Dissertations / Theses on the topic 'Food and Processing'

Agroterrorism is the deliberate introduction of a plant or animal disease with thegoal of causing fear, economic instability, illness, or death. After the 2002 terroristattacks on the World Trade Center, the security of the food supply is of increasingconcern to the United States. A major incidence of agroterrorism or food tampering would have far reaching impacts on the economy and public health. The first objective of this project was to determine knowledge and concern of agroterrorism in meat processing facilities in Kentucky, and to determine knowledge and concern of food tampering and food defense in food service establishments in Warren County, Kentucky. The second objective was to determine security strategies that were being implemented by these facilities. Two separate surveys, one for meat processors and the other for food service establishments, were designed to meet these objectives. An observational study was conducted for meat processing facilities. It was found that these facilities were generally unconcerned with agroterrorism, although a reasonable amount of security implementations were in place at these facilities. A statistical comparison between restaurants and non-restaurant food service establishments, such as schools, hospitals, and hotels, was performed. Both types of food service establishments expressed little concern about a food tampering event. Non- restaurant food service establishments were slightly more concerned than restaurants about both food tampering and food defense.

Solo una piccola parte dell’enorme quantità di proteine presenti negli alimenti è allergenica, sia nella loro forma nativa sia nelle modifiche derivanti dai processi alimentari. È necessario sviluppare metodi analitici sensibili e veloci per rilevare la presenza di allergeni negli alimenti, nonché analizzare le modifiche indotte dai processi. Questa tipo di ricerca è importante se pensiamo agli sviluppi di nuove strategie analitiche a supporto della riduzione del potenziale allergenico degli alimenti. Oggigiorno, la spettrometria di massa e la cromatografia liquida (LCMS) sono ampiamente utilizzate per la caratterizzazione di proteine e peptidi allergenici, infatti è stato recentemente coniato il termine “allergenomica” per descrivere l’applicazione della proteomica all’analisi di allergeni. Tuttavia, la variabilità degli allergeni alimentari rende difficile sviluppare un metodo generico e universale per la loro caratterizzazione. Una sfida importante per le tecniche di MS è la preparazione del campione e gli aspetti correlati, come avviene ad esempio per gli allergeni da Apiaceae, per molti dei quali vi è una carenza di riferimenti e metodologie. Questo progetto di ricerca mira a dare un contributo alla determinazione degli allergeni alimentari tramite LCMS e a valutare l'effetto di alcuni processi sul potenziale allergenico del cibo attraverso cromatografia liquida nano hplc e spettrometria di massa in trappola ionica con sorgente di ionizzazione elettrospray (nanoHPLC-ESI-IT-MSn). Un approccio bioinformatico dedicato è stato sviluppato al fine di individuare i più importanti allergeni alimentari da formaggio spalmabile e da campioni vegetali della famiglia delle Apiaceae e allo scopo di descrivere gli effetti di diversi sistemi di condizionamento sul potenziale allergenico del formaggio spalmabile. In questo lavoro, il peptide FVAPFPEVF dell’ allergene di latte vaccino Bos d 9 e il peptide QEPVLGPVRGPFPIIV dell’allergene Bos d 11 sono stati identificati e proposti per la rilevazione di allergeni del latte e per le analisi future in questo campo come ad esempio per scopi di quantificazione. Inoltre, i risultati hanno dimostrato l'effetto di alcune tecniche di condizionamento sulla riduzione del potere allergenico totale del formaggio spalmabile, e hanno rilevato il trattamento il trattamento S1 (basato su sorbato di potassio) come una soluzione ottimale per ridurre la potenziale allergenicità di questo prodotto, sia in termini di intensità che in termini di variabilità allergeniche. Utilizzando una strategia simile, diversi esperimenti sono stati eseguiti per rilevare la presenza di allergeni di Apiaceae da campioni vegetali e caratterizzare uno o più potenziali marcatori per la loro rilevazione dal cibo utilizzando tecniche di LCMS. Tra questi, il peptide idrofilo FYETKDTDILAAFR dell’allergene Spi o Rubisco viene proposto come potenziale marcatore per il rilevamento di routine di allergeni da Apiaceae attraverso ESI-MSn. In questo caso altri aspetti riguardanti questo allergene dovrebbero essere studiati, come gli effetti da processi alimentari e il suo ruolo nelle reazioni allergiche (caratterizzazione degli epitopi). In quest'ultima fase, una particolare attenzione è stata prestata alla preparazione del campione e alla selezione di tamponi estraenti eco-compatibili, e alla ottimizzazione globale delle condizioni sperimentali dell’analisi LCMS.
Food contains a lot of proteins, but only a small fraction of them are allergens either in their native forms or in products resulting from food processing. There is a need for sensitive and rapid methods for detecting the presence of allergens in foods, as well as analyse the modifications induced by food processing. This research is important if we realize the potential of new analitycal strategies andnovel processing techniques that may reduce the allergenicity of foods. Nowadays, mass Spectrometry and Liquid Chromatography (LC) are extensively used for the characterization of allergenic proteins and peptides: the application of proteomics for the analysis of allergenic proteins has been recently termed allergenomics. Unfortunately, the variability of food allergens makes it difficult to develop a generic and universal method for their characterization. A major challenge for MS techniques is sample preparation and its related issues, as in the case of Apiaceae allergens, for many of which there is a lack of reference materials and methodologies. This PhD thesis research project aimed to make a contribution for the determination of food allergens by LCMS and to evaluate the effect of some food processing on allergenicity of food through nanoliquid chromatography and electrospray ionization-ion trap mass spectrometry (nanoHPLC-ESI-IT-MSn). A specific bioinformatic approach was developed, in order to characterize the most important food allergens from soft cheese and plant samples from the Apiaceae family and to describe the effects to the allergenic potential of soft cheese samples during several conditioning systems. In this work, the peptides FVAPFPEVF from cow’s milk (CM) allergen Bos d 9 and the peptide QEPVLGPVRGPFPIIV from CM allergen Bos d 11 were identified and proposed as valid marker peptides for CM allergens detection and for future analysis in this field, e.g. for quantification purposes. In addition, the results demonstrated the effect of some packaging conditions on reducing the total allergenic power of soft cheese, and showed the condition treatment S1 (based on potassium sorbate) as an optimal solution for reducing the total potential of soft cheese, both in terms of allergenic intensity and in terms of allergen variability. Using a similar strategy, several experiments were also performed for detecting the presence of Apiaceae allergens from plant samples and to characterize one or more potential markers for their detection in food using LCMS. Among those, the hydrophilic peptide FYETKDTDILAAFR from the allergen Spi o Rubisco is proposed as a potential marker for routine detection of Apiaceae allergens in food through ESI-MSn. Other aspects regarding this allergen should be investigated, such as its behaviour under food processing and its role in the allergenic reactions (epitope mapping). In this last step, a particular attention was given to the sample preparation and to the selection of eco-compatible extraction buffers, and to the overall optimization of LCMS experimental conditions.

Obesity and being overweight have become growing concerns due to their association with many diseases, such as type II diabetes, several types of cancer and heart disease. Thus, obesity treatments have been the focus of a large number of recent studies. Because of these studies, researchers have found that the treatment of obesity and being overweight requires constant monitoring of the patient’s diet. Therefore, measuring food intake each day is considered an important step in the success of a healthy diet. Measuring daily food consumption for obese patients is one of the challenges in obesity management studies. Countless recent studies have suggested that using technology like smartphones may enhance the under-reporting issue in dietary intake consumption. In this thesis, we propose a Food Recognition System (FRS) for calories and nutrient values assumption. The user employs the built-in camera of the smartphone to take a picture of any food before and after eating. The system then processes and classifies the images to detect the type of food and portion size, then uses the information to estimate the number of calories in the food. The estimation and calculation of the food volume and amount of calories in the image is an essential step in our system. Via special approaches, the FRS can estimate the food volume and the existing calories with a high level of accuracy. Our experiment shows high reliability and accuracy of this approach, with less than 15% error.

