Application of cassava by-product as fillers in starch-based biocomposite films for packaging materials

In this study, cassava bagasse (CB), an agro-industrial waste, was used to produce cassava starch (CS)-based films plasticized with glycerol (GL) using the casting technique. To investigate the effects of the components on the mechanical properties of the films, a central composite rotational design (CCRD) was applied, varying the concentrations of CS (3.0–7.0 g/100 mL of water), CB (0.5–1.5 g/100 mL of water), and GL (0.7–1.7 g/100 mL of water). In addition, the films’ thickness, microstructure, and water barrier properties, including water vapor permeability rate (WVTR), moisture sorption kinetics, and moisture diffusion coefficient, were determined. The results indicated that the CB content significantly influenced (p < 0.05) the films’ mechanical and water barrier properties. The tensile strength increased by 545.5% due to a reduction in the mobility of the starch polymer chains caused by the presence of CB. Adding CB also reduced the WVTR by an average 54% compared to the control film (without CB addition) and decreased the moisture diffusion coefficient (from 3.62 ± 0.056 × 10⁻¹⁰ m² s⁻¹ to 2.11 ± 0.029 × 10⁻¹⁰ m² s⁻¹) due to the more hydrophobic nature of CB. Furthermore, the films exhibited compact and cohesive structures, evidencing the potential of CB as a reinforcement material in producing biocomposite films for packaging applications.