The widespread use of non-meat protein in meat products necessitates a method for the robust, unequivocal quantification of meat in foods. Protein-bound levels of the co- or post-translationally modified amino acid, 3- methylhistidine, virtually unique to the myofibrillar proteins actin and myosin, have previously been proposed as such an index, determination being by high-performance liquid chromatography of acid stable fluorescamine derivatives. Although robust to the severest processing conditions, variations in the titres of 3-methylhistidine in certain manufacturing cuts have been reported. The present study has revealed that such variations can be attributed to the low level of 3-methylhistidine in the myosin of muscles high in "red" (oxidative) fibres, such as ruminant Masseter; constant levels of 3-methylhistidine being found in all actins investigated. Methods for the determination of actin-bound 3- methylhistidine have therefore been developed. Electrophoretic separation of actin with 3-methylhistidine determination of the resulting actin band was found to be only semi-quantitative. The isolation of actin by conventional SOS-gel filtration was time consuming and resulted in low yields of 3-methylhistidine. SDSgel filtration using the Pharrnacia fast protein liquid chromatography (FPLC) system, allowed rapid, reproducible and quantitative isolation of actin-bound 3-methlhistidine. Using too latter method, constant levels of actin-bound 3-methylhistidine have been found for all muscles investigated. A new unequivocal definition of "meat", is proposed as that which has an actinbound 3-methylhistidine content of 3mg/g non-connective tissue nitrogen. This is expected to be robust to all but the severest processing conditions. Such an index, based on connective tissue free units, requires the accurate determination of hydroxyproline, for which a sensitive method using gas chromatography-mass spectrometry has been developed. The use of an assumed average "factor" for the conversion of hydroxyproline to connective tissue appears valid, since the hydroxyproline contents of the connective tissue of all muscles investigated were similar.

A newly recruited sensory panel was trained in magnitude estimation and time intensity sensory techniques. Sensory analysis was combined with instrumental analysis using MS Nose to investigate the relationship between stimulus and perception using simple model food systems. Volatile release data was collected after swallowing aqueous solutions containing a cocktail of aroma compounds. The compounds varied in their persistence during subsequent exhalations dependent on the degree of association with the mucous lining of the throat. The rate of breathing had no effect on the shape or intensity of the release profile. The data was successfully modelled using the basic principles of interfacial mass transfer. The mechanistic model included some estimated parameters for un-measurable anatomical and physiological variables, kinetic properties of the flavour compound and terms to represent the oscillatory breathing and airflow rate. Aside from the 1st exhalation, the model fitted the data very well. The panel rated the intensity of minty flavor in a 6% gelatine gel, containing varying concentrations of carvone. The flavor was assessed using Magnitude Estimation and Time Intensity Methods. In addition, the quantity of carvone released from the gel and reaching the assessors nose was measured, breath by breath during eating, using the MS Nose. The results showed that the quantity of volatile delivered to the nose was directly proportional to the concentration in the sample, however, the absolute quantity varied greatly between individuals. Further differences were observed in the temporal dimension of their release profiles, which related to differences in their anatomy, physiology and eating habits. In some cases, these differences were mirrored by the sensory data. The relationship between perceived intensity and sample concentration was linear for both types of sensory data. Neither the speed of eating nor the concentration of volatile reached in-nose, affected an individuals ability to judge intensity. There was evidence to suggest, however, that the speed of eating affected the level of adaptation to the carvone stimulus. The affinity of the aroma compound for water (hydrophobicity) was an important factor in influencing the temporal characteristics of the instrumental and sensory data. When aroma release was rapid (< Tmax) the sensory response occurred slightly later whereas when the aroma release was much slower (>Tmax), with intensity increasing more gradually, the sensory response preceded the instrumental data. These phenomena were explained in terms of a lag phase for neural processing when the stimulus was presented quickly and adaptation to the stimulus when it was delivered over a longer period of time. A trained sensory panel assessed flavour and sweetness intensity in solutions containing varying concentrations of Hydroxy Propyl Methylcellulose (HPMC), sugar and flavour volatile. The flavour and sweetness of the viscous solutions were rated using magnitude estimation with a controlled modulus. In addition, the concentration of volatile released on the breath was measured using MS Nose. For low concentrations of HPMC (<0.5g/100g), perceived flavour intensity remained the same, however, a steady decrease was noted at higher concentrations (>0.6g/100g). The change in perceived intensity occurred at the point of random coil overlap (c*) for this hydrocolloid. The perceived sweetness of the solution showed a similar pattern with increasing HPMC concentration, although the inflection at c* was not so obvious. Despite the change in perceived flavour intensity, the actual concentration of volatile measured on the breath was not affected by the change in HPMC concentration. Low order polynomial models were produced to describe perceived flavour intensity and sweetness in viscous solutions containing HPMC and potential explanations for the changes in perception were discussed.

