Non-Saccharomyces as Biotools to Control the Production of Off-Flavors in Wines

Off-flavors produced by undesirable microbial spoilage are a major concern in wineries, as they affect wine quality. This situation is worse in warm areas affected by global warming because of the resulting higher pHs in wines. Natural biotechnologies can aid in effectively controlling these processes, while reducing the use of chemical preservatives such as SO2. Bioacidification reduces the development of spoilage yeasts and bacteria, but also increases the amount of molecular SO2, which allows for lower total levels. The use of non-Saccharomyces yeasts, such as Lachancea thermotolerans, results in effective acidification through the production of lactic acid from sugars. Furthermore, high lactic acid contents (>4 g/L) inhibit lactic acid bacteria and have some effect on Brettanomyces. Additionally, the use of yeasts with hydroxycinnamate decarboxylase (HCDC) activity can be useful to promote the fermentative formation of stable vinylphenolic pyranoanthocyanins, reducing the amount of ethylphenol precursors. This biotechnology increases the amount of stable pigments and simultaneously prevents the formation of high contents of ethylphenols, even when the wine is contaminated by Brettanomyces.

Automated summary

Off-flavors due to microbial spoilage are a major concern for wineries, especially in warm regions affected by global warming. Natural biotechnologies such as bioacidification and the use of non-Saccharomyces yeasts can help control these processes and reduce the use of chemical preservatives. By promoting fermentative formation of stable pigments and inhibiting the formation of ethylphenols, these biotechnologies can improve wine quality even in the presence of Brettanomyces contamination.