Properties of sericin-glucomannan composite films

Sericin is a natural silk protein which is removed from silk in a process called degumming. Thus, finding a use for the extracted sericin as a biopolymer film will create added value which will benefit both the economy and society. It was found that extracted sericin could not form stand-alone films. Therefore, glucomannan was incorporated with or without glycerol to form a flexible film. Sericin and glucomannan ratio (S:G) affected film properties. Increasing sericin content (S:G = 2:1) slightly reduced film water vapour permeability (WVP) without adding glycerol (Gly). This indicated that sericin provided film flexibility without increasing film WVP. As expected, increasing glycerol content increased film WVP as well as decreased tensile strength and elastic modulus but increased dramatically % elongation. It is interesting that adding beeswax to form a composite film did not improve film water vapour barrier. Thus, sericin-based film properties are dependent on components used to form film and can tailor to form the desired film flexibility and minimise permeability of films for application.