Effect of xanthan gum on the physical and mechanical properties of gelatin-carboxymethyl cellulose film blends

The aim of this study is to develop composite edible films from three different polymers to induce cross-link reactions that improved the quality of films made from two polymer types. Gelatin-carboxymethyl cellulose (CMC)-xanthan gum films were prepared by casting to study effects from the addition of different concentrations (0, 5, 10, 15, 20 and 25%, w/w solid) of xanthan gum to gelatin-CMC film. Physical and mechanical properties of the respective films were evaluated. The addition of xanthan gum increased the thickness, moisture content and water vapour permeability of gelatin-CMC film (p < 0.05). Furthermore, Ultraviolet (UV) light shielding increased along with reduced visible light transparency (p < 0.05) and increased thermal stability (T-g) (p < 0.05). No new functional groups formed although slight shifts in intensity values by Fourier Transform Infrared (FTIR) spectroscopy were observed. X-ray diffraction (XRD) analysis showed a diminished crystalline peak. The resulted films also demonstrated lower tensile strength with diminished elongation at the break point, as well as higher puncture force and lower puncture deformation, indicating higher puncture resistance than comparable gelatin-CMC film. Overall, gelatin-CMC film with xanthan gum (5%, w/w solid) demonstrated improved physical and mechanical properties more than films prepared from comparable formulations. (C) 2016 Elsevier Ltd. All rights reserved.