Bast fibre is composed of bundles of cells cemented together with noncellulosic substances and occurs between the outer bark and woody central cylinder of stems. Jute is the most important bast fibre and is mainly cultivated in India and Bangladesh, producing around 50% of the world's jute. Jute fibres are obtained from the stems of Corchorus capsularis and Corchorus olitorius plants through retting, extraction, and processing. Retting is the process of loosening fibres from the stem through microbial decomposition over 10-30 days depending on the method. Proper retting is crucial for producing quality jute fibres.

1. BAST FIBRE
• Composed of bundles of many cells,cemented together with
NONCELLULOSIC SUBSTANCES
• PART OF STEM STRUCTURE
Occurs in between outer bark and woody central cylinder
Eg :- 1. Jute , 2. Flax,3.Hemp,4.Kenaf,5. Sunn ,6. Ramie,7. Urena

2. Based on botanical origin, the two cultivated species of jute out of eight species
discovered so far - Corchorus olitorius L. (tossa jute) and Corchorus capsularies L. (white
jute) constitute world’s foremost bast fiber cash crops and the second most important
textile fibre next to cotton. Jute is mainly grown in South East Asian countries like India,
Bangladesh, China, Nepal, Indonesia, Thailand, Myanmar and some South American
countries. In India jute is grown in Eastern region covering over 0.8 million hectare,
producing 1.8 million tones of fiber including the production of two cultivated species of
mesta (Hibiscus cannabinus L. and Hibiscus sabdariffa L.) which is about 50 percent of
world production. The share of mesta is about 15 percent of the total jute production in
India. The major jute and mesta growing states are West Bengal, Assam, Bihar, Orissa,
Megalaya, Tripura and Andhra Pradesh. Jute being a labour intensive crop, about 40 lakh
farm families derive their sustenance by cultivating jute in the country. Moreover, 2.5
lakh people are employed in the organized jute industry and over 25 lakhs people are
engaged in jute based ancillary and jute diversified sectors. India earns annually about
1200 crore rupees as foreign exchange by exporting various jute products. The cultivation
of jute improves soil fertility status by shedding its leaves in the field. The crop also suits
well in crop rotation. Thus the production of jute fibre assumes high socio-economic
significance in our country. Jute is also known as golden fibre of India.

3. JUTE
• Classified as natural, cellulose, bast, multicellular fibre
• DENSITY :- 1.48 -1.50 gm/cc
• PRODUCTION :- 85% In India & Bangladesh , Burma, Farmosa, China,
Brazil, Nepal, Vietnam, Taiwan, Thailand, Paris
• Obtained from stems of two plants
• BOTANICAL NAMES :- Corchorus Capsularis & Corchorus Olitorius

4. Seed yield varies between 4.5 and 7.8 quintal per hectare and
the average yield of jute fibre from these seeds is about 20
quintal per hectare.

5. CULTIVATION OF JUTE
• SOIL TYPE :- Low-lying , Slightly Acidic, Alluvial ( a deposit left by a
flood)
• RAINFALL :- 80mm - 100 mm
• HUMIDITY :- 65%-90%
• TEMPRATURE :- 25 to 40 degree Centigrate
• Firstly soil is prepared by ploughing and harrowing ( the process of
breaking up soil by a heavy frame of metal spikes )
• C. capsularis are shown early in FEB and MARCH & C.olitorious in
month of April and May

6. • Seed germination takes 3-5 days
• When plant length is 8-15 cm, WEEDING & THINNING is done
• After plantation, it grows as single stalk
STEM HEIGHT :-2-5 mts
• Time to grow up to full length :- 90 days -120 days
• After maturation , colour of plant changes from GREEN to yellow & then REDDISH
YELLOW
• Small buds of yellow flower with sweet smell appears which provides seeds for next crops
• Time taken from sowing to harvesting :- 100-130 days
(FROM MIDDLE JUNE TO END OF SEPTEMBER )
• At flowering or pod formation, plants are harvested by hands
• Due to rain or flood , early harvesting lowers the yield and gives short and pale fibres
• Late harvesting gives higher yield with inferior quality of fibre
• The stems are cut and tied into bundles and left to lie in the field for 3-4 days occasionally
their leaves are stripped

7. RETTING
• Process of loosening & separating bark from woody stalk, to remove
non-cellulosic material like lignin and hemi-cellulose , which is done
by combined actions of water and micro organisms.
• FACTORS AFFECTING RETTING :- 1. Hardness of water
2. Presence of O₂ & Iron in water
3. Presence of micro-biological
agents like fungi & bacteria
4. PH.
5. Temperature

8. Retting & Fibre Extraction
Conventionally retting is the total process of loosening of fibre
strands from the woody core by decomposing the non-fibrous
matters linking the fibres to the bark with the help of aquatic
microbes when put into water (ponds, canals, rivers and retting
tanks) for about fifteen days, mechanical extraction of fibres,
washing and drying of jute fibres before marketing of the same.
Retting plays an important role in quality fibre production. As the
conventional whole plant retting does not suit to the farmers in water
crisis situation, mechano-microbial retting technology has been
developed which needs some more studies for commercialization.
Under mechano-microbial method, green bark containing the fibre
bundles are extracted from jute stems by a mechanical device and
the extracted green ribbons are then sprayed with a microbial
consortium and kept overnight covering with polythene sheet. Next
morning, the sprayed ribbons are steeped vertically in polythene
lined pit for retting and retting is completed in about seven days.
Efficiency of retting and quality of fibre depends on factors like crop
age, fertilization of crop, quality of retting water including pH and
temperature, activators, covering materials etc. Other techniques like
dew retting and chemical retting are also practiced to some extent.

