Preparation and Properties of Sanxan/Sodium Alginate Edible Composite Film

The aim of this study was to investigate the synergistic effect of Sanxan (SAN) and Sodium alginate (SA) and the properties of composite film. SAN and SA were mixed at different mass ratios, and glycerin was added as plasticizer to prepare composite films. The tensile strength of films, elongation at break, light transmittance, solubility and water vapor transmittance were measured. Differential scanning calorimetry analysis of composite films was carried out. The microstructure of films was characterized by fourier transform infrared spectrum and scanning electron microscope. The results showed that the tensile strength of the SAN/SA film with the mass ratio of 5:5 was the highest, and the difference between the film with the ratio of 4:6 was not significant (P>0.05), but was significantly higher than that of other films (P<0.05). The flexibility of film with SAN/SA mass ratio of 6:4 was significantly increased (P<0.05), the water vapor transmittance and solubility of this film were the lowest. Differential scanning calorimetry analysis showed that the heat resistance of the composite film was improved. According to the results of fourier transform infrared spectrum, hydrogen bond interaction existed between SAN and SA molecules, indicating good compatibility and synergistic effect between them. The microstructure showed that the network structure of the composite film was arranged more orderly and the pores of the film surface were smaller. The results showed that SAN had a good synergistic effect with sodium alginate, and the properties of SAN/SA composite film were significantly improved. As a newly approved natural polymer which can be used in the food field, the application prospect of SAN is broad.