Developing a novel, low-cost, antimicrobial, and biodegradable pectin/HEC/ZnO biofilm for edible food packaging applications

Abstract

The purpose of this study was to investigate the potential of pectin extracted from orange waste by acid hydrolysis and prepared Pectin/ hydroxyethyl cellulose (HEC)/ZnO nanoparticles (ZnO-NPs) biofilm for food packaging applications. The pectin/HEC/ZnO biofilms were prepared in an aqueous solution at room temperature using solvent casting method and characterized by different techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM). Also, thermal gravimetric analysis (TGA), mechanical properties, and water vapor permeability-WVP were evaluated. Moreover, its antimicrobial activity against Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella enterica Typhimiurium) and two Gram positive bacteria (Listeria monocytogenes and Staphylococcus aureus), and also has antifungal activity against Candida albicans was assessed. The obtained results display that the water vapor permeability (WVP) indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2, which indicates that our pectin/HEC/ZnO bionanocomposite biofilm could efficiently decrease moisture transfer, thereby potentially extending the shelf-life of packaged food products. Furthermore, the results showed enhanced tensile strength and flexibility in the biofilms with the addition of 1% ZnO nanoparticles from 1.2 to 2.6 MPa and 4.5 to 13 MPa respectively. The WVP indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2. The antimicrobial activity against pathogens such as Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Candida albicans was significant, with a 99.96% reduction in E. coli counts at a biofilm concentration of 200 mg/mL. Furthermore, the current study revealed that the synthesized bionanocomposite biofilms had excellent qualities such as transparency, flexibility, low cost, and being environmentally friendly. The pectin/HEC/ZnO bionanocomposite was found to be an ideal biofilm for food packaging due to its safety and affordability, which is able to prolong food shelf-life.