Analysis and Modeling of Mechanical and Barrier Properties of Arracacha Starch-Chitosan Composite Biodegradable Films

This work sought to formulate, analyze, model, and optimize Arracacha ( Arracacha xanthorrhiza ) starch-chitosan based biodegradable films to assess their use as food coating. To study these films, prepared through the casting technique, a Box–Behnken design was used with three factors at three levels (starch 3–4%; glycerol 0.75–1.25%; chitosan 1–2%) to determine the individual and interactive effects of these parameters on the mechanical properties (tensile TS, and elongation at break, %E) and barrier properties (water vapor permeability, WVP) of the films. The results were analyzed by using the Pareto analysis of variance (ANOVA). The descriptive response surfaces were obtained and second-order polynomial models were developed for each response evaluated, which showed good fit to the experimental data with high determination coefficient (R 2 > 0.95), finding relation between the experimental and predicted values. The optimal film formulation, according to the desirability function by Derringer, with the aim of minimizing the SS and WVP values and maximizing the %E values, was obtained with that containing 4% starch, 1.11% glycerol, and 2% chitosan, presenting low stress strain and permeability and high flexibility, conditions favorable for the desired application.