Tannin

tanninshamamelitannintantanniferousextract woodFeldmann's methodgoldbeater's skin testLöwenthal's methodStiasny's methodtannic
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.wikipedia
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Polyphenol

polyphenolsphenolicphenolics
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.
The historically important chemical class of tannins is a subset of the polyphenols.

Phlorotannin

localization of phlorotanninsphlorotanninsphysode
Phlorotannins are a type of tannins found in brown algae such as kelps and rockweeds or sargassacean species, and in a lower amount also in some red algae.

Oak

Quercusoak treeoak trees
The term tannin (from Anglo-Norman tanner, from Medieval Latin tannāre, from tannum, oak bark) refers to the use of oak and other bark in tanning animal hides into leather.
The wood is very resistant to insect and fungal attack because of its high tannin content.

Hydrolysable tannin

hydrolyzable tanninhydrolyzable tanninshydrolysable type
Condensed tannins, e.g., quebracho tannin, and Hydrolyzable tannins, e.g., chestnut tannin, appear to be able to substitute a high proportion of synthetic phenol in phenol-formaldehyde resins for wood particleboard.
A hydrolyzable tannin or pyrogallol-type tannin is a type of tannin that, on heating with hydrochloric or sulfuric acids, yields gallic or ellagic acids.

Proanthocyanidin

proanthocyanidinsCondensed tannin
Tannins have molecular weights ranging from 500 to over 3,000 (gallic acid esters) and up to 20,000 (proanthocyanidins).
More complex polyphenols, having the same polymeric building block, form the group of tannins.

Astringent

astringencyastringentsdrying agent
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.
Astringency, the dry, puckering mouthfeel caused by the tannins in unripe fruits, lets the fruit mature by deterring eating.

Oligostilbenoid

oligostilbene
Oligostilbenoids (oligo- or polystilbenes) are oligomeric forms of stilbenoids and constitute a class of tannins.
Some molecules are large enough to be considered polyphenols and constitute a class of tannins.

Hide (skin)

hideshideanimal hide
The term tannin (from Anglo-Norman tanner, from Medieval Latin tannāre, from tannum, oak bark) refers to the use of oak and other bark in tanning animal hides into leather.
Various tannins are used for this purpose.

Catechu

cutchcatechutannic acidTerra Japonica
Catechu ( or ) is an extract of acacia trees used variously as a food additive, astringent, tannin, and dye.

Pyrogallol

pyrogallic acid1,2,3-trihydroxybenzenepyrogallic
Ellagic acid, gallic acid, and pyrogallic acid were first discovered by chemist Henri Braconnot in 1831.
Presently gallic acid is obtained from tannin.

Bark (botany)

barktree barkperiderm
The term tannin (from Anglo-Norman tanner, from Medieval Latin tannāre, from tannum, oak bark) refers to the use of oak and other bark in tanning animal hides into leather.
Bark tissues make up by weight between 10–20% of woody vascular plants and consists of various biopolymers, tannins, lignin, suberin, suberan and polysaccharides.

Flavan-3-ol

flavanolcatechinsflavanols
Higher order polymers, anthocyanidins, exhibit deepening reds and become tannins.

Ellagic acid

ellagicC14H6O8ellagic acids
Ellagic acid, gallic acid, and pyrogallic acid were first discovered by chemist Henri Braconnot in 1831.
Plants produce ellagic acid from hydrolysis of tannins such as ellagitannin and geraniin.

Maximilian Nierenstein

Max Nierenstein
Maximilian Nierenstein studied natural phenols and tannins found in different plant species.
He also studied natural phenols and tannins found in different plant species.

Blackwater river

blackwaterblack waterblackwater stream
The leaching of highly water soluble tannins from decaying vegetation and leaves along a stream may produce what is known as a blackwater river.
As vegetation decays, tannins leach into the water, making a transparent, acidic water that is darkly stained, resembling tea.

Ergastic substance

raphideraphid
Tannins are classified as ergastic substances, i.e., non-protoplasm materials found in cells.
The latter are usually organic or inorganic substances that are products of metabolism, and include crystals, oil drops, gums, tannins, resins and other compounds that can aid the organism in defense, maintenance of cellular structure, or just substance storage.

Tannic acid

tannicgallotannic acidAcidum tannicum
Adding baking soda to the water to raise its pH level will accelerate the process of leaching, as the more alkaline solution can draw out tannic acid from the wood faster than the pH-neutral water.
Tannic acid is a specific form of tannin, a type of polyphenol.

Anacardiaceae

cashew familysumac familyAnacardiaceae sp.
The best known families of which all species tested contain tannin are: Aceraceae, Actinidiaceae, Anacardiaceae, Bixaceae, Burseraceae, Combretaceae, Dipterocarpaceae, Ericaceae, Grossulariaceae, Myricaceae for dicot and Najadaceae and Typhaceae in Monocot.
Tannin sacs are also widespread among the family.

Bog

peat bogbogspeat bogs
Water flowing out of bogs has a characteristic brown color from dissolved peat tannins.
Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins.

Tannosome

In all vascular plants studied so far, tannins are manufactured by a chloroplast-derived organelle, the tannosome.
Tannosomes are formed when the chloroplast membrane forms pockets filled with tannin.

Carapichea ipecacuanha

ipecacuanhaCephaelis ipecacuanhaipecac root
It also contains the pseudo-tannin ipecacuanhic acid or cephaëlic acid.

Agathis australis

kauriKauri treeKauri (Agathis australis)
Leaf litter and other decaying parts of kauri (Agathis australis), a tree species found in New Zealand, decompose much more slowly than those of most other species.
Besides its acidity, the plant also bears substances such as waxes and phenols, most notably tannins, that are harmful to microorganisms.

Guarana

guaranáPaullinia cupanaDa lágrimas do tupã, nasce o fruto divino: o guaraná

Acacia

wattleacaciaswattles
Studies conducted in 2002 on in vitro ammonia release and dry matter degradation of soybean meal comparing three different types of tannins (quebracho, acacia and chestnut) demonstrated that chestnut tannins are more efficient in protecting soybean meal from in vitro degradation by rumen bacteria.
One ton of wattle or mimosa bark contained about 150 lbs of pure tannin.

Goldbeater's skin

gold beater's skingoldbeaters skin
They do not change color during the Goldbeater's skin test, unlike hydrolysable and condensed tannins, and cannot be used as tanning compounds.
The goldbeater's skin test is used to assess the tanning properties of a compound.