Hydroxycinnamic acids – As an early biomarker of Brett in Georgian red wines

Abstract

In Georgian red wines, we studied the formation of hydroxycinnamic acids, which are precursors of volatile phenols, the prerequisite for Brett disease. Wines were produced from Georgian red wine grape varieties using classical technology. From the 2025 harvest season, grapes of the Saperavi, Cabernet-Sauvignon, Aleksandrouli, Mujuretuli, Ojaleshi, Tavkveri, and Shavkapito varieties were harvested at technological maturity, processed, and alcoholic fermentation of the destemmed pomace was carried out at 25 °C in three options for each variety: (1) control – spontaneous fermentation; (2) fermentation with the Italian strain CBS2499 of Brettanomyces/Bruxellensis; (3) fermentation with the Georgian strain AUG01 of Brettanomyces/Bruxellensis. These yeast strains were isolated in September 2025 at the University of Milan (Microbiology Laboratory) from Italian and Georgian red wines affected by Brett disease. Yeast strains were identified based on DNA analysis.In the wine materials produced according to these variants, para-coumaric, ferulic and caffeic acids were determined using the HPLC method. In all control wine materials, p-coumaric acid was found to be dominant. Changes in the concentrations of all three acids were observed in the presence of Brettanomyces/Bruxellensis yeasts, with the Italian strain showing a more intense effect compared to the Georgian strain. After completion of the formation process of the experimental wine materials, analysis of hydroxycinnamic acids and volatile phenols in the resulting wines will allow us to confirm our hypothesis—whether hydroxycinnamic acids can be considered an early biomarker of Brett in Georgian red wines.