Condensed Tannin Reacts with SO2 during Wine Aging, Yielding Flavan-3-ol Sulfonates

• DOI: 10.1021/acs.jafc.8b01996
• Publication Date: 2018-05-24T10:08:01Z
• Authors: Lingjun Ma; Aude A. Watrelot; Bennett Addison; Andrew L. Waterhouse
• Keywords: Flavan; Tannin; Condensed tannin; Terroir

Numerous monomeric and oligomeric flavanol sulfonation products were observed in 10 wines. Levels of 0.85-20.06 0-14.72 mg/L quantified for two sulfonated flavan-3-ols and, surprisingly, generally higher than the well-known native flavan-3-ol monomers. Increasing SO2 levels during wine aging increased sulfonate-modified monomers dimers along with concentrations The results indicate that >10% is reacting C-4 carbocation, formed from acid cleavage interflavan bond, perhaps by a bimolecular SN2-type reaction, as reducing agent. In addition, high had lowest protein-binding tannin levels, activity, mean degree polymerization (mDP), acidic treatment condensed abolishes protein binding. Thus, changes composition aging, substantial formation may provide an additional explanation reduction astringency aged red