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Ng, Sing Kwei. "Application of microwave sensors for rapid food analysis." Thesis, Manchester Metropolitan University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479020.
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Mohammadazari, Pejman. "Application of Capacitive Temperature Sensors for Food Processing Applications." Thesis, Southern Illinois University at Edwardsville, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13421017.
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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.
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Florea, Anca Stefana. "Electrochemical affinity sensors for biomedical, food and environmental applications." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10126/document.
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Les capteurs électrochimiques sont des outils pour la détection fiable, peu coûteux, avec une haute sensibilité et sélectivité, pour la détermination des composés biologiques et chimiques dans les domaines du diagnostic clinique, l'environnement et l'industrie alimentaire. Particulièrement, les Immunocapteurs, alliant une très grande spécificité. Également des nouveaux techniques produisent des résultats similaires, par exemple, les capteurs basés sur la technique des Polymères à empreinte moléculaire, la quelle produise des récepteurs artificiels. La technique devient très important dans les sciences bioanalytiques parce qu'il porte des avantages inhérents sur les récepteurs naturels: une grande stabilité dans des diffèrent environnement et conditions, également comptent avec une grande flexibilité dans la conception, une large gamme de molécules peuvent être utilisées. L'objectif du travail présenté ici est de développer des capteurs électrochimiques avec une très grande affinité et spécificité pour une analyte. Les quelles comprennent des applications très divers comme dans la protection de l'environnement, la sécurité alimentaire et le domaine biomédical. La première partie de la thèse présent l'état actuel de la conception et techniques de fabrication des biocapteurs. Ensuite, les aspects généraux des immuno capteurs électrochimiques et capteurs base sur des aptamères sont présentés ici, ainsi que plusieurs exemples rapportés dans la littérature pour la détection de marqueurs biologiques du cancer. Les avantages de l'intégration nanomatériaux dans les dispositifs de détection sont présentés. Ensuite, plusieurs aspects sur la technique des Polymères à empreinte moléculaire sont introduits. La partie personnelle de contribution est structuré en trois chapitres: en premier temps la méthodologie et les résultats obtenus pour le développement de deux essais biologiques pour la détection du marqueur tumoral Mucinl. Le premier chapitre est dédié sur un capteur à base de billes magnétiques, dans le deuxième chapitre une capteur aptamère base sur des nanoparticules d'or sans aucun marquage et finalement un capteur basée sur la technique des Polymères à empreinte moléculaire, cette protocole a été appliqué pour la détection d'explosifs, des médicaments, des hormones et les pesticidesElectrochemical sensors provide reliable and inexpensive tools for the determination of biological and chemical compounds with high sensitivity and selectivity, in the fields of clinical diagnosis, environment protection and food industry. Immunosensors hold particular promise, combining the high specificity of immuno- reactions with the sensitivity of electrochemical methods. Artificial receptors based on molecularly imprinted technique attracted considerable attention in bioanalytical sciences due to inherent advantages over natural receptors, such as high stability in harsh conditions and freedom of molecular design towards a wide range of molecules. The aim of the thesis presented here was to develop electrochemical affinity sensors based on various recognition receptors for environment monitoring, food safety and biomedical field. The first part of the thesis reviews the current state of knowledge in these fields. General aspects of electrochemical immuno- and apta-sensors are presented herein, together with several examples reported in the literature for the detection of cancer biomarkers. The advantages of integrating nanomaterials in sensing devices are then presented. At last, several aspects of the molecularly imprinted polymers are introduced. The personal contribution part is structured in three chapters, that include the methodology and results obtained for the development of biosensors for the detection of Mucinl tumor marker, the first chapter being focused on bioassays based on magnetic beads and second chapter on a label-free aptasensor based on gold nanoparticles, and finally, a third chapter dedicated to the molecularly imprinted-based sensors for the detection of explosives, drugs, hormones and pesticides
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Lerud, Ryan M. "Sensors and Portable Instruments for Postharvest Agriculture." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/4994.
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The sensing needs for the fresh produce industry can be split into two primary stages: during maturation in the field, also referred to as Precision Farming, and during storage and transport of the produce, or Postharvest Storage. This work seeks to improve the accuracy and reliability of commercially available electrochemical and spectroscopic sensors tailored to the sensing needs of the fresh produce industry. For electrochemical sensing, this study proposes the use of an inline filter to remove polar organic compounds, which can interfere with the readings of a platinum-based electrochemical sensor. A 50% improvement in measurement accuracy was achieved when monitoring the storage headspace of a container of apples. For portable spectroscopy instruments, this study suggests improvements for the alignment of the optical bench and the spectral collect protocol. Methods to reduce the influence of environmental noise, such as variability of background light (sunlight in the field) and thermal effects on hardware performance, are presented. This study also presents the first report of the calibration transfer of spectral regressions developed with Karl Norris's Derivative Quotient Method. The motivation for this aspect of research was to develop methods to collect stable and accurate data in the field, which can be used to improve the quality of fresh produce reaching the customer and reduce premature food spoilage.
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Mascini, Marcello. "DNA and peptide based sensors for food and environmental applications." Thesis, Cranfield University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399122.
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Taterka, Heather. "Optical prediction models of whey protein denaturation in thermally treated milk for the development of an inline sensor." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399172.
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Un sensor de proteínas del lactosuero desnaturalizadas, en línea, sería de gran interés en la industria láctea para monitorizar las variaciones entre lotes de leche durante el procesado y obtener productos de alta calidad. Se ha demostrado que el mecanismo de desnaturalización de las proteínas del suero depende del pH; a pH más bajo (pH 6,3) las proteínas desnaturalizadas tienden a formar complejos con la κ-caseína en la superficie micelar, mientras que a valores de pH más altos (pH 7,1) las proteínas de suero desplegadas forman preferentemente complejos de carácter soluble con otras proteínas de suero desnaturalizadas. El objetivo de esta tesis doctoral ha sido desarrollar con éxito modelos de predicción de las diferentes conformaciones que presentan las proteínas de suero en leche tratada termicamente mediante parámetros obtenidos empleando un sistema óptico de medida con potencial para la aplicación en línea durante el procesado térmico de leche.
El sistema óptico de medida fue desarrollado con vistas a su aplicación en línea, con el objetivo de determinar los efectos de la temperatura, el pH y el tiempo sobre los cambios en la dispersión de luz observados en la leche desnatada tratada térmicamente, y relacionar dichos cambios con la desnaturalización de las proteínas del lactosuero. Las variables a correlacionar con la señal de dispersión de luz fueron el tamaño de partícula y la concentración de las diferentes configuraciones de proteína sérica que se producen en la leche después del tratamiento térmico: proteínas nativas, proteínas desplegadas unidas a la superficie de la micela y agregados solubles de seroproteínas desnaturalizadas. En el segundo y tercer experimento, se evaluó la espectroscopia de fluorescencia front-face del triptófano para comparar dicha tecnología optica con las medidas de dispersión de luz.
