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consists of pure and composite forms of chitins to give maximum flexibility to the

body and due to which it can move easily.

Chitin will not be soluble in the water but soluble in sodium hydroxide and potas-

sium hydroxide solutions at 160–180 °C. It gives a complex derivative known as

chitosan which is stained brown by iodine. Dilute sulphuric acid also gives the

chitosan reaction.

The chitin microfibrils are embedded into the protein matrix firmly, resulting in

the formation of endochitin and exochitin. In peritrophic membranes, the microfibrils

are normally arranged as a network in the amorphous matrix [7].

In the form, all chains of chitin exhibit an anti-parallel orientation. This orientation

allows tight packaging into chitin microfibrils that are stabilized by a high number

of hydrogen bonds. This arrangement may contribute to mechanical strength [8].

In the form, the chains are arranged in a parallel manner. In the form, sets of two

parallel strands alternate with a single anti-parallel strand and chains are moderately

less packed than form with the reduced number of inter-chain hydrogen bonds and

are able to react with water. The high degree of hydration and reduced packaging

help soft chitinous structures such as peritrophic matrices and cocoons.

The chitin microfibrils are embedded into the protein matrix and stabilize it in

a way that resembles constructions of steel-reinforced concrete complex patterns

and textures [9]. By contrast, in peritrophic matrices, the microfibrils are normally

arranged as a network of randomly organized structures [7]. Insect cuticles form an

exoskeleton to keep body growth under the influence of moulting hormones.

Applications of Chitin

Recent studies have revealed that chitin is a good inducer for defence mechanisms

in various plants, and hence, it can be used as a fertilizer to improve crops.

It is widely used in various industries for different applications such as food

processing. Chemically modified chitin helps in forming edible films to stabilize

foods and pharmaceuticals. It is also used as a binder in dyes, fabrics and adhesives

and also in the paper industry.

In recent times, many researchers delivered a reproducible form of bio-degradable

plastic that finds usage in 3-D bio-printing.

It is used as a surgical thread due to its flexibility and bio-degradability [2]. Chitin

may increase the allergies in human beings and animals. However, it has to be

emphasized that many insects are eaten by animals including human beings.

Exoskeletal chitin mass appears to increase at a lower rate with mass in flying

insects as compared to non-flying insects.

Chitin-chitosan material is used as a bone filling material.

Chitin-oligomers have been claimed as anticancer drugs.

The Mechanical Properties of chitin are favourable in applications involving

various levels of designs, viz. the exocuticle of crab has very high hardness.