Study on the thermal stability of chitosan/gelatin composite films for food preservation

Chitosan/gelatin composite films were prepared by solution blending, then the light transmittance, the water-solubility and the thermal degradation by thermogravimetry analysis of composite films were determined.Results showed that the light transmittance, the thermal stability and water-solubility of composite films rose with the increment of the content of gelatin. Thermal analysis results showed that the thermal degradation of composite films in the nitrogen was a two-steps reactions, and the degradation temperature (T) rose with the gelatin content (X) :the initial temperature of weight loss To=0.03467X+246.5, the temperature at the maximum weight loss rate Tp=0.3460X+282.1 and the final temperature at weight loss Tf=1.001X+311.9. Cp and Cf were the degradation rates which correspond to Tp and Tf separately, they were not affected by X, and the average value of Cp and Cf were 35.32%±2.54% and 56.28%±1.56%, respectively. The activation energy (E) and frequency factor (A) of the thermal degradation of composite films changed during the three reaction processes.