Optimization of Lignin-Nanofiber-Filled Thermoplastic Starch Composite Film Production for Potential Application in Food Packaging

The optimization of production of lignin-nanofiber-filled thermoplastic starch composite film for potential application in food packaging was carried using Response Surface Methodology (RSM), through the adoption of the Box-Wilson Central Composite Design (CCD) with 1 center point. The effects of filler loading on moisture absorption (MAB), tensile strength [TS], percent elongation [PE] and Young’s modulus [YM]) of the films were investigated in order to construct the desirability indices of the composite. The quality of the fitting model was expressed by the coefficient of determination, R2 and the adjusted R2. Results showed that the nanocomposite films were best fitted by a quadratic regression model with a high coefficient of determination (?2) value. The selected film has desirability of 76.80%, close to the objective function, and contained 4.81% lignin and 5.00% nanofibre. The MAB, TS, YM and PE of the selected film were 17.80 %, 21.51 MPa, 25.76 MPa and 48.81%, respectively. The addition of lignin and nanofiber to starch composite reduced the moisture absorption tendency but increased the mechanical properties of the films due to the good filler/matrix interfacial adhesion. Conclusively, results suggested that these films would be suitable for packaging application.