Extrusion has been widely used as a high-temperature short-time process to produce commercially shelf stable extruded products. Many physical and chemical changes take place during the process, including the gelatinization of starch, denaturation of protein and even complete cooking. To fully understand changes during the process, evaluation of the effect of extrusion process variables on the extruded product is very important. There are many process and product-dependent variables associated with the extrusion process such as barrel temperature, screw speed, die diameter and raw material composition (moisture, starch, protein and fat contents). In general, commercial extruded products have mainly focused on starch-rich products which are generally are low in protein content. The overall objective of this research was to prepare high-value protein-rich products through the use of extrusion processing.In order to evaluate the influence of added protein [soy protein isolate, (SPI)] to a corn-based system, a two step procedure was employed. Firstly, the effect of feed moisture, screw speed and barrel temperature on physical properties of extruded corn flour and SPI blends was evaluated to generate a basic understanding of the influence of operational parameters. This was expanded to include higher protein levels in the subsequent study. The physical properties of the extruded material considered were expansion ratio, bulk density, breaking strength, water solubility index, rehydration ratio and color. All these properties were significantly (P ≤ 0.05) affected by the process variables. An optimization study was performed to determine optimum variable levels to achieve desirable properties of extruded product within selected constraints.As residence time distribution (RTD) is an important aspect of the extrusion process. The RTD of SPI and corn flour mixtures was studied under different screw speeds (75, 100 and 125 rpm), raw material moisture (25, 30 and 35%) and die diameter (3 and 5 mm) configurations. Two conventional flow models served to represent the RTD patterns in the extruder: the frequency model (F distribution) and the cumulative RTD model (E-distribution). The parameters of these models – the half concentration internal age and particle accumulation rate – were determined by a nonlinear regression. These models' parameters were found to be responsive to process variables, and both F and E distributions were well predicted.As extruded products produced under the above conditions remained high in moisture content and water activity, in order to achieve shelf stability it was necessary to lower their moisture and water activity levels. The effect of extrusion process variables on the drying behavior of the product was studied next. Since there were many test samples, a simple drying set-up operating under moderate temperature (55°C), humidity and airflow conditions was used. The extrusion process variables were found to significantly (P ≤ 0.05) affect the drying behaviour of the product. Models were developed to predict drying times to reduce the product moisture to stable levels (water activity below 0.75). Selected extrusion products with 50% protein content were subjected to frying at different temperatures (145ºC, 165ºC, 185ºC) and for different durations (0 to 660 s). The resultant products' physical characteristics, including breaking strength, oil uptake, color and moisture content were evaluated, and a sensory test was performed to describe the acceptability of the products. Frying conditions which yielded products of acceptable quality were identified.Overall, the research contributes to a better understanding of the extrusion process of high SPI content corn flour blends. Together with post extrusion treatments including drying and frying, the process can produce good quality protein-rich extrusion products for use in further preparations or as a fried snack.
Processus à haute température et de courte durée, l'extrusion permet la production de produits d'extrusion comestibles à longue vie commercial. Durant ce processus il survient des changements incluant la gélatinisation de l'amidon, la dénaturation des protéines, ainsi qu'une cuisson uniforme et complète. Pour bien maîtriser ces changements, une évaluation de l'effet des variables du processus d'extrusion sur l'extrudat est de rigueur. Plusieurs variables, soit la température du fourreau, la vitesse de la vis, le diamètre de la filière et la composition de la matière première (teneur en eau, en amidon, en protéines et en gras), sont liées au processus ainsi qu'au produit. Les produits commerciaux extrudés demeurent riche en amidon, mais pauvre en protéines. La présente recherche visa à préparer, par l'entremise d'une transformation par extrusion, des produits de haute valeur, riches en protéines.Afin d'évaluer l'influence d'un ajout de protéine [isolats de protéine de soya, (IPS)] à un système à base de maïs, un processus à deux étapes fut étudiés. L'effet de la teneur en eau du matériel, de la vitesse de la vis et de la température du fourreau sur les propriétés physiques d'extrudats d'un mélange d'ISP et de farine de maïs furent évalués, pour évaluer l'influence des paramètres opérationnels. L'inclusion de teneurs en protéine plus élevés suivi. Les propriétés physiques de l'extrudat considérés furent le taux de foisonnement, la densité apparente, la résistance à la rupture, l'indice de solubilité dans l'eau, le taux de réhydratation, et la couleur. Toutes celles-ci furent influencées (P ≤ 0.05) par les variables de transformation. Une optimisation des variables de transformation pour obtenir un extrudat aux propriétés voulues sous certaines contraintes d'opération suivit.La distribution temps séjour (DTS) est un important aspect du processus d'extrusion. La DTS de mélanges d'IPS et de farine de maïs fut déterminée sous différentes vitesses de vis (75, 100 ou 125 rpm), teneurs en eau du matériel brut (25, 30 ou 35%) et diamètre de la filière (3 ou 5 mm). Deux modélisations conventionnelles du débit, l'une liée à la fréquence (distribution F) et l'autre cumulative (distribution E), servirent à représenter le cours du DTS dans l'extrudeur. L'âge interne à mi-concentration et le taux d'accumulation de particules, déterminés par régression non-linéaire, répondirent bien aux variables de transformation, les distributions E et F étant prédites avec exactitude.Comme ces extrudats maintinrent une teneur et une activité en eau élevée, il fut nécessaire, afin d'obtenir une bonne stabilité sur les tablettes, de diminuer ces derniers. Un étude sur l'effet des variable du processus d'extrusion sur le séchage subséquent de l'extrudat fit suite. Étant donné le grand nombre d'échantillons, un simple appareillage de séchage, fonctionnant à de températures, taux d'humidités et flux d'air moyens, fut utilisé. Les variables du processus d'extrusion influencèrent (P ≤ 0.05) le séchage du produit. Des modélisations furent développées afin de prédire le temps nécessaire pour réduire la teneur en eau du produit à un niveau stable (activité de l'eau en deçà de 0.75). Des extrudats d'une teneur en protéine de 50% furent frits à des températures de 145ºC, 165ºC, et 185ºC pour 0 à 660 s. La résistance à la rupture, l'absorption d'huile, la couleur et la teneur en eau des produits frits furent évalués. Un test organoleptique évalua l'acceptabilité des produits. Les conditions de friture donnant une qualité acceptable furent identifiées.Ces études contribuèrent à une meilleure compréhension du processus d'extrusion de mélanges de farine de maïs à haute teneur en ISP. Apparié aux traitements post-extrusion de séchage ou de friture, le processus permet de produire des extrudats de qualité à haute teneur en protéines pouvant passer par une étape de préparation additionnelle ou être consommées directement comme croustille frite.

The food processing industry is dominated by large corporations. These firms play a critical role in forming the derived demand faced by agricultural producers, but little is understood about how these companies make strategic choices. Organizational economics provides a framework for exploring the firm's decision process. However, several theories exist in this discipline, operating in fundamentally different ways. This paper examines the two prevalent organizational theories, Transaction Cost Economics and Agency Theory, through a study of the food processing industry. This sector is thoroughly analyzed in order to make predictions from each theory regarding the aspects of capital structure and firm expansion. With accounting data for a sample of food processing firms, these predictions are then tested empirically using an ICAPM model in a cross-section of expected stock returns. Our results indicate that Agency Theory is the relevant organizational model for food manufacturers, making it the appropriate tool for evaluating the actions of these firms in agricultural markets.

