Résumé : |
The paper presents a necessarily brief review of tannins and tanning, covering the following topics. Tannins : Occurence of tannins in nature, reason for existence and relationship to plant metabolims. Chemical types - classification into condensed tannins, ellagitannins and gallotannins.
Tanning : Tannin/protein interaction - electrovalent and hydrogen bonds and hydrophobic interaction. Equilibrium between tannin and protein-tanning as a polar absorption. Principles of vegetable tanning. Importance of acids, salts and other osmotic considerations. |