TANNIN Flashcards
The term Tannin was first applied by _____ in _____ to denote substances present in plant extracts which were
able to combine with protein of animal hides, prevent their putrefaction and convert them into leather.
SEGUIN (1796)
was first applied by Seguin in 1796 to
denote substances present in plant extracts which were able to combine with protein of animal hides, prevent their putrefaction and convert them into leather.
TANNIN
Is a substance which is detected qualitatively by a Tannin Test (Goldbeater’s Skin Test) and is determined
quantitatively by its absorption on standard hide powder.
TANNINS
Tannin is a substance which is detected qualitatively by a ________ and is determined quantitatively by its absorption on standard hide powder.
TANNIN TEST ( GOLDBEATER’S SKIN TEST)
Many tannins are ______
GLYCOSIDES
Are source of fruit acids (Glycolic, Lactic, Mandelic, Malic, Tartaric and Citric acid)
TANNINS
Tannins are a source of fruit acids.
GLYCOLIC
LACTIC
MANDELIC
MALIC
TARTARIC
CITRIC ACID
Found in immature fruits
TANNINS
Found in specific plant parts (leaves, fruits, barks or stems)
TANNINS
Found in great quantities in dead or drying cells.
TANNINS
Occur in solution in cell sap, often in distinct vacuoles.
TANNINS
❑ Plant polyphenols
❑ “Tannin Extracts”
❑ Non-crystallizable
❑ Complex substance– a mixture of polyphenols and
non-crystallizable compounds
❑ Precipitate proteins
❑ Sharp “puckering” taste
TANNINS
a mixture of polyphenols and
non-crystallizable compounds
COMPLEX SUBSTANCE
This may be hydrolyzed by acids
or enzymes such as Tannase.
HYDROLYSABLE TANNINS
Hydrolysable Tannins may be hydrolyzed by acids or enzymes such as _____.
TANNASE
They form several molecules of phenolic acids as Gallic acid and Hexahydroxy-diphenic acid which are united by
ester linkages to a central glucose molecules.
HYDROLYSABLE TANNINS
They form several molecules of phenolic acids as _______ and ________ which are united by
ester linkages to a central glucose molecules.
GALLIC ACID
HEXAHYDROXY-DIPHENIC ACID
dry distillation, Gallic acid and similar components are converted to Pyrogallol.
FORMERLY KNOWN AS PYROGALLOL TANNINS
When treated with acids/enzymes– phenolic acids (Gallic acid, Ellagic Acid and Glucose)
HYDROLYSABLE TANNINS
Phenolic acids
GELLIC ACID
ELLAGIC ACID
GLUCOSE
Gallic acid
GALLITANNINS
Hexahydroxy-diphenic acid units
ELLAGITANNINS
Hydrolysable Tannins
(Ferric chloride)
BLUE
Hudrolysable Tannins
(Bromides)
No Precipitate
Condensed Tannins (Proanthocyanidins, Polyflavonoid, Catechol-type, Pyrocatecollic-type tannins)
NON-HYDROLYSABLE TANNINS
Are not readily hydrolyzed to simpler molecules and they do not contain a sugar moiety.
NON-HYDROLYSABLE TANNINS
Are related to the Flavonoid pigments and have polymeric Flavan-3-ol structures
NON-HYDROLYSABLE TANNINS
Catechins which also occur with the tannins and Flavan in the biosynthesis of the molecules..
NON-HYDROLYSABLE TANNINS
When treated with acids/enzymes– converted into red insoluble compounds known as Phlobaphenes– give the
characteristic color to many drugs (red cinchona bark)
NON-HYDROLYSABLE TANNINS
When subjected to dry distillation
CATECHOL CALLED AS CATECHOL TANNINS
Non-hydrolysable tannins
(Ferric Chloride)
Greenish
Non-hydrolysable tannins
(Bromides)
PRECIPITATE