The quantity, quality and variety of food ingested by humans largely determines the intake of the essential mineral micronutrients required for normal human physiological functioning, growth and development. Inadequate dietary intake, low bioavailability, and failure of the human body to utilize ingested essential minerals lead to mineral micronutrient deficiencies (MNDs), an invisible form of undernutrition also known as hidden hunger. With the aim of aiding future human nutrition policy planning, the extent of dietary MNDs of calcium (Ca), copper (Cu), iodine (I), iron (Fe), magnesium (Mg), selenium (Se) and zinc (Zn) were estimated by integrating food supply and composition, estimated average requirement and demographic data. National level dietary Ca, Mg and Zn deficiency risks between 1992 and 2011 were estimated for the populations of 145 countries. Globally, in 2011, 3.5 and 1.1 billion people were at risk of Ca and Zn deficiency, respectively, due to inadequate dietary supply; 14 million people were at risk of Mg deficiency during the same period. Ninety percent of those at risk of Ca and Zn deficiency in 2011 lived in Africa and Asia. Considering the limited policy-making relevance of the low resolution national estimates of mineral MNDs, sub-national level assessments of the prevalence of dietary mineral MNDs were made for Malawi in 2011 using a 7-day household dietary recall survey data (n = 12117). It was estimated that >50% of households in Malawi were at risk of energy, Ca, Se, or Zn deficiencies due to inadequate dietary supplies, but supplies of Fe, Cu and Mg were adequate for >80% of households. Interventions to address dietary mineral deficiencies, such as dietary diversification using underutilized multipurpose and hardy tree/shrub species (e.g. Moringa spp.), were considered. Greater than 78% of Moringa growing households in southern Ethiopia and Kenya use M. oleifera (MO) and M. stenopetala (MS) trees as a source of food. Increasing the dietary consumption of MO and MS leaves, as a fresh vegetable or in powdered form, can reduce the prevalence of mineral micronutrient deficiencies, most notably Se deficiency. Daily consumption of 100 g Kenyan MO or MS fresh leaves could provide 100% and 144%, respectively, of the Se recommended daily allowance for a healthy adult man. Research and development to promote the use of these species in the fight against hidden hunger, are necessary. Continuing to reduce mineral MND risks through dietary diversification, and food and agricultural interventions, including fortification, crop breeding and use of micronutrient fertilisers, will remain a significant challenge during the global Sustainable Development era.

