Food, while it is essential for survival, is a dynamic and complex marketplace. The drive to be innovative and popular, combined with ever changing public perception and scientific knowledge, makes the food industry fascinating. One of the recent trends, including sugar and salt, has been the reduction of fat in our diets. However, consumers like to treat themselves and fatty foods give a pleasurable eating experience. These two things are often at odds. This work focusses on the development and use of a novel fat replacement technology known as air filled emulsions (AFEs) as a substitute for the function, both structurally and organoleptically, of the fats present within emulsion products. AFEs are micron sized pockets of air coated in a protective protein coat. This work demonstrates that they can be produced reliably at kilogram scales with great potential for further scale-up. This work successfully supplemented emulsions with AFEs and demonstrated the possibility of reducing the fat concentration by over 45%. AFE substitution also had the advantage of significantly improved resistance to separation.

A Positron Emission Particle Tracking (PEPT) based technique was developed and used to study laboratory grinding of calcium carbonate in a vertically stirred media mill. The PEPT data along with particle fracture data obtained by micromanipulation were used to understand the grinding mechanisms. The PEPT methodology allowed measurements of grinding media occupancy, velocity, force, stress and media–media collisions at different positions within the mill. The stresses exerted by the media were compared with calcium carbonate strength measurements made using the micromanipulator to determine the percentage of the grinding media with sufficient stress to overcome the strength of the calcium carbonate particle. The collision frequency and total number of collisions were estimated using a modified Arrhenius equation approach by measuring the mean relative velocity of the grinding media (estimated to be the standard deviation of velocity measurements made in a block volume) and the number of media particles in a unit volume. This approach was used to characterise the behaviour of a benchmark grinding experiment performed under standard conditions and to understand the effect different operating conditions had on the number of collisions and stress exerted at these collisions. A number of suggestions for improved mill performance are given.

Encapsulation technology has been widely researched and applied to different industry sectors. There are vast examples of encapsulation for controlled release of hydrophilic or hydrophobic ingredients to the target place. However, it is still difficult to encapsulate the small water-soluble salts or molecules, achieving long-term sustained release or even no release in water. Herein, a novel type of organic-inorganic composite solid microsphere, comprised of polystyrene sulfonate and silica was developed here to achieve a sustained release of K+ ions in aqueous environment for over 48 hours. Furthermore, a novel type of melamine formaldehyde (MF) based has been developed to encapsulate KCl and allura red, showing a sustained release of KCl and allura red for 12 h and > 10 days in water, respectively. Finally, a novel formulation for encapsulation of KCl and allura red has been developed based on the formation of melamine formaldehydeoctadecyltrichlorosilane- melamine formaldehyde (MOM) microcapsules, achieving no release in aqueous environment for 1 month. It is a breakthrough to prevent the leakage of small water soluble ingredients from the carrier, which is of great significance for their long-term storage until they are delivered to a target place via triggered release in many applications.

Environmental degradation promoted by the presence of sludge piles in the steam generators of Pressurised Water Reactors (PWR) can pose a threat to their safe and continuous operation. The use of dispersants can reduce the rate at which sludge accumulates. Polyacrylic acid (PAA) is currently the only dispersant used in PWRs. Settling rate tests identified several dispersants with the potential to outperform PAA, notably Hydroxyethylidene-1,1-diphosphonic Acid (HEDP). To estimate the dispersant concentration required during plant operation, optimum concentrations were identified for both PAA and HEDP. Nuclear magnetic resonance spectrometry was used to investigate the thermal stability of HEDP between 230 and 270oC, revealing that HEDP decomposes more rapidly than PAA. The dominant HEDP decomposition product was shown to be orthophosphate but several other long lived intermediate products were detected. The effect of dispersants on the environmental degradation of grade 316 stainless steel was determined by electrochemical methods and by constant extension rate tests. Rates of general corrosion measured by linear polarisation resistance and electrochemical impedance spectroscopy were shown to be very low (on the order 10-5 mm/year) under aerated and deaerated conditions both at room temperature and at 70oC. Corrosion rates were slightly reduced in the presence of PAA and HEDP. Constant extension rate tests demonstrated that neither PAA nor HEDP promote stress corrosion cracking at 250oC. It was concluded HEDP would not be suitable for use in PWRs due to its rapid thermal degradation rate. The decomposition products were shown to rapidly concentrate in steam generators thereby preventing accurate control of water chemistry.

Much of our everyday nutrition is based on foods that are emulsions or have been emulsified at a certain stage during their processing. Emulsions’ inherent metastable state urges the introduction of emulsifiers, as a physical barrier that prevents droplets from coming together. In lieu of this approach, Pickering emulsions (i.e. droplets stabilised by solid particles) have amassed a great deal of both theoretical and commercial interest due to their scope of added functionalities. These include an exceptionally high stability and the compliance with the current demand for/appeal of formulations based on natural ingredients. Yet, their large scale adoption by the food industry has been hampered by the lack of a reservoir of edible structures that can be used as Pickering stabilisers. This thesis suggests the use of particles made of lipids as an alternative option for the design of Pickering-type emulsion stabilisers. Colloidal crystalline structures were fabricated via a melt-emulsification and subsequent crystallisation route. Solid particle characteristics, crucial for Pickering stabilisation (e.g. size, interfacial behaviour), could be controlled by adjustments to formulation and processing parameters. Building upon the knowledge gained from this initial study, colloidal lipid particles were assessed for their effectiveness to act as emulsifiers in oil-in-water (o/w) emulsions and also, for their aptitude to undergo a dehydration and rehydration process without variation of dimension or Pickering functionality.

