On the Formation of Yuba-like Film from Wheat Gluten

To elucidate the mechanism of the formation of Yuba-film, wheat gluten was applied instead of soybean protein, and the conditions of film formation, strength, strain and other properties of the film were studied. The Yuba-like films from gluten solution were formed under conditions as follows; at pH 10.2-12.5 and pH 4.9-2.2, or in the solution containing 3.3-4.0M urea or 0.25-0.5% sodium dodecylbenzenesulfonate. It seems to be necessary that protein is completely solubilized and unfolded to a certain extent and that coagulation of protein molecules on the surface of the solution is not prevented. These conditions of solvents varied the properties of the film. Addition of 2-mercaptoethanol decreased the strength of the film from alkaline solution, while it increased the strength and decreased the strain of the film from urea solution. Addition of N-ethylmaleimide, the modifying reagent of sulfhydryl group, decreased the strength and increased the strain of the film. Remarkable differences were observed between the fractions of gliadin and glutenin on strength, strain and transparency of film.