Impact of Malolactic Fermentation on Red Wine Color

In this study the impact of MLF on red wine color and the ability of Oenococcus oeni to degrade\ud compounds important to the development of stable color were studied. Pinot noir and Merlot wines were\ud produced, where simultaneous alcoholic and malolactic fermentations were induced in half of the wines.\ud At dryness, all wines were pressed prior to sterile-filtration through 0.45 μm membranes. Wines that had\ud not undergone malolactic fermentation (MLF (-)) were then either (a) inoculated with one of three strains\ud of O. oeni (MLF (+)) or (b) pH adjusted to the same pH as MLF (+) wines. All wines were sterile-filtered,\ud bottled, and stored at 13°C for analyses. MLF (+) wines had lower concentrations of acetaldehyde,\ud pyruvic acid, and caftaric acid than MLF (–) wines. MLF (+) wines had significantly lower color and\ud polymeric pigments than MLF (–) wines while containing significantly higher monomeric anthocyanins.\ud These differences were consistent throughout 12 months of storage demonstrating that MLF can affect red\ud wine color independent of pH change and that O. oeni can impact phenolic and non-phenolic compounds\ud involved in red wine color development