Odorous impact of volatile thiols on the aroma of young botrytized sweet wines: identification and quantification of new sulfanyl alcohols.

Specific extraction of volatile thiols using sodium p-hydroxymercuribenzoate revealed the presence of three new sulfanylalcohols in wines made from Botrytis-infected grapes: 3-sulfanylpentan-1-ol (II), 3-sulfanylheptan-1-ol (III), and 2-methyl-3-sulfanylbutan-1-ol (IV). The first two have citrus aromas, whereas the third is reminiscent of raw onion. In addition, 2-methyl-3-sulfanylpentan-1-ol, which has a raw onion odor, was tentatively identified. Like 3-sulfanylhexan-1-ol (I), already reported in Sauternes wines, compounds II, III, and IV were absent from must. They were found in wine after alcoholic fermentation, and their concentrations were drastically higher when Botrytis cinerea had developed on the grapes. In the commercial botrytized wines analyzed, the mean levels of II, III, and IV were 209, 51, and 103 ng/L, respectively. Despite their low odor activity values, sensory tests showed additive effects among I, II, and III, thus confirming their olfactory impact on the overall aroma of botrytized wines.