Effect of Cross-linking System on Properties of Sodium Alginate/Gum Ghatti Blend Film

In order to explore the effect of cross-linking system on the properties of sodium alginate/gum ghatti blend film,three different Ca²⁺-H⁺ cross-linking systems of calcium chloride-citric acid,calcium chloride-lactic acid and calcium chloride-malic acid were selected. The mechanical properties,water vapor permeability and water solubility were used as indicators. Meanwhile,the microstructure was characterized by FTIR and SEM. When the calcium chloride-citric acid cross-linking system had a Ca²⁺ concentration of 1.5% and a H⁺ concentration of 1.0% and the crosslinking time was 5 min,the results showed that the tensile strength was 34.11 MPa and the elongation at break was 15.27%. The water vapor permeability was 6.99×10^-11 g/(m·s·Pa)and the water solubility was 6.41%. The sodium alginate/gum ghatti blend film was found to gain the optimal comprehensive properties in this condition. In addition,FTIR and SEM also showed that the cross-linked film formed by the calcium chloride-citric acid crosslinking system had a tight,uniform microstructure and a high degree of cross-linking. In this study,a new type of blend film was successfully prepared,which provided a theoretical basis for its applictation in the field of food packaging.