Little is known about the food practices of UK university students. 'Student food' often carries a negative connotation of being 'improper' or 'unhealthy'. This thesis investigates the accounts of food practices offered by undergraduate students at the University of Nottingham. This thesis introduced Goffman's ideas of self-presentation of everyday life to examine the main theoretical approaches in the study of food and eating. Students' discourse about food practices at three stages was examined: food practices at home, in university accommodations, and in private accommodations. This thesis shows students' self-presentation through their discourse about the transitions in food practices in these three living situations. The focus in students' discourse shifts gradually from constructing institutional images to personal images, as students acquired more autonomy in food practices. When talking about the period before university, students' self presentation emphasised 'institutional images' or 'family images'. When they talked about food practices after entering university, their 'personal images' gradually became more prominent. This thesis also provides an account of students' discourse about Science, technology and food, using a case study of Genetically Modified (GM) food. Students' discourse about GM food was associated with their self presentation as Natural Science or Humanities and Social Science (HSS) students. This thesis concludes that students' discourse about food has shown that their self- presentation was often constructed according to what they expected their audience to consider as appropriate for university students in UK society. The university period was portrayed as a transition in developing their personal images as they learned to present themselves as responsible independent beings in the society and located themselves within particular communities of knowledge. This thesis suggests that university students' food practices are shaped by various factors. The assumption that students do not care about their food and eating should be challenged. Furthermore, this thesis also demonstrates the way in which people talk about GM food. This is to show that, in order to understand people's views about GM food, it is important to take their self- presentation into account when interpreting their responses.

In this thesis, the impact of the interactions between the hydrophilic emulsifiers and aroma compounds as well as emulsion microstructure including droplet size, droplet size distribution, emulsion stability and creaming on aroma release over water-in-oil-in-water (w/o/w) emulsions was investigated. Polyglycerol polyricinoleate (PGPR) was used as the only hydrophobic emulsifier to stabilise the internal water droplets in the primary water-in-oil (w/o) emulsion of the w/o/w emulsions throughout this research. Three hydrophilic emulsifiers investigated to stabilise the w/o droplets in w/o/w emulsions included a low molecular weight non-ionic surfactant, polyoxyethylene 20 sorbitan monolaurate (Tween 20), a chemically modified starch, octenyl succinic anhydride (OSA) starch and a protein, pea protein isolate (PPI), as the large molecular weight emulsifiers. The two emulsification methods of high shear mixing and stirred cell membrane emulsification were used. Controls of water and oil-in-water (o/w) emulsions were prepared with the formulation and process conditions as for the w/o/w emulsions. Emulsion microstructure was characterised in terms of droplet appearance, droplet size, droplet size distribution as well as emulsion stability over time. Both static and dynamic headspace analyses were carried out to investigate the aroma release behaviour over w/o/w emulsions. The results showed that w/o/w emulsions were a suitable vehicle for short time aroma entrapment, which was most successful for the hydrophilic aroma acetoin compared to the hydrophobic aromas acetyl pyridine and hexanal. This entrapment of the hydrophilic aroma resulted from the barrier of the oil phase in the w/o droplets to delay its diffusion or the PGPR micelles in the oil phase to entrap it in the polar inner core. The complex food emulsifiers OSA starch and PPI were for the first time successfully used in stirred cell membrane emulsification to produce similarly sized o/w and w/o/w emulsions. These were produced to eliminate the effect of droplet size in the study of aroma release. The release of aromas (i.e. diacetyl and 3-pentanone) was affected by the combination of the type of the hydrophilic emulsifier (Tween 20, OSA starch and PPI) and the type of the emulsion system (i.e. o/w and w/o/w emulsions) as well as the emulsion microstructure including droplet size, emulsion stability, interface thickness, creaming and diffusion of the internal water phase into the external water phase of w/o/w emulsions. The thinner interface laden by Tween 20 might lead to a quicker diffusion of the hydrophobic aroma 3-pentanone from the w/o droplets into w2. OSA starch interacted with the hydrophilic aroma diacetyl and 3-pentanone, and PPI interacted with 3-pentanone. These findings help to better understand the effect of the hydrophilic emulsifier and emulsion microstructure on aroma release and present a novel study to produce similarly sized emulsion droplets with complex food emulsifiers.