Cues are stimuli that precede, and through conditioning, eventually predict rewards. Cues associated with reward are an instrumental and motivating force behind learned behaviours, such as smoking a cigarette, or even eating. Much of this conditioning process takes place in the brain.Research suggests that the brain processes food and smoking cues in similar ways. It also shows that biological influences such as genetics and hormones can shape the way we process drugs and foods. For example, the gene CYP2A6, has been linked to increased smoking activity and decreased smoking cessation rates, which may be due to differences in smoking cue conditioning. In addition, acute administration of the hunger signaling hormone, ghrelin, has been linked to increased response to food cues in the brain. Despite the current research, details of the brain network involved in processing rewarding cues is not known, and there is still much to learn about the biological influences of reward cue signaling in the brain. In this thesis, we test the hypothesis that food and smoking cues elicit the same network in the brain by carrying out a meta-analysis of food and smoking brain imaging studies. We also test the hypothesis that individual differences in responding to cues is shaped by biological mechanisms, such as nicotine metabolism and hormonal signaling, by looking at the influence of nicotine metabolism and the CYP2A6 gene when processing smoking cues in the brain, and also by exploring the effect of ghrelin and the consequences of changes in cue sensitivity on active decision making and value when processing food cues in the brain. This thesis outlines the importance of cues that are associated with reward by summarizing what parts of the brain consistently responds to food and smoking cues, and demonstrating how biology can shape the brain's processing of cues, as measured using functional Magnetic Resonance Imaging.
Les signaux déclencheurs sont des stimuli qui précèdent et peuvent éventuellement par le conditionnement prévoir des récompenses. Ces signaux associés à la récompense sont une force instrumentale et motivante derrière les comportements appris, comme fumer, ou même manger. Une grande partie de ce processus de conditionnement a lieu dans le cerveau.Les données de la litérature suggèrent que le cerveau traite les signaux déclanchant l'alimentation et le comportement tabagique de la même façon. Il a également était montré que certaines influences biologiques, tels que la génétique et les hormones,, peuvent modifier notre rapport aux drogues et aux aliments. Par exemple, le gène CYP2A6, est lié à une augmentation de la consommation de tabac ainsi qu'à une diminution du taux de sevrage tabagique, qui peuvent être dues à des différences de conditionnement face aux signaux déclencheurs. En outre, l'administration aiguë de l'hormone de signalisation de la faim, la ghréline, est liée à une augmentation de la réponse aux signaux alimentaires dans le cerveau.Malgré les recherches en cours, le détail des réseaux neuronaux impliqués dans le traitement des signaux déclencheurs n'est pas connu, et il y a encore beaucoup à apprendre sur les facteurs biologiques influençant ces signaux de récompense dans le cerveau. Dans cette thèse, nous avons testé l'hypothèse que les signaux déclenchant l'alimentation et le comportement tabagique impliquent le même réseau neuronal, et ce par la réalisation d'une méta-analyse des études en imagerie cérébrale sur l'alimentation et le tabagisme. Nous avons également testé l'hypothèse que les différences interindividuelles dans la réponse à ces signaux est sous-tendue par des mécanismes biologiques, tels que le métabolisme de la nicotine et la signalisation hormonale, et ce en examinant l'influence du métabolisme de la nicotine et du gène CYP2A6 lors du traitement cérébral des signaux déclenchant le comportement tabagique, et en explorant l'effet de la ghréline et les conséquences des changements de sensibilité aux signaux déclencheurs sur la prise de décision active et la valence lors du traitement de signaux alimentaires dans le cerveau.Cette thèse souligne l'importance des signaux déclencheurs associés à la récompense en montrant les parties du cerveau répondant systématiquement aux signaux déclenchant l'alimentation et le comportement tabagique, et en démontrant comment la biologie peut façonner le traitement neuronal de ces signaux, mesurés à l'aide de l'imagerie par résonance magnétique.

Generally, food industries employ traditional technologies and bulk devices for mixing, aeration, oxidation, emulsification and encapsulation. These processes are characterized by high energy consumption and result in high cost product, with limited diversity and usually with non-competitive quality. Moreover, the byproduct is also high. In recent years immense efforts have been dedicated to overcome these issues and major advances in food engineering have come from transfer and adaptation of knowledge from related fields such as chemical and mechanical engineering. It is well known that the majority of elements contribute to transport properties, physical and rheological behavior, texture and sensorial traits of foods are in micro-level. In this context invention at microscopic level is of critical importance to improve the existing foods quality while targeting also the development of new products. Therefore, microfluidics has a significant role in future design, preparation and characterization of food micro-structure. The diminutive scale of the flow channels in microfluidic systems increases the surface to volume ratio and is therefore advantageous for many applications. Furthermore, high quality food products can be manufactured by means of innovative microfluidic technology characterized by less energy consumption and a continuous process in substitution to the problematic batch one. To meet these challenges, this work is focused on main two tasks: (i) efficient micromixing, and (ii) production of microbubbles and microdroplets. Firstly, two novel 3D split and recombine (SAR) micromixers are designed on an extensive collection of established knowledge. Mixing characteristics of two species were elucidated via experimental and numerical studies associated with microchannels at various inlet flow-rate ratios for a wide range of Reynolds numbers (1-100); at the same time, results are compared with two well-known micromixers. It was found that performances of the mixers are significantly affected by their design, inlet flow-rate ratios and Reynolds numbers. The proposed micromixers show better efficiency (more than 90%) in all examined range of Reynolds numbers than the well-known basic mixers at each desired region; the required pressure-drop is also significantly less than that of the previous mixers. Furthermore, numerical residence time distribution (RTD) was also explored, which successfully predicts the experimental results. In a word, the presented new micromixers have advantages of high efficiency, low pressure-drop, simple fabrication, easy integration and ease for mass production. Secondly, four micro-devices are designed for the mono-dispersed droplets and bubbles generation. Two different experimental setups were used to create water droplet in silicone oil (W/O) and air bubble in silicone oil (A/O) for continuous flow rate from 10 ml/h to 230 ml/h. The mean size of droplet and bubble as well as frequency of generation can be controlled by dispersed and continuous flow rate. Besides, squeezing and dripping flow regimes are observed inside the four devices over a broad range of Capillary numbers: 0.01~0.18. Among the examined four devices, T-1 and T-2 provide smaller droplet (100 µm) and higher production rate. Furthermore, negative pressure setup provides more robust bubble generation but positive pressure yields better production rate. In addition, droplet and bubble diameter is about four times less than the microchannel dimension, therefore small droplet and bubble can be generated spending less energy. In summary, the investigation in this dissertation reflects that both SAR micromixers and micro-devices are very efficient and can be applied to meet the growing demands of food industries. The first part of the thesis, chapters 1 to 5, addresses state of art, design, experimental technique and results of micromixers. The second part, chapters 6 to 9, presents background, construction of devices, tests and results related to the production of microdroplets and microbubbles. Finally, chapter 10 summaries the whole presented work.

Dietary phytochemicals are thought to reduce the incidence of chronic degenerative diseases. The concentration of these phytochemicals has been extensively studied, but less is known about their stability during food processing. The objective of this study was to determine the stability of lignans and other phytochemicals during the vinification and brewing processes. The amount of secoisolariciresinol diglucoside (SDG), gallic acid, caffeic acid, coumaric acid, chlorogenic acid, and ferulic acid increased up to 45 % during the vinification process; however, the amount of folic acid remained unchanged. SDG content was determined in barley for the first time. The SDG content also varied among barley varieties and showed a year-to-year variation. In addition, no SDG was detected during the mashing, lautering, boiling, and fermentation steps of the brewing process. Overall, processing techniques used in this study caused various effects on the stability of phytochemicals.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第15425号
農博第1810号
新制||農||979(附属図書館)
学位論文||H22||N4524(農学部図書室)
27903
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 東 順一, 教授 二井 一禎, 教授 縄田 栄治
学位規則第4条第1項該当

The object of this research was to develop a retort for research and development of thermal processes which use common commercial thermal processing techniques. An FMC 500W laboratory sterilizer, designed to operate with an FMC weir product racking system, was modified for conventional steam, positive flow steam/air and water immersion/air overpressure thermal processing of foods in thin profile retortable packages. The research included the modification of the retort plumbing and the fabrication of a set of product trays and a racking system. The completed system was tested for temperature distribution and stability, and heat transfer distribution for each processing mode. The latter was achieved by comparing the heat penetration parameters calculated from the centerpoint temperature histories of conduction heating teflon transducers.
Applied Science, Faculty of
Graduate

