Rungsinee Sothornvit, Rungsima Chollakup, and Potjanart Suwanruji

pp. 17 - 22

Abstract

Sericin is the second main component in cocoons, which are removed in the silk reeling process of the raw silk
industry and in the silk waste degumming of the spun silk industry. The main amino acid of sericin, serine, exhibits a skin
moisturing and antiwrinkle action, which is interesting to use for film formation in this study. The extraction conditions of
sericin from two silk wastes, pieced cocoon and inferior knubbs were studied to find the optimum extraction conditions.
Boiling water extraction was considered based on the response surface methodology (RSM) in order to identify the
important factors for the sericin extraction. The two factors considered were time and temperature. Both factors were needed
to be independent parameters in the predicted equation in order to improve the model fit with R²
 = 0.84. The components of
extracted sericin were 18.24% serine, 9.83% aspatate, and 5.51% glycine with a molecular weight of 132 kDa. Film formation from extracted sericin was carried out to find the optimum conditions. Extracted sericin could not form a stand-alone
film. Therefore, polysaccharide polymers, such as glucomannan, were incorporated with glycerol to form a flexible film.
Sericin-based films were characterized for its properties in terms of solubility and permeability before application. It was
found that sericin-based films showed a film flexibility and solubility without an increasing film water vapor permeability