Los resultados del primer experimento mostraron una correlación entre la intensidad de dispersión de luz y el tamaño de partícula, concretamente a pH 6,3, mientras que a pH 7,1 no se observaron cambios notables en la intensidad de dispersión de luz ni en el tamaño de partícula con el aumento de la temperatura del tratamiento térmico. En el segundo experimento, las curvas de dispersión y fluorescencia versus tiempo a pH 6,3 fueron similares a las curvas de tamaño de partícula y de proteína de suero unida a la micela, no observándose diferencias significativas entre sus constantes cinéticas de primer orden. El tercer experimento incluyó un rango de porcentajes de grasa (<0,5%, 1,3% y 3,7%) y exhibió una intensidad de dispersión de luz y de tamaño de partícula notablemente mayor al aumentar el contenido en grasa.
Se obtuvieron con éxito modelos de predicción del tamaño de partícula en función de la dispersión de luz. Los modelos de interación de proteína de suero-caseína a pH 6,3 se ajustaron mejor a los parametros obtenidos a partir de los espectros de dispersión de luz, mientras que los modelos de predicción del contenido de agregados solubles de proteína de suero desnaturalizada se ajustaron mejor a las determinaciones de fluorescencia de triptófano. Un hallazgo significativo fue la correlación exponencial obtenida entre el tamaño de partícula y la intensidad de dispersión de luz, que permitió obtener una ordenada en el origen que se corresponde bastante fielmente con los valores medios iniciales de tamaño de las micelas de caseína antes del tratamiento térmico. Un modelo combinado en un rango de pH 6,3, 6,7 y 7,1 permitió predecir el tamaño de partícula en función de valores de intesidad de dispersión de luz, mostrando potencial para el desarrollo de un sensor de dispersión óptica en línea que permitiría estimar el tamaño de partícula dentro de un rango de valores de pH y de intesidades de tratamiento térmico.An inline whey protein denaturation sensor would be of interest to the dairy industry to monitor milk batch variations and to achieve the highest quality products. It has been well-established that whey protein denaturation is a pH-dependent mechanism, in which proteins at lower pH values (pH 6.3) tend to form complexes with κ-casein on the surface of the casein micelle, and at higher pH values (pH 7.1) the preference is for unfolded whey proteins to for serum complexes, in general, with other denatured whey proteins. The objective of this PhD was to develop successful prediction models of whey protein denaturation variables utilizing an optical sensor set-up with the potential for inline implementation during thermal processing. The optical sensor system was developed with inline implementation in mind, with the goal being to measure the effects of temperature, pH and time on the changes in light scatter of thermal treated skim milk and relate these changes to the denaturation of whey proteins. Variables to be compared to the optical light backscatter response were particle size and the whey protein concentration of the three whey protein configurations that occur in milk after thermal treatment: native, micelle-bound and soluble aggregate whey protein. In the second and third experiments, tryptophan front-face fluorescence spectroscopy was also tested with the potential for sensor development and compared to light backscatter technology. Results of the first experiment showed a relationship between light backscatter intensity and particle size, in particular at pH 6.3 whereas at pH 7.1 no notable changes in the light backscatter intensity or particle size were observed with an increasing in heat treatment temperature. In the second experiment, curves of LB and FFF intensity versus time at pH 6.3 resembled curves of particle size and bound whey protein, and their first-order kinetic rate constants were not statistically different. The third experiment included a range of fat percentages (<0.5%, 1.3% and 3.7%) and exhibited a noticeably greater amount of light scatter and larger particle size with increasing fat content. Model equations showed successful predictions of particle size as a function of light backscatter. In the second experiment, models of bound whey protein at pH 6.3 were best fit to models as a function of the light backscatter spectra, whereas soluble aggregate whey protein content showed best fit when using tryptophan fluorescence measurements. Light backscatter regions which corresponding to best-fit models for particle size and bound whey protein models were near the maximum intensity wavelength (540-600 nm) or included a ratio combination of a numerator value between 387-569 nm and denominator from 963-1033 nm. Front-face fluorescence models also exhibited good R2 values near the maximum intensity wavelength, however a ratio of numerator near 340 nm combined with a denominator around 390 nm yielded models with a better fit. An interesting finding was the relationship exhibited by particle size models as a function of light backscatter, which exhibited an exponential character using an equation with the intercept value similar to the initial particle size. Combined models over a range of pH values (6.3, 6.7 and 7.1) predicted particle size as a function of light backscatter, giving promise to the development of an optical inline backscatter sensor technology.
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Bhadra, Sharmistha. "Electrode-based wireless passive pH sensors with applications to bioprocess and food spoilage monitoring." IEEE, 2011. http://hdl.handle.net/1993/30366.
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This thesis purposes and develops inductively coupled LC (inductive-capacitive) pH sensors based on pH-sensitive electrode pair. The LC resonator circuit is based on a varactor and measures the low frequency potential difference. For wireless pH monitoring, the resonator circuit is integrated with a pH-sensitive electrode pair. This sensor demonstrates a linear response over 2 to 12 pH dynamic range, 0.1 pH accuracy and long-term stability. Accurate measurement of pH using electrode-based sensors is affected by temperature variation. A technique of simultaneously measuring two parameters, pH and temperature, with a single RLC resonator based sensor is presented. An algorithm is developed, which applies both pH and temperature measurement to incorporate temperature compensation in pH measurement. For in-fluid applications, an encapsulation method is applied to the LC resonator based sensor to reduce the influence of medium permittivity and conductivity on the sensor measurement. Non-invasive way to obtain reliable pH information from bacterial culture bioprocesses is demonstrated with the fluid embeddable sensor. The pH sensor is remodeled to an acidic and basic volatile sensor by embedding the electrodes in a hydrogel host electrolyte. Tests demonstrate that the volatile sensor has a detection limit of 1.5 ppm and 2 ppm for ammonia and acetic acid vapor, respectively. Application of the volatile sensor to fish spoilage monitoring shows that the sensor is capable of detecting the product rejection level with good sensitivity in real-time. It is important to develop low cost wireless passive pH sensor technologies for embedded applications such as bioprocess and food spoilage monitoring. The electrode-based passive LC sensor approach employed in this thesis overcomes drawbacks of some of the early developed passive pH sensors and can lead to an inexpensive implementation using printed electronics technology.
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Jones, Erica Nicole. "Development of Biopolymer Based Resonant Sensors." University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1272992841.