There is significant interest by the food industry in applying milder processing conditions. A major area of research within predictive modelling has been the search for models which accurately predict the effect of combining multiple processes or hurdles. For a mild process, which has temperature as the major microbial injury step, the effect of the other combined hurdles in inhibiting growth of the injured organisms must be understood. The latter means that the inoculum size dependency of the time to growth must also be fully understood. This essentially links injury steps with the potential for growth. Herein, we have been developing the use of optical density (O.D) for obtaining growth rates and lag times using multiple inocula rather than using the traditional methods which use one single inoculum. All analyses were performed in the Bioscreen analyser which measures O.D. The time to detection (TTD) was defined as the time needed for each inoculum to reach an O.D=0.2 and O.D was related to microbial numbers with simple calibration curves. Several primary models were used to predict growth curves from O.D data and it was shown that the classic logistic, the Baranyi and the 3-phase linear model (3-PLM) were the most capable primary models of those examined while the modified Gompertz and modified logistic could not reproduce TTD data. Using the Malthusian approximation of the logistic model the effect of mild temperature shifts was studied. The data obtained showed that for mild temperature shifts, growth rates quickly changed to the new environment without the induction of lags. The growth of Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli was studied at 30⁰C and/or 37⁰C, in different NaCl concentrations, pH and their combinations. The classical 3-parameter logistic with lag model was rearranged to provide the theoretical foundation for the observed TTD and accurate growth rates and lag times could be estimated. As the conditions became more unfavourable, the lag time increased while the growth rate decreased. Also, the growth rate was found to be independent from the inoculum size; the inoculum size affected only the TTD. The Minimum Inhibitory Concentration (MICNaCl and MICpH) was calculated using the Lambert and Pearson model (LPM) and also the Growth/No Growth (G/NG) interface was determined using combinations of NaCl and pH. These data were transformed in rate to detection (RTD) and fitted with a response surface model (RSM) which was subsequently compared with the Extended LPM (ELPM). The LPM and the ELPM could analyse results from individual and combined inhibitors, respectively. Following a mild thermal process a lag due to thermal injury was also induced, the magnitude of which was dependent on the organism and environmental conditions; the observed distribution of the lags appeared, in general, to follow the Log-normal distribution. After the lag period due to injury, growth recommenced at the rate dictated by the growth environment present. Traditional growth curves were constructed and compared with the data obtained from the Bioscreen under the same conditions. From the results obtained, it can be suggested that the increased lag times and growth rates obtained from the traditional plate counts compared with the values obtained from the Bioscreen microbiological analyser, might be an artifact of the plating method or may be due to the use of the modified Gompertz to study the growth. In conclusion, O.D can be used to accurately determine growth parameters, to give a better understanding and quantify the G/NG interface and to examine a wealth of phenomena such as fluctuating temperatures and mild thermal treatments. The comparison between the traditional growth curves against the data obtained from the Bioscreen showed that the TTD method is a rapid, more accurate and cheaper method than the traditional plate count method which in combination with the models developed herein can offer new possibilities both to the research and the food industry.

Made available in DSpace on 2014-10-09T12:50:26Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T13:58:53Z (GMT). No. of bitstreams: 1 10896.pdf: 6511897 bytes, checksum: 2156950a1e6d3ef4708b9cd1203a39c7 (MD5)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Published Article
The initial section of this manuscript focus on the ultra-structure of a unique class of heat stable cell-bound lipopolysaccharides (endotoxin) produced by Gram-negative bacteria. Subsequently, this paper summarises literature on the human body's response when challenged with endotoxins present in food and further explores the influence of food manufacturing and storage practices on endotoxin production and release by bacteria commonly isolated from food. Finally, this paper presents a brief description on the methods applied by the food industry to quantify endotoxins.

The main aim of this thesis was to design a persuasive and gamified version of the implicit association test. The goal of the mobile application is to help people adopt healthier eating habits. Poor diet is a major factor in many diseases and contributes negatively to life quality. Additionally, healthcare systems and employers are also affected in the form of production losses and treatment costs. The underlying research aim is to utilize the artefact to investigate whether exposing a user to possible cognitive dissonances in thinking can lead to reflection. Reflection in turn can lead to reduction of dissonances and in turn, behaviour change. Additionally, the application allows the user to rehearse responses towards different types of foods, which is accomplished by associating healthy foods with positive words and unhealthy foods with negative words. The purpose of Persuasive Systems Design (PSD) model, the main design framework used in this thesis, is to design behaviour change support systems. Behaviour Change Support Systems (BCSSs) are systems that aim to change behaviour and attitude without the use of any unethical means. Implicit association test (IAT) is a tool in the field of social psychology that is used measure implicit attitudes towards different concepts. Gamification can be defined as the use of game elements and mechanics in non-game contexts. The development process started with an analysis done with PSD model. Following it, mock-ups and a prototype based on the PSD model analysis and the original version of the IAT were created. After that, gamification features were designed by using a gamification framework. The original IAT was a strong influence in determining what types of persuasive and gamification features would be present in the application. Design science research guidelines were utilized as a checklist throughout research. The artefact and its persuasiveness were evaluated with a perceived persuasiveness questionnaire. The results showed slightly positive responses on the constructs of Primary Task Support (support for carrying out primary task), Dialogue Support (feedback), Perceived Credibility and Design Aesthetics. Perceived Persuasiveness responses were slightly negative. The reward feature that included unlocking different food icons and their health information was especially well received. This thesis contributed a detailed description of the development process of a BCSS. During the development process it was shown that the PSD model and the gamification framework could be used together without conflicts to design an artefact. The research on the artefact’s effectiveness in causing behaviour change is left for further study.

All human societies process their food extensively by thermal and non-thermal means. This feature distinguishes us from other species, and may even be compulsory given that humans are biologically committed to an energy-rich diet that is easy to chew and digest. Yet the energetic consequences of food processing remain largely unknown. This dissertation tests the fundamental hypothesis that thermal and non-thermal processing lead to biologically relevant increases in energy gain from protein-rich meat and starch-rich tubers, two major caloric resources for modern and ancestral humans that present divergent structural and macronutrient profiles. The energetic consequences of food processing are evaluated using three indices of energy gain, each of which account for costs not currently captured by conventional biochemical assessments of dietary energy value. Chapter 2 investigates the effects of cooking and pounding on net energy gain as indexed by changes in body mass, controlling for differences in food intake and activity level. Chapter 3 examines the effect of cooking and pounding on diet-induced thermogenesis, the metabolic cost of food digestion. Chapter 4 considers the effort required to engage in food processing, arguing that the advantageous ratio of benefit to cost has likely had important effects on human life history. By each of these definitions of energy gain, food processing is shown to have substantial energetic significance. Overall, energetic gains due to thermal processing exceeded those of non-thermal processing, consistent with recent proposals that the adoption of cooking had a particularly important influence on human biology. Gains due to food processing were observed in both meat and tuber substrates, supporting a transformative role for habitual food processing in the evolution and maintenance of the human energy budget.
Human Evolutionary Biology

This thesis presents the design, analysis and optimization of a MEMS capacitive temperature sensor. The capacitive sensors are utilized in a wide range of applications from industrial and automotive applications to biomedical and food processing. A capacitive sensor has two conductive electrodes and its working principle depends on the change in the position of the electrodes or their effective area, which ultimately results in a change in the capacitance of the device. This thesis describes the modeling and the simulation results of a capacitive temperature sensor with a set of bimorph beams working as thermal actuators. The thermal actuator creates out-of-plane displacements and changes the distance between the electrodes as the ambient temperature changes. The presented bimorph capacitive temperature sensor consists of two bilayer silicon-gold beams and two capacitive electrodes, one of them is fixed to the substrate and the second one is connected to the beams. Different beam sizes and electrode shapes are designed and simulated and the characteristics capacitance-temperature (C-T) response of the sensor is obtained. The goal of this work is to modify and optimize the sensor geometry such that the C-T response is more linear, providing nearly constant sensitivity. ANSYS mechanical APDL is used as the finite element software for simulation and optimization of the sensor design, and coupled-field multiphysics solver is utilized to solve the electrostatic and structural domains. The simulation results show that for a given fabrication process, where the thickness of the structural and sacrificial layers in fabrication process is fixed, it is possible to modify the dimensions and geometry of the sensor such that a C-T response with high linearity is obtained.