9. TYPES OF RETTING
1. DEW RETTING
2. STAGNANT WATER RETTING
3. RUNNING WATER RETTING
4. CHEMICAL RETTING

10. DEW RETTING
1. Jute stem kept in warm & humid atmosphere
2. Stretched in thin layer over green grass for 7-15 days with
occasional turn-over
3. By this process , jute stalks get direct exposure to bright sun-light in
days & to moisture in nights
4. Gradually leaves , small branches , loose bark come out

11. STAGNANT WATER RETTING
1. Jute stalk bundles are weighted with stones & immersed under
water , 4”-6” below surface , in tank or pond
2. After fermentation, stalks float due to formation of CO₂ inside the
bundles
3. After proper retting , bundles are taken out for extraction of fibres
4. Time for retting :-10-20 days ( depending upon the temperature of
water and condition of stalks )

12. RUNNING WATER RETTING
1. Jute stalks are immersed in a current of flowing water in big bundles
& loose conditions
2. Left for 20-30 days according to suitable conditions
3. When fully retted , bundles are taken out for extraction of fibres

13. CHEMICAL RETTING
1. Process consists of softening the tissues by boiling with 1% of NaOH
or 0.5% of H₂SO₄ at boiling temperature for 6-8 hrs.
2. Non-cellulosic matters are hydrolysed & degraded to their
respective lower products
3. Then fibres are washed with clean water
4. Quiet costlier process as required chemicals and proper vessels for
the treatment

14. DURATION OF RETTING OF JUTE FIBRE
S.NO PROCESS DURATIONS
1. DREW RETTING 7-15 Days
2. STAGNATED WATER RETTING 10-20 Days
3. RUNNING WATER RETTING 20-30 Days
4. CHEMICAL RETTING 6-8 Hrs.

15. EXTRACTION
1. DRYING :- After retting , bundles of stalks are dried to make the
fibres partially separated from the stalks
2. CRUSHING OR BREAKING :-
• After drying, the decomposed stalks are crushed manually (using hammer )or
passing through fluted iron rollers
• It breaks and reduces the stalks to small pieces called shieves
3. SCUTCHING (SWINGLING):-
Broken shieves are removed from fibres by scutching knife (wooden).This
process is called scutching

16. 4. HACKLING :-
• It is simple combing process as carding
• Straightens the fibres
• Separates short stapled fibres from longer ones
• Leaves longer fibres in parallel order
• By this process , clean jute fibres are extracted by removing hard woody
particles
• Hackling is carried out by a comb consist of a board set with steel teeth
(spikes)
• Normally simple hand comb with teeth set in a series of decreasing size are
used

17. CHEMICAL COMPOSITION
• Mainly composed of cellulose but larger % of gum
• CELLULOSE :- 64%
• GUM :- 24%
• Small amount of water , Fat ,Wax and Ash

19. ANATOMY OF JUTE STEM

20. PROPERTIES OF JUTE
• The smallest unit of raw jute is known as ‘reed’
• Length :- the length of the reeds varies from 1m to 4.5m, depending
upon the grade
• Diameter :- 6-20 microns
• Density :- 1.48-1.5 gm/cc
• Colour :- varies from yellow to brown to dirty grey depending upon
the conditions of growth , retting etc.
• Lusture :- moderately lustrous
• Tenacity :- 45-72 gm/tex (5-8 gm/denier) moderately strong
• Moisture regain :- 13% at 65% RH & 22⁰ C temp (std conditions )

21. • ELASTICITY :- jute are stiff fibres due to materials cementing the cell
together and so it has lower elasticity . This gives an advantage to jute
to be used as a bagging material , they will retain their shape when
loaded
• THERMAL PROP. :- like other cellulosic fibre , is not affected by heat .
Prolonged heating degrade the fibre.

22. CHEMICAL PROPERTIES
• EFFECTS OF ACID :- At ordinary conditions , dil. solutions of organic &
mineral acids have no actions. with strong acids at boiling conditions ,
hydrocellulose is formed , which leads to higher loss in strength
• EFFECTS OF ALKALIS :- dilute solutions of alkalis has little effect on
jute fibres but concentrated alkalis bring about profound swelling and
loss in strength
• ACTION OF SUNLIGHT :-jute fibre undergoes tendering with the
colour changes from yellow to brown or deep brown on long
exposure to sunlight.
• DYE AFFINITY :-sulpher,acid and direct dyes can be used to dye the
jute fibre.

23. • ACTION OF OXIDISING AGENT :- ordinary oxidizing agents have no action
on jute. Only strong oxidizing agents will form oxycellulose.
• ACTION OF MICRO-ORGANISM:- jute is more resistant to micro-
biological attack than cotton and flax.
• End uses :-
1. In woven & tufted carpet
2. Packing for cables of telephone
3. Small domestic ropes , twines
4. As stuffer material in car seats
5. Home furnishing fabrics , decorative fabrics , wall
coverings
6. Bagging cloth or hessian cloth
7. Bed & pillow linings , tarpaulins etc.