These are organic compounds if butter taste which Occur in different plants tissues. They
have an acid reaction and are very astringent.
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
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,
Tannin derived from acorn cup
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.
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