Eliminating Brettanomyces and lactic acid bacteria in wine: the potential of Ultra-High Pressure Homogenization (UHPH)

Abstract

Ultra-High Pressure Homogenization (UHPH) is an innovative technology that can be seamlessly integrated at various stages of winemaking. Its application helps minimize or even eliminate the need for sulphites and other antimicrobial or antioxidant treatments, offering a faster and more sustainable alternative. Recently, the OIV has approved UHPH among the recommended practices in the international oenological code [1]. UHPH is a continuous, high-pressure process applied directly to the wine, which is pumped into the equipment at a pressure of 200 MPa or higher and then rapidly depressurized through a high-resistance valve. As wine passes through the valve, it undergoes intense mechanical forces, primarily impact and shear, along with cavitation and friction. These forces generate a potent antimicrobial effect by effectively eliminating microorganisms such as yeasts and bacteria [2, 3, 4]. This study explores the potential of UHPH as an effective technique for the inactivation of Brettanomyces sp., a spoilage yeast in winemaking. Additionally, in base wine intended for sparkling wine production, UHPH is evaluated as a preventive solution against a common challenge faced by some producers: the occurrence of malolactic fermentation (MLF) in the bottle, which compromises the sensory quality of the final product. So, the study also aims to assess the effectiveness of UHPH in eliminating lactic acid bacteria (LAB). Red wines naturally contaminated with Brettanomyces were treated with UHPH at 300 MPa and compared to untreated control wines and treated with chitosan. The evolution of this yeast population, volatile phenols, and acetic acid in bottled wines was monitored over time. The UHPH treatment effectively inactivated Brettanomyces, resulting in a >5 log reduction in the population of this spoilage yeast after 6 months of aging. To study the inhibitory effect of UHPH on lactic acid bacteria in base wines, MLF was induced, and three conditions were analysed: a control condition (C -), where MLF was not induced in the base wine; a second control condition (C +), where MLF in the bottle was not stopped by any method; and a third condition with UHPH treatment at 300 MPa and an inlet t^a of 30ºC (UHPH), aimed at eliminating LAB present in the base wines to prevent MLF. The population of LAB, along with malic and lactic acid levels, was measured at 0 and 42 days, and after 5 months of sparkling wine aging. The UHPH treatment achieved >7 log reduction in LAB cells, effectively preventing MLF.

Acknowledgements

Project FRUHPH “Application of Ultra High Pressure Homogenization in fruit juices and wines to improve quality and preservation without additives”. Grup Operatiu from Generalitat de Catalunya (PDR 2014-2022).

References

[1] OIV. RESOLUTION OIV-OENO 594B (2020). https://www.oiv.int/public/medias/7587/oiv-oeno-594b-2020-en.pdf

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