The aim of this project was to develop the tools and knowledge to reduce dietary sodium by mitigating restrictions to flavour delivery and enhancing saltiness perception through sodium contrast effects in the mouth. This is achieved by restructuring semi-solid and liquid model food systems to achieve maximum flavour delivery for enhanced perception. The project considered two model systems: stable foams and double emulsions. Stable foams were developed to evaluate air inclusions as a potential sodium reduction strategy. Saltiness perception was enhanced as the levels of air inclusion increased and the incorporation of air also increased the delivery of a congruent mushroom aroma, ultimately this resulted in an enhanced overall flavour perception. The release of volatile aroma compounds from the aerated matrix was dependent on the hydrophobicity (Log P) of the volatile. Double water-in-oil-in-water (w1/o/w2) emulsions were evaluated as vehicles to entrap (during storage) and then deliver sodium during oral processing, ultimately to enhance saltiness perception. The emulsions (w1/o/w2) stabilised with a commercially modified octenyl succinic anhydride (OSA) starch (NC46) were able to encapsulate sodium within the inner water phase (w1), retaining 97 % of this sodium for up to 90 d and partially releasing the sodium during oral processing. The release mechanism was the digestion of the stabilising starch by oral α-amylase. When compared to a protein stabilised emulsion, a 23.7 % decrease in overall salt was achieved using NC46 stabilised w1/o/w2 emulsions, without compromising perceived saltiness. To optimise the stability and delivery of sodium from the double emulsion, different levels of OSA modification were evaluated. High levels (3%) of OSA modification increased storage stability and low (0 % OSA) and intermediate levels offered enhanced saltiness. The optimised (1.5% and 2 % OSA) w1/o/w2 emulsion was stable and conferred a 15 % reduction in total sodium without compromising saltiness. These results provide new insights into using colloidal systems to efficiently deliver sodium and aroma volatiles for perception. The sodium redistribution and contrast effects demonstrated in this work may provide new avenues to achieve sodium reduction, particularly in semi-solid and liquid systems.

Previous research has shown that the sticky behaviour of rice may be affected by the composition and structural properties of the rice starch (amylose and amylopectin) as well as the protein and lipid components. Analyses tend to have been based on whole rice grains even though the sticky texture of rice is largely a surface phenomenon; hence, it is essential to develop an understanding of the external composition of rice grains. The objective of this PhD project is to provide an analysis of the internal and external structure of raw rice grains and to investigate how these structure data correlate to the sticky behaviour of cooked rice. The results of Attenuated Total Reflectance – Fourier Transform Infrared spectroscopy show that there is a significant difference in amide and lipid peaks and order of starch between the centre of rice grains and the external regions while X-Ray Diffraction exhibit differences in starch crystallinity. Results of Fourier Transform Infrared microspectroscopy also demonstrated the non-uniformity of amide and lipid peaks across the cross-section of a rice grain. With the aid of chemical analysis, it was concluded that the sticky texture of cooked rice is negatively correlated to the external protein and lipid amount whereas the correlation to the order of starch and starch crystallinity was positive. This is further confirmed as the removal of protein and lipid from the surface of rice grains resulted in a more adhesive cooked rice texture. This project highlights the importance of a surface study when considering rice stickiness.

Over recent decades, the push in consumer trends towards the production of clean label, functionalised foods has resulted in food manufacturers looking towards plant fibres as a source of alternative stabilisers. Not only can plant fibres be considered as sustainable ingredients but they are also able to, due to the functional properties that they possess, allow the food manufacturer to meet the functional foods demand. Plant fibres were assessed as an alternative source of ice cream stabilisers. Firstly, a selection of plant fibres of different plant origin where characterised and their functional properties in suspension were determined to identify which plant fibres provided the most potential as ice cream stabilisers. These fibres were then incorporated into ice cream formulations and it was found that their addition had no impact on the correct microstructure formation. Heat shock is the process whereby ice cream is stored in inappropriate temperature conditions or experiences breaks in the frozen-chain. Such drastic changes in temperature can alter the microstructure of ice cream reducing the sensory quality. Hydrocolloids are added to ice cream formulations to prevent such sensory deteriorations and for plant fibres to be a suitable source of alternative stabilisers they too must be able to prevent such deteriorations. It was found that the ability to control ice recrystallisation was dependent on the water binding capacity of the fibre, which in turn was related to the total fibre content. However, under heat shock conditions, this ability to control the rate of ice recrystallisation was largely dependent on the freeze-thaw stability of the fibre. It was found, in comparison to a hydrocolloid stabilised sample, that plant fibres have no impact on the rate of ice cream meltdown, nor the final mass loss, but could inhibit the time to first drip due to the ability of plant fibres to behave as ‘sponges’, absorbing the water from melting ice and hindering the rate of drainage by the formation of a fibrous network with the matrix phase. Higher apparent viscosities were also associated with improved meltdown properties. However, when plant fibres were co-stabilised with guar gum at the concentrations studied, improvements in the meltdown properties and control over microstructural deteriorations were observed but samples became undesirably over texturised. Sensory analysis was performed to determine the impact of plant fibres on the sensory perception of ice cream as well as the ability of plant fibres to retain sensory quality under heat shock conditions. It was found that plant fibres impart a powdery and mouth drying sensation due to the presence of insoluble fibre particles. Plant fibres of a high enough total fibre content were also found to be able to impart the correct mouthfeel properties in ice cream. Under heat shock conditions, it was found that the more freeze-thaw stable fibres were able to control increases in the iciness perception. However, plant fibres were not found to be able to control the sensory changes that are related to the structure of air, as cryo-Scanning Electron Microscopy imaging identified that plant fibres behave as anti-foams in ice cream formulations under temperature cycling conditions.

