Development of Eco-Friendly Method for Degumming of Eri Cocoons

Abstract

In this study, a new eco-friendly degumming technique was developed for Eri cocoons without any chemicals. A newly developed eco-Eri degumming process was tried at 110 °C, 120 °C, 130 °C and 140 °C temperatures for 10, 20 and 30 min with soft and hard water. The novel eco-friendly degumming method was compared with the existing method of degumming viz. Soap-soda along with the enzymatic method. After degumming, weight loss per cent, changes in the fibre surface morphology concerning SEM imaging and fibre properties concerning tensile strength and elongation were studied. The eco-Eri degumming method at 130 °C for 30 min using soft water removed the maximum sericin content (degumming loss 15.7%) from Eri cocoon shells and had optimum degumming efficiency. In the eco-Eri degumming method, the degummed Eri cocoons were uniformly softened. The soap soda method of degumming resulted in 14.5% weight loss whereas enzymatic degumming resulted in a maximum of 13% weight loss (12% dosage). Enzymatic degumming significantly reduced the tensile strength but no results found in the tensile properties of Eri silk fibres were observed in new eco-friendly and soap-soda methods. SEM images indicated optimal fibre surface with the smoother surface until 130 °C, but fibre damage and fibrillation occurred at 140 °C and also with the Soap-soda method. An optimal condition for degumming Eri cocoons with the new eco-Eri degumming process is 130 °C for 30 min using soft water. The eco-Eri degumming method is better compared to other methods used presently in the industry.

Diversified post-harvest treatment of eri cocoon and its effect on spun yarn

“…The tenacity and elongation were found higher in cocoon treated with mustard plant ash and black gram dal as 0.91g/denier, 23.00% and 0.89g/denier and 26.69% respectively due to incomplete degumming. In this same context, Sreenivasa and Padaki, 2023 [10] states that raw (undegummed) eri shows higher elongation percentage of 17.8% than degummed cocoon treated with soap-soda sample (16.4%) due to presence of sericin. Breaking load is also found higher and with least yarn count shows that sodium-bi-carbonate though help to remove sericin from fibroin but effects the fiber quality to withstand wear and tear.…”

“…Higher concentration of sodium bi carbonate with longer duration of boiling results complete degumming but effects fiber tenacity and elongation (Chattopadhyay et al, 2016) [3] The result reveals that sample treated with alkaline solution of paddy straw extract (10.5%) as well as mustard plant ash extract (10.2) have minimal degumming loss. In this same context, Sreenivasa and Padaki, 2023 [10] states that the sericin content of raw eri silk is in the range of 13-17% and weight loss % of eri silkworm during degumming is ranges from 8-15%. However, higher boiling temperature and high pressure also effect sericin removal.…”