How to modulate the formation of negative volatile sulfur compounds during wine fermentation?

Rafael Jimenez-Lorenzo,Jean-Marie Sablayrolles,Carole Camarasa,Audrey Bloem,Vincent Farines

doi:10.1093/femsyr/foab038

Abstract

ABSTRACTBeyond the production of positive aromas during alcoholic fermentation, Saccharomyces cerevisiae metabolism also results in the formation of volatile compounds detrimental to wine quality, including a wide range of volatile sulfur compounds (VSCs). The formation of these VSCs during wine fermentation is strongly variable and depends on biological and environmental factors. First, the comparison of the VSCs profile of 22 S. cerevisiae strains provided a comprehensive overview of the intra-species diversity in VSCs production: according to their genetic background, strains synthetized from 1 to 6 different sulfur molecules, in a 1- to 30-fold concentration range. The impact of fermentation parameters on VSCs production was then investigated. We identified yeast assimilable nitrogen, cysteine, methionine and pantothenic acid contents – but not SO2 content – as the main factors modulating VSCs production. In particular, ethylthioacetate and all the VSCs deriving from methionine catabolism displayed a maximal production at yeast assimilable nitrogen concentrations around 250 mg/L; pantothenic acid had a positive impact on compounds deriving from methionine catabolism through the Ehrlich pathway but a negative one on the production of thioesters. Overall, these results highlight those factors to be taken into account to modulate the formation of negative VSCs and limit their content in wines.

Highlights

Wine aroma is one of the most important determinants of quality, because the perception of volatile molecules through their interactions with the consumer’s olfactory senses strongly contributes to the acceptance or rejection of the product
Only 10 (SMTA, ethylthio acetate (ETA), MTHTP, 2MTE, ethyl 3-(methylthio)-propanoic acid (E3MTP), 3MTPAc, ME, ETP, 3-(methylthio)-propanoic acid (3MTPA) and 2ME) of the 17 compounds analyzed were detected in the wines
In addition to H2S whose formation has been extensively investigated (Spiropoulos et al 2000; Linderholm et al 2008; Ugliano et al 2009; Huang et al 2017), a wide range of volatile sulfur compounds (VSCs) can be synthetized during fermentation, with even a low level of production negatively impacting wine quality

Summary

Introduction

Wine aroma is one of the most important determinants of quality, because the perception of volatile molecules through their interactions with the consumer’s olfactory senses strongly contributes to the acceptance or rejection of the product. Volatile sulfur compounds (VSCs) are an important class due to their abundance and their strong impact on the final quality of wines due to a very low perception threshold. Sulfur compounds are considered as a ‘double edged-sword’ as some of them positively contribute to wine aroma, whereas others are considered as off-flavors (reductive aromas) undesirable in wines.

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