Development and characterization of active edible packaging film based on orange fleshed sweet potato starch and Moringa stenopetala leaf extract

Abstract

The growing demand for sustainable packaging has accelerated interest in biopolymer-based active films derived from renewable resources. This study aimed to develop and characterize an active biodegradable film based on orange fleshed sweet potato (OFSP) starch incorporated with Moringa stenopetala leaf extract (MSLE). OFSP starch was extracted and modified by pre-gelatinization, with commercial corn starch used as a control. The modified OFSP starch exhibited significantly higher (P < 0.05) swelling power, solubility, water-binding capacity, and pasting clarity than native starch, while X-ray diffraction confirmed a similar C-type crystalline pattern with improved thermal stability. MSLE was obtained using microwave-assisted extraction and incorporated into the film formulation. Moringa extract showed level of phenolic compounds of 8.56 ± 0.04 mg GAE/g, a total flavonoid content of 9.38 ± 0.26 mg QE/g, and a ferric reducing capacity of 8.72 ± 0.08 mg AAE/g. Response surface methodology optimized the concentrations of modified starch (4 g), glycerol (40% w/w), and MSLE (1.5% w/w). The optimized active film showed improved tensile strength (7.38 MPa) and reduced water vapor permeability (3.145 × 10⁻⁹ g m⁻¹ s⁻¹ Pa⁻¹) compared with the neat film. The active film contained appreciable antioxidant compounds (6.08 ± 0.06 mg GAE/g total phenolics, 6.30 ± 0.21 mg QE/g flavonoids, and 3.18 ± 0.04 mg AAE/g ferric reducing capacity). Antimicrobial testing revealed zone of inhibition values of 12.0 ± 0.02 mm for Moringa stenopetala leaf extracts (MSLE) and 9.2 ± 0.42 mm for the active film against Staphylococcus aureus, and 9.0 ± 0.48 mm for MSLE and 6.0 ± 0.43 mm for the active film against Escherichia coli. In addition, the films demonstrated good biodegradability within 30 days. Overall, OFSP starch-based films incorporated with Moringa stenopetala extract show strong potential as sustainable active packaging materials with enhanced functional and environmental performance.