Background: Whole grain consumption is associated with reduced risk of chronic disease. One-fifth of UK adults and children do not consume any whole grains, and adolescents have low consumption rates. There is little research on correlates of whole grain consumption in this age group. This study aimed to identify the socio-demographic, environmental, and behavioural factors associated with whole grain intake in UK adolescents, based on the health behavioural Reasoned Action Approach (RAA) model. Methodology: In Study I, five focus groups explored 50 adolescent’s attitudes towards, knowledge and consumption of wholegrain foods, as well as barriers to, and facilitators of, consumption. Focus groups were analysed using thematic analysis. Study II conducted SenseCam assisted in-depth interviews with eight adolescents. Participants wore SenseCam for three days, then undertook traditional 24-hour recalls and in-depth interviews for attitudes, knowledge and consumption of wholegrain foods; as well as barriers and facilitators to consumption. SenseCam images prompted conversation during the interviews, which were audio-recorded and analysed using inductive content analysis. In study III, an RAA-based online survey was developed, as informed by Studies I and II. A total of 160 participants completed an online Food Frequency Questionnaire to estimate whole grain intake, and a survey examining their knowledge, attitudes, and consumption of wholegrain foods, as well as barriers and facilitators to consumption. Linear regression models, adjusted for demographic characteristics, were used to identify factors associated with whole grain intake. Participants in this thesis were adolescents of mixed genders and ethnicities, aged 11-16 years; recruited from schools in Leeds city area. Results: Most participants had heard of whole grains but their consumption levels were generally low. The mean whole grain intake was around 10 servings of wholegrain food per week – approximately 1.4 servings per day. Breads and breakfast cereals were the most commonly consumed products. Adolescents were more influenced by parents and online media than by peers. Most adolescents related “whole grains” to wholemeal toast, and were not aware that varieties they already consumed, such as popcorn, quinoa and brown rice, were whole grain as well. Many recognised whole grain health benefits related to digestive health but not those related to heart disease or cancers. Barriers to whole grain consumption included negative sensory properties, poor availability and lack of varieties in stores, a lack of knowledge of the health benefits and difficulties in identifying wholegrain products. Suggested facilitators to consumption included promotion through social media celebrities, increased parental awareness and school-based education, improved sensory appeal, increased availability and variety, and tailoring of products for young people. Key factors significantly associated with increased whole grain intake (survey results, p < 0.01): home availability of whole grains (R2=0.21), a supportive friend and family environment to consume more wholegrain foods (R2=0.19), personal dietary-consciousness (R2=0.18) and higher physical activity levels (R2=0.17), followed by positive attitudes to whole grains (R2=0.13), and intention to consume more wholegrain foods (R2=0.11). Being male and from a higher family socioeconomic status were also associated with greater whole grain consumption (R2=0.10). Frequency of eating out and getting lunch from school – non-RAA construct factors – were negatively associated with whole grain consumption (R2=0.17, and R2=0.15, respectively). The constructs of RAA successfully captured a number of whole grain consumption correlates among adolescents, explaining 19.9% of the variance in whole grain consumption. Conclusion: Findings of this study suggest future interventions should address a broad range of factors, in particular awareness to improve parental and adolescent attitudes and increased home availability of wholegrain foods. Study outcomes may inform future interventions to increase whole grain intake in this age group.