Peanut allergy typically results from sensitisation to one or more integral seed storage proteins; Ara h 1, 3 or 2/6. Reactions can be triggered by as little as 3 mg protein in 10% of allergic individuals and are often severe, inducing anaphylaxis which can be fatal. Accidental exposure through unintended presence can therefore be hazardous and foods must be labelled appropriately. Thermal processing is one of the main factors affecting protein properties in food systems, including the formation of Maillard reaction products. Research has suggested a link between the allergenicity of foods and cooking methods employed. A systematic study was undertaken to assess the thermal dependence of these hazard proteins, focusing on changes to solubility and chemical modifications which may alter IgE binding. Proteomic profiling was used to assess the allergenic content of peanut products and develop alternative methods for allergen analysis to support evidence-based application of precautionary allergen labelling. Runner variety peanuts were processed (boiled, fried, roasted) and their protein content determined. Proteins extracts were characterised by 1D- and 2D-polyacrylamide gel electrophoresis, including differential in-gel electrophoresis. Proteomic profiling was undertaken using label-free analysis to assess allergen composition and investigate the formation of Maillard reaction products on the most clinically relevant proteins. Peanut allergen peptide targets were then identified and used to develop label-based quantitation methods and applied to (i) investigate effects of processing on peptide targets and (ii) determine peanut in chocolate products in comparison with a commercial ELISA kit. Orthogonal studies were performed using serum samples from peanut allergic patients obtained from the Manchester Respiratory, Allergy and Thoracic Surgery (ManARTS) Biobank. Patient IgE reactivity to peanut and processed peanut products was assessed by immunoblotting, inhibition ELISA and mediator release assays. Protein solubility was reduced by thermal processing and processed protein required harsh denaturing conditions for extraction. Qualitative analysis highlighted decreased solubility of key allergens, modifications and aggregation after heating. Proteomic profiling identified and quantified different isoforms of the major peanut allergens. The protein content of processed peanuts was reduced by boiling, specifically the 2S albumins, which transferred into the cooking water. The performance of peptides selected for targeted MRM experiments was influenced by thermal processing and the presence of cocoa phenolics. Ara h 2 peptides flanked by arginine were thermostable and may prove more reliable for quantification. Application of microfluidic separation enhanced the efficiency of target ionisation in complex matrices acquiring important sensitivity gains. Maillard modifications to clinically relevant proteins Ara h 2/6 were found within IgE binding domains in raw and processed peanuts. IgE reactivity studies confirmed reduced IgE binding capacity of extensively boiled peanut and hydrolysed protein, but this did not correlate to a reduction in mediator release in poly-sensitised patients. While effective extraction limits the efficacy of analyses, buffers used in MS analyses are more robust in analysing processed protein. Proteomic profiling provides a means of characterising and profiling of allergenic proteins including food ingredients used in clinical applications. Peptides selected for targeted analyses should be validated to assess their suitability in model foods. Cooking waters collected from extensively boiled peanuts may provide an alternative and safer immunotherapy agent for patients predominantly sensitised to Ara h 2/6.

Master of Science
Department of Grain Science and Industry
Sajid Alavi
This study relates raw material particulate rheology to the granular flow in a single screw food extruder. Raw materials based on corn (i.e. meal, flour, and starch), wheat (i.e. farina, flour and starch), and sucrose (i.e. granulated, superfine, and powdered) were used as model particulate systems for the study. Various particulate-scale characteristics and flow parameters of these nine materials were determined using a powder rheometer. Properties such as basic flow energy, cohesion, flow function, and effective angle of internal friction were good indicators of flowability in an extruder. Corn meal exhibited lower energy requirements and a higher propensity for flow than corn flour (6.7mJ/g versus 10.7mJ/g, and “free-flowing” versus “cohesive,” according to Flow Function classifications), with wheat farina showing similar results when compared to wheat flour (5.8mJ/g versus 7.9mJ/g, and “highly free-flowing” versus “cohesive”), although both wheat systems showed lower energy requirements than their comparable corn systems. Sugar, being of a different base material and particle shape, behaved differently than these starch-based materials—flow energy decreased and propensity to flow increased as particle size decreased (51.7mJ/g versus 8.0mJ/g, and “free flowing” versus “highly free-flowing”). This large energy requirement for coarse sugar particles was attributed more to particle shape than composition, as the sharp edges of sugar can interlock and restrict movement through the sample. The starch-based results were validated in a particulate flow study involving the above model systems (corn meal, corn flour, wheat farina, and wheat flour) in a pilot-scale single screw extruder. Visualization data, obtained using a transparent plexiglass window during extrusion, confirmed that the flours exhibited higher flow energy requirements and a lower flow factor compared to coarser-particle size during extrusion, seen by the increased peak heights and barrel fill. Additionally, moisture changes were analyzed, showing an increase in energy required for starch-based materials as moisture increases and a decrease in energy for sucrose. Due to the hygroscopic nature of sucrose, moisture was absorbed more rapidly than starch products and the edges of individual particles softened, forming a soft solid. These physiochemical differences resulted in decreased energy requirements for sucrose as moisture was increased (51.7mJ/g to 13.6mJ/g), while corn meal and wheat farina yielded increased energy requirements (6.7mJ/g to 9.1mJ/g and 5.8mJ/g to 9.5mJ/g, respectively). Again, results of starch-based materials were validated using a plexiglass cover during extrusion, clearly showing an increase in barrel fill as moisture content increased for both materials, with corn meal flowing more readily than farina. Lastly, temperature of corn meal and farina was increased to show the difference in behavior of starch-based materials, where farina decreased in energy as temperature increased (14.4mJ/g to 12.1mJ/g ) while corn meal energy requirements increased (12.9mJ/g to 17.2mJ/g). With the results developed from these three experiments, and validated where physically possible, it was concluded that offline powder rheometry is a useful tool for predicting the behavior of food powders. These results were then developed into a computer-simulated model to allow for virtual and visual representation of the conveying action inside an enclosed steel barrel.

It is generally accepted that a food perceived as sticky would adhere easily to oral surfaces (e.g. teeth and soft tissues) and lead to many irregular movements of the jaw and the tongue. However, there are two major issues with this assumption. Firstly, there has been no supporting experimental evidence. Secondly, the stickiness measurements in the research lab are often conducted under conditions very dissimilar to those in the mouth and, therefore, their correlations to oral experience are somewhat questionable. This project investigated food stickiness and its effects on oral experience using three approaches: instrumental characterization, sensory assessment, and oral physiological analysis. Six semi-solid confectionery foods, standardized in size and shape, were used for investigation. Their stickiness was characterized quantitatively using penetration tests performed in a Texture Analyser and evaluated sensorially through assessment by a taste panel of 14 young subjects. Oral response to food stickiness was characterised using surface Electromyography (sEMG) technique to record the activities of major oral/facial muscles. Products were well discriminated not only according to their stickiness but also their hardness. Instrumental characterization of food stickiness was carried out with two different probes: a flat 5mm stainless steel probe and a natural tooth probe, and measured dry and wet to mimic oral conditions. It was found that food products can be categorised into two groups: those in which stickiness increased and those in which the stickiness decreased after surface wetting. The measured wet stickiness exhibited very good correlations with sensory stickiness. Measurements from the sEMG of 10 subjects showed that the activities of oral muscles during mouth closing (masseters and temporalis), mouth opening (digastric muscle), and tongue movements respond directly to food stickiness. Increases in muscle work per chewing sequence W (µV-s) for both opening and clossing muscles were closely associated to the perception of food stickiness rather than with food hardness. Association of muscle activity, of closing muscles, to stickiness sensation is believed to arise from the increased difficulty and uncomfortable sensation of applying shearing action between teeth when the sticky food tends to hold them together.

