Tannins, tea and trees
by Chris, 12 January, 2018, 1 comments
We come across tannins in various foods and drinks. They contribute to the taste of a cup of tea, a mug of coffee or a glass of wine. Tannins contribute an astringent taste - a sensation of “dryness” in the mouth. Tannins are molecules made by plants - they are complex polyphenols built from several phenolic molecules. A phenol is made from a hexagon-shaped carbon ring with one or more hydroxyl groups (-OH) attached to it (see diagram).
They are generally water-soluble molecules and they can combine with proteins, cellulose, pectins etc. Tannins are generally stored in the vacuole of plant cells (as are various oils, resins, crystals of calcium oxalate etc). Collectively, these materials are sometimes referred to as ergastic substances. Read more...
