and non inoculated), phenolic acids predominated over flavonoids. In inoculated samples a considerable rise in the amounts of gallic acid was observed (about 33%) while the amounts of t-CAFTA, t-COUTA, caffeic and p-coumaric acids suffered a statistically significant decrease.