Synthesis, characterization and antimicrobial evaluation of carrageenan /TiO2 nanocomposite materials
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Date
2021
Authors
Journal Title
Journal ISSN
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Publisher
The University of Dodma
Abstract
Food loss due to spoilage by microorganisms is still a problem in most developing
countries. Antimicrobial nanoparticles (NPs) can be used to make edible coatings
that are subsequently applied to fruits and vegetables to increase their shelf life and
improve storage quality. This study aimed to synthesize and analyze
carrageenan/TiO2 nanocomposite as food additives for antimicrobial purposes. The
combination of metal oxides and polysaccharides is gaining and drawing more
attention. A substantial research focus has been on understanding the relationship
between polysaccharides and metal oxides, aiming at mastering the pore size
distribution, morphology, configuration and composition of hybrid materials. In this
study, a highly crystalline anatase/rutile mixed phase carrageenan/TiO2
nanocomposite having a larger surface area has been synthesized by the sol-gel
process followed by calcination at 450°C and 650°C. The nanocomposites obtained
were analyzed for their functional groups and phase formation using Fourier
Transform Infrared Spectroscopy (FTIR) and the X-ray Diffraction (XRD).
Furthermore, the specific surface area of synthesized materials was analyzed by
using Brunauer-Emmett-Teller (BET), while the surface morphology, dispersions,
and elemental characteristics were done by scanning electron microscopy (SEM) and
energy dispersive X-ray (EDX). FTIR spectra revealed variations in bond
frequencies in the nanocomposite materials compared to their reference samples,
while the XRD pattern revealed the existence of both rutile and anatase phases of
titanium dioxide in the composite materials. The surface of the nanocomposite was
observed to be morphologically porous by SEM, while the EDX proved the presence
of titanium, oxygen and carbon elements in the composite calcined at 450°C and
650°C. The carrageenan/TiO2 nanocomposites calcined at 450°C showed excellent
antibacterial activity against selected bacteria (Staphylococcus aureus and
Escherichia coli). These findings suggest that the potential of carrageenan/TiO2
nanocomposites to inhibit bacteria is influenced by their crystalline nature, porosity,
surface area, and small size. Its antimicrobial property makes it a promising
candidate as a food additive in the food industry.
Description
Dissertation (MSc Chemistry)
Keywords
Microorganisms, Developing countries, Antimicrobial nanoparticles, Storage quality, Carrageenan, Food industry, Bacteria
Citation
Majinyari, D. E. (2021). Synthesis, characterization and antimicrobial evaluation of carrageenan /TiO2 nanocomposite materials (Master's dissertation). The University of Dodoma, Dodoma.