Development of chitosan based extended-release antioxidant films by control of fabrication variables.

In this study, mechanical, optical and permeability to water vapor of chitosan containing α-tocopherol film as the function of preparation conditions including concentration of emulsifier and speed of homogenization have investigated. In addition, the effect of above mentioned variables and presence of ethanol as co-surfactant on the release rate of α-tocopherol from chitosan film to fatty food simulant (ethanol 95%) were investigated. Fourier transform infrared spectroscopy and differential scanning calorimetry were employed to analyze the structural and thermal properties of the films. Results showed that the incorporation of α-tocopherol and preparation conditions affected the physical and mechanical properties of the chitosan films. Obtained results indicated that increasing the concentration of Tween 80 increased the release rate of α-tocopherol in the most studied films. Increasing the stirring speed of homogenization and the presence of ethanol considerably decreased the release rate of α-tocopherol at the most film samples. The lowest amount of released antioxidant was 8.6-10% of total incorporated α-tocopherol at the first stages and is obtained when ethanol used during preparation of film forming solution. Our results indicated that the release rate of α-tocopherol could be controlled by changing the stirring speed of homogenization and especially ethanol presence, considerably.