116

N. Chari et al.

Table 8.1 Average chemical

composition of raw silk fibre

Content

Percent

Fibroin

75

Ash of silk fibroin

0.5

Sericin

22.5

Fat and wax

1.5

Mineral salts

0.5

Table 8.2 Commercially exploited sericigenous insects of the world and their food plants

S. no

Common name

Scientific name

Origin

Food plant

1

Mulberry Silkworm

Bombyx mori

China

Morus indica

M. alba

M. multicaulis

M. bombycis

2

Tropical Tasar Silkworm

Antheraea mylitta

India

Shorea robusta

Terminalia tomentosa

T. arjuna

3

Oak Tasar Silkworm

Antheraea proylei

India

Quercus incana

Q. serrata

Q. himalayana

Q. leuco tricophora

Q. seicarpifolia

Q. grifithi

4

Oak Tasar Silkworm

Antheraea frithi

India

Q. dealdata

5

Oak Tasar Silkworm

Antheraea compta

India

Q. dealdata

6

Oak Tasar Silkworm

Antheraea pernyi

China

Q. dendas

7

Oak Tasar Silkworm

Antheraea yamamai

Japan

Q. acutissima

8

Muga Silkworm

Antheraea assamensis

India

Litsea polyantha

L. citrate

Machilus bombycine

9

Eri Silkworm

Philosamia ricini

India

Ricinus communis

Manihot utilisma

Evodia fragrance

Raw silk is further treated to remove gummy materials along with other impurity

types by using Scouring Process. The silk fibre produced will be applied for different

products and fabrications (Table 8.2).

Texture of Silk Thread

The raw silk threads have a slight lengthwise striation. It is made up of two fibrion

filaments cemented in so-called silk gum or sericin. The detailed structure of fibroin