Development of model for barrier and optical properties of tapioca starch based edible films

The film forming solutions composed of tapioca (cassava) starch (1-3 g), glycerol (0.5-1.0 ml), agar (0.5-1.0 g) and span 80 (0.1-0.5 ml) were prepared according to a three-level, four-factor Box-Behnken response surface experimental design. The films were obtained by casting method and they are homogenous and transparent. The influence of film composition (tapioca starch, glycerol, agar and span80) on the barrier and optical properties of the tapioca starch based edible films was evaluated. The results showed that, hydrophilic nature and plasticizing effect of glycerol increases the water vapor permeability, oxygen permeability, moisture content, solubility and swelling capacity of the films. But surfactant (span80) incorporation reduces the mobility of the polysaccharide matrix and decreases the barrier properties of the films. Transparency of the films was influenced by plasticizer and surfactant concentration due to the dilution effect of glycerol and span80. The results were analyzed by Pareto analysis of variance (ANOVA) and second-order polynomial models were developed using multiple regression analysis. The models developed from the experimental design were predictive and good fit with the experimental data with high coefficient of determination (R(2)) values (more than 0.95). The optimized conditions were obtained were tapioca starch of 1.95 g, glycerol of 0.8 ml, agar of 0.7 g and span 80 of 0.3 ml, respectively.