Ceramic slurries for investment casting with the potential to replace the use of zirconium silicate have been investigated. Alumina, aluminoslicates, mullite, zirconia-mullite and zircon refractory materials were characterised and paired with colloidal silica to evaluate their slurry properties. It was found that the particle size distribution of the filler affected the viscosity of the slurries under a shear rate of drainage. A larger proportion of fines in the filler were shown to form slurries with a longer draining time. This was found to impact the shell thermo-mechanical properties by influencing the type of siloxane network formed and the rate of sintering. A combination of synthetic fused mullite and alumina fillers with different ratios was evaluated. It was shown that the shell mechanical properties at cast temperatures could be altered by adjusting the proportion of alumina present, which influenced the extent of reaction sintering occurring. The compatibility of colloidal silica types with mullite and alumina fillers were assessed to determine the stability of slurries. An optimised slurry formulation that substitutes zirconium silicate with synthetic refractories was developed; with long slurry stability and the ability to tailor the shell strength at cast temperatures, through changing the filler ratio. Casting of turbine blades was performed with the optimised shell system and found to give satisfactory casting performance for the number of trials undertaken.

Lignin is abundant naturally occurring biopolymer currently produced as a by-product from the pulping and paper industry, where the process generates lignin in the form of lignosulphonates. While there are many applications for lignin there are all low value and attempts to add value to lignin are hindered by its complex physico-chemical nature and the presence of sulphur. Adopting the biorefining concept the study evaluates the impact of direct (DE) and sequential extraction (SE) of Miscanthus x giganteus using sub-critical water with associated modifiers on the physical and chemical properties of the extracted lignin. Even though higher delignification was achieved by DE (81.5%) than SE (58.0%), the lignin recovered from the SE process showed significantly higher purity (91.5%). Fourier Transform Infrared Spectroscopy (FTIR) analysis also revealed the abundance of free hydroxyl groups (OH) within the lignin derived from SE. Further it was demonstrated that lignin agglomerates, which are widely known to form post extraction, could be de-agglomerated by simply reducing the ethanol concentration from 50% to 1% and therefore intramolecular forces. Although the finding does not offer an adequate explanation regards to the driving forces of lignin aggregates at different ethanol concentration, the esterification reaction to attach C12 fatty acids to lignin derived from SE at 50% ethanol concentration (5 mg/mL) demonstrated that the amount of hydroxyl groups available increased the level of fatty acid incorporated onto the lignin macromolecule with 81.2% esterification conversion. A modified lignin produced has the potential to be used as a precursor for added value bio-based materials.

The ever-growing emission of greenhouse gases has been a major contributor to climate change. Solutions include CO2 storage and utilisation. Moreover, scarcity of non-renewable resources has driven adoption of biocomposites. Therefore merging CO2 utilisation with biocomposites was investigated. Combinations of natural fibres and solutions were screened for their CO2 capture capacity, and chosen for optimisation of reaction pressure, temperature and time using the response surface method (RSM) to maximise CO2 capture. Thermogravimetric analysis (TGA) was used to carry out kinetic analysis of isothermal CO2 capture, using the optimised sorbents. Sorbents were also pyrolised and decomposition temperatures indicated presence of ammonium bicarbonate and carbonate, and sodium bicarbonate, which were also confirmed with FTIR and Scanning Electron Microscopy. Recycled LDPE was compounded with sorbents to make biocomposites, and the effect of sorbent loading and extruder die temperature on their physical properties was modelled with RSM. The densities, yield and ultimate strengths were higher at lower sorbent-loadings and die temperatures, whereas Young’s moduli were higher at higher sorbent-loadings and die temperatures. TGA of biocomposites showed single-step decomposition and the same temperature of maximum degradation rate. Kinetic analysis revealed that some biocomposites increased the thermal stability of LDPE.

Cleaning inside automatic dishwashers (ADWs) represents an example of a ‘black box’ problem. The description of the phenomena occurring during a typical wash cycle is not currently well known. This thesis aims to illustrate and expand the in-depth knowledge required to better understand the wash process by analysing the different mechanical and chemical factors involved as well as the interactions between them. Online measurements techniques (Positron Emission Particle Tracking, scanning Fluid Dynamic Gauge or Image Analysis) were combined with statistical and numerical modelling to investigate the evolution over time of the cleaning system.

Hydrolysis, esterification and transesterification reactions were conducted in different reactor configurations, with the overall objective of enhancing the fundamental knowledge of Free Fatty acids (FFA) and biodiesel production, while providing key processing parameters and kinetic models for process design. Hydrolysis and esterification reactions were conducted in a non-catalytic continuous flow reactor, esterification reactions in a stirred batch reactor and transesterification reactions in a state-of-the-art Downflow Gas contactor Reactor (DGCR). The DGCR was operated in batch mode with a recycle loop. All samples were collected as a function of time and the concentrations of FFA and Fatty Acid Methyl/Ethyl Esters (FAME/FAEE) were determined, using gas chromatography for FFA and FAME/FAEE and titration for FFA. Tested processing variables for each reaction were varied according to the reaction objectives and reactor limits. Extensive kinetic models for continuous flow and batch reactions were performed and rate constants were established. FFA are an important intermediate for several industrial applications. Non-catalytic continuous flow hydrolysis with the aid of subcritical water produced high quality FFA with a maximum yield of 92 % at 350 \(^0\)C, 20 MPa and 50:50 water oil volume ratio. Temperature, time and water/oil initial ratio were found to be significant factors in the hydrolysis reactions. However, pressure had a minor influence.