Contribution of cysteine and glutathione conjugates to the formation of the volatile thiols 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA) during fermentation by Saccharomyces cerevisiae

Winter, G., van der Westhuizen, T., Higgins, V. J., Curtin, C. and Ugliano, M. (2011) Contribution of cysteine and glutathione conjugates to the formation of the volatile thiols 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA) during fermentation by Saccharomyces cerevisiae. Australian Journal of Grape and Wine Research, 17 2: 285-290. doi:10.1111/j.1755-0238.2011.00127.x


Author Winter, G.
van der Westhuizen, T.
Higgins, V. J.
Curtin, C.
Ugliano, M.
Title Contribution of cysteine and glutathione conjugates to the formation of the volatile thiols 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA) during fermentation by Saccharomyces cerevisiae
Journal name Australian Journal of Grape and Wine Research   Check publisher's open access policy
ISSN 1322-7130
1755-0238
Publication date 2011-01-01
Sub-type Article (original research)
DOI 10.1111/j.1755-0238.2011.00127.x
Volume 17
Issue 2
Start page 285
End page 290
Total pages 6
Place of publication Richmond, VIC Australia
Publisher Wiley-Blackwell Publishing Asia
Collection year 2011
Language eng
Formatted abstract
Background and Aims: 3-Mercaptohexan-1-ol (3MH) and its ester 3-mercaptohexyl acetate (3MHA) are potent aromatic thiols that substantially contribute to varietal wine aroma. During fermentation, non-volatile 3MH conjugates are converted by yeast to volatile 3MH and 3MHA. Two types of 3MH conjugates have been identified, S-3-(hexan-1-ol)-L-cysteine (Cys-3MH) and S-3-(hexan-1-ol)-glutathione (GSH-3MH). Yeast-driven formation of 3MH from these precursors has been previously demonstrated, while the relationship between 3MHA and GSH-3MH remains to be established. This paper aims to investigate yeast conversion of GSH-3MH to 3MH and 3MHA, and to assess the relative contribution of each individual conjugate to the 3MH/3MHA pool of finished wines.

Methods and
Results: Fermentation experiments were carried out in model grape juice containing Cys-3MH and GSH-3MH. We found 3MH formation from GSH-3MH to be significantly less efficient than that of Cys-3MH. Conversely, esterification of 3MH to 3MHA was higher when 3MH was formed from GSH-3MH. Additional in vitro assays for measuring enzyme cleavage activity suggest the involvement of a different mechanism in 3MH conversion for the two precursors.

Conclusions: These results indicate that although both 3MH conjugates can be converted by yeast, the type of precursor affects the rate of formation of 3MH and 3MHA during fermentation. Significance of the Study: Management of the pool of aromatic thiols during fermentation can depend on relative proportions of different 3MH conjugates.
Keyword Fermentation
Thiol precursor
Sauvignon Blanc Wines
Alcohol Acetyltransferase
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Advanced Water Management Centre Publications
 
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Created: Mon, 15 Apr 2013, 19:36:54 EST by Gal Winter on behalf of Advanced Water Management Centre