RETTING PROCESS IN JUTE

RETTING

1. Introduction important natural fibre crop. Raw material for packaging industries. Its silky lusture , high tensile strength, low exhaustibility, considerable heat resistance and long staple length are qualities that, synthetic fibre don’t have. Provides direct employment to 0.37 million workers & supports livelihood of 4.0 million families. West Bengal has max. 70 jute mills .

2. RETTING Retting is a microbial process in which bast fibre gets loosened for an easy separation from woody stalks During retting, gums, pectins and other mucilaginous substances are removed from the plants by combined action of water and microbiological action.

3. Types of retting Dry retting and Wet retting When water is not available for retting immediately after harvest, plants are allowed to dry, whenever monsoon occurs, dried plants are retted. This process is called Dry retting.. Harvested plant s are immediately retted directly in water without drying and this process is called Wet retting.

4. After 2-4days of harvesting, plants are shaken for complete leaf shedding then they are tied into bundles of 25cm diameter. Then bundles are steeped in standing water vertically, bundles are submerged in water. in a horizontal position laid side by side and tied together to form a sort of platform called “ Jak ”.

5. Jaks are covered with plants like water hyacinth Float is then kept with weight to make the float completely immersed in water. Wood logs and concrete slabs may be used for this purpose. Freshly cut mango logs or banana stems should not be used. tannins coming out from stems reacts with iron of retting water and gives black color to fibre called “ Shyamala ”. This colour can be removed or reduced by adding 2% tamarind solution.

6. For ideal retting, JAKS should be kept submerged of at least 20cm deep . Most of the defects in fibre quality are due to improper or incomplete or faulty retting. Incomplete submergence results in under retting produces a fibre called “crappy fibre” where as over retting results into “dazed fibre ”.

7. gently flowing fairly deep clean and soft water are congenial for ideal retting. Optimum temperature of water should be around 34 C . Retting period is 8-30 days. Incase of stagnating water, addition of Ammonium sulphate will hasten up retting process.

8. finding out exact end point of retting, JAKS must be examined every 10-12days. Fibre should be slip from the wood easily when the plants are pressed between thumb and finger. Soon after the end point, JAKS or platforms should be taken out of the water and fibre should be extracted.

9. STRIPPING Process of removal of fibres from the stalk after completion of retting is called Stripping. Fibre may be extracted in two ways – Single Reed method and Break – Break – Jerk Method. Fibre is extracted by hands either from individual plants or from bundle of 10-12 plants.

10. Difference between Bast Fibre Extractor and CRIJAF Jute Extractor

11. Advantages of different retting processes the traditional process jute jute is retted in open natural water bodies. There is no need to require any further artificial activities as it is retted naturally. the labor is only required for cutting the jute stem in the field and carrying out it from field to the ditches, ponds and other water bodies to submerge under water. ribbon retting process requires more labor for disintegrate the fiber from the stem and forming the process. In the traditional process the requirement of man-hr is comparatively low and there is no required the skilled labor to retting the jute stem .

12. Washing After extraction, fibre is washed thoroughly in the running water Fibre is Squeezed for Excess Water Sun Drying After squeezing the fibre for excess water, fibre is dried on bamboo frames in the mild Sun .

13. Factors hastening up Retting Process Warm water Retting in already used water Harvesting time Climate Conditions like high temperatures Deep water ( Too deep water will delay retting ) Addition of Chemicals

14. Comparison between traditional and improved retting method of jute

15. Quality Parameters Length of Fibre Strength of Fibre Colour of the Fibre Luster of the Fibre Stiffness and Hardness Fitness of Fibre Percentage of Cuttings of Stem or Percentage of Cutting of Fibre Proportion of faulty materials

16. Factors influencing Quality of Fibre RettingWater Materials used as weights on JAKS Seed rate should be more Stage of harvesting Method of Retting Variety of Jute Method of fibre extraction Period of Retting

17. JUTE PRODUCTS

18. Effect of efficient pectinolytic bacterial isolates on retting and fibre quality of jute Biswapriya Das et al.,(2010) Industrial Crops and Products 36 (2012) 415–419

19. IMPACT OF JUTE RETTING ON NATIVE FISH DIVERSITY AND AQUATIC HEALTH OF ROADSIDE TRANSITORY WATER BODIES: AN ASSESSMENT IN EASTERN INDIA Dipankar Ghosh et al.,(2015) Journal of Ecological Engineering Volume 16, Issue 4, Oct. 2015, pages 14–21

20. Effect of retting period on fibre strength, fibre yield and quality of C.capsularis Jute Advances in Jute and allied fibres post-harvest processing technologies in Bangladesh Md. Mahbubul Islam et al.,(2013) Research WebPub Vol. 1(2), pp. 20-30, September 2013