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Wu, Junjie. "Consumers' psychological reactions during a food safety incident and WTP for nano-sensors in meat products." Thesis, University of Reading, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.701804.
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Risk communication disseminated during a food safety incident plays an important role in shaping consumer purchasing behaviour. Consumer research shows that immediately after a food safety incident the demand of indicted products falls rapidly and then starts to increase slowly when consumer confidence is restored. Another important aspect of risk communication is to understand how messages influence the magnitude of consumers' perceived risk and how this element can affect food purchasing behaviour. However, very little is known about the cognitive process that consumers undertake when markets are shocked by food scares and how perceived risk influence consumers' choices. In order to fill such a gap this study aims at understanding how people react and behave in food markets with and without a food safety incident caused by E. coli in meat products. To achieve this objective models of social psychology and economics were combined to assess how consumers' subjective probability (De Finetti's theorem on exchangeability) and psychological reactions (Protection Motivation Theory) impact on willingness to pay (WTP) of hypothetical meat products packaged with nanosensors. WTP for these products was elicited both by means of a payment card and a stated choice experiment and estimated respectively with a Tobit regression and a scale adjusted latent class model. The survey was administered in the UK between February and March 2015 and 627 respondents in the UK took part in the study. Results show that risk overestimated attitude in risk markets is influenced by sociodemographic and economic characteristics of respondents. Psychological elements and subjective probability have also different impacts in the simulated market scenarios of risk and no risk In particular, WTP for meat packaged with nanosensors varies under different psychological reactions and subjective probability fits well the identification of latent classes and consumers' choices. Marketing and policy implications of these findings are discussed.
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Abdelgawad, Eid Ahmed Rabiea. "Inline optimization of cheese making using a near infrared light backscatter sensor technology." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/400021.
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L’elaboració de formatge es pot considerar un “procés controlat d’eliminació d’aigua de la llet”. Aquest procés concentra la proteïna, el greix i altres nutrients de la llet, augmentant la seva vida útil. La fabricació de formatge consta de diverses etapes d’entre les quals, dues de les més importants, tenen lloc en el tanc de formatgeria: la coagulació de la llet i la sinèresi de la quallada.
La monitorització a temps real de la coagulació de la llet i l’enduriment del gel lacti, així com la predicció del temps de tall, són essencials per la producció de formatge ja que aquests factors exerceixen un impacte substancial tant en el rendiment formatger com en la qualitat del formatge final. Hi ha nombrosos factors que afecten el procés de fabricació de formatge mitjançant la modificació de la quantitat, la qualitat i les propietats tecnològiques de la llet. Si bé la majoria d’aquests factors són ben coneguts, alguns no han estat suficientment estudiats.
L’objectiu general d’aquesta tesi fou avaluar l’impacte de la mescla de llet (i. e., diferents proporcions de llet de cabra, ovella i vaca) i la llet de baixa qualitat (i. e., llet d’animals amb mastitis subclínica) en la predicció del temps de coagulació, del temps de tall, de la velocitat d’eliminació del sèrum i de diversos altres índexs de producció formatgera, mitjançant la monitorització de la coagulació i la sinèresi amb vàries tecnologies de sensors de dispersió de llum d’infraroig proper: sensor de coagulació de laboratori CoAguLAb; sensor de coagulació CoAguLite i sensor de sinèresi LFV. Els dos darrers, instal·lats en la paret d’un tanc de formatgeria de deu litres a escala de planta pilot.
El paràmetre de dispersió tmax i diversos altres paràmetres òptics de temps es correlacionaren significativament amb els temps visual i reològics de coagulació i de tall, així com amb els rendiments de sèrum i formatge i amb el recompte de cèl·lules somàtiques.
Es va observar que les mescles de llet i la raça dels animals no tingueren un efecte significatiu (P ≥ 0,05) en els indicadors òptics ni reològics del temps de coagulació, mentre que la concentració d’enzim, la temperatura de coagulació i la infecció subclínica tingueren un efecte significatiu sobre tots els índexs, tant òptics com reològics, relacionats amb el temps de coagulació i la velocitat d’acoblament del gel lacti (i. e., agregació micel·lar i enduriment del gel). La mastitis subclínica, la mescla de llet, la temperatura i la raça tingueren un efecte significatiu sobre la sinèresi de la quallada, mentre que el rendiment formatger es veié afectat per la mastitis subclínica i la raça (cal fer notar que els efectes de la concentració d’enzim, la temperatura i la mescla de llet no foren avaluats directament).
S’obtingueren models de predicció pels temps de coagulació i de tall, tant visuals com reològics, l’angle de fase (tgδ) en el moment de tall, la velocitat de sinèresi i diversos indicadors de rendiment formatger. Els nostres resultats confirmen la utilitat de la monitorització a temps real mitjançant dispersió de llum d’infraroig proper tant de la coagulació de llet com de l’eliminació de sèrum de la quallada, amb la finalitat de millorar el control d’aquestes dues etapes crítiques de l’elaboració del formatge. Els resultats obtinguts demostren que l’impacte de factors com la mescla de llets i la mastitis subclínica s’ha de tenir en consideració en les operacions de control de processos de l’elaboració de formatge.La elaboración de queso puede considerarse como un "proceso controlado de eliminación de agua de la leche". Este proceso concentra la proteína, grasa y otros nutrientes de la leche, aumentando su vida útil. La fabricación de queso consta de varias etapas, de entre las cuales dos de las más importantes tienen lugar en la cuba quesera: la coagulación de la leche y la sinéresis de la cuajada. La monitorización a tiempo real de la coagulación de la leche y el endurecimiento del gel láctico, así como la predicción del tiempo de corte es esencial para la producción de queso ya que dichos factores ejercen un impacto sustancial tanto en el rendimiento quesero como en la calidad del queso final. Existen numerosos factores que afectan al proceso de fabricación de queso mediante la modificación de la cantidad, calidad y propiedades tecnológicas de la leche. Si bien la mayoría de dichos factores son bien conocidos, algunos no han sido suficientemente estudiados. El objetivo general de esta tesis fue evaluar el impacto de la mezcla de leche (i.e., diferentes proporciones de cabra, oveja y vaca) y la leche de baja calidad (i.e., leche de animales con mamitis subclínica) en la predicción del tiempo de coagulación, del tiempo de corte, de la velocidad de desuerado y de varios otros índices de producción quesera, mediante la monitorización de la coagulación y la sinéresis con varias tecnologías de sensores de dispersión de luz de infrarrojo próximo: sensor de coagulación de laboratorio CoAguLAb; sensor de coagulación CoAguLite y sensor de sinéresis LFV. Los dos últimos, instalados en la pared de una cuba de quesería de diez litros a escala de planta piloto. El parámetro de dispersión tmax y varios otros parámetros ópticos de tiempo se correlacionaron significativamente con los tiempos visuales y reológicos de coagulación y de corte así como con los rendimientos de suero y queso; y con el recuento de células somáticas. Se observó que las mezclas de leche y la raza de los animales no tienen un efecto significativo (P ≥ 0,05) ni en los indicadores ópticos ni en los reológicos del tiempo de coagulación, mientras que la concentración de enzima, la temperatura de coagulación, y la infección subclínica tuvieron un efecto significativo sobre todos los índices tanto ópticos como reológicos relacionados con el tiempo de coagulación y la velocidad de ensamblado del gel láctico (i.e., agregación micelar y endurecimiento del gel). La mastitis subclínica, la mezcla de leche, la temperatura y la raza tuvieron un efecto significativo sobre la sinéresis de la cuajada, mientras que el rendimiento quesero se vio afectado por la mastitis subclínica y la raza (nótese que el efecto de la concentración de enzima, la temperatura y la mezcla de leche no fue evaluado directamente). Se obtuvieron modelos de predicción para los tiempos de coagulación y de corte tanto visuales como reológicos, el ángulo de fase (tgδ) en el momento del corte, la velocidad de sinéresis y varios indicadores de rendimiento quesero. Nuestros resultados confirman la utilidad de la monitorización a tiempo real tanto de la coagulación de leche como del desuerado de la cuajada mediante dispersión de luz de infrarrojo próximo, a fin de mejorar el control de esas dos etapas críticas de elaboración de queso. Los resultados obtenidos demuestran que el impacto de factores tales como la mezcla de leches y la mastitis subclínica debe ser tenido en consideración en las operaciones de control de procesos de la elaboración de queso.