The present study showed the effects of a number of hydrocolloids in terms of adding them dry, pre-hydrated or solubilised and gelled, using unmodified wheat starch, 3 types of carrageenan (kappa, iota and lambda), locust bean gum (LBG), and finally citrus fibre on meat stability, textural properties, and microstructure. The study further elucidated the role of heat induced gelation in texture formation of processed meat products. The finding of the study revealed that the maximum hardness related to the dry state of all hydrocolloids when added to a product containing 65% meat (i.e. 7.4% unmodified wheat starch, 1% LBG and 3% citrus fibre, except the carrageenan treatment, which is related to 2% gelled kappa carrageenan). Furthermore, the elasticity or rubbery texture of the sausages increased with 3% pre-hydrated wheat starch, 1 % dry LBG and citrus fibre and finally 1% solubilised kappa carrageenan with 65% meat. However, ameliorating elasticity of LBG and citrus fibre, which are 1 and 3%, respectively, took place with the dry state. The Differential Scanning Calorimetry (DSC) results showed that starch and carrageenan showed clear irreversible and reversible transitions, respectively, on the timescale of the experiment in the region of 60 ̊C, whereas locust bean gum and citrus fibre showed no transitions. No interaction between carbohydrates and proteins was signalled by the transition temperatures of the unaffected transitions and the addition of enthalpies which was linear. The rheology result indicated that storage modulus (G ́) was greater than the loss modulus (G ̋) during the test (G ́ > G ̋), which implied predominant elastic behaviour of the sample for the whole range of deformation experimented. Finally, confocal scanning laser microscopy (CSLM) demonstrated that the void space is augmented (visa-a-vis the control sample of 65% meat) after adding dry LBG. However, the size of cavity shrank after adding gelled kappa carrageenan, dry citrus fibre, and dry wheat starch. In all treatments, the fat droplet decreased in mean size in the wake of adding hydrocolloids in the systems. Both of these findings indicate that an increase in batter texture upon the addition of hydrocolloids was sufficient to break up air cells and emulsion droplet, and then had enough strength to maintain the smaller cells droplets. The findings of the study in hand, provide a new approach to meat product manufacturing.

The rat was used as a model for the assessment of a high fat diet (HFD) and HFD/streptozotocin (STZ) induced Type II diabetes upon lipid deposition and development of inflammation in metabolically active tissues. HFD feeding for a period of 10 weeks did not induce significant weight gain in animals compared to those fed on normal chow (NC). There was also no significant effect of HFD feeding upon blood glucose and insulin levels. Adipose and skeletal muscle tissues showed minimal effects of HFD feeding at both the histological and molecular level. Histological assessment of liver tissue revealed marked steatosis in HFD fed animals. Molecular studies showed that genes involved in lipid and glucose metabolism and insulin signalling were decreased while genes involved in endoplasmic reticulum (ER) stress were elevated. Liver triglyceride fatty acid profiles resembled those of the diet with no significant differences in lipoprotein triglyceride levels observed between experimental groups. STZ injection induced hypoinsulinemia and hyperglycaemia. The changes observed at the molecular level were related to insulin depletion. Pioglitazone intervention did not cause any major changes in the STZ treated animals. The main conclusion was that HFD induces liver steatosis due to increase lipid flux from the diet despite the absence of weight gain or increased adipose tissue or skeletal muscle lipid content. This suggests that consumption of a high fat diet may cause the development of fatty Liver disease in the absence of weight gain or overt obesity.

