tannin yielding plants

TANNIN YIELDING PLANTSANAND CHARVIN.G

WHAT ARE TANNINS?

■ Tannins are secondary metabolites of plants, non-nitrogenous, phenolic in nature.

■ They have a property to tan animal skin to convert to leather or hide.

■ Conversion imparts resistance to water, heat, abrasives.

■ They can be extracted using water-acetone/alcohol mixture.

■ They have a property to precipitate gelatin & heavy metals.

■ Tannins are widely distributed in several plant species and are found in wood, bark, leaves and fruits

TANNIN CLASSES

HYDROLYSABLE TANNINS

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.

NON-HYDROLYSABLE TANNINS

(Condensed tannins)

Non-hydrolysable

tannins on heating with

hydrochloric acid yield

phlobaphenes like

phloroglucinol.

PSEUDO TANNINS

Pseudo tannins are low

molecular weight

compounds

associated with other

compounds.

CLASSIFICATION OF TANNING MATERIAL

On the basis of plant part from where tannins are obtained, they

are classified into the following four groups.

WOOD TANS BARK TANS FRUIT TANS LEAF TANS

TANNIN YIELDING PLANTS

WOOD TANS

Quebracho colorado(Quebracho)

Anacardiaceae

Acacia catechu (Khair)

Leguminosae

WOOD TAN

Quebracho colorado(Quebracho)

The heartwood contains 20-27% tannin, which is obtained by cutting the wood into

small chips and extracting the tannin with water.

Native to South America (Argentina)

WOOD TAN

In India, the cutch obtained from khair is used for tanning purposes and well as a

blend, Along with wattle, it is used for producing heavy leather and also for dyeing

leather.

Found in warmer regions of IndiaAcacia catechu (Khair)


Acacia mearnsii(Wattle,Mimosa)

Fabaceae

BARK TANS

Acacia nilotica(Babul)

Fabaceae

Cassia auriculata(Avaram)

Fabaceae

Cassia fistula(Konnoi)

Fabaceae

BARK TAN

• The bark yields an excellent quality of tannin which is astringent, catechol type.

• It is used in blends, plywood industries and in adhesive formulations.

a fast-growing, extremely invasive leguminous

tree, native to Australia.Acacia mearnsii(Wattle,Mimosa)

BARK TAN

• The tannin content of the bark vary from 7-20%.

• The bark from older trees are richer in tannin and has a deeper color.

• This tannin is suited fro heavier leather rather than for kips and half tanned hides.

Native to India.Acacia nilotica(Babul)

BARK TAN

• The bark of this species is regarded as one of the best known tanning material in India.

• It has 15-23% tannin content.

• It penetrates the hide very quickly.

A Shrub found in south and western IndiaCassia auriculata(Avaram)

BARK TAN

• Tannin contents of bark vary from 10-14% while that of leaves ranges from 8-10%

• It produces a smooth grained pale leather.

• Twig bark gives better leather color than bole bark.

Widely distributed through out tropical IndiaCassia fistula(Konnoi)


Caesalpinia coriaria(Divi-divi)

Fabaceae

Zizyphus xylopyrus(Kath-ber)

Rhamnaceae

Terminalia chebula(Myrobalan)

Combretaceae

Tamarindus indica(Tamarind)

Fabaceae

FRUIT TANS

Acacia nilotica(Babul)

Fabaceae

FRUIT TAN

• The pods of babul produce good quality tannins.

• Tannin content is 12-20% in pods and 18-30% after the removal of the seeds.

• Pods also impart good color to leather and render it soft.

Native to India.Acacia nilotica(Babul)

FRUIT TAN

• Pods have high tannin content (24-41%)

• Leather is affected with weather conditions, Hence it is blended with other tans.

• Also used as mordanting agent in textile industries.

a leguminous tree native to the Caribbean &

Mexico.Caesalpinia coriaria

(Divi-divi)

FRUIT TAN

• Tannin contents vary upto 10%

• The fruits impart black color to leather.

• Used for tanning bags and purses.

Found Throughout the North-Western India,

PakistanZizyphus xylopyrus

(Kath-ber)

FRUIT TAN

• It produces soft, mellow, spongy leather which lacks good wearing properties. Hence,

it is blended with quick penetrating tans such as babul, avaram barl etc.

• The Myrobalans of salen district (TN) are regarded as the best in India for color and tannin content.

Found extensively in southern IndiaTerminalia chebula(Myrobalan)

FRUIT TAN

• The seed teste yields a dark colored leather• It is used with myrobalans and other hydrolysable tanning in the procession of heavy

leathers.

A large tree commonly found through out India.Tamarindus indica(Tamarind)


Anogeissus latifolia(Axle wood, Dhawal sumac)

Combretaceae

Carissa spinarum(Karaunda)

Apocynaceae

Emblica officinalis(Aonla, Indian goose-berry)

Phyllanthaceae

LEAF TANS

LEAF TAN

• Yields a tannin known as Dhawa sumac. It's dry leaves contain about 32% tannins.

• It penetrate quickly and produces pale colored leather with a greenish tinge.

• It is used to tan various types of skins and hides.

A large tree commonly found through out india.Anogeissus latifolia(Axle wood, Dhawal sumac)

LEAF TAN

• The tannin contents of the leaves vary from 9-15%

• It acts slowly and causes swelling on the hide.

• It can be mixed with other tan material.

It a thorny, evergreen shrub found along the foots of the

Shiwaliks, Central IndiaCarissa spinarum

(Karaunda)

LEAF TAN

• The leaves of the tree yield tannin which is generally used by the local tanneries.

• The tannin content in leaves is about 22%

A common tree found in dry deciduous forests of IndiaEmblica officinalis(Aonla, Indian goose-berry)

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tannin yielding plants

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