Evolution of Brettanomyces bruxellensis during secondary fermentation of sparkling wines and counteraction strategies

The scope of this work is the study of the evolution of Brettanomyces bruxellensis, the main wine spoilage yeast, during bottle fermentation of sparkling wines. Lambrusco (Emilia, Italy) was considered as a model wine, for its high concentration of precursors for B. bruxellensis activity, especially cinnamic acids. Five Lambrusco base wines furnished by a cooperative winery were inoculated with a 3-log concentration of B. bruxellensis and then underwent secondary fermentation in the bottle. Two strategies of contrast to B. bruxellensis, already successfully applied in red winemaking, were tested here for the first time in bottle fermentation: chitosan and a yeast proposed as a biocontrol agent. Bottle fermentation was monitored from a chemical and microbiological perspective. The resulting sparkling wines were analyzed by GC and HPLC–MS/MS to verify the presence of the key molecules indicating B. bruxellensis activity—biogenic amines, volatile phenols, and pyridines. Sensory analysis was also performed to establish the effects of the treatments on the overall wine profile. The results demonstrate that B. bruxellensis is capable of growing up to 5-log units, causing severe alterations of the wines, both from a chemical and sensorial point of view. The addition of chitosan at the beginning of bottle fermentation effectively mitigated the effects of B. bruxellensis, resulting in the wines being similar to the uncontaminated control. The effectiveness of the biocontrol agent under these conditions was lower and requires further investigation