Edible films based on gum tragacanth and gelatin.

This article focuses on the development and characterization of edible films composed of gelatin (GL), an animal-derived protein, and gum tragacanth (GT), a polysaccharide, aiming to explore GT as a sustainable alternative to GL in food and drug applications. Films were prepared using composite (coacervation) and bilayer methods with varying GT:GL ratios and tested for swelling behavior in distilled water and salt solutions (0.5 M CaCl₂ and NaCl). Results showed that swelling rates depended on biopolymer ratio, film thickness, and swelling medium, with certain GT-GL formulations (notably H1GT1GL and H1GT3GL) demonstrating stability and favorable swelling in all media, suggesting GT can partially replace GL while reducing total biopolymer content. Rheological analysis revealed non-Newtonian, shear-thinning behavior of film-forming solutions, with gel-like properties observed only in the 3:1 GT:GL mixture, correlating with improved film stability in water. The study highlights the importance of molecular interactions and ionic environment on film properties and suggests potential applications of these films as substrates in advanced food technologies such as 4D printing.