Dates are the fruit of the palm, which the Greeks call “Phoenix”, a word taken from the Phoenician language. Saudi Arabia is currently one of the largest dates producing countries in the world. There are several varieties of dates grown in Saudi Arabia. Date fruits contain compounds that are potentially bioactive, with many health benefits; for example, vitamin E, carotene (precursor for vitamin A) and phenolic compounds. Dates represent an excellent source of antioxidants due to their high concentrations of phenolic compounds as well as the presence of selenoproteins. Moreover, dates are also potentially a very good source of several minerals in fact; there are at least 15 minerals found in dates. The work presented in this thesis will determine the nutritional composition of nineteen varieties of dates sourced from four, environmentally diverse, regions in Saudi Arabia. These varieties were selected because of their popularity, economical price, as well as availability during the year. The results indicated that the range of moisture contents (10% - 30%) found within the four regions were quite similar. For levels of fat, protein and ash all varied significantly between varieties but were all very low. Carbohydrate content was variable between samples (70 - 80%). The results indicated that glucose and fructose concentrations in theses Saudi dates were generally similar and the present of sucrose being normally associated with a corresponding reduction in the level of glucose and fructose. Potassium was the major mineral found in all the varieties with concentrations as high as 1173.29 mg/100g. The mean values for phosphorus in the dates from the different regions were close to each other. The amount of selenium was generally very low in all varieties and some did not contain any selenium at all. It would appear that it is variety and not region of production that has the major impact on nutritional composition. Moreover, this research will also determine the antioxidant capacity and phenolic content of a sub-set of these varieties at four different stages of ripening. Results showed that the levels of phenolics, anthocyanin and antioxidant capacity all decreased throughout development in all the seven selected varieties. There were strong correlations between this antioxidant capacity and the total phenolic and anthocyanin levels suggesting that these are major contributors to this nutritional property of dates. A preliminary screen tentatively identified some phenolic compounds and indicates that there may be some compositional variation between date varieties.

There has been growing interest in research focused on understanding the breakdown properties of foods in the gastro-intestinal (GI) tract, with a view to better design food systems that can control digestion with additional beneficial physiological effects (e.g satiety) to help tackle the obesity epidemic. The objective of the work presented in this thesis was to design a novel food emulsion microstructure, based on a dairy food matrix, to control digestion (measured in vitro). To achieve this, initially, skimmed milk powder (SMP), and either low or high molecular weight guar gum (GG) were used to establish SMP-GG phase diagrams at 5oC and pH 6.5 to better understand the phase behaviours of these systems. As expected, the compatibility of the SMP-GG system was found to increase with decrease in molecular weight of the GG. Confocal laser scanning microscopy (CLSM) clearly showed that the microstructure was dependent upon starting composition which in turn determined the relative phase volume of the two phases. This phase separated microstructure of SMP-GG can be considered as a water-in- water (W/W) emulsion. Through the incorporation of oil into these systems with designed microstructures based on the phase diagram, it was possible to form model systems of SMP-GG-OIL, showing the lipid phase within the protein phase within the polysaccharide phase. This can be described as ‘Matryoshka Composites’ and therefore being viewed as ‘O/W/W’ emulsion when the starting aqueous phase is either polysaccharide continuous or bi-continuous. Although the addition of a low volume fraction of oil has indicated an influence on the thermodynamic equilibrium of the SMP-GG system, through chemical analysis and rheological measurement; the in vitro digestibility of such phase separated model systems of SMP-GG-OIL with different microstructures was investigated using a pH Stat method. The microstructures were shown to be able to control lipid digestion. For a selected tie-line, the lipolysis of protein continuous > bi-continuous > polysaccharide continuous system, at a certain level of oil addition. The mechanism involved in the lipolysis of the designed formulations/microstructures was dependent upon the protein, rather than GG, and was driven by the protein concentration. As a comparison, in the case of adding different amounts of oil, the lipolysis was found to decrease with increasing oil phase volume. Confocal laser scanning microscopy revealed structural changes that occurred to the emulsified lipid droplets as they passed through a model gastro-intestinal (GI). The effect of the addition of non-ionic surfactants (Tween 20) on lipolysis of 20% sunflower oil included in the SMP-GG system has also been studied via the pH Stat method, as commercial products often contain other surface active materials. The presence of Tween 20 increased lipolysis, although it resulted in the increased droplet size arising from emulsion destabilization due to the competitive adsorption of protein and Tween 20 at the O/W interface leading to depletion flocculation. Moreover, the ‘unexpected synergism’ between Tween 20 and protein in facilitating lipolysis was enhanced with increasing Tween 20 concentration, indicating partial displacement of proteins by Tween 20 at the interface. The droplet surface laden with both protein and Tween 20 appeared like the surface of a ‘Golf Ball’ surface, so a 3D ‘Golf Ball’-like interfacial displacement model has been proposed. In contrast, if complete displacement occurred, lipolysis in the presence of Tween 20 was not further increased nor was it decreased. In addition, the oil type and physical state of lipid demonstrated an influence on lipolysis, but this was mainly dependent upon the lipid compositions and their melting points. These findings suggest the potential applications for food product design in regulating satiety effects by triggering the Ileal brake mechanism, and may provide opportunities to control delivery of specific nutrients during digestion.

