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Author Spotlight: Exploring the Fermentation Microbiome Through Next-Generation Sequencing
Published on: December 1, 2023
Pre-fermentation addition of grape tannin increases the varietal thiols content in wine
Roberto Larcher1, Loris Tonidandel1, Tomás Román Villegas1
1FEM-IASMA Fondazione Edmund Mach - Istituto Agrario di San Michele all'Adige, via E. Mach 1, 38010 San Michele all'Adige (TN), Italy.
Abstract:
The recent finding that grape tannin may contain significant amount of S-glutathionylated (GSH-3MH) and S-cysteinylated (Cys-3MH) precursors of the varietal thiols 3-mercapto-1-hexanol and 3-mercaptohexyl acetate, characteristic of Sauvignon blanc wines, offers new opportunities for enhancing the tropical aroma in fermented beverages. In this study this new hypothesis was investigated: Müller Thurgau (17 samples) and Sauvignon blanc (15 samples) grapes were fermented with and without addition of a selected grape tannin. As expected, the tannin-added juices were higher in precursors, and they produced wines with increased free thiols. Preliminary informal sensory tests confirmed that in particular the Sauvignon wines produced with the tannin addition were often richer with increased "fruity/green" notes than the corresponding reference wines. This outcome confirms that grape tannin addition prior to fermentation can fortify the level of these compounds.
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