Development of a New Assay for Measuring H2S Production during Alcoholic Fermentation: Application to the Evaluation of the Main Factors Impacting H2S Production by Three Saccharomycescerevisiae Wine Strains

Irene De Guidi,Jean-Luc Legras,Bruno Blondin,Vincent Farines

doi:10.3390/fermentation7040213

Abstract

Hydrogen sulfide (H2S) is the main volatile sulfur compound produced by Saccharomycescerevisiae during alcoholic fermentation and its overproduction leads to poor wine sensory profiles. Several factors modulate H2S production and winemakers and researchers require an easy quantitative tool to quantify their impact. In this work, we developed a new sensitive method for the evaluation of total H2S production during alcoholic fermentation using a metal trap and a fluorescent probe. With this method, we evaluated the combined impact of three major factors influencing sulfide production by wine yeast during alcoholic fermentation: assimilable nitrogen, sulfur dioxide and strain, using a full factorial experimental design. All three factors significantly impacted H2S production, with variations according to strains. This method enables large experimental designs for the better understanding of sulfide production by yeasts during fermentation.

Highlights

Saccharomyces cerevisiae yeast is one of the most important microorganisms in winemaking, mainly because it has an unrivalled ability to ferment sugars, producing heat, carbon dioxide and ethanol
As H2 S is produced all along fermentation, it is necessary to trap this gas to assess the total production of one alcoholic fermentation
We used the capacity of metal salts to trap H2 S during alcoholic fermentation of a sulfide producing yeast MTF1832 in SM200 medium

Summary

Introduction

Saccharomyces cerevisiae yeast is one of the most important microorganisms in winemaking, mainly because it has an unrivalled ability to ferment sugars, producing heat, carbon dioxide and ethanol. It can colonize its environment, coping successfully with adverse conditions prevailing in grape juice, such as low pH, high initial sugar content and increasing concentrations of alcohol. Alcoholic fermentation and yeast multiplication in grape must are accompanied by the production of numerous metabolites necessary for yeast growth These metabolites can be excreted from the cell (i.e., into the must) and may have an impact on wine aroma, color or taste. Hydrogen sulfide is highly reactive: its combination with either must or wine molecules can lead to the synthesis of other volatile sulfur compounds such as ethanethiol [3], dimethyl disulfide, dimethyl trisulfide, and dimethyl tetrasulfide, known to be detrimental to wine quality (reviewed by Waterhouse, Sacks and Jeffery [4])

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