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Fabrication of zinc oxide nanoparticles and films by banana peel extract food waste and investigation on their antioxidant and antibacterial activities
Food waste is one of the major problems of today's world and thus there is a need to utilize it in innovative applications to reduce the problems associated with it. One of those is the utilization of banana peels in the green synthesis of nanoparticles where the extract of such peels was found to c...
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| Format: | Thesis |
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AUC Knowledge Fountain
2018
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| Summary: | Food waste is one of the major problems of today's world and thus there is a need to utilize it in innovative applications to reduce the problems associated with it. One of those is the utilization of banana peels in the green synthesis of nanoparticles where the extract of such peels was found to contain polyphenolic compounds that would serve as capping agents for the growing nanoparticles. Our aim in this study was to investigate the use of banana peel extract (BPE) in the synthesis of zinc oxide nanoparticles (ZnO NPs) and to compare the prepared NPs with commercial bulk ZnO particles and also with ZnO NPs prepared using nonionic and anionic surfactants. All samples were characterized by using different characterization techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), zeta sizer and UV-vis spectrophotometry. The antioxidant and antibacterial activities of the ZnO NPs were also investigated to select the NPs that could be incorporated in a biodegradable food packaging film. The ZnO NPs synthesized using the BPE were found superior to all NPs prepared in this study in most of the characterization steps. These NPs were found to have the smallest particle size (6 nm), as well as attaining this size for several days in aqueous solutions without significant size fluctuation. In addition, a more uniform spherical morphology was observed for these NPs, unlike the non-uniform flake like structures of the remaining NPs. Moreover, the capping of the BB extract components on these NPs rendered them antioxidant with a DPPH scavenging activity of 76.91%, even though ZnO NPs are known to produce reactive oxygen species (ROS). With regards to the antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), all ZnO NPs were found to be potent antimicrobial agents with minor differences amongst them against E. coli and slight differences against S. aureus. ZnO NPs were then incorporated in a biopolymer (starch) for the synthesis of biodegradable films aimed for antimicrobial food packaging. The starch/ZnO NPs film composites were compared with commercial nylon/evoh film with regards to antioxidant and antimicrobial activity. It was found that the films with ZnO NPs derived from BPE exhibited DPPH scavenging activity of 20.9%, which was 50% higher than that of the commercial film. In addition, the films with ZnO NPs exhibited antibacterial properties towards S. aureus and E. coli when tested using disk diffusion method unlike the commercial nylon/evoh film which did not exhibit any antibacterial activities. |
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