Occurrence of Ehrlich-Derived and Varietal Polyfunctional Thiols in Belgian White Wines Made from Chardonnay and Solaris Grapes

Chenot, Cécile [UCL] Briffoz, Laura [UCL] Lomartire, Antonin [UCL] Collin, Sonia [UCL]

Although almost disappeared at the end of the 20th century, Belgian wine production reached a million liters in 2017. The aim of the present work was to identify aroma markers for two white cultivars widespread in Belgium: Chardonnay (the most commercially grown cultivar worldwide) and Solaris (an interspecific fungus-resistant variety). Specific p-hydroxymercuribenzoic acid extraction followed by gas chromatography with a pulsed flame photometric detector was applied to single-varietal wine samples from 2015 to 2018 harvests. Among the Ehrlich-derived thiols, all found below their sensory thresholds, 3-sulfanylpropyl acetate usually outranged 3-sulfanylpropan-1-ol, while 2-sulfanylethan-1-ol concentrations always exceeded 2-sulfanylethyl acetate levels. The data confirm the occurrence, in both Chardonnay and Solaris wines, of 3-sulfanylhexan-1-ol and phenylmethanethiol (grapefruit and gunflint aroma, respectively), at concentrations far above their thresholds. This work also revealed, for the first time, the presence of 3-sulfanylheptan-1-ol, the branched alcohols 2-methyl-3-sulfanyl propan-1-ol, 2-methyl-3-sulfanylbutan-1-ol, and 3-sulfanyl-3-methylbutan-1-ol, and the carbonyls 3-sulfanylbutan-2-one (not in sparkling wines) and 3-sulfanylpentanal.