RESUMO
Interest in Metschnikowia (M.) pulcherrima is growing in the world of winemaking. M. pulcherrima is used both to protect musts from microbial spoilage and to modulate the aromatic profile of wines. Here, we describe the isolation, characterization, and use of an autochthonous strain of M. pulcherrima in the vinification of Chasselas musts from the 2022 vintage. M. pulcherrima was used in co-fermentation with Saccharomyces cerevisiae at both laboratory and experimental cellar scales. Our results showed that M. pulcherrima does not ferment sugars but has high metabolic activity, as detected by flow cytometry. Furthermore, sensory analysis showed that M. pulcherrima contributed slightly to the aromatic profile when compared to the control vinifications. The overall results suggest that our bioprospecting strategy can guide the selection of microorganisms that can be effectively used in the winemaking process.
RESUMO
A fast, sensitive and reproducible method using LC-MS/MS for simultaneous quantification of glutathione (GSH), glutathione disulfide (GSSG) and glutathione-S-sulfonate (GSSO3H) was developed, optimised and applied in analysis of grape juice and wine samples. The results show that only GSH (10-60 mg·L-1) and GSSG (2-11 mg·L-1) are found in grape juice when SO2 is not added. GSSO3H was detected in must samples treated with SO2 but only at a low concentration (<1 mg L-1). In the wine samples, the dominant form of glutathione was GSSO3H (5-11 mg L-1), followed by GSH (0-5 mg L-1) and GSSG (0-6 mg L-1), underscoring the importance of GSSO3H quantification. GSSO3H formation in wine was correlated with the total SO2 level in the wine. We believe this is the first report on GSSO3H quantification in wine.