Cleaner process for extraction of sericin using infrared

• Infrared (IR) heating used to extract sericin from silk waste.
• Complete extraction of sericin achieved using lower temperature, time and water consumption.
• HTHP extraction and tray drying degrade sericin.
• Assessment of sericin protein using UV and Fluorescence spectra.
• Method controls pollution and minimizes waste in silk processing.

Silk fibre as produced by the silk worm, comes encased in a gum called sericin which is removed to impart lustre, handle and smoothness to the silk filament. In recent years, sericin has itself been credited with important biological properties and is being used by the food, pharma and cosmetics industry. Conventional processes used for the removal of sericin are based on soap and alkali, and discharge large volumes of sericin and chemicals into the textile wastewaters. Others like the high temperature high pressure (HTHP) process damage silk, are energy intensive and degrade sericin considerably. In this study, a novel approach is proposed to control pollution and minimize waste in wet processing of silk. Process conditions for extraction of sericin from silk waste using infra-red (IR) machine have been developed. Complete extraction of sericin from silk waste could be obtained using a lower temperature, lower time of treatment and lesser water consumption as compared to the conventional high temperature high pressure (HTHP) process. Not only does the process reduce the amount of water and chemicals required in conventional processing, it would also reduce the pollution load considerably by not allowing any sericin to go into the effluent. Complete recovery of non-degraded sericin is achieved by a simple spray drying method as compared to multiple filtration and precipitation processes required in soap degumming. The paper also proposes a complete protocol for qualitative and quantitative assessment of sericin protein based on UV, FTIR and Fluorescence spectra. Results show for the first time that IR heating can be used to develop a greener and more efficient degumming process for silk.