Oxygen exposure during red wine fermentation modifies tannin reactivity with poly-l-proline.
- Authors
- Type
- Published Article
- Journal
- Food chemistry
- Publication Date
- Nov 01, 2019
- Volume
- 297
- Pages
- 124923–124923
- Identifiers
- DOI: 10.1016/j.foodchem.2019.05.197
- PMID: 31253258
- Source
- Medline
- Keywords
- Language
- English
- License
- Unknown
Abstract
Red wines injected with nitrogen or oxygen during fermentation were used to identify the effect of gas exposure on tannin structure and reactivity with poly-l-proline. Tannin was purified from wine after fermentation and after three years of bottle storage. Tannin from nitrogen-treated wine had a lower percentage of galloylation and were less pigmented than tannin from oxygen-exposed wine. Self-aggregation of tannin was measured by nanoparticle tracking analysis and a larger particle size was observed for the oxidized treatment. The interaction of tannin and poly-l-proline was measured by isothermal titration calorimetry, and involved more hydrogen bonding than hydrophobic interactions in the case of nitrogen-treated wine tannin. Conversely, oxidized tannin was more hydrophobic and the association with poly-l-proline was entropy-driven due to a change of solvation. The results show meaningful changes in the structure and reactivity of tannin as a result of oxygen exposure during fermentation, which may impact astringency perception. Copyright © 2019 Elsevier Ltd. All rights reserved.
