Effects of vineyard biological control agents on fermentation and wine quality

Abstract

The reduction of synthetic fungicide use in viticulture has promoted the development of alternative strategies such as Biological Control Agents (BCAs) for the control of Botrytis cinerea. Although several BCAs have proven effective in limiting disease incidence in vineyards, their potential impact on the evolution of the alcoholic fermentation and the final wine quality requires further evaluation. In this study, the potential effect of four different BCAs (Bacillus velezensis, Aureobasidium pullulans, Hanseniaspora uvarum and Pichia kudriavzevii) on the winemaking process was investigated using two grape varieties (Nebbiolo and Trebbiano). Grapes were inoculated with each BCA prior to vinification, followed by alcoholic fermentation initiated by inoculation with Saccharomyces cerevisiae. Fermentation kinetics and microbial population dynamics were monitored to evaluate S. cerevisiae performance and changes in the associated microbial communities during alcoholic fermentation. Must and wine samples were collected at different fermentation stages for subsequent chemical analysis, including organic acids and volatile compound profiles. Additionally, sensory analysis was conducted to evaluate possible effects of the treatments on wine sensory attributes. The results showed that although some BCAs initially affected fermentative vigor, all fermentations reached dryness (residual sugars < 0.5 g/L), indicating that yeast activity was not adversely affected. Notably, the use of certain BCAs led to favorable analytical changes: A. pullulans increased glycerol content, a compound associated with enhanced wine body, while several treatments significantly reduced volatile acidity in Trebbiano wines compared to the untreated control. Furthermore, grape treatment with H. uvarum resulted in a decrease in malic acid concentration in Nebbiolo wines. In summary, these findings suggest that the evaluated BCAs are compatible with the winemaking process and can modulate specific chemical and sensory parameters, supporting their use as sustainable tools for the control of B. cinerea in viticulture without compromising, and potentially enhancing, wine quality.

References

Zhang, H.; Godana, E.A.; Sui, Y.; Yang, Q.; Zhang, X.; Zhao, L. (2020). Biological control as an alternative to synthetic fungicides for the management of grey and blue mould diseases of table grapes: a review. Crit. Rev. Microbiol. 46(4), 450–462.