Fabrication and characterization of bio-nanocomposite from sweet potato starch and Moringa oleifera leaf extract loaded with carbon quantum dots from Coffea arabica grounds

Abstract

The study aims to generate and characterize a bio-nanocomposite film derived from sweet potato starch and Moringa oleifera leaf extract and carbon quantum dots (CQDs) derived from Arabica coffee grounds employing the solvent casting method. The effect of various concentrations of CQDs (0–400 ppm) was investigated on the physicochemical properties, UV-barrier, antioxidant properties, and biodegradability of the bionanocomposite (BNC) films. The morphological surface of the bio-nanocomposite was examined using scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed to evaluate the thermal stability of the samples. Mechanical properties, including tensile strength (TS) and elongation at break (EB), were also assessed. The results show that the incorporation of CQDs with starch-based biofilms had a remarkable impact on the properties of BNC. SEM images confirm the homogeneous structure of the films with slight granulations. Colorimetric analysis indicates the increase in color difference of BNCs as the concentration of CQDs varied. The BNC100 formulation confirmed batter opacity, transparency, and UV-barrier properties while BNC50 possessed significant improvement in tensile, elongation as well as a substantial increase in the melting point. FTIR and XRD analysis confirmed proper chemical interactions among the components within the polymeric structure of the BNC film. In addition, CQD integration has also steadily enhanced the antioxidant properties and biodegradability of BNC films. The fabricated films with CQDs have demonstrated a better quality in terms of optical properties, physical properties, thermomechanical properties, biodegradation rate, and antioxidant behavior that suggest the film's application in food packaging or other relevant fields.