Synthesis of Functional Nanoparticles and Their Applications in Degradable Food Packaging

功能性納米顆粒的合成及其在可降解食品包裝中的應用

Student thesis: Doctoral Thesis

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Award date17 Jul 2020

Abstract

Nanotechnology has been receiving growing attention in agriculture and food industry. It is one of the most promising technologies in the world, leading to the huge revolution throughout the whole food industrial chain, from initial ingredients manufacturing process to final product packaging. The large ratio of surface area to the volume in nanomaterials imparts them with many extraordinary properties, such as excellent absorption ability, superb electronic capability and outstanding optical performance etc. These benefits of nanomaterials can boost their applications in optical devices and food packaging industry. Three research projects have been proposed in this thesis to develop functional nanomaterials and explore their application in food packaging.

Chapter one of this thesis focuses on the introduction of emerging role of nanotechnology and nanomaterials in food industry. In this chapter, methods to synthesize gold and semiconductor nanomaterials have been reviewed, meanwhile the optical and antibacterial properties have been briefly introduced. Afterwards, the current situation of nanofood packaging including nanomaterial fillers, degradable packaging materials and intelligent packaging have been reviewed.

Chapter two aims to propose aqueous synthesis methods for gold nanoparticles of different size and morphologies. Gold nanoparticles in the shapes of sphere, rod, porous sphere and cuboid have been controllably synthesized from gold (Au) ions solution. The optical properties and plasmonic effect of gold spheres and nanorods have been studied due to two vital factors of size and morphology to influence many properties of nanoparticles. It has been found that rod-shaped gold nanoparticles perform better in surface enhanced Raman scattering (SERS) application and large sized gold nanorods could lead to an improved efficiency (from 9.64% to 10.41%) of organic solar cell due to plasmonic effect.

Chapter three focuses on gold-titanium dioxide (Au-TiO2) nanocomposites incorporated sodium alginate food packaging film. Firstly, the synthesis processes of functional Au-TiO2 nanocomposites have been described. Then the casting method for sodium alginate nanocomposite film has been introduced. Thirdly, light absorption ability, water resistance, antibacterial property and degradation of the nanocomposite film have been investigated. In addition, the mechanism of the antibacterial property has been discussed. According to the experiment results, it can be noted that incorporation of Au-TiO2 nanocomposites could largely increase the water resistance and antibacterial property of sodium alginate film. The reactive oxygen species (ROS) production in the light condition is mainly responsible for the antibacterial property.

Chapter four is to investigate zinc oxide (ZnO) nanoparticles incorporated soy bean protein isolate film for food packaging. Here, ZnO nanoparticles have been obtained by a hydro-thermal synthesis method, which are then incorporated into soy bean protein isolate films. The mechanical properties, oxygen permeability and antibacterial properties of the films have been studied. The film morphology and interactions between nanoparticles and soy bean protein have been characterized by scanning electron microscopy (SEM) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) measurements. It is noticed that the linking of protein could be changed by ZnO nanoparticles, therefore influencing the film properties. In this chapter, ZnO nanoparticles incorporated soy bean protein isolate films show great potential in packaging industry.

Chapter five provides conclusions including the general discussion and conclusion of these three projects. The prospects and outlook of applying functional nanomaterials in food packaging have also been mentioned and expostulated. Finally, future work has been recommended as well.

    Research areas

  • Nanomaterials, Food packaging, Plasmonic effect