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Haplochromis spp. is an underutilized fish stock abundant in L. Victoria and occurring in many African lakes. Its small size and boniness make it unpopular as human food. A process for producing fish powder for human consumption from whole HapLochromis by partial acid hydrolysis was developed. Whole fish was minced and mixed with hydrochloric acid in the ratio. 30:100 v/wo The mixture was continuously stirred for 30 minutes, neutralised with NaOH to the original pH of the mince, homogenized and drum dried or spray dried. The effect of varying temperature, acid concentration and using cooked or uncooked fish as raw material on hydrolysis were investigated by determining changes in TCA-soluble N of the hydrolysate over the 30 minute period. Seven temperatures between 25 and 84cC and four acid concentrations (2.5M, 5M, 7.5M and 1l.3M) were investigated. The overall extent of hydro lysis for each run was determined by calculating the nett increase in TCA-soluble N expressed as % of total N, and it ranged between 0.8% and 10.4% and 6.7% and 34.1% for cooked and uncooked fish respectively. The extent of hydrolysis was greater in uncooked than cooked fish due to the synergistic effect of the endogenous proteolytic enzymes in uncooked fish and its absence in cooked fish. Cooking had destroyed the enzymes. Eight different products were produced. Data for crude protein, true protein, amino acid profiles, total lipid, ash, NaCl, aw, in vitro digestibility, colour, particle size distribution and sensory evaluation of the products were obtained. The data indicated the products had a high nutritional value and would be micrcbiologically stable for several months but susceptible to oxidative rancidity unless antioxidant were added. Using the data a process in which uncooked fish would be partially hydrolysed with 2.5M HCl at 48°C (approximately) for 30 minutes and the hydrolysate spray dried was proposed.

The subject of this research was an experimental study of the development of chocolate aroma during the commercial processing of cocoa beans. The components of unroasted aroma cocoa beans have been fractionated, and the various groups of substances obtained tested for the development of aroma when roasted. The results obtained provide further evidence of the involvement of simple amino acids, reducing sugars and flavonoids in the formation of the primary aroma of chocolate products, and a mechanism for the formation and mixing of these substances during cocoa fermentation is described. Model mixtures of these compounds have been examined in order to assess the extent of the contribution of individual compounds to the production of the aroma. The reaction of these model mixtures have also been examined under the conditions obtaining during commercial bean roasting, and combined gas chromstography-mase spectrometry has been used to compare their volatile reaction products with these present in roasted cocoa beans. The results of these studies indicate the importance of the natural environment of the precursors in the control of the extent of subsequent reactions, and the consequences of the 'dry state' reaction conditions in this respect. Various types of compound formed in these reactions are described and their possible importance in the recognition of chocolate aroma is discussed. The experimental results are discussed in terms of literature surveys of the current state of knowledge of both chocolate aroma development, and the aroma potential of amino acid-reducing sugar reactions.

Arabinoxylans (AXs) are major components of non-starch polysaccharides (NSPs). Recently, AXs have attracted a great deal of attention, because of their possible antitumor and immunomodulation activities. These activities have been suggested to be related to the content of low molecular weight (Mw) AXs, in particular those with a Mw below 32 kDa. Rice bran and wheat pentosan are rich sources of AXs. However, extraction of AXs is difficult and often gives low yield. Various methods have been used to increase the extraction yield of AXs with varying degrees of success, such as alkaline hydrolysis and enzymatic treatment. However, some of these treatments have been reported to be either expensive or produce hazardous wastes and non-environmentally friendly. Extrusion processing has been used to increase the solubility of cereal dietary fibre, however, these studies used alkaline or enzyme treatments with the extrusion to maximise the extraction yield. The use of extrusion alone as a pre-treatment method to increase the extraction yield and reduce the molecular weight (Mw) of AXs from rice bran or wheat endosperm pentosan has not been investigated. Hence, the current study aimed to determine if extrusion alone could change the extraction yield and Mw of the AXs. Wheat endosperm pentosan and rice bran were extruded with a twin-screw extruder at screw speeds of 80 and 160 revolutions per minute (rpm). It was found that the extraction yield of AXs increased with an increase in screw speed and was accompanied by a decrease in the Mw of the AXs. In vitro studies using immunoassays to measure proinflammatory markers showed that AXs from extruded rice bran and wheat pentosan significantly (P < 0.05) increased nitric oxide (NO) and tumour necrosis factor α (TNFα) production from both U937 monocytes and macrophages in a concentration-dependent manner at (50, 500 and 1000 μg/ml), respectively. Moreover, the immunomodulatory activity of AXs was associated with the very low Mw of AXs. Moreover, inhibition of toll like receptor 4 (TLR4), which is known to be the receptor for bacterial lipopolysaccharides (LPS), significantly inhibited the AXs-induced increase in NO and TNFα production in both U937 monocytes and macrophages (P < 0.05), suggesting the actions of AXs may be mediated at least in part through TLR4. The findings of this study indicate that AXs may compete with LPS for the same receptor TLR4, resulting in decreasing the inflammatory response that LPS produces during the infection. Thus AXs can produce a non-detrimental moderate increase in the inflammatory response.