Cheese making is the “controlled process of removing water from milk”. This process concentrates the milk protein, fat and other nutrients and increases its shelf life. Cheese manufacture consists of two main steps occurring in the cheese vat, milk coagulation and curd syneresis. Real-time monitoring of milk coagulation, curd firming and syneresis as well as inline prediction of cutting time is essential for cheese making as those factors exert a substantial impact in both cheese yield and quality. Many factors affect the cheese manufacturing process by modifying the quantity, quality, and processing properties of the produced milk. The general objective of this dissertation was to evaluate the impact of milk mixture (i.e., different proportions of goat, sheep and cow milk) and low quality milk (i.e., milk from animals with subclinical mammary infections) in the prediction of clotting time, cutting time, syneresis rate and several other cheese making indexes based on monitoring milk coagulation and syneresis using NIR light backscatter sensor technologies. Several optical devices: a lab-scale coagulation tester (CoAguLab), an inline coagulation sensor and an inline large field of view (LFV) syneresis sensor were used to monitor milk coagulation, cutting time, and whey separation during Manchego cheese manufacture. Optical parameter tmax and several other time-based light backscatter parameters were highly correlated with visually- and rheologically-derived clotting and cutting times as well as cheese yield, yield of whey and SCC. It was observed that milk mixtures and animal breed did not have a significant (P ≥ 0.05) effect on optical and rheological time parameters related to clotting time, while different enzyme concentrations, coagulation temperatures, and subclinical infection had a significant effect on all optical and rheological parameters related to milk clotting time, and gel assembly rate (i.e., aggregation and firming rates). Subclinical mastitis, milk mixtures, temperature, and breed had a significant effect on curd syneresis while cheese yield was affected by subclinical mastitis and breed (note that syneresis effect of enzyme concentration, temperature and milk mixtures was not directly evaluated). Prediction models using light backscatter parameters alone or in combination with protein/solids concentration were successfully obtained for visually determined clotting and cutting times, rheologically derived gelation and cutting times, tanδ at cutting, syneresis rate constant and several cheese yield indicators. Our results confirm the usefulness of light backscatter inline monitoring of milk coagulation and curd syneresis for improved process control of those two critical cheese making steps. The results obtained show that the impact of factors such as milk mixtures and subclinical mastitis in cheese manufacture needs to be considered on cheese making process control operations.
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Kirchner, Patrick [Verfasser], and Michael [Akademischer Betreuer] Keusgen. "Thin-film calorimetric gas sensors for hydrogen peroxide monitoring in aseptic food processes / Patrick Kirchner. Betreuer: Michael Keusgen." Marburg : Philipps-Universität Marburg, 2013. http://d-nb.info/1038786169/34.
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Flanagan, Shane Patrick. "Application of catalysts and nanomaterials in the design of an electrochemical sensor for ochratoxin A." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1013328.
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Ochratoxin A is the most potent chlorinated derivative of the ochratoxin group, consisting of a 5'-chlorinated dihydroisocoumarin moiety linked by an amide bond to l-phenylalanine. Produced as a secondary fungal metabolite by several species of Aspergillus and Penicillium, ochratoxin A has been shown to readily contaminate a large variety of commodities including cereals, groundnuts, dried fruit, spices and coffee. This has led to widespread contamination of ochratoxin in wine, beer, milk and meat products. As ochratoxin A is a potent nephrotoxin exhibiting teratogenic and carcinogenic properties, the development of a rapid screening platform for the cost effective control of ochratoxin A content in foodstuffs is therefore required. The evaluation of metallophthalocyanine and carbon nanotube electrode modification toward the development of a nanostructured biosensor capable of enhancing the electrochemical detection of ochratoxin A in complex media is presented. Cyclic voltammetry at a glassy carbon electrode allowed for the optimization of detection parameters including pH and type of supporting electrolyte. Britton-Robinson buffer was found to be the most suitable supporting electrolyte in terms of sensitivity and reproducibility obtaining a LOD of 0.28 μM as determined by differential pulse voltammetry. Subsequent analysis determined the dependence of OTA oxidation on pH in acidic media which proceeds with the transfer of two electrons to form a quinone/hydroquinone couple shown to adsorb to the electrode surface. Passivation of the electrode through adsorption of oxidation products was shown to severely limit the detection of OTA upon successive detection cycles. Comparison of various metallophthalocyanine modifiers showed an increase in sensitivity toward the detection of OTA at phthalocyanine complexes with metal based redox processes. However with the exception of NiPc and CoTCPc complexes, phthalocyanine modification was limited by the increase in deviation of current response and extent of fouling. NiPc modification showed an increase in sensitivity by two fold with fouling characteristics comparable to an unmodified electrode while low improvements in fouling was observed at CoTCPc modified electrodes with sensitivity in detection comparable to an unmodified electrode.Modification of the electrode with multi- and single walled carbon nanotubes produced a significant increase in sensitivity toward the detection of ochratoxin A. The electrocatalytic activity of nanotube modifiers was attributed to the increase in surface area and to the addition of oxygenated functional groups upon acid treatment as confirmed by Raman spectroscopy. Acid functionalization of the carbon nanotubes for a period of two hours produced the greatest increase in sensitivity obtaining a respective LOD of 0.09 μM and 0.03 μM for analysis of ochratoxin A at multi- and single walled carbon nanotube modified electrodes. Centrifugal purification of carbon nanotubes was deemed necessary to improve the electrocatalytic activity of the nanotube modifiers through the removal of carbonaceous impurities as visualized by atomic force microscopy. Furthermore, a crude lipase preparation, lipase A, was investigated as a potential biological recognition element for selective detection of ochratoxin A in complex media. Lipase A enabled the hydrolysis of ochratoxin A to the electroactive species ochratoxin α as confirmed by thin layer chromatography and voltammetric analysis. Additional isolation of a pure hydrolase from the lipase A preparation is required prior to utilization within a nanostructured biosensor platform capable of detecting ochratoxin A in complex media.