Estery and woody flavour notes are important characteristics of distilled spirit flavour. It has been reported for malt whisky that the estery character of mature whiskies typically declines relative to that of the new make spirit, even though the analytical concentrations of esters remain broadly constant. One potential explanation for this observation would be a sensory interaction between mature and estery characters. The work described in this thesis was designed to test this hypothesis and to further explore the nature of the congeners responsible for eliciting these characteristics across different spirit types, as influenced by their maturation conditions (time, temperature, cask provenance etc.). In the research described in Chapter 2, four pairs of non-mature and mature spirits (tequila, bourbon and 2 malt whiskies) were characterized by instrumental analysis with the aim of defining the key aroma compounds that determined the mature character in each spirit. According to PLS analysis of the full data set, concentrations of 17 congeners were positively correlated with ageing time and might thus influence the mature character of the aged spirits. In Chapter 3, the same eight spirit samples were analysed by GC-Olfactometry using the AEDA (aroma extraction dilution analysis) approach. Aged spirits presented a more complex aroma than new make spirits, and contained more compounds with the highest FD-factors. Whilst a full GC-O characterisation was completed, the main focus was on identifying compounds which contributed to the estery and woody/mature characters of each spirit. In Chapter 4 we attempted to reproduce these characters for each spirit through aroma recombination, based on blends of the odiferous compounds identified at high FD factors and their analytical concentrations in the actual samples as reported in Chapter 3. It soon became apparent that relatively simple mixtures of esters on the one hand and maturation-linked compounds on the other did not adequately reproduce the nature of these characteristics in the spirits themselves. This implied either that our analysis had missed some significant compounds contributing to these characteristics, or that the complexity of the full spirit matrix is required to give the groups of compounds the nuanced flavour that they lacked in isolation. The latter hypothesis was tested by adding in additional blends of compounds to increase the complexity of the recombinant aroma mixtures. It was concluded that the authenticity of the aroma blends overall was improved by both the addition of a cocktail of ‘low boiling compounds’ (those analysed by a separate direct injection GC technique) and the introduction of a ‘structuring’ compound (ethyl hexadecanoate) at a concentration that would cause agglomeration within the whisky (micellar structures) thus influencing aroma partitioning and release. It was concluded that these modifications produced recombinant aromas which were close enough to the authentic spirit characters to use them in sensory interaction studies (Chapter 5). As opposed to interaction effects there was simply a tendency for the woody/mature characters to suppress the corresponding estery character of mature spirits, particularly at the higher concentrations of added wood extractives. Because the woody/mature compounds which characterised maturation were broadly similar across the spirit types, but differed in concentration according to the maturation conditions, we decided finally to investigate the extraction kinetics of wood-derived compounds from oak sticks as a function of ageing time, temperature, spirit type and alcohol content (Chapter 6). Temperature and alcohol content were the most significant factors that determined the extraction rate and final concentrations of all 18 wood-extractive compounds (P < 0.05) analysed. Not surprisingly, extraction rates increased with increasing temperature, but the trend in terms of alcoholic strength depended on the particular compound. Overall this thesis has improved knoEstery and woody flavour notes are important characteristics of distilled spirit flavour. It has been reported for malt whisky that the estery character of mature whiskies typically declines relative to that of the new make spirit, even though the analytical concentrations of esters remain broadly constant. One potential explanation for this observation would be a sensory interaction between mature