Phenolic compounds in red wine subjected to industrial malolactic fermentation and ageing on lees

A liquid chromatography method with photodiode array and mass spectrometry detection was applied to study the changes in non-anthocyanin phenolic compounds from 47 red wines as a result of different technological processes. The procedures used include: malolactic fermentation in barrels or in stainless steel containers, the ageing of wines or not in the presence of lees, including periodic stirring of the lees, racking, clarification, cold stabilization and filtration. Wine samples were taken before and after malolactic fermentation and during the 3 months of the experiment until they had been aged for 14 months in oak barrels. Cluster analysis, analysis of variance and stepwise discriminant analysis were applied to the wine data. During malolactic fermentation, disappearance of the tartaric esters of caffeic acid (caftaric acid) and p-coumaric acid (coutaric acid) was detected, coinciding with an increase in the corresponding free acids. With the statistical treatments used, the greatest differences in the low molecular weight phenolic compounds in the wines were due to ageing time, whereas the winemaking practice did not significantly influence phenolic compounds. A significant change in the concentration of most phenolic compounds was observed in the wine at the end of the 14 months of ageing.