Studies on the Alternative Method for Softening of Multi×Bi Cocoons during Extraction of Silk Filament during Silk Reeling
Subhasish Mandal
Department of Zoology, Murshidabad University, Pin-742101, West Bengal, India.
Deepsikha Mukherjee
Department of Zoology, Berhampore Girls College, Pin-742101, West Bengal, India.
Kunal Sarkar *
Udaychandpur High School (H.S), Jibanti, Kandi, Murshidabad, Pin-742136, West Bengal, India.
Soumik Chatterjee
Central Silk Board, Central Silk Technological Research Institute, Regional Silk Technological Research Station, Malda, India.
*Author to whom correspondence should be addressed.
Abstract
Cocoons are comprised of silk filaments which are cemented together with the help of protein glue called as sericin. The main object of cocoon cooking is to soft the sericin for better unwinding of filament from the cocoon. Conventionally cocoon cooking is done by dipping the cocoon in hot water for certain duration. In present study an alternative method is done to use commonly available Papaya latex reagents for softening of sericin instead of dipping cocoon in hot water. Present study indicated that when Multi×Bi (Nistari×NB4D2) Cocoons were treated with papain reagents at a concentration ranging from 0.01% to 1% and soaking duration ranging from 8 hours to 48 hours, it was observed that softening percentage of cocoon and raw silk percentage of cocoons were increased with the increasing of concentration and soaking time. It was observed that when Multi×Bi (Nistari×NB4D2) Cocoons were treated with papain reagents at a concentration of 1% for duration of 24 hours, percentage of softening was increased to 70%- 75% and simultaneously raw silk percentage was increased to 40%-45%. Present study indicated that when Multi×Bi (Nistari×NB4D2) Cocoons were treated with papain reagents at duration of 48 hours softening percentage was increased to 75% but raw silk percentage reduced to 0%. It was happened due to dissolving of both fibroin and sericin. It was observed that when Multi×Bi (Nistari×NB4D2) Cocoons were treated with Papaya latex reagents at a concentration of 1% for duration of 48 hours, it gives similar result as papain reagents at a concentration of 1% for duration of 24 hours i.e percentage of cocoon softening was 75% and raw silk percentage was around 45%. Present study revealed that in both the occasions raw silk percentage was far below than normal hot water reeling technique where raw silk percentage was around 70%-80%. Besides that, number breaks were also more in enzyme treated technique. It was happened due to lack of water penetration inside the cocoon in enzyme treated technique and it results in jumping of cocoons during reeling which ultimately increases number of breaks. But present study brings hope that ecofriendly cold reeling technique may become an alternate from of crude hot water reeling technique. Present investigation invites an ample scope of research in this direction.
Keywords: Cocoon, cooking, sericin, enzyme