Microalgae have become recognized as excellent sources for many valuable nutrients. Chlamydomonas reinhardtii is a green microalga which has attracted attention as a model organism for recombinant protein and vaccine production, but its nutritional value and key functional components have not been previously assessed. Initial comparisons with species already used in this manner (Chlorella and Spirulina) indicated that microalga had potential to be added as a nutritional addition to food. C. reinhardtii was characterised by a high omega 3 fatty acids content and a good source of pigments (chlorophyll (a+b), β-carotene (provitamin A) and lutein). In-vitro digestion trials were conducted to determine the concentrations of digestive enzymes (pepsin and pancreatin) released from cells. The digestive conditions caused major changes in structure, cell shape and partially unlocked nutrients from the cells. Grinding C. reinhardtii with liquid nitrogen increased accessibility of β-carotene from 6% for intact cells to 14%, iron from 4.04% to 8.8% and inclusion of PLRP2 significantly improved lipid hydrolysis. Determining growth and other significant parameters for zebrafish fed with C. reinhardtii revealed a significant improvement when compared with zebrafish consuming a standard fish diet. Interestingly, fish on a diet containing C. reinhardtii was characterised by a significantly higher linolenic acid (C18:3 n-3) content (P≤ 0.05). Inclusion of the fatty acid hexadecatrienoic acid (C16: 4-n-3) ensured that C. reinhardtii lipid was hydrolysed and absorbed in the zebrafish intestine. A visible yellow pigmentation of zebrafish (egg in the female and skin in the male) fed with C. reinhardtii was distinct from the control, this yellow pigmentation was determined to be lutein which the zebrafish had assimilated from C. reinhardtii cells. There was a significant increase in retinol in C. reinhardtii fed fish (10 and 20%) when compared to the control. Thus, it is deducted that zebrafish was able to assimilate β-carotene and convert it to vitamin A. All things considered, C. reinhardtii displayed a great potential as a functional food and feed ingredient which is characterized by relatively good digestibility both in vivo and in vitro.

The aim of this research is to illuminate the experience of vocational trainees, specifically trainee cooks, on work placement. Previous ethnographic research in vocational education has tended to converge on sociologically oriented concerns and link the provision of vocational education to the reproduction of social classes. This provided a rich but nonetheless limited understanding of the student experience in this education sector. Professional socialisation studies typically focused on students in higher education and newcomers working in white-collar settings; few studies were carried out with individuals joining vocational trades. Moreover non-sociological studies rarely involved participant observation in data collection and non-linguistic studies rarely emphasised local interactions and verbal exchanges between participants. Studies in blue-collar settings are equally rare. Through a linguistic ethnographic approach, this research offers a detailed picture of the everyday experience of trainee cooks on work placement in professional kitchens. Data was collected through participant observation, fieldnotes, interviews and audio-recordings over a 16-week period involving more than 550 hours in nine professional kitchens. Constituted by physical action, kitchen work involved extensive engagement in doing and for trainees in particular, watching. Doing involved engagement in assigned tasks and working in the capacity of specific workers at their stations, here described as ‘doing Nellie’s work’. Watching was mandated by workers, treated as a mode of learning and gave trainees a legitimate presence in the kitchens. A third action termed as origination was also uncovered in this context. Origination is a self-directed voluntary action of bringing about work, carrying it out and contributing purposefully to work situations. Constituted by physical actions and the general physicality of work, task performance involved verbal interactions that were often minimal. Occasions of extended talk however showed the construction of particular relationships. These extended interactions provided important learning opportunities. The study supports, reinforces and extends findings in workplace research. It also makes a theoretical contribution through the concepts of origination and legitimate presence, and illustrates the use of a linguistic-ethnographic approach in a minimal talk context. Its outcomes are useful for understanding the nature of work/learning at work placement and offer practical insights of value to professionals involved in work preparation programmes.