Odorous Impact of Volatile Thiols on the Aroma of Young Botrytized Sweet Wines:  Identification and Quantification of New Sulfanyl Alcohols

Abstract

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.

Botrytized wines – current perspectives

“…During the last decade, several new volatile thiols have been identified as important odorants of Sauternes wines, such as 3-methyl-3-sulfanylbutanal (bacon-petroleum), 63 3-sulfanylpentan-1-ol (3SP, citrus and sulfur), 3-sulfanylheptan-1-ol (3SHp, grapefruit), and 2-methyl-3-sulfanylbutan-1-ol (2M3SB, raw onion). 70 Thiols are practically not present in grape, only in wines, and are released from precursor molecules during alcoholic fermentation, as presented in a previous section. Botrytis infection highly enhances the formation of the precursors in the grape, and the various yeast strains have a further impact on the final composition of thiols in the wine.…”

Origins of Grape and Wine Aroma. Part 1. Chemical Components and Viticultural Impacts

“…The most abundant volatile sulfur compounds in wines are H 2 S, methanthiol, dimethylmercaptans (dimethylsulfide, dimethyldisulfide, dimethyltrisulfide), methylthioesters (Smethyl thioacetate, S-methyl thiopropanoate, and S-methyl thiobutanoate), and liberated glutathione and cysteine polyfunctional thiols (4-mercapto-4-methylpentan-2-one, 4MMP; 3-mercaptohexan-1-ol, 3MH; and 3-mercaptohexyl acetate, 3MHA) , Dubourdieu and Tominaga 2009, Roland et al 2010. A myriad of other sulfur-containing compounds have been identified in wines, suggesting that there is still much to be discovered in this area , Bailly et al 2006, Sarrazin et al 2007b, Dubourdieu and Tominaga 2009.…”

Selective preconcentration of volatile mercaptans in small SPE cartridges: Quantitative determination of trace odor‐active polyfunctional mercaptans in wine

“…On the other hand, the most powerful aroma molecules in nature are polyfunctional mercaptans, which are molecules combining a second chemical functionality in the molecule. Most of such polyfunctional mercaptans have very strong and distinctive smells and are responsible for the aroma and flavor of numerous vegetable species, such as box, blackcurrant, grapefruit [4], passion fruit [5,6], onions [7,8] and green tea [9], of some foods such as coffee [10,11], meat [12][13][14], Iberian ham [15] and wine [16][17][18][19] and even have been described as majorly responsible for the odor of some species of mammals such as skunks [20], cats [21] or even humans [22]. There is an obvious need for analytical strategies not only for their quantitative determination, but also for their selective isolation.…”