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Investigations into the levels of horticultural food wastes in Western Australia and a waste valorisation strategy using waste Daucus carota for producing high-value Silver nanoparticles with antimicrobial properties

Ghosh, Purabi (2018) Investigations into the levels of horticultural food wastes in Western Australia and a waste valorisation strategy using waste Daucus carota for producing high-value Silver nanoparticles with antimicrobial properties. PhD thesis, Murdoch University.

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Humanity faces many challenges today that will increase in severity in the future. The urgent need to increase food production levels to meet the needs of an ever-increasing global population is also creating an ever-growing amount of food waste and directly influences food security. The disposal of large and ever increasing amounts of food waste is not only a significant financial loss, but it also creates a serious environment problem. Food waste problems are a major factor preventing sustainable economic growth, acceptable environmental safe guards and sustainable development of food resources. Food waste arises from a variety of sources, starting on the farm, and continuing through post-harvest handling, distribution, wholesale, retail and finally ending with the consumer. However, concerns about hunger, conservation, environmental degradation and the socioeconomic impact of food waste has accelerated research into developing strategies that can reduce food waste levels and promote effective waste utilisation strategies. Because of these concerns, global research interest has focused on developing sustainable eco-friendly practices and innovative strategies that can valorise food waste. Importantly, food waste is a renewable resource that is composed of a wide variety of useful organic materials. Waste valorisation strategies are designed to convert food waste into different value-added products such as bioactive compounds, biofuels and pharmaceuticals. However, to fully exploit this largely under-utilized renewable resource, validated information is needed to clearly elucidate the levels of waste produced within the food supply chain. Currently, there is very little validated information available that specifies the amounts of waste being produced by the various stages within the food supply chain between farm and fork. Also, to fully develop this largely under-utilized renewable resource new manufacturing processes are needed, and conversional manufacturing facilities need to be re-engineered to handle food waste.

The present work examines food waste using a holistic and multi-disciplinary approach to first gain a better understanding of the extent of the problem both globally and locally in Western Australia. And secondly, develop a unique waste valorisation strategy that uses a green chemistry-based process to produce high-value Ag nanoparticles using food waste. From the global perspective, the first part of the thesis examines various articles currently reported in the literature and quantifies waste levels and examines the trends in wastage for various food sectors such as fruit and vegetable, fisheries, meat and poultry, grain, milk and dairy. Also investigated were issues such as factors contributing to food waste, effective cost/benefit food waste utilisation methods, sustainability and environment considerations and public acceptance. All of these factors were identified as hurdles that prevent large scale food waste processing. From an Australian perspective, food waste is estimated to cost around AUS$8 billion annually. This large and unacceptable amount of waste results in significant economic losses for Australia, inefficient use of local resources and has a serious impact on the environment. However, prior to this work there were very few studies reporting the amount and types of wastes being generated. The present work, for the first time, carried out two extensive surveys and assessments in Western Australia Horticultural sector that were designed to identify the types of fruit and vegetable wastes, and their respective waste levels. The first collected data regarding fruit and vegetable wastage produced by Western Australian farmers (growers), and second looked a wastes generated by wholesalers operating at Market City Canning Vale, Perth. Data from both assessments identified the types and amounts of waste generated within Western Australia.

Waste valorisation is an appealing concept for promoting and developing manufacturing processes that converts renewable food wastes into valuable marketable products. The present work developed a new and innovative waste valorisation strategy that produced high-value silver (Ag) nanoparticles form a significant food waste (Carrot, Daucus carota) generated in Western Australia. The economic importance of Ag nanoparticles stems from their incorporation in new pharmaceuticals and antibiotic medications. The results of this work have clearly demonstrated “proof of concept” for this waste valorisation strategy. The Ag nanoparticles produced by this low-cost and one-pot green synthesis approach were found to have positive antimicrobial properties towards two human pathogens, namely, Escherichia coli and Staphylococcus epidermidis. Thus, demonstrating food waste can be used to produce high-value Ag nanoparticles with antimicrobial properties that have the potential to be used in antibiotic pharmaceuticals.

Item Type: Thesis (PhD)
Murdoch Affiliation(s): Chemistry and Physics
United Nations SDGs: Goal 12: Responsible Consumption and Production
Supervisor(s): Poinern, Gérrard Eddy Jai and Fawcett, Derek
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