Physicochemical characterisation of Salvia macrosiphon gum based edible films incorporated with various fatty acids

In the present study, the influence of different concentrations of three fatty acids (palmitic, stearic, and oleic acids) on improving the physicochemical, barrier, mechanical, thermal and surface properties of Salvia macrosiphon seed gum (SSG) edible films was investigated. The results revealed that the selected fatty acids promoted an increase in hydrophobicity of SSG films; characterized by significantly lower moisture uptake, solubility, water vapour permeability, and considerably higher contact angles. The opacity and tensile strength of SSG films increased by addition of the fatty acids, while elongation at break decreased. The estimated values of surface free energy inferred that dispersive component of surface energy increase by incorporation of the fatty acid, whereas its polar component decreased. Among the selected fatty acids, the efficiency of oleic acid on improving the characteristics of films was higher than saturated fatty acids, i.e., palmitic and stearic acids. Concluding, incorporation of fatty acids to SSG films seems to be necessary to fabricate films with lower affinity to water, especially for those applications that require less hydrophilic films.