Animal skin tanning

Leather is the material made from animal skin by the process of tanning, which entails chemically altering the composition of the skin so as to make it durable and resistant to decay. Leather is therefore not a protein but a protein derivative. Although the tanning process alters the composition of skin, leather retains the fibrous structure and utilitarian functionality that make skin suitable for multifarious applications. Shelter, clothing, and decorative objects made from leather are, unlike skin or hide, stable to physical, chemical, and biological decay under dry or wet conditions (O Flaherty et al. 1965 ... 

All the tannins readily react with proteins, forming insoluble, stable compounds when they react with collagen, the main constituent of animal skin, they form leather, a material that is resistant to hydrolysis, oxidation, and biological attack and therefore stable to weathering and resistant to decomposition. Since tannins from different plant sources have different chemical compositions, each tannin used for tanning skin produces a leather having slightly different properties and color. Tannins that have... 

There has always been an abundance of natural fibers and elastomers, but few plastics. Of course, early humans employed a crude plastic art in tanning the protein in animal skins to make leather and in heat-formed tortoise shells. They also used naturally occurring tars as caulking materials and extracted shellac from the excrement of small coccid insects Coccus laced). 

In the north, the Inuit regarded antler in much the same way as they regarded bone and ivory. The materials existed to be utilised, and little went to waste. The meat fix)m the animal was eaten, the skin tanned to make leather, fur provided clothes and bedclothes, and the bones, teeth and antlers were carved into anything from harpoon points and amulets to children s toys. 

Leather. Leather is animal skin that has been treated to produce pliancy and resistance to rotting. The tanning process by which leather is made is very old, but it is still not completely understood, mainly because the structure of animal skin is still unknown. In general, skin is polypeptide-containing collagen (see Section 10.4.5), but there are also present various amounts of keratin, reticulin, elastin, and water, plus other components such as carbohydrates, lipids, waxes, and triglycerides (1311). 

Mangrove forests are commercially important in some places. Lumber can be manufactured from all of the mangrove trees, but the most durable wood is that of Ceriops. Where it is abundant, Rhizophora may be harvested to manufacture lumber or pulp. In some places, mangroves trees are harvested and used to manufacture charcoal. The bark of mangroves is rich in tannins, and has been used for the commercial production of these chemicals, which are utilized to tan animal skins into leather. Mangrove forests are also commonly harvested for local use as firewood. 

Coordination polymers have been utilized since before recorded history, although not recognized as such until recently. For instance, the tanning of leather depends on the coordination of metal ions with the proteins that make up the hide. These complexes resist the bacterial attack, wear and weathering that typically befall nontanned animal skins. Metals bound to natural polymers, including proteins, affect numerous enzymatic and membrane interactions. 

Tannins are, by definition, substances capable of producing stable combinations with proteins and other plant polymers such as polysaccharides. The transformation of animal skins into rotproof leather results from this property, as does astringency, fining and enzyme inhibition. Tannins react with proteins in each instance collagen in tanning. 

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