Zhao Mouming

Development and physical properties of film of wheat gluten cross-linked by transglutaminase

Films were developed from the modified wheat glutens by microbial transglutaminase (MTGase, [E/S]=10u/g, 15u/g and 20u/g) in order to improve physical and barrier properties of the films. Glycerol was used as a plasticizer. The films prepared from the modified-glutens by MTGase show a lower elongation at break(E) and a water vapor permeability (WVP), and a higher tensile strength (TS) than the native gluten films. When the modified gluten films by different concentrations of MTGase are immersed in water at 25°C, their weight losses decreased significantly, and their water resistance increases obviously as expected, compared with the control gluten films. Moreover, an addition of glycerol as plasticizer greatly modified water vapor barrier and mechanical properties of the films.

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

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.