The effect of different concentration of polymer and plasticizer on the physical, microstructure and mechanical characteristics of tragacanth edible film for use in food packaging

Appropriate concentration of base material and plasticizer is required to obtain good physical and mechanical properties of edible film for food packaging and preservation functions. The aim of this study was to obtain the best combination of the base material and plasticizer in the manufacture of tragacanth films based on physical, structure and mechanical properties. For this reasons at the first the mechanical, structure and physical properties of different concentrations of tragacanth (0.5, 0.75, 1 and 1.25%) were studied. The results showed, increasing tragacanth concentrations resulted in the increase in the film thickness, elongation at break (E) and water vapor properties, but decreased the contact angle and transmittance of film. According to the results the best concentration of tragacanth was 0.75%, and different concentration of glycerol (20, 30 and 40%) was added to this film. The results showed that, tragacanth film with lower concentration of glycerol had the better mechanical, structure and physical propertis. All in all, the best concentration combination of tragacanth and glycerol in this study was 0.75 and 20%, respectively