Characteristics of Edible Films Made by Potato / Wheat Starch and Gelatin

Edible films and coatings are thin layers of biopolymers which have been used as food coatings. Due to numerous disadvantages of synthetic packaging materials including migration, environmental pollution and recycling problems, starch-based films were used because of abundance and low cost of starch. However, regarding weak mechanical properties of starch, gelatin was used for improving the properties of starch film. In this study, edible films were made using potato starch, wheat starch, and gelatin at 4:1, 1:4, and 1:1 levels and then their physical properties (thickness, elasticity resistance, and elongation), solubility in acid and water, water vapor permeability, transparency, color as well as morphological properties were measured. The results showed that as the gelatin content increased, acid solubility, elasticity resistance, elongation, water vapor permeability, and transparency of film samples significantly increased (p≤0.05) and increasing in starch content led to increased turbidity, elongation, and acid- and water-solubility. Wheat starch-based films showed higher thickness and less elongation than potato starch-based films while potato starch-based films had better elasticity and barrier properties