Fermented foods and beverages represent an important part of human nutrition in every food culture around the world. Some of the most popular fermented products derive from grain, fruit and vegetables and are alcoholic based, for instance the notable variety of traditional beers and wines. Originally, fermentation can be regarded as a biological method of food preservation, but it is increasingly understood that some fermented foods also promote human health through the contribution of microorganism leading to further properties unlike to the starting food materials, beyond basic nutrition. Indeed, there is evidence that some fermented foods provide beneficial effects through direct microbial/ probiotic action and indirectly via the production of metabolites and breakdown of complex proteins. Kefir, for example, can help to relieve gastrointestinal disorders and reduce the symptoms of lactose intolerance besides having antioxidant, antimicrobial, anti-tumor and immunomodulation effects. Moderate wine consumption has undeniable health benefits as a decrease in the probability of cardiovascular disease, to delay the onset of noninsulin-dependent diabetes mellitus, combat hypertension, and reduce the frequency of certain cancers and several other diseases. In the last years, there is a growing interest in winemaking without added of sulfites, owing to the perception that sulfites may cause negative health effects. The absence of sulfites in wine can be regarded as a quality factor, because consumers are attracted to foods without added additives, which are considered as healthy and genuine. Several methods for sulfites removal or reduction during winemaking have been studied, but the complete substitution with a product performing the same roles without the disadvantages of sulfites has been to date unsuccessful. Conversely, the wine production without addion of sulfites is becoming increasingly feasible due to technological improvement in winemaking. Furthermore, in the last years, there is a increased interest in the world wine market of red wines with fruity characteristics and old techniques developed some decades ago such as thermovinification, are becoming more widespread. Thermovinification is a winemaking process consisting of heating grapes to improve the extraction of grape anthocyanins and polysaccharides, responsible for color and roundness, whereas it reduces the tannins extraction, thus exogenous tannins are often added. Within fermented foods, milk kefir is becoming more popular in European countries due to various health benefits linked for example to bioactive peptides. In particular, phosphopeptides are a subgroup of mulitphosphorylated bioactive peptides, which for instance can enhance the absorption of minerals in the gastrointestinal tract because binding and solubilizing bivalent metal ions such as Ca2+. Formation of phosphopeptides during the manufacture of kefir is affected of production technology. Finally, a great attention is paid to offer an alternative to conventional dairy-based drink, such as soy drink kefir, which could be a substitute food for vegans and people suffering from lactose intolerance or allergies. The purpose of the present Ph.D. work was the study of influence of several technological parameters on the composition of two fermented foods: wine and kefir. In the first part, the work was focused on the study of several factors affecting the quality of white and red wines, whereas, in the second part, Ph.D. research regarded the influence of some technological parameters on the production of phosphopeptides in kefir. Finally, the characterization of microbiological and peptide profiles of kefir prepared with kefir grains from soy-drink was achieved. As concerning wine, a study of the evolution in bottle of white wine produced by reductive winemaking, with and without sulfites, under several experimental conditions, was carried out over 15 months. Dark storage at 12 °C and 30 °C were compared to investigate the temperature effect, meanwhile uncontrolled temperature and light conditions were selected to simulate inadequate storage conditions. Results showed that volatile acidity and the absorbance at 420 nm increased at 15 months of storage particularly in both samples without sulfur dioxide addition and stored at 30°C and uncontrolled temperature and light conditions. Total SO2 and free SO2 decreased with time in wine samples with sulfites, with the exception of wine stored at 12°C, due to SO2 action as antioxidant. Seventeen phenolic compounds were determined by HPLC-DAD-MS/MS analysis including hydroxycinnamate derivatives and minor compounds resulting from oxidation processes. At 15 months, the sample without sulfites addition and stored at the constant temperature of 30°C was the most browned, followed by samples stored at inadequate temperature and light conditions and at constant temperature of 12°C both without sulfites added. Besides the oxidation compounds, the absence of sulfites seems to have favored the presence of cis forms of hydroxycinnamate derivatives and caffeic acid derivatives. Furthermore, the combination of inadequate conditions of light and temperature favored hydrolysis reactions more than the effect due to the only high temperature. Finally, results concerning volatile profile showed that the presence of sulfites helps the typical aroma of young wines; contrarily the storage without sulfites accelerated the hydrolysis of acetate esters and contributed to increase furfural, 5-methyl-2-furancarboxaldehyde, and benzaldehyde contents. The appropriate storage in the dark, at low temperature seems to be the most important condition as improper storage conditions favor aroma degradation regardless sulfite addition. In the second work, the influence of thermovinification on ochratoxin A (OTA) content in red wines was studied. Two heating treatments were investigated (60-65°C for 2 h and 80-85°C for 30 min), both treatments applied with and without added tannins. To achieve this goal, a rapid and automatable method for the determination of OTA in wine using a microextraction by packed C18 sorbent followed by high performance liquid chromatography with fluorescence detection was developed and validated for a successful application in the context of wine production. Important experimental parameters, such as sample and eluent volumes, extraction mode, draw and dispense speeds, number of eluent passes up and down through the stationary phase, were optimized. The validation included the comparison of the sensitivities related to solvent-matched, matrix-matched and standard addition calibrations and the participation to a proficiency test in an inter-laboratory circuit. Matrix effects were also investigated. Accuracies relevant to real samples were estimated to range between 76 and 100%, at 0.2 μg/L, and between 84 and 108%, at 1.0 μg/L, in compliance with the EU Regulation 401/2006; the limits of detection and quantification were of 0.08 and 0.24 μg/L, respectively, i.e. much lower than the maximum level currently permitted for OTA in the European Union (2.0 μg/kg, corresponding to ca 2.0 μg/L). As concern thermovinification process, no significate differences on OTA concentration among the wines studied were found. As regards the second part of the thesis, first, the profiling of multi-phosphopeptides in kefir was carried on, and phosphopeptides were selectively enriched on hydroxyapatite and further analyzed with mass spectrometry analysis. Thus, 22 phosphopeptide sequences were identified in kefir, mainly derived by β-casein, and 9 of them showed the polar acidic motif pSpSpSEE (pS= phosphoserine), which is the most active in binding minerals. Then, the influence of temperature (18 or 25°C), pH (4.0 or 4.7) and the repeated use of grains with 2-step fermentation (back-slopping approach) on phosphopeptide profile in milk kefir prepared using kefir grains was studied. Microbiological characterization was carried out in each sample, considering both grains and kefir, before and after fermentation. The total lactic acid bacteria, acetic acid bacteria and yeasts are increased after fermentation steps and, in particular, microbial growth, at the investigated conditions, was affected only quantitatively by the fermentation temperature whereas both quantitatively and qualitatively by the final pH. The LC-ESI-QTOF-MS/MS study revealed a phosphopeptide profile of kefir that include 93 phosphopeptides with lengths ranging from 10 to 43 amino acids, and of which, 82 showed the typical acid motif “SSSEE”, crucial for exhibiting the bioactive properties of mineral binding. Furthermore, kefir processing, in particular pH, largely influenced the proteolysis of kefir grains microorganisms and the profile of microbial population. A reduced proteolysis rate was observed in kefir prepared with back-slopping approach, indicating a low reproducibility of proteolytic activity of kefir grains. Moreover, a sensory evaluation was carried out on the kefir samples and no statistically significant differences (p< 0.05) were observed in odor, taste and acidity between kefir products. Finally, the microbiological evaluation and a comprehensive analysis of peptide profile in kefir, prepared with kefir grains from soy-drink were performed. As concerning microbial population, only lactic acid bacteria and yeasts were found in soy drink and grains kefir; acetic acid bacteria were not detected. One hundred seventy-nine peptides were identified mainly derived from glycinin and lipoxygenase and ranged from 9 to 37 amino acids. The released peptides from the parent proteins are not distributed equally among the protein sequences, indeed, there were distinct parts in the proteins where more peptides are released than in other parts. However, the specificity of lactic acid bacteria proteinases in soy-based fermented foods has not been equally investigated as the proteolytic behavior on milk proteins. Results showed 62 bioactive sequences, encrypted within the investigated peptides, which are known for ace-inhibitory, antihypertensive, antioxidative, hypocholesterolemic and antimicrobial activities. All results described in the present PhD thesis contributed to increase the knowledge on wine and kefir, on relationships between quality and processing and potential health benefits, providing important tools to improve quality of wine and kefir productions.

