Development of novel biodegradable bioplastics for packaging film using mango peels

Plastic pollution and greenhouse gases emitted by fruit waste in landfills are detrimental to human and environmental health. Implementing biodegradable, eco-friendly, and sustainable bioplastic films derived from fruit wastes could solve both issues. In this study, bioplastic film produced from mango peels was developed through an environmentally-friendly, aqueous, hydrolysis process using a 5% vinegar solution. We hypothesized that natural biopolymers in mango peels would be released from the destructed peel cell wall to form bioplastic upon acid treatment, and the bioplastic film properties could be tailored through the processing conditions. The film properties, including roughness, transparency, thickness, tensile strength, elongation, water vapor transmission rate (WVTR), degradation, and water resistance, were characterized. Then, the mechanical performance was optimized through adjusting the hydrolysis temperature, duration, and the plasticizer type and concentration. Bioplastic films with the best surface morphology and tensile strength were formed at 50°C for 48 hours. Among the three plasticizers evaluated, 20% polyglycerol-3 showed the best results to improve film elongation without compromising strength. When the film was dip-coated in a hydrophobic solution, the water resistance was significantly enhanced, as evidenced by the improvement of the WVTR and the water contact angle value. We also evaluated the in-soil degradation of the films and the effect of adding chitosan to inhibit bacterial growth. Overall, our results showed the developed bioplastic film had tensile strength equivalent to commercial petroleum-based plastic food wrap, was biodegradable, bacteriostatic, and has the potential to be used as packaging film.