Modulation of volatile thiol and ester aromas by modified wine yeast

Jan H. Swiegers*, Robyn Willmott, Alana Hill-Ling, Dimitra L. Capone, Kevin H. Pardon, Gordon M. Elsey, Kate S. Howell, Miguel A. de Barros Lopes, Mark A. Sefton, Mariska Lilly, Isak S. Pretorius

*Corresponding author for this work

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

The volatile thiols, in particular 4-mercapto-4-methylpentan-2-one (4MMP), 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA) are potent aroma shown to contribute strongly to the varietal aroma of Sauvignon Blanc wines. The thiols 4MMP and 3MH exist as non-volatile, aroma-inactive cysteine bound conjugates in the grape must and during fermentation the thiol is cleaved from the precursor. However, no cysteine conjugate for 3MHA has been identified. In this work we showed that 3MHA is formed from 3MH by the wine yeast Saccharomyces cerevisiae during fermentation. Furthermore, the alcohol acetyltransferase, Atf1p, the enzyme involved in the formation of the ester ethyl acetate, was shown to be the main enzyme responsible for the formation of 3MHA. Both a laboratory yeast and a commercial wine yeast overexpressing the ATF1 gene produced significantly more 3MHA than the wild-type. Although an atf1Δ laboratory yeast strain showed reduced 3MHA formation, it was not abolished, indicating that other enzymes are also responsible for its formation. Therefore, overexpression of the ATF1 gene in a wine yeast presents the possiblity of modulating both the thiol and ester aromas in wine.

Original languageEnglish
Pages (from-to)113-116
Number of pages4
JournalDevelopments in Food Science
Volume43
Issue numberC
DOIs
Publication statusPublished - 2006
Externally publishedYes

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