This thesis discussed the non-thermal food processing technologies being used within the United States of America. The technologies discussed in this thesis are High- Pressure Processing (HHP), Pulsed Electric Field, Pulsed Light, Irradiation, Ultra Sound, Oscillating Magnetic Fields, and Cold Atmospheric Plasma. A survey was designed and conducted to study the major reasons behind a preference for a particular technology by the organization, and the limitations for not implementing specific technologies. The survey participants were management level, food scientists and, food technologists employed by food processing companies. The questionnaire consisted of ten questions related to demographics, current technology, barriers from other technologies, and research and development of new technologies. There were a total 223 respondents from various regions of the United States. The respondents had a wide array of industry experience. Of the respondents, 91% of the respondents had either a Bachelor’s Degree, Master’s Degree or Ph D. Thirty-six percent of the participants chose high pressure processing and 20 % chose pulsed electric as the most commonly used non-thermal food processing technologies. Rapidly increasing technologies included cold atmospheric plasma and oscillating magnetic fields. Seventyone percent mentioned the main driver for them to choose non-thermal food processing was better nutrient and sensory properties. As per the results, 41% of respondents believed the major limitations in implementing non-thermal food processing technologies was high investment. The results indicated the main drivers for innovation were equipment manufacturers and research. These researches were either academic or government funded.

Taken as an engineering material, mozzarella cheese can be considered as a complex food system that has dynamic structure and complex flowproperties. Food scientists have been actively developing methods to characterize mozzarella cheese rheologically, but most of these methods are empirical in nature. In the past decades, there has been a paradigm shift towards the utilization of well-developed rheological methods which have been widely applied in the study of commercial synthetic polymers. In this work, the rheology of mozzarella cheese was studied using well-developed rheological techniques. Utilizing various rheometers, the linear and non-linear rheology of mozzarella cheese was examined. General practical properties of mozzarella cheese such as meltability, flowability and stretchability were extracted from these results. Capillary flow and rolling experiments were also performed to determine their suitability as innovative post-production processing techniques for mozzarella cheese. Finally, a comparative study on the effect of frozen storage on the rheology of three different brands of mozzarella cheese was performed. In general, it was found that mozzarella cheese can be classified as a pseudoplastic (shear thinning) semi-solid material possessing a yield stress at room temperature. Upon heating, the yield stress gradually diminishes and it can be considered as a viscoelastic fluid. The results obtained from the various rheometers indicate that the yield stress, duration of experiment, sample geometry and temperature greatly affect the consistency of the results. It was also shown that extrusion can be used as a processing technique for mozzarella cheese above a certain temperature where the cheese is in a melt state. Rolling was also found to be a potentially feasible processing method. Finally, in terms of the effect of frozen storage, in general, the dynamic moduli decrease with the period of storage due to the freezing of the proteins in the cheese.

In the Morder-Client Food Service, a waiter/waitresses orders meals via a wireless handheld device. By reading the order items listed on the screen of a personal computer which is in a kitchen, the cook can make the correct dishes. This system can improve service quality and efficiency.

Ice cream mix was fermented with yogurt cultures of Streptococcus thermophilus and Lactobacillus bulgaricus to four different pH's then frozen in a batch ice cream freezer. A consumer panel of 120 people tasted samples of strawberry flavored product with pH's of 4.4, 4.7, 5.1, and 5.4 and commercial frozen yogurt as a standard. Results from the panel were used to predict a preferred pH of 4.9. Another panel of 181 people compared product at pH 4.9 with 10, 15 and 20% strawberry flavoring. There was not a statistically significant difference among levels of flavoring. Starter culture populations and lactase activity were monitored for one month both in yogurt and in the frozen fermented ice cream mix. Lactase activity and colony counts progressively decreased in refrigerated yogurt at 4°C during the 30-day period. In frozen fermented ice cream mix, lactase activity and colony counts decreased slightly. The fermented ice cream mix can be held frozen for more than one month with active lactase activity, and viable colony counts, but refrigerated yogurt does not have a shelf life of more than one month.

The physical, chemical, and antioxidant properties of extrudates prepared from specialty tannin sorghum (CSC3xR28) and Tx430 black sorghums were evaluated. White food type sorghums (ATx631xRTx436) and commercial corn meal were also extruded. Sorghums were extruded as whole kernels or cracked (broken) kernels through a Maddox MX-3001 high-friction extruder. Cracked sorghum fortified with bran (0 -50%) derived from decortication or roller-milling were also extruded. Tannin sorghums extruded similarly to white food-type sorghums, with very little difference in extrudate quality. Cracking the sorghums produced lower feed rates, higher specific mechanical energy (SME) and extrudates that were less dense, more expanded, and softer than whole kernel extrudates. Whole and cracked sorghum materials had feed rates similar to corn meal, but lower SME. Corn meal extrudates were less dense, more expanded, and softer than sorghum extrudates. Cracked and whole black sorghum extrudates were less expanded than hi-tannin and white sorghum extrudates, due to the black sorghum's soft endosperm and thick, fibrous pericarp. With increased fiber, all extrudates had decreased SME and expansion, with increased bulk density and breaking force with the addition of bran. These effects, were more pronounced in extrudates containing decorticated bran vs. roller-milled bran. The decorticated bran had smaller particle size, higher density, lower endosperm content, and greater dietary fiber content than roller-milled bran. Also, increases in dietary fiber content in the extrudates were strongly correlated to increases in bran fortification in the raw feed stock. Tannin and black bran extrudates showed increased phenol, tannin (high-tannin), and antioxidants where bran was added. Phenols, tannins, and antioxidants in tannin extrudates ranged between 10.3-30.9 mg GAE/g, 7.1-55.2 CE mg/g, and 68.3-212.2 umol TE/g, respectively. Phenols and antioxidant activity in black sorghum extrudates ranged from 4.2 -7.8 mg GAE/g and 39.7 - 73.3 umol TE/g, respectively. Specialty tannin and black sorghums can be used to produce extruded snacks high in fiber and antioxidant activity. Optimum product characteristics, along with nutraceutical benefits, will need further determination.

Food cleaning behavior has been observed among laboratory squirrel monkeys. A Wilcoxon signed-ranks test showed that significantly more cleaning behavior occurred when hard monkey chow pellets and soft fruit were coated with edible debris. Monkeys removed fewer pieces of fruit from a food crock containing fruit coated with edible debris in a timed test. A principal component analysis of the food cleaning behaviors showed two underlying correlated factors. The first factor was the use of the body to clean food. The second factor was the use of the environment to clean food. Two groups of squirrel monkeys, one without previous learners and one with previous learners, were subjects in a fishing study. The presence of previous learners in the social group was not significant for monkeys fishing in water filled crocks. But there was a significant difference in the number of fishing attempts made by the No Previous Learners Group when fishing in wading pools. The Previous Learners group did not make significantly more fishing attempts fishing in wading pools than in crocks. A significant difference was observed in fishing attempts during Phase 1 and Phase 2 of the wading pool experiment for both groups. All monkeys in the group fishing experiments ate fish when it could be obtained. Monkeys who did not learn to fish successfully learned alternative behaviors to obtain fish. The Previous Learners group in the wading pool experiment were subjects in a more difficult fishing test. Significantly fewer fishing attempts were made but the number of monkeys that caught fish was larger. Caged squirrel monkeys scored a lower percentage of fishing attempts than squirrel monkeys living in a social group. While Cebus monkeys caught fish, unlike squirrel monkeys, they did not attempt to eat them.