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Akpolat, Hacer. "Improvement of Tomato Breeding Selection Capabilities using Vibrational Spectroscopy and Prediction Algorithms." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574812034661898.
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TAIPINA, MAGDA S. "Efeito da radiacao gama sobre o conteudo de tocoferois em produtos naturais e industrializados e avaliacao sensorial." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9381.
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Made available in DSpace on 2014-10-09T12:26:23Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:04:27Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Bisschop, Sean M. "Food sounds, sensory, acoustic, and mechanical analysis of two snack foods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24445.pdf.
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Szulc, Ricardo Leme. "Síntese de polímeros condutores e sua aplicação em narizes eletrônicos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/46/46135/tde-29112007-163315/.
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O trabalho desenvolvido consistiu na síntese eletroquíca de 4 polímeros conjugados da família dos PPVs, substituídos por cadeias laterais formadas por unidades - CORS (tioéster) com grupos R de comprimentos distintos. A caracterização desses polímeros foi feita por métodos espectroscópicos, análises térmicas e cromatografia por exclusão de tamanho. Os polímeros foram dopados com ácido canforsulfônico. Sensores foram construídos pela deposição de filmes poliméricos finos sobre eletrodos interdigitados. Suas respostas resistivas, frente à exposição aos vapores de substâncias voláteis, foram estudadas. Um equipamento foi desenvolvido para testar os sensores. Através dessa ferramenta, os sensores foram conectados a condutivímetros, cujas saídas foram lidas e digitalizadas por um microcontrolador, qeu enviou esses dados a um computador (PC). O conjunto de dados colhidos permitiu gerar gráficos de resposta vs. tempo e de PCA (análise das componentes principais), utilizados na avaliação da seletividade dos sensores. Os sensores foram expostos a ar saturado com vapores de compostos orgânicos voláteis. Os resultados mostraram que esses são capazes de distinguir os compostos testados. O arranjo de alguns sensores diferentes gerou padrões distintos de resposta para cada substância analisada, possibilitando o emprego de programas de reconhecimento de padrões na avaliação dos analitos. Em testes com odores mais complexos, os sensores foram expostos aos vapores de diversas marcas de café e de cerveja que evidenciaram a seletividade. O desempenho dos sensores em análises quantitativas foi avaliado por meio da exposição aos vapores de soluções alcoólicas aquosas. Foi verificada a sensibilidade dos sensores à quantidade de etanol presente nas soluções. Através do método de adição de padrão foi possível determinar o teor de etanol em bebidas alcoólicas comerciais.The electrosynthesis of four conjugated polymers of the PPV family, presenting as side-chains -COSR (thioester) groups of different lengths, is described. These polymers were characterised spectroscopically, by thermal analyses and by size exclusion chromatography (SEC). The polymers were doped with 10-camphorsulfonic acid. Casting thin polymeric films onto interdigitated electrodes assembled sensors whose response and selectivity were evaluated by exposing them to volatile organic compounds (VOCs). The resistance over the contact pairs was continuously monitored with an accurate conductivity meter connected via an analogue-to-digital converter to a PC in which a software enabled plotting resistance vs. time graphs and PCA (principal component analysis) plots. The sensors were able to discriminate the tested VOCs showing a different response pattern for each compound. The sensors also exhibited good selectivity when exposed to complex odours as, for instance, different brands of coffee and beer. They were also tested in quantitative analyses allowing determination of the ethanol content in alcoholic drinks.
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Belaizi, Yassin. "Etude et conception d'un capteur-RFID passif en bande UHF : application à l'agroalimentaire." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS061/document.
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La technologie d’identification radiofréquence (RFID) se décline aujourd’hui dans des milliers d’applications. Parmi elles nous pouvons citer les applications de gestion logistique des palettes/cartons dans les entrepôts industriels (RFID UHF) ainsi que l’identification des abonnés dans les réseaux de transports urbains (RFID HF). Depuis quelques années, des contributions scientifiques autour des technologies d’identification radiofréquence (RFID) avec un couplage capteur sont de plus en plus visibles. L’intérêt grandissant pour ce type de technologie s’appuie sur la possibilité d’une utilisation en masse de capteurs bon marchés pouvant être intégrés sur chaque objet. On parle alors d’objet connecté ou d’internet des objets (IoT). Dans cette thèse, nous nous focalisons sur l’étude et le développement d’un capteur RFID passif fonctionnant en bande UHF. Cette orientation technologique est dictée par l’application visée, l’agro-alimentaire, qui requiert des coûts de fabrication les plus faibles possibles et une distance de lecture supérieure au mètre. Pour l’élément sensible, nous utilisons un bio-polymère, plus précisément le gluten de blé dont les propriétés diélectriques en fonction de l’humidité relative ont été étudiées précédemment. Nous nous attachons à traiter toutes les problématiques liées à la communication entre un lecteur et un capteur RFID passif, l’objectif ultime de cette thèse étant de récupérer une information capteur à l’aide d’un lecteur RFID conventionnel respectant les standards du domaine et les directives radio en vigueur dans les différentes régions du monde. Pour valider cette étude, nous mettons en œuvre des capteurs-RFID pour réaliser un démonstrateur d’emballage « intelligent » permettant le suivi de la qualité des alimentsRadio frequency identification (RFID) technology is available today in thousands of applications. Among them we can mention the logistics management applications pallets / cardboard in industrial warehouses (RFID UHF) and the identification of subscribers in urban transport networks (RFID HF). In recent years, scientific contributions around the radio frequency identification (RFID) technologies with a sensor coupling are increasingly visible. The growing interest in this type of development rely heavily on a mass use of inexpensive sensors that can be integrated on each object.It is calledconnected objects or Internet of Things (IoT). In this thesis, we focus on the study and development of a passive RFID sensor operating in UHF band. This technological orientation is dictated by the targeted application, the food industry, which requires the lowest possible manufacturing costs and a reading distance greater than one meter. For the sensitive element, we use a biopolymer, specifically wheat gluten whose dielectric properties as a function of relative humidity have been studied previously. We are committed to dealing with all the issues related to the communication between a reader and a passive RFID sensor, the ultimate objective of this thesis being to get a sensor information using a conventional RFID reader complying with the standards and the radio directives imposed in different regions of the world. To validate this study, we are implementing RFID sensors to create a smart packaging demonstrator for monitoring the quality of food
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Dobiáš, Vojtěch. "Senzor kvality prostředí potravinového obalu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449725.
