Preparation and characterization of fibroin based pH sensitive films

In this work, films made of SF aqueous solution were prepared and characterized. SF was obtained from silkworm cocoons from which sericin was previously removed. In order to make films less brittle, plastisizer polyethylene glycol 200 (PEG 200) was added into aqueous solution of SF. SF films with added red cabbage dye were also made. Red cabbage dye is natural pigment used
mainly as a food color. Anthocyanins are compounds that contribute to the color of this dye. The pH of red cabbage solution can affect both its color and intensity. In this work, the red cabbage dye was evaluated as a potential pH indicator that can be used for food packaging. The obtained films were characterized for FTIR analysis, water barrier and optical properties, solubility, and tested to color change on different concentrations of base, which imitates food spoilage.