Mycotoxins are toxic secondary metabolites produced by fungi that contaminate various agricultural commodities either before harvest or under post-harvest conditions. The most important producing genera are Aspergillus, Fusarium and Penicillium. Mycotoxins can be present in a wide range of products and their intake is of concern because they can produce a wide range of harmful effects to human and animal. Cereal products represent one of the main sources of exposure to mycotoxins. Several mycotoxins have been identified up to the present, but those of special interest in food and feed safety are: aflatoxins (B1, B2, G1 and G2), fumonisins (Fbs), ochratoxin A (OTA), patulin, trichothecenes (deoxynivalenol and nivalenol), and zearalenone (ZEN). However, unaltered mycotoxins might not be the only threat for health consumers, because they can be present in conjugated forms which cannot be detected in the routinary mycotoxins analysis, but they can become as dangerous as parent mycotoxins. The objectives of this thesis were determine the presence of some mycotoxins in cereal products, study the stability of them during the food process and assess the mycotoxin exposure. To reach these aims different studies have been done. Firstly, cereals and cereal based food commercial samples have been analysed to study the presence of aflatoxins (Afs), deoxynivalenol (DON), nivalenol (NIV), ZEN, OTA and some of them conjugated mycotoxins. Bread making and pasta making processes have been deeply studied and some factors have been evaluated to observe the stability of mycotoxins. Mycotoxins exposure has been assessed through two different methods: 1) the combination of contamination data with consumption data and 2) using biomarkers.
Les micotoxines són metabòlits secundaris produïts per fongs que poden contaminar diferents productes agrícoles abans o després de la collita. Els gèneres més importants de fongs productors de micotoxines són Aspergillus, Fusarium i Penicillium. Les micotoxines poden estar presents en una gran varietat de productes i la seva ingesta pot ser de gran perillositat perquè produeixen una gran varietat d’afectes perjudicials per la salut dels humans i animals. Els productes a base de cereals representen una de les principals fonts d’exposició a les micotoxines. Varies micotoxines s’han identificat fins a dia d’avui, però aquelles micotoxines amb major interès per la seguretat dels aliments i el pinso són: les aflatoxines (B1, B2, G1 i G2), les fumonisines (Fbs), la ocratoxina A (OTA), la patulina, els tricotecens (deoxinivalenol i nivalenol) i la zearalenona (ZEN). Però, les micotoxines no alterades poden no ser l’únic problema per la salut dels consumidors, perquè també poden estar presents les micotoxines conjugades. Aquestes poden no ser detectades durant els anàlisis rutinaris encara que poden arribar a tenir la mateixa perillositat que les micotoxines lliures. Els objectius d’aquesta tesis eren determinar la presència d’algunes micotoxines en els productes fets a base de cereals, estudiar l’estabilitat de les micotoxines durant el processat dels aliments i avaluar l’exposició a aquest tipus de compostos. Per aconseguir aquests objectius s’han elaborat diferents estudis. En primer lloc, s’han realitzat alguns anàlisis de cereals i aliments a base de cereals procedents del mercat per estudiar la presència de les aflatoxines (Afs), el deoxinivalenol (DON), el nivalenol (NIV), la ZEN, la OTA i alguns dels seus conjugats. A continuació s’ha estudiat en profunditat el procés d’elaboració del pa i de la pasta i alguns factors que afecten la seva estabilitat han estat avaluats. L’exposició a les micotoxines s’ha realitzat a través de dos mètodes diferents: 1) combinació de les dades de contaminació amb dades de consum i 2) utilitzant biomarcadors.
Las micotoxinas son metabolitos secundarios producidos por hongos que pueden contaminar a varios productos agrícolas antes o después de la cosecha. Los géneros más importantes de hongos productores de micotoxinas son Aspergillus, Fusarium y Penicillium. Las micotoxinas pueden estar presentes en una gran variedad de productos y su ingesta puede ser peligrosa porque producen una gran variedad de efectos dañinos para la salud de los humanos y los animales. Los productos a base de cereales representan una de las principales fuentes de exposición a las micotoxinas. Varias micotoxinas se han identificado hasta la fecha, pero las micotoxinas con interés especial para la seguridad de los alimentos y los piensos son: las aflatoxinas (B1, B2, G1 y G2), las fumonisinas (Fbs), la ocratoxina A (OTA), la patulina, los tricotecenos (deoxinivalenol y nivalenol) y la zearalenona (ZEN). Sin embargo, las micotoxinas no alteradas pueden no ser el único problema para la salud de los consumidores, debido a que también pueden estar presentes las micotoxinas conjugadas. Este tipo de compuestos pueden no ser detectados en los análisis rutinarios aunque pueden llegar a ser igual de peligrosos que las micotoxinas libres. Los objetivos de esta tesis fueron determinar la presencia de algunas micotoxinas en los productos a base de cereales, estudiar su estabilidad durante el procesado de los alimentos y evaluar la exposición a este tipo de compuestos. Para lograr estos objetivos se han elaborado distintos estudios. En primer lugar, se han realizado varios análisis de cereales y alimentos a base de cereales procedentes del mercado para estudiar la presencia de aflatoxinas (Afs), deoxinivalenol (DON), nivalenol (NIV), ZEN, OTA y algunos de sus conjugados. A continuación, se ha estudiado en profundidad el efecto del proceso de elaboración del pan y de la pasta en la concentración de las micotoxinas y también se han evaluado algunos de los factores que podrían afectar al contenido final de las micotoxinas. Para la evaluación de la exposición a los metabolitos secundarios producidos por hongos se han utilizado dos métodos distintos: 1) combinación de los datos de contaminación con los datos de consumo y 2) utilización de biomarcadores.

As people across the globe are becoming more interested in watching their weight, eating more healthily, and avoiding obesity, a system that can measure calories and nutrition in everyday meals can be very useful. Recently, there has been an increase in the usage of personal mobile technology such as smartphones or tablets, which users carry with them practically all the time. In this paper, we proposed a food calorie and nutrition measurement system that can help patients and dieticians to measure and manage daily food intake. Our system is built on food image processing and uses nutritional fact tables. Via a special calibration technique, our system uses the built-in camera of such mobile devices and records a photo of the food before and after eating it in order to measure the consumption of calorie and nutrient components. The proposed algorithm used color, texture and contour segmentation and extracted important features such as shape, color, size and texture. Using various combinations of these features and applying a support vector machine as a classifier, a good classification was achieved and simulation results show that the algorithm recognizes food categories with an accuracy rate of 92.2%, on average.

The principle objective of this study was to describe and record all the gathering and processing skills of vervet monkeys for a variety of different foods. The study was conducted on two troops of vervet monkeys living in the Palmiet Valley, Natal, South Africa. There was sufficient data to analyze the processing of four foods of differing complexity; termites, leaf shoots, sugarcane and fruit. Milton (1988) proposed that the intellectual difficulties of finding and processing food led to the evolution of intelligence. In the only study of food processing skill, Byrne and Byrne (1993) showed that gorillas use a hierarchical organization perhaps reflecting imitation at the program-level. The question to be asked in this study was, would vervets also organize their processing into a few techniques for specific foods and would it then be possible to identify learning mechanisms used by the monkeys? The current literature suggests that monkeys use simple solutions to their foraging problems, there is no evidence for imitation of feeding skills in monkeys. At the most detailed level of analysis, grip types used in the processing of foods were described. Existing definitions in the literature were not adequate to explain the monkeys' hand use, and new definitions were added. High individual idiosyncrasy was a feature of grip usage across all four foods, although firm conclusions are not possible because of the known effects of sample size. Cluster analysis was considered the most appropriate method to look at individual variation in grip usage. There was an age effect for leaf shoots and sugarcane, with juveniles restricting their usage to the necessary core grips. The hand preferences for individuals across tasks gave no support for the theory of the evolution of laterality presented by MacNeilage et al. (1987). There was a low degree of individual preference for five out of six tasks, with only termite feeding showing a hand preference. There was some evidence for a right hand reaching, left hand manipulation preference, opposite to MacNeilage's prediction. There was an age effect in direction and strength for two tasks, adults having a stronger left hand preference in contrast to a weaker right hand preference in juveniles for leaf shoots and large fruit. Matrices of the transitional probabilities between two elements, were used to construct the common pathways of processing skill for each individual. Flow diagrams were then created to represent the minimal decision processes used by the monkeys. The diagrams were used to compare individuals' choice of pathways. Cluster analysis was used to analyze pathway choice in detail; none of a variety of independent variables could explain the high individual variation. Whether whole foods or just parts of foods were eaten did explain some of the variance for sugarcane and fruit. The most parsimonious explanation is that social enhancement resulting in trial and error learning best described individuals' acquisition of processing skill, although a number of other factors may explain the observed results.