Wheatfeed is a low value by-product of the cereal milling industry and has potential as an ingredient of pet foods. However, it has a high fibre content and this renders it unsuitable for non-ruminants unless some means can be found to convert the fibre to more digestible substances. This work considers enzyme hydrolysis as a means for improving the nutritional value of wheatfeed. Preliminary investigations focused on evaluating mixtures of enzymes in various combinations. The extent of hydrolysis was routinely assayed by measuring the release of sugars and proteins. Further experiments were performed to establish the optimal conditions under which a mixture of enzymes, comprising cellulase, hemicellulase and pectinase, hydrolysed wheatfeed. Studies were also conducted where these enzymes were added sequentially to wheatfeed and useful information was gained on the composition of the susceptible components. Steam explosion was investigated as a pretreatment of wheatfeed to make subsequent enzyme treatment more effective. However, the results were inconclusive. Trials were carried out using commercially available enzymes to compare their effectiveness on the wheatfeed. A cellulase, was selected for further investigation into the effects of particle size, extent of agitation, and enzyme concentration on sugar release. An empirical mathematical model describing the action of this enzyme was developed. Enzyme treatment of wheatfeed was also performed under conditions of reduced water content, or 'solid state'. However, enzyme action was limited, yielding lower quantities of sugars and protein. The treatment of wheatfeed with enzymes was shown to increase digestibility of the substrate. However, the high costs of enzymes would effectively rule this out as a commercial option and alternative methods such as for example a form of composting using cellulolytic fungi might prove more economic.

This PhD thesis is concerned with improving the retention of volatiles in the manufacture of instant coffee powders. Two processes have been studied in depth: spray drying and spray freeze drying. Spray freeze drying consisted of a combined spraying and freezing operation, followed by sublimation in a fluidised bed under partial vacuum. The aroma quality was measured using headspace solid-phase micro-extraction (HS-SPME) technique followed by gas chromatography coupled with mass spectrometry (GC/MS). Experiments were also performed with maltodextrin as the encapsulating matrix for comparison.

This research project is concerned with the recovery of Functional Fish Protein from fish filleting waste by an extraction method utilising sodium chloride solutions. It was found that the greatest amount of extracted protein could be obtained after one hour of extraction time using 4% NaCl as a solvent. The optimum solid-to-liquid ratio was 1:8 and the best particle size was found to be 0.04 cm diameter. The Silverson homogenizer was found to give a higher protein yield than other extraction apparatuses which utilise orbital or rotary motions. It was found that minced fish waste samples stored at -30°C for sixty days did not result in a noticeable deterioration in protein extractability values. Those values decreased by about 27% and 60% after seventy days storage at -15°C and 0°C respectively. The protein–saline extract was desalted and concentrated by means of an ultrafiltration process. The effect of protein concentration, temperature and pH of the feed stream on the flux rate were studied. It was found that the flux rate: (i) decreased as protein concentration rose; (ii) increased with increasing temperature of solution; (iii) did not change at basic pH, but decreased at acidic pH. The functional properties of the freeze-dried product were assessed. The characteristics of solubility, coagulation, foam and emulsification showed that Fish Protein Concentrate was suitable for use as a functional agent in food products.