and estery characters. The work described in this thesis was designed to test this hypothesis and to further explore the nature of the congeners responsible for eliciting these characteristics across different spirit types, as influenced by their maturation conditions (time, temperature, cask provenance etc.). In the research described in Chapter 2, four pairs of non-mature and mature spirits (tequila, bourbon and 2 malt whiskies) were characterized by instrumental analysis with the aim of defining the key aroma compounds that determined the mature character in each spirit. According to PLS analysis of the full data set, concentrations of 17 congeners were positively correlated with ageing time and might thus influence the mature character of the aged spirits. In Chapter 3, the same eight spirit samples were analysed by GC-Olfactometry using the AEDA (aroma extraction dilution analysis) approach. Aged spirits presented a more complex aroma than new make spirits, and contained more compounds with the highest FD-factors. Whilst a full GC-O characterisation was completed, the main focus was on identifying compounds which contributed to the estery and woody/mature characters of each spirit. In Chapter 4 we attempted to reproduce these characters for each spirit through aroma recombination, based on blends of the odiferous compounds identified at high FD factors and their analytical concentrations in the actual samples as reported in Chapter 3. It soon became apparent that relatively simple mixtures of esters on the one hand and maturation-linked compounds on the other did not adequately reproduce the nature of these characteristics in the spirits themselves. This implied either that our analysis had missed some significant compounds contributing to these characteristics, or that the complexity of the full spirit matrix is required to give the groups of compounds the nuanced flavour that they lacked in isolation. The latter hypothesis was tested by adding in additional blends of compounds to increase the complexity of the recombinant aroma mixtures. It was concluded that the authenticity of the aroma blends overall was improved by both the addition of a cocktail of ‘low boiling compounds’ (those analysed by a separate direct injection GC technique) and the introduction of a ‘structuring’ compound (ethyl hexadecanoate) at a concentration that would cause agglomeration within the whisky (micellar structures) thus influencing aroma partitioning and release. It was concluded that these modifications produced recombinant aromas which were close enough to the authentic spirit characters to use them in sensory interaction studies (Chapter 5). As opposed to interaction effects there was simply a tendency for the woody/mature characters to suppress the corresponding estery character of mature spirits, particularly at the higher concentrations of added wood extractives. Because the woody/mature compounds which characterised maturation were broadly similar across the spirit types, but differed in concentration according to the maturation conditions, we decided finally to investigate the extraction kinetics of wood-derived compounds from oak sticks as a function of ageing time, temperature, spirit type and alcohol content (Chapter 6). Temperature and alcohol content were the most significant factors that determined the extraction rate and final concentrations of all 18 wood-extractive compounds (P < 0.05) analysed. Not surprisingly, extraction rates increased with increasing temperature, but the trend in terms of alcoholic strength depended on the particular compound. Overall this thesis has improved knowledge of the chemical and sensory changes that accompany spirit maturation and has highlighted some of the factors that cause differences in mature character across spirit types. / Moreover, it concludes that the sensory perception of woody/mature generally suppresses the fresh estery characteristic of new make spirits, even though analytically the esters are still there in similar concentrations. wledge of the chemical and sensory changes that accompany spirit maturation and has highlighted some of the factors that cause differences in mature character across spirit types. Moreover, it concludes that the sensory perception of woody/mature generally suppresses the fresh estery characteristic of new make spirits, even though analytically the esters are still there in similar concentrations.

