Effect of addition of sodium dodecyl sulfite on physical properties of wheat gluten films

Abstract

Films were made from the wheat glutens treated with 5%, 10%, 15%, 20%, 25% and 30% (wt% of gluten) of sodium dodecyl sulfite (SDS) in order to improve the properties of the films. Glycerol was used as a plasticizer. An addition of SDS in wheat glutens prior to forming films significantly increased the elongation at break (E) (P<0.05) and reduced notably the water vapor permeability (WVP) (P<0.05). In contrast, a decrease in the tensile strength (TS) of the films from gluten containing-SDS was found. Moreover, a significant decrease in Po2 and Pco2 of films from gluten treated with SDS was noticed. Although SDS-treated gluten film was slightly more yellow and darker than control one, it was not visually detrimental. It is indicated that the treatment with SDS prior to forming films greatly enhances the mechanical properties of wheat gluten films. The obivous improvement in water vapor permeability and extensibility of gluten films means that the use of SDS is a potential choice for improving properties of gluten filsm. The edible film was used to preserve tomatoes. The experimental results show that the shelf life of tomatoes coated with the edible film is extended, and the nutritional quality is kept well.