A new technique to simultaneously and instantaneously resolve 3D velocity/2D strain rate fields and scalar/scalar gradient fields was developed and evaluated in this study. This technique combines Planar Laser Induced Fluorescence of the NO radical (NO-PLIF) and Stereoscopic Particle Image Velocimetry (SPIV). It was found that the NO-PLIF technique allowed the determination of various iso-c contours and as such would, in principle, allow the study of the influence of the heat release on various properties, provided a calibration of the NO-PLIF signal as a function of temperature is achieved. It was also shown that the NO-PLIF technique may not be unambiguous at detecting flame extinction. The SPIV technique allowed the determination of the velocities in 3D and of the strain rates in 2D from which the most extensive and the most compressive strain rates but not the intermediate strain rate could be extracted. Information on strain rates and progress variable gradients were of particular interest in this study as they were needed to study the turbulence-scalar interaction which appears explicitly in the transport equation for the scalar dissipation rate which was derived recently. Using the technique above mentioned, this work also aimed at gathering and analysing data such as flame normal orientation, progress variable gradients, velocity change across the flame front and strain rates along the flame contours in turbulent premixed hydrogen/air flames with added nitrogen. The flame normal orientation was found to be consistent with the regime of the flames studied. A new method was designed and presented to infer from the progress variable gradients the component of the flame normal in the third dimension. The velocity change across the flame front, inferred from the SPIV data, was found to be extremely small. It is thought that the (low) heat release of the flames studied contributed more to corrugation of the flame front than acceleration of the gases across the flame front. The strain rates were studied along apparently non-wrinkled and clearly wrinkled flame contours. Their variation could not successfully be linked to curvature solely. Their values were mostly below the value expected for extinction strain rates. Last, this study aimed at investigating the turbulence-scalar interactions in turbulent premixed hydrogen/air flames with added nitrogen via the characteristics of the alignment of the flame normal vectors with the principal strain rates. The results of this study are quite different from earlier experimental results obtained for turbulent premixed ethylene/air flames. The strong preferential alignment of the flame front normal with the most extensive strain rate observed for ethylene/air flames could not be observed for the hydrogen/air flames with added nitrogen studied in the present work. The key outcome of this study was that no preferential alignment could be observed for most of the flames. A slight preferential alignment of the flame front normal with the most compressive strain rate was observed for the flames with very low adiabatic flame temperature. The differences observed were attributed partly to Lewis number effects and partly to the low heat release superimposed on the hydrodynamic fields in the flames studied.

This thesis describes the research that has been completed for the application of polyaniline as a food quality indicator. It has been reported by WRAP (Waste and Resources Action Programme) that in the UK alone, a third of all purchased food items are thrown away regardless of the quality or condition. It has also been reported by DEFRA (Department for Environment Food and Rural Affairs) that the food manufacturing and processing industry is one of the UK’s largest producers of land filled waste. At present, the available technology for food freshness determination is largely based on use-by dates which are often recognised as unreliable - or qualitative time temperature indicators (TTIs); which can be costly and do not give an actual measurement of bacterial activity. It is anticipated that the technology produced from this research will give a viable and low cost solution to help minimize preventable food waste from consumers - as well as improving food industry process efficiency, especially in the field of food supply chain management. The sensors being developed employ a conducting polymer film as a sensor which reacts with volatiles evolving from selected food products (salmon and herring). As food biochemically degrades, the concentrations and volumes of these gases change, and this has been studied by analytical techniques such as gas chromatography and SIFT-MS. Food spoilage has also been followed by the growth and identification of specific spoilage bacteria. The sensor exhibits a number of quantifiable physical changes when exposed to differing volatile mixtures produced by the food stuffs. These physical properties include colour and conductivity changes which are distinctive and easily measurable. Correlations have been shown between increases in microbial activity and the change in conductivity of the films. These sensors will be able to inform consumers more reliably when the food is safe to consume as well as providing the food industry with more information on traceability and stock conditions of fresh meat and fish. In the context of the catering industry, these sensors will also aid in the decreasing the number of reported cases of food poisoning by observing - in real-time - the condition and safety of food.