Impact of Oenococcus oeni on Wine Hydroxycinnamic Acids and Volatile Phenol Production by Brettanomyces bruxellensis

The ability of commercial strains of Oenococcus oeni to degrade tartaric acid ester-bound hydroxycinnamic acids (TAE-HCAs) and their impact on the production of volatile phenols by Brettanomyces bruxellensis was investigated. Of 10 commercial O. oeni strains evaluated, only one strain, O. oeni Viniflora Oenos (VFO), was able to degrade TAE-HCAs during growth in a Pinot noir wine. This degradation resulted in an increase in the corresponding free forms of the hydroxycinnamic acids in the wine. As a result, growth of B. bruxellensis UCD-2049 in Pinot noir wine where malolactic fermentation (MLF) was conducted by VFO resulted in higher concentrations of 4-ethylphenol and 4-ethylguaiacol in this wine than in wine that did not undergo MLF or underwent MLF with O. oeni strains that did not degrade TAE-HCAs. While wineries must continue to use sound winemaking practices to prevent the growth of Brettanomyces spp. in their wines, minimizing the amount of free hydroxycinnamic acids in the wine will reduce the production of volatile phenols if growth of Brettanomyces spp. does occur. The use of an O. oeni strain that cannot degrade TAE-HCAs is a simple and practical strategy to help achieve this.