Effect of Alginate gum and Walnut leaf Extract on Mechanical, Physical and Antimicrobial Properties of Wheat Protein Isolate

The aims of this study were to produce biodegradable and antimicrobial films based on wheat gluten and investigate the effects of adding alginate gum (0 to 1.5%) and walnut leaf extract (800, 400 and 200 ppm) on their physical and chemical properties. The results showed that by adding different amounts of alginate gum and extract to the films, the solubility and permeability of the films to water vapor was significantly reduced. The film containing 1.5% gum and 800 ppm of the extract, had the lowest solubility (22.109%) and water vapor permeability at a rate of 5.039 -10 10-10 g / m.s. By adding the extract and increasing the concentration used in the composition of the films, there was a significant increase in the antioxidant content of the films. Thus, the film samples containing 800 ppm of extracts had the highest antioxidant capacity. Evaluation of the mechanical properties also showed that the addition of alginate extract and gum caused a significant reduction in the percentage of tensile strength and tensile strength of the films compared to the control sample. The maximum no growth halo diameters of the sample containing 800 ppm of the extract on E. coli and Staphylococcus aureus were 27.631 and 25.076 mm, respectively. The results illustrates that walnut leaf extract can be used as a natural preservative in combination with film for food packaging.