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The aim of this study was to prepare thin polymer layers able to give a color change response to oxygen. Thin layers were prepared with different polymers and dyes. The rate of photocatalytic reduction of a dye and the rate of the color change response to oxygen were studied. To verify oxygen sensitivity of a prepared layer, oxygen absorbers were used to create anaerobic conditions. The effect of visible light irradiation on a prepared layer was examined as well. Influence of glycerol content on the kinetics of the photocatalytic reduction and the color change response was studied. Considering both reactions, the glycerol content of 1 % was found to be the most suitable. Methylene blue in prepared layer was reduced 48 s after previous UVA irradiation with intensity of 0,1 mWcm-2. The color change response to oxygen is readily distinguished by the naked eye within 20 minutes.
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Rose, Grenville John, of Western Sydney Hawkesbury University, Faculty of Science and Technology, and School of Food Science. "Sensory aspects of food preferences." THESIS_FST_SFS_Rose_G.xml, 1999. http://handle.uws.edu.au:8081/1959.7/130.
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Little is known about how liking for different foods develops from birth to adulthood. Although there are both cultural and sensory aspects to the development of food preferences, the focus of this study is on the sensory aspects of food preference development, in particular, preferences for meat. Two main aims are addressed : 1/. To develop a robust methodology that can be used to determine pre-literate and recently literate children's liking for different foods and the determinants of that liking. 2/. To investigate the effects of early experience with foods on later food preferences.Several tests were conducted and results noted. Overall the results of this thesis show that it is possible to gather reliable hedonic data from young, even pre-school children, and that it is possible that very early feeding experience has some influence on adults' food preferences.Doctor of Philosophy (PhD)
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Rose, Grenville. "Sensory aspects of food preferences /." [Richmond, N.S.W.] : School of Food Sciences, University of Western Sydney, Hawkesbury, 1999. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030430.141239/index.html.
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Temple, Elizabeth C., of Western Sydney Hawkesbury University, and Faculty of Science and Technology. "Aspects of the development of the sense of taste in humans." THESIS_FST_xxx_Temple_E.xml, 1999. http://handle.uws.edu.au:8081/1959.7/61.
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Very little research has been conducted on the development of taste perception in humans. Therefore there is a lack of knowledge, first, about how children perceive taste, especially when compared to what is known about how adults experience taste, and second, about the functioning and development of the gustatory system, including when the system is fully mature and functioning in an adult-like manner. The aims of this thesis were (i) to investigate the growth pattern of the tongue throughout childhood / adolescence, and (ii) to determine the state of maturity of some of the aspects of the sense of taste in mid-childhood. Overall, the data in this thesis indicate that children respond similarly to adults with regard to single-point measures of sensitivity and perceived intensity, but there are some differences in the overall temporal experience of taste, from onset of perception through to extinction, and the way in which it is perceived by adults and 8-9 year old children. The latterMaster of Science (Hons)
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Riddle, Ryan T. "Maximizing sulforaphane delivery and sensory acceptability of a novel soy-tomato-broccoli sprout beverage." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1323373292.
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Di, Donfrancesco Brizio. "Sensory analysis and acceptability of pet food." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34524.
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Doctor of PhilosophyDepartment of Food, Nutrition, Dietetics, and Health
Kadri Koppel
The pet food industry represents a competitive and growing part of the food industry that is constantly looking for innovation to differentiate products in the market. In recent years, the pet food market has undergone a humanization trend that has transformed pet owners into parents. In the light of this trend, pet owner acceptance has become even more crucial to product developers as the owners are the ones who make purchasing decisions. Performing descriptive sensory analysis on pet foods utilizing a human panel can assist in understanding the sensory characteristic of products. Knowing the sensory profile of pet food can then be useful in product development, in order to relate the descriptive data with palatability data from pets and to understand specific sensory attributes that drive pet liking. At the same time descriptive analysis can help understand what drives consumer acceptance of the products. The first objective of the research was to develop a sensory lexicon that could assist researchers and sensory professionals working in the pet food industry to describe appearance, aroma, flavor, and texture characteristics of dry dog food. More than seventy sensory terms were identified, defined, and referenced. The second objective was to utilize this sensory lexicon to understand relationships between sensory properties of products and pet owners’ liking. Results indicated that appearance played a major role in driving consumer liking of dry pet food. The next objective of the research was to understand sensory qualities and acceptance of extruded dry dog food manufactured with different fractions of red sorghum through some of the developed concepts. Sorghum is an important crop to Kansas that represents the first producer in USA. Sorghum characteristics such as a low glycemic index and antioxidant properties make it a perfect fit for pet food industry. A process such as extrusion may then help improve some negative characteristics such a lower digestibility that has been associated with sorghum in the past. Descriptive sensory analysis was performed and results indicated that aroma and flavor profile of the sorghum diets were not dissimilar to the ones of a control diet manufactured with rice, wheat, and corn, grains that are typically used by the pet food industry. Acceptance of pet owners was then assessed through a Central Location Test involving 105 consumers. The whole sorghum diet resulted to be the most liked sample by consumers, at the same level of the control diet. The next objective was then to understand how the experimental diets would be accepted by pets compared in a home situation. Thirty dogs were fed the diets in their own household environment over 20 consecutive days. No differences in acceptance for the diets were found. The last portion of the research was to determine volatile compounds present in the four diets and try to identify possible relationship with the sensory properties of the samples. Thirty-six compounds were identified with aldehydes being the most abundant volatiles group. Several relationships with sensory characteristics of samples were found.
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Kupongsak, Sasikan. "Food process control based on sensory evaluations /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3115564.
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McCrickerd, Keri. "Optimising beverages for satiety : the role of sensory characteristics, expectations and nutrient content." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/51674/.
