Effect of gelatin addition on properties of pullulan films.

The gelatin was added into pullulan films to improve their performances and lower their cost. The gelatin addition raised the tensile strength of the gelatin-pullulan composite films, and reduced the oxygen permeability. The cost of composite films was reduced comparing to that of the pullulan films. Moreover, the molecular interaction of the composite film was evaluated. The interactions of gelatin and pullulan in the composite films were detected, such as (1) formation of 2 glycosylated proteins; (2) improvement of β-sheet content; (3) formation of the interchain hydrogen bond and a semicrystalline region. Therefore, the molecular interaction was the main reason for the performance improvement of the composite films.