Development of biodegradable and eco-friendly fruit peel-derived bioplastic film with antibacterial potential for food packaging application

Synthetic polymers are of utmost significance in humans' everyday life with applicability in all possible fields. But the worldwide utilization of these polymers causes threatening environmental pollution. Their non-biodegradability and reliance on non-renewable fossil resources are the serious challenges the world is facing today. Therefore, to address the global climate hazards, production of environmentally safe and biodegradable polymers has become essential. This study centers on the green fabrication of a variety of novel bioplastic films by using waste fruit peels, viz., orange, mango, banana, and sapodilla. Instead of acetic acid, lemon extract has been utilized in the synthesis of bioplastic films which represents novelty and paves a way towards more convenient, eco-friendly, greener, and sustainable process. Glycerol and sorbitol were employed as plasticizers in the synthesis of these bioplastic films. The interaction of bioplastic films' material with water and alcohol has been emphasized to appraise the impact of plasticizers. Glycerol-containing films display higher values of moisture content (13.29-19.28%), water solubility (51.01-58.56%), and alcohol solubility (44.09-50.63%) which are found to be higher than sorbitol-based bioplastic films. The highest value of moisture content, i.e., 19.28 +/- 3.34%, has been reported for banana peel-based bioplastic films and these films have also shown lower solubility in water (51.01 +/- 5.11%) as well as in alcohol (44.09 +/- 3.72%) as compared to other bioplastic films. Water absorption capacity of glycerol-based bioplastic films is found to be more in contrast to sorbitol-containing films. The orange peel-based bioplastic films have shown maximum water absorption (134.50-120.73%) probably because of their hygroscopic nature. The bioplastic films' characterization by Fourier transform infrared spectroscopy, thermo-gravimetric analysis, scanning electron microscopy, and X-ray diffraction analysis explicates their possible chemical interactions, good thermal stability, irregular surface morphology, amorphous nature, and other physicochemical features. The outcomes reveal that all the synthesized bioplastic films are found to be biodegradable in nature and the percentage biodegradation increases with the use of lemon extract in the films. Among all the bioplastic films, mango peel-derived films exhibit most biodegradability (80.25-86.67%). The bioplastic films have been found to possess significant antibacterial activity against Escherichia coli by virtue of which their future potential could be harnessed in packaging of food items.