Investigation of physical and mechanical properties of edible film prepared from opopanax gum (Commiphora guidottii)

The purpose of this study was to investigate the possibility of producing a biodegradable film from a new source known as opopanax gum and investigating its physical and mechanical properties. Opopanax gum was purified after two extraction steps and the film was prepared with 4% gum solution and 2.5% glycerol in deionized water. The apparent viscosity of the film solution showed the non-Newtonian shear thickening behavior of the solution. The contraction ratio obtained from opopanax gum film was -0.267 ± 0.095. Water vapor permeability (WVP) of opopanax film was 25.059 ± 0.623. The tensile strength and the elongation percentage at break point obtained for opopanax gum film were 0.</span>376 ± 0.</span>124 MPa and 350.625±</span>108.599, respectively. The opacity percentage of the film was 15.633 ± 0.404, which indicates the desirable clarity of the film. The average contact angle for the film was 34.618 ± 1.992, which can be said that the film is relatively sensitive to humidity. The X-ray diffraction spectrometer pattern showed the semi-crystalline structure of the film. Two endothermic peaks and two exothermic peaks were observed in the DSC thermograms. The thermal analysis of the film also showed 4 mass losses. The structure of the film was investigated using Atomic Force Microscopy. The FTIR test showed that the main part of the film is polysaccharide. The total results from different experiments showed that opopanax gum has the ability to form film. However, opopanax gum is not alone desirable to produce edible film due to its high thickness, high solubility in water, high permeability to water vapor and poor mechanical properties. Therefore, it could be an appropriate option for combining with other films to enhance biodegradability of the films.