Bioprotection using a selected strain of <i>Metschnikowia pulcherrima</i> as an alternative to SO<sub>2</sub> for preventing the browning of white grape must

Enzymatic browning of grape must still represent one of the major problems in oenology today (Li et al., 2008), and is especially serious when the grapes are affected by grey rot (Ky et al., 2012). Sulphur dioxide is the most common tool used in wineries to protect grape must against enzymatic browning. This additive is a potent inhibitor of tyrosinase and laccase (Giménez et al., 2023) and also has antimicrobial properties (Ough and Crowell, 1987). However, the wine industry is currently trying to reduce and even eliminate sulphur dioxide due to its negative effects on the environment and human health. Hence, to prevent browning, some alternatives to sulphur dioxide additives have been proposed over recent years, such as the use of inert gases, oenological tannins, ascorbic acid, reduced glutathione, inactivated dry yeasts rich in glutathione and bioprotection using some Non-Saccharomyces yeasts (Giménez et al., 2023; Windholtz et al., 2023; Bustamante et al., 2024a). Different microorganisms have been proposed for Bioprotection, but according to recent literature, Metschnikowia pulcherrima seems to be the most promising microorganism for wine bioprotection against enzymatic browning due to its high capacity for consuming oxygen (Giménez et al., 2023; Bustamante et al., 2024b). The aim of this paper is therefore to study the bioprotective effect of a selected strain of Metschnikowia pulcherrima (MP1) against enzymatic browning caused by polyphenol oxidases.