These are organic compounds if butter taste which Occur in different plants tissues. They


are mostly

have an acid reaction and are very astringent.


glucosidal. Generally




metabolic waste


are regarded






Droducts, since they tend to accumulate in


dead or physiologically inactive tissues sch

as heartwood, cork and old leaves. They could


also be found in many unripe fruits.


Tannins are of economic interest because of

their ability to unite with certain types of

proteins, such as gelatin in animal skins, to

lorm a strong. flexible, resistant insoluble


Substance known as leather. Tannins could


be yellowish or brownish in colour. This gives


cathers its brown colour. Because of this



tannin-containing materials


fa ngreat demand. In the absence of this


n treatment, skins become hard. brittle

and leather objects.


They also aid in the protection of the plant.

Tannins are also used in the manufacture of

certain types of inks. Tannin forms a blue-

black or green-black substance when it reacts

with soluble iron compounds.


Their astringent nature makes them useful in


Tanning materials are also utilized in oil

drilling to reduce the viscosity of the drill

without reducing the specific gravity.


Examples of tannins include:

Wattle: Acacia spp. It is used in tanning sole

leathers. It belongs to the family Fabaceae.


Hemlocks: Tsuga canadense, T. heterphylla.

They belong to the family Pinaceae. nea193/


Tannins derived from woods

Chestnuts: Castanea dentate, C. sativa


Quebracho: Schinopsis spp.


Tannins derived from leaves


White cutch: Uncaria gambir. It belongs tob

the family Rubiaceae. It is used in tanning

leathers. It is used as a dyestuff, masticatory,

and medicines.

Tannin derived from acorn cup



Quercus macrolepis:


Tt is a tree of the family Fagaceae.It is found in

the Mediteranean region.The Valonia Oak is a


majestic, semi-evergreen tree which is being

threatened with extinction because of human


activities over many centuries.


lt is extremely photophilic, a characteristic

which makes it to grow very sparsely and

to from a sparse crown so that no branch overshadows another. Because of this, the


shadow and protected from drought. As a

result of this the development period of the

vegetation which grows in the area around the

tree is prolonged by 4 to 6 weeks.


surrounding the tree is in light



It is native to the southeastern United States,

Cuba, and the Bahamas. It is a distinct fan

palm (Arecaceae tribe Corypheae), with a bare

petiole which extends as a center spine or

midrib, (costa) half to two- third the length

into a rounded.

numerous leaflets.

The flowers are yellowish-white, produced in

large compound panicles up to 8.2inches long

and 20 inches across, extending out Deyotd

the leaves. The fruit is a black drupe about

inches long containing a single seed. It is

Extremely salt-tolerant and is often Seen

growing near the Atlantic Ocean coast.

Mangrove: rhizophora mangle

It belongs to family rhizophoraceae

Uses of Mangrove

The bark, leaf shoots and leaves of the trees supply tannin used for dyes, leather preservatives and furniture stains





Updated: February 10, 2020 — 8:18 pm

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