Improved stoves have been promoted in the global South by international organisations from the North since the 1970s for a variety of reasons including mitigation of health and environmental hazards related to the widespread use of solid biomass for cooking. However, uptake of these stoves by poor households in the South remains low, bearing negatively on efforts to alleviate energy poverty and achieve the Millennium Development Goals (MDGs). This thesis examines the framing and impact of participatory and market-based approaches to stove development and dissemination which have been widely promoted since the mid-1980s to address the failures of the predominantly expert-led, subsidy-based models favoured in the early years. Specifically, I investigate and compare two Northern-led stove projects, one established by Project Gaia in Nigeria, where stove development efforts targeted at addressing energy poverty have been limited, and the second by Practical Action in Kenya, where such efforts are more visible. Drawing on empirical data gathered from field observations, interviews and key documents, I argue that despite the rhetorical shift from expert-led to context-responsive approaches, engagement with local priorities is still limited, and the interests and priorities of Northern organisations continue to shape the stove development agenda. The research establishes that Project Gaia’s CleanCook project in Nigeria remains an expert-led intervention that fails to connect with the bottom of the socio-economic pyramid while seeking to create local market conditions for transferring stove technology. In Kenya, Practical Action has been more responsive to local realities in its efforts to engage marginalised women’s groups in participatory stove development; however, success is limited by the constraints of project funding and assumptions about homogeneity of the poor. Cultural preferences and socio-economic differences within Southern target populations challenge the Northern vision of improving stove dissemination through a combination of participatory methods and neoliberal market solutions.

Early in the life of this thesis, Britain became the world's third largest consumer of organic produce with sales of organic food exceeding one billion pounds. Drawing on a conceptual framework based on Foucault's texts, the research investigates this little word "organic" and asks how organic food production is regulated. The empirical study begins with a genealogy/archaeology of organic farming regulation, including very recent history in the making during the research period. Using Foucault's concepts of code- and ethics-oriented morality and focusing on self-regulation, the study considers commitment to organic farming by producers as ethical subjects. An ethnography carried out within a self-managing cooperative organic farming community shifts the research to a local level. The research investigates the various organic truths produced by individuals through subjectivisation-objectivisation interplay. The code-oriented morality of the Soil Association is an absent presence that is at variance with a looser set of values and rules associated with the self-sufficiency movement and handed down as an oral tradition. Within a heterogeneity of organic, the care of the self practice parrhesia is used to analyse how community members establish collective organic farming practices through decision-making practices. The research uncovers the hidden complexities and ambiguities embedded in organic food production. The thesis reveals too how power relations are at play within the context of equality in a headless organisation. The thesis addresses the under-researched area of agriculture within business schools. Moreover, the thesis provides a comprehensive and accessible working example of Foucault's main themes and contributes to an emerging body of work based on the interplay of subjectivisation and objectivisation. Finally, the thesis contributes an empirical study of self-management to the emerging research field within Critical Management Studies of alternative organisational forms.

Dispersion of aroma compounds in food matrices is a common process in the production of many food products. However, the degrees of dispersion on the distribution and subsequent release of these compounds during consumption may have considerable consequences for perception of these flavours. This thesis investigates the effects of a range of dispersion techniques on the delivery and release of aroma compounds from several solid and semi-solid matrices which commonly contain added flavourings. Dispersion was achieved on three main scales ranging from molecular, through micro regions to physical separation or layering. The effects of different levels of mixing were assessed by measuring aroma release in vitro and in vivo via APci-MS. Having defined the stages of mixing, systems were developed to measure the influences of different dispersion techniques on aroma delivery. Layering to physically separate homogenous aroma-rich layers showed no significant effects on aroma release or perception from gelatine sucrose gels. It seems that mastication is very effective in re-mixing these systems and, in vivo there is no difference in aroma release. Although the degree of mixing could be controlled using a static mixer system for yoghurts, no effects of the different levels of mixing were observed on aroma release. Stirred yoghurts showed that mixing could influence equilibrium headspace concentrations but overall release in vivo was inconclusive. Sample selection in these systems may be important for influencing perception. Visual and textural cues may be more important for perception, in these mixing examples, than aroma release. Using co-solvents as dispersion agents significantly increased the ease of dispersion of a range of aroma compounds. Static headspace analysis confirmed that all the carrier solvents influenced the partition of aroma compounds and in vivo release from model confectionery systems. Increasing solvent concentration increased the solubility of a range of aroma compounds in the liquid phase. Release from gels was also influenced by the presence of solvents with hydrophobic aroma compounds showing patterns of release similar to those of hydrophilic compounds when dispersed using solvents. Finally, this work studied release from phase separated systems where the aroma compound was present as a microdroplet. Release was very intense and rapid and was investigated in aqueous solutions and gelatine-sucrose gels. In this case the release mechanism was not the conventional air-liquid partition but was based on direct release from the air-liquid interface. Release was dependent on both hydrophobicity and vapour pressure.

