Effect of composite surfactants on the property of the gelatin solution and its film-forming performance

In present study, the interaction between Tween20 and Span20, and its effects on bulk-phase property of gelatin solution and film performance produced by casting (CA) or electrostatic spraying (ES) were studied. Isothermal titration calorimetry and fluorescence probe spectrum indicated that Tween20 and Span20 were preferentially combined in solution and synergistically influenced the polarity and wettability. Surfactant aggregation in the resulted film became smaller and more uniform as the proportion of Tween20 increased with average distribution diameter decreasing about 93%, while water sensitivity of the film enhanced by nearly 40%. Correlation analysis further verified that the polarity of the gelatin solution could affect the water vapor permeability, elongation at break and transmittance of the film. The comprehensive performance of coating system was the best at Tween20/Span20 of 1:1, which also had the best preservation effect. ES produced film with better performance than CA, and would be a promisingly edible coating technology.