Influence of glycerol and chitosan on tapioca starch-based edible film properties

The individual and interactive effects of glycerol and chitosan on tapioca starch-based edible film properties were investigated using response surface methodology. Tests were run on the polymeric matrices to determine film forming solution apparent viscosity, mechanical and dynamic-mechanical properties, water vapour permeability (WVP) and color. All film forming solutions exhibited pseudoplastic behaviour. It was observed from the mechanical characteristics point of view, that the chitosan had a positive effect while the glycerol had a negative effect. The tan delta values were affected more by glycerol than the chitosan. With regards to WVP data, the chitosan addition had a negative effect, whereas the glycerol one had a positive influence. Moreover, both the chitosan and glycerol influenced the color indices. It can be concluded that the concentrations of chitosan and glycerol led to changes in tapioca starch edible film properties, potentially affecting film performances. (C) 2008 Elsevier Ltd. All rights reserved.