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Regularly consuming caloric beverages has been linked to obesity and weight gain and evidence suggests this is because beverages have a weak impact on satiety responses (behavioural and physiological). Using a series of experimental studies this thesis explored the cognitive and sensory features of caloric beverages that might enhance the anticipated and actual satiating power of their nutrients. Paper one characterised the sensory characteristics associated with expectations of hunger, fullness and thirst, finding that food and beverage products anticipated to be creamier and thicker were expected to be more satiating and less thirst-quenching. Paper two established that people can perceive subtle changes in beverage viscosity and manipulating thick and creamy textural cues strongly influenced the expectation that a beverage would be filling and supress hunger after consumption. This was extended in paper three, which reported evidence suggesting that a sensorially enhanced beverage is selected and consumed in smaller portions. Papers four and five investigated the satiating power of a caloric beverage consumed with satiety-relevant cognitive and sensory information. Paper four reported tentative evidence that a labelled satiety message influenced the satiating effect of caloric beverages when combined with thick and creamy sensory cues. Participants in Paper five reported greater satiety responses to a covert manipulation of beverage energy when consumed as a ‘snack' rather than a drink. However, consuming the same beverage in a subtly thicker sensory context (without extra information) generated the largest satiety response to the different nutrient loads, perhaps because textural characteristics are the most reliable cue for nutrients. Overall these studies suggest that caloric beverages may generate weak satiety responses because their nutrient-generated effects are not expected. Encouraging people to consider caloric beverages as a snack, or adding in nutrient-relevant sensory characteristics, may both help consumers regulate energy intake when consuming these products.
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Agarwala, Edward K. "Food For Thought: When Information Optimization Fails to Optimize Utility." Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1244147146.
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Thesis (M.S.)--Case Western Reserve University, 2009Title from PDF (viewed on 19 August 2009) Department of Mathematics Includes abstract Includes bibliographical references Available online via the OhioLINK ETD Center
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Robins-Hobden, Sarah Louise. "Sensory-specific satiety and repeated exposure to novel snack foods : short- and long-term changes in food pleasantness." Thesis, University of Sussex, 2012. http://sro.sussex.ac.uk/id/eprint/42959/.
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Sensory-specific satiety (SSS) is a significantly greater pleasantness decline for a consumed (Eaten) food, than foods that are tasted but not consumed (Uneaten). SSS occurs during consumption, reaches optimal magnitude immediately afterwards, and returns to baseline within two to three hours. The phenomenon is dependent on the sensory properties, rather than the energy or macronutrient content of the food. To the extent that an Uneaten food shares similar sensory properties with the Eaten food, the Uneaten food may be subject to pleasantness decline: a transfer effect. Repeated exposure to a food stimulus may alter liking in the long-term, through mere exposure, monotony, and dietary learning paradigms resulting in an association between the novel target food and either a known food stimulus, or a consequence of consumption. Novel foods are more susceptible to these effects than familiar foods, for which learned associations may have already formed. Repeated consumption alone does not modulate SSS, but to date such studies have not tested novel foods. Through six experiments this research explores the influences of long-term pleasantness changes of novel foods and the number and type of Uneaten foods present during SSS testing, on the magnitude of SSS for snack foods. While no evidence of mere exposure or dietary learning was found, and in some instances experiments failed to induce SSS, these negative results are likely due to methodological, and sometimes procedural issues in the design and conduct of experimental testing. Findings revealed SSS to be vulnerable to a number of procedural and methodological factors, such as: portion size; baseline novelty and pleasantness ratings; hunger; perceived ambiguity of measurement scales; and expectations raised by the type and number of Uneaten foods present during testing.
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Smeets, Astrid Jose Pierre Gertrude. "Triggers for food intake regulation sensory and metabolic effects of specific food components /." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Universiteit Maastricht [host], 2008. http://arno.unimaas.nl/show.cgi?fid=11858.
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Irvine, Paul Andrew. "Food structural and sensory factors in the regulation of appetite and food intake - the role of food volume and food gas." Thesis, University of Ulster, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529568.
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Vinaixa, Crevillent Maria. "Improving ms-sensor technologies for food quality assessment." Doctoral thesis, Universitat Rovira i Virgili, 2008. http://hdl.handle.net/10803/8462.
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Food industry is demanding for fast screening methodologies in order to guaranty food quality and safety. These methodologies should allow high throughput with sufficient accuracy and reproducibility. In this context, MS-Sensor is a challenging approach since it allows simultaneous determination of compounds in food matrices and complex mixtures with a high sample throughput. The basic working principle of MS-Sensor systems is based on the introduction of volatile components extracted from the headspace of a sample into the ionization chamber of a mass spectrometer. The mass spectra resulting from the ionization and fragmentation of this extract constitute a very complex ionization pattern that can be seen as a 'fingerprint' which is characteristic of the matrix being analyzed. These ionisation patterns are then processed by pattern recognition engines to perform tasks such as classification, recognition and, to a limited extent, quantification.This thesis is devoted to study the possibilities and capabilities of MS-Sensor approach to its application in several food quality related problems such as the determination rancidity levels in crisps; the detection of fungal spoilage in bakery products, the monitoring of sardines freshness under cold storage; the classification of virgin olive oils according its organoleptic properties and the discrimination of two Iberian ham qualities according pig's feeding. In each one of these applications it has been demonstrated the feasibility of using a MS-Sensor to solve the food quality problem under study. It has been widely demonstrated that the MS-Sensor profile can be considered as a useful fingerprint technique for characterization of the targeted quality property and, as in certain cases, even for quantification of several parameters correlated with this problem.Despite that feasibility of MS-Sensor has been widely demonstrated for the applications under study, this approach stills suffer from some weakness or drawbacks that may influence performance of MS-Sensor. Main drawbacks are the inherent high dimensionality of data response matrices and the low selectivity of m/z fragments pseudosensors used as variables in these matrices.These two drawbacks could be responsible for the lack of reproducibility showed by MS-Sensor systems in certain applications mentioned above. In order to success in the development of such applications it was necessary to figure out different strategies for overcoming this high dimensionality and the low selectivity. In order to handle the low selectivity of m/z fragments several new methodologies based on the use of multi-way algorithms has been implemented for the first time in the framework of this thesis. Besides, new variable selection algorithms has been developed and implemented in order to avoid high dimensionality