The phenolic composition of red wine vinegar produced in barrels made from different woods

The presence of phenolic compounds has been extensively studied in Sherry and Balsamic vinegars due to their impact on quality but little work has been done on red wine vinegars. Phenolic compounds were monitored during the acetification of red wine vinegars produced by surface culture in different wood barrels (oak, chestnut, acacia and cherry). A total of 166 samples were analysed for phenolic compounds using LC-DAD, the total phenol index (TPI) and the total monomeric anthocyanins (TA). Twelve phenolic compounds were identified corresponding to phenolic acids, flavanols and stilbens. Most phenolic acids did not significantly change their concentrations in the different acetifications. (+)-Catechin and resveratrol glycoside underwent significant decreases during acetification while gallic acid and gallic ethyl ester increased substantially for those vinegars produced in chestnut wood. The concentrations of phenolic compounds were used to build the functions for discriminant analysis. Samples belonging to two wine substrates (groups F and T) were correctly classified with 98.6% (group F) and 100% (group T) for the four types of wood barrels. During acetification a decrease (∼50%) in the content of total monomeric anthocyanins was observed. According to the results of triangle difference test the panel was able to distinguish most of the vinegars according to the different woods they were made in. The results of descriptive sensory analysis show that oak and cherry gave the maximum scores for most of the descriptors.