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Tannins produce different colors with ferric chloride (either blue, blue black, or green to greenish-black) according to the type of tannin. Iron gall ink is produced by treating a solution of tannins with iron(II) sulfate. [72] Tannins can also be used as a mordant, and is especially useful in natural dyeing of cellulose fibers such as cotton ...
Tannin (Hebrew: תַּנִּין tannīn; Syriac: ܬܢܝܢܐ tannīnā plural: tannīnē; Arabic: التنين tinnīn, ultimately from Akkadian 𒆗𒉌𒈾 dannina) or Tunnanu (Ugaritic: 𐎚𐎐𐎐 tnn, likely vocalized tunnanu [1]) was a sea monster in Canaanite and Hebrew mythology used as a symbol of chaos and evil.
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Castalagin is a representative ellagitannin, characterized by coupled gallic acid substituents. The ellagitannins are a diverse class of hydrolyzable tannins, a type of polyphenol formed primarily from the oxidative linkage of galloyl groups in 1,2,3,4,6-pentagalloyl glucose.
Vegetable tanning uses tannins (a class of polyphenol astringent chemicals), which occur naturally in the bark and leaves of many plants. Tannins bind to the collagen proteins in the hide and coat them, causing them to become less water-soluble and more resistant to bacterial attack. The process also causes the hide to become more flexible.
Schematic representation of a condensed tannin molecule. Condensed tannins can be linear (with 4→8 bounds) or branched (with 4→6 bounds - dotted line).. Condensed tannins (proanthocyanidins, polyflavonoid tannins, catechol-type tannins, pyrocatecollic type tannins, non-hydrolyzable tannins or flavolans) are polymers formed by the condensation of flavans.
A gallotannin is any of a class of molecules belonging to the hydrolysable tannins. Gallotannins are polymers formed when gallic acid , a polyphenol monomer, esterifies and binds with the hydroxyl group of a polyol carbohydrate such as glucose .