There is conflicting information on the mechanical properties and ageing kinetics of starch-water-glycerol systems. This makes understanding the changes occurring on storage of edible products difficult to predict. The work described in this thesis looks at model systems consisting of thermomechanically extruded plasticized starches (waxy maize, rice and wheat) and commercial products. The objectives of the work were to evaluate how the presence of polyols effects glass transition temperature (Tg), sorption isotherms, diffusion rates and texture parameters and to create models that could be used to predict behaviour. Very similar results were obtained for the starch samples except that monolayer (ma) values were higher for the waxy maize starch than for the wheat and rice. The waxy maize also was more brittle at equivalent moisture content when compared to the other two starches. Glycerol had a major impact on the water absorption. For RHs > 70% more water absorbed up by samples containing glycerol while the opposite occurred at RHs <60%. Monolayer values for GAB and BET confirmed this finding. The behaviour could be predicted if an interaction factor <1 was used in weight fraction models. Tg of the samples was measured by DSC and also by using predictive models, where the ten-Brinke Karas equation was found to give the best predictions. A value that was found to be most beneficial for the prediction of retrogradation was (storage temperature minus Tg). Change in texture was associate with (T-Tg), although the brittle ductile transition occurred 40°C below T-Tg=O. Diffusivity values increased with plasticizer level up to 8*10 3 m'z/s. There was an apparent fall in values when the samples were above Tg. However, it is suggested that this is due to sample geometry change rather than a change in diffusion mechanism. The Tg values also were found to be a good predictor of the type of change occurring in the model systems and food products during storage. Below Tg physical aging (enthalpy relaxtion) could be seen in the samples and retrogradation of the starch occurred above Tg. The rates of retrogradation were not affected by glycerol content directly and knowledge of Tg and storage temperature were sufficient to predict the retrogradation. Products became stiffer on storage and this was associated with molecular reassociation of the starchy component, but control of the moisture was also critical as water still dominated product behaviour even in the presence of glycerol.

The relationship between in vivo captured data from an atmospheric pressure chemical ionisation mass spectrometer (APCI-MS) and sensory/psychophysical analyses was investigated. The stimuli used were mainly single volatiles under gas phase control or calibration by development of different olfactometry methods. Gas phase concentration retronasal (via the mouth to the nasal cavity) and orthonasal (via the nostrils) thresholds were determined for a trained panel of 13 individuals. Four volatiles were used with different sensory/physico-chemical properties and an adapted staircase method was employed to measure the individual thresholds. The data showed good repeatability over short durations of one week and also longer ones of eight months. It was used to test the hypothesis that thresholds varied between people due to differences in their in-nose concentration as measured or estimated by the APCI-MS. The analysis did not support this theory but relationships between orthonasal and retronasal thresholds were shown, in which the latter were -50 times lower than the former. Threshold determination of a larger group of 20 individuals revealed clusters of individuals. Methods of producing square edged pulses of aroma compound in the gas phase were developed using a modified chromatograph autosampler with a gas flow of 5 mL. min 1 and pulse rate of 0.6 secs. A trained panel of 23 individuals performed two types of sensory test using pulsed and constant olfactometer outputs of isoamyl acetate. The original intention was to reveal whether pulsed odorants were perceived as the same as or different to constant concentration. Initial experiments yielded results that were difficult to interpret, although the nature of the results was clarified when simultaneous breath by breath analysis techniques were employed. Here it was shown that each individual in different repetitions disrupted the olfactometer output pattern in unpredictable ways. This pattern disruption was measured in two instrumental configurations, as either volatiles in an exhalation or volatiles as they were inhaled together with two types of sensory test. In both sensory tests the pattern of aromas in an inhalation revealed a relationship with perception. In particular, the sensory response in the time intensity study was related to differences in the inhalation profiles between people, which in turn was related to an individual's breathing. This shows that physiological differences such as breathing and the structure of the nasal cavity have an impact on perception.