modelling. It has been demonstrated that use of the developed algorithms leads to a simpler and more parsimonious models and consequently to a better performance and more reproducible results.In addition, several issues related to use of MS-Sensor in food analysis has been studied: the use of different headspace sampling techniques; the comparison of MS-Sensor systems performance against classical MOS based 'electronic noses'; the application of new algorithms for pre-processing MS-Sensor signals; the correlation of MS-Sensor response and the well-established methods to assess the quality property under study, etc.MS-Sensor is a powerful device set-up, capable of producing large amounts of highly selective information. Optimal use of this device implies both, a correct use of analytical techniques (sample handling and instrumental) and a rational use of subsequent data analysis. That can be only attained if analytical people in charge of experimental set-up work side by side with data analysis and software developers. This thesis aims to bring nearer this close collaboration.La indústria alimentària exigeix el desenvolupament de mètodes analítics que puguin donar resposta immediata i que al mateix temps puguin garantir la qualitat i la seguretat dels productes de forma acurada i reproduïble. En aquests context, els mètodes que utilitzen un sistema MS-Sensor poden ser uns bons candidats ja que permeten fer l'anàlisi de volàtils de matrius complexes d'una manera ràpida i també permeten processar moltes mostres en poc temps. El funcionament d'un MS-Sensor es basa en la introducció dels compostos volàtils que s'extreuen de l'espai de cap d'una mostra en la font d'ionització d'un espectròmetre de masses sense prèvia separació cromatogràfica i sense necessitat d'una preparació de mostra prèvia. L'espectre de masses resultat de la ionització i fragmentació de tots els compostos volàtils presents en l'extracte es pot considerar com una empremta digital característica de la matriu que s'està analitzant. Els espectres de masses generats es processen a posteriori amb un sistema de reconeixement de patrons per tal de realitzar tasques associades a aquests sistemes com son la classificació i el reconeixement de noves mostres i dins de certs límits la quantificació d'aquestes.Aquesta tesi està dedicada a l'estudi de les capacitats i possibilitats d'aquests sistema a donar resposta a tot un seguit d'aplicacions relacionades amb l'anàlisi de la qualitat de diferents tipus d'aliments com son: la determinació del grau d'enranciment de patates fregides; la detecció del creixement fúngic en productes de brioxería industrial; la monitorització del grau de frescor de sardines guardades en fred; la classificació de diversos olis d'oliva en base a les seves propietats organolèptiques i la classificació del pernil ibèric en base a la seva qualitat determinada per l'alimentació del porc. Per cada una d'aquests aplicacions s'ha demostrat l'aplicabilitat i la fiabilitat del sistema MS-Sensor a l'hora de resoldre les diferents qüestions plantejades sobre qualitat alimentària. S'ha demostrat àmpliament que el perfil de volàtils que s'obté amb un MS-Sensor pot cosiderar-se com una empremta digital vàlida i molt útil en la caracterització del problema que es vol resoldre i fins i tot en alguns casos, s'ha demostrat que aquesta mateixa empremta es pot correlacionar amb el paràmetres d'anàlisi clàssics que s'usen més habitualment per tal de resoldre aquests problema o que inclús aquests sistema es pot fer servir per predir-los.Encara que la viabilitat del sistema MS-Sensor en les aplicacions plantejades ha estat demostrada àmpliament en el decurs d'aquesta tesis, aquests sistema té petits inconvenients o punts febles que resten per resoldre. Aquests inconvenients poden afectar de manera directa els resultants que se n'obtenen. Els principals punts febles del MS-Sensor son d'elevada dimensionalitat de les matrius de resposta que s'obtenen que és inherent al propi sistema i la baixa selectivitat del fragments m/z considerats com a variables en aquestes matrius.Aquests dos inconvenients poden ser els responsables de la falta de reproductibilitat que s'ha obtingut en algunes aplicacions. Per tal d'obtenir bons resultats en alguna d'aquestes aplicacions es van haver de plantejar noves estratègies que poguessin salvar les dificultat derivades de la baixa selectivitat de les variables i de la seva elevada dimensionalitat. Per primera vegada i dins del marc d'aquesta tesis s'ha plantejat l'ús d'algoritmes multi-way i la inclusió del temps de retenció com a variable que pugui reportar informació addicional en el processat de les respostes del MS-Sensor. A la vegada, s'ha desenvolupat i implementat nous algoritmes per a la selecció de variables per tal d'evitar en la mesura del possible l'elevada dimensionalitat en les matrius de resposta. S'ha demostrat que l'ús d'aquests nous algoritmes permet obtenir models més simples i robustos i per tant podem aconseguir un millor funcionament del sistema i resultats més reproduïbles.A més a més s'han estudiat diferents aspectes relacionats amb la utilització d'un sistema MS-Sensor per a l'anàlisi d'aliments com son: l'ús de diferents tècniques de mostreig d'espai de cap, la comparació del sistema MS-Sensor amb sistemes clàssics d'olfacte electrònic, l'aplicació i desenvolupament d'algoritmes de pre-processament dels espectres generats, la correlació de les respostes obtingudes amb un sistema MS-Sensor amb mètodes d'anàlisi d'aliments tradicionals, etc.El MS-Sensor es un dispositiu molt potent, capaç de produir una elevada quantitat de dades. L'ús òptim d'aquests sistema es composa d'una banda d'un ús correcte dels aspectes instrumentals com son el propi sistema en si i les tècniques de mostreig i per altra banda d'un ús racional de les tècniques d'anàlisi de dades. Això només s'aconsegueix si els analítics que treballen amb el set-up de l'experiment treballen colze a colze i en estreta col·laboració amb la gent encarregada de fer l'anàlisi de dades. Aquesta tesi, pretén fer més estret l'espai entre aquests dues disciplines i dóna les eines per ajuntat i promoure aquesta col·laboració.
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Parillon, Nicola Ann. "Sensory cues and food choice in the Yakushima Macaque." Thesis, Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20906717.
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Moody, A. P. "A peroxide sensor for the food and beverages industry." Thesis, Cranfield University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269479.
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Hollis, James H. "A study of food intake and nutrition in the elderly." Thesis, University of Central Lancashire, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275923.
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Dibsdall, Louise Anne. "Physiological and sensory influences on food intake in learnt satiety." Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364518.
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This Thesis examined the contributions of gastrointestinal and/or sensory influences to the control of food intake in everyday life. The postingestional effects at first exposure to an unfamiliar variant of a familiar food were measured by correcting the observed satiating effects with what the eater expected them to be. Physical forms of fat or chemical compositions of carbohydrate in familiar foods differed in the timing of these postingestional satiating effects. Cream, which is hypothesised to empty rapidly from the stomach into the intestine, satiated rapidly but transiently. Conversely, oil that was liable to separation in the stomach produced a delayed and more prolonged satiating effect. Learning about the postprandial effects of foods containing unfamiliar levels of a form of nutrient occurred at first exposure to the after-effects of that variant: that is, sensory recognition of that variant at the second exposure resulted in participants' predictions of its satiating effect becoming more realistic. A more prolonged satiating effect was expected from yoghurts containing a higher amount of fat. At the same time, repeated exposure to a particular flavour of yoghurt induced more accurate predictions of the postprandial effects of the amount of fat associated with that flavour. Expected duration of hunger suppression by familiar and identifiable foods was related to some extent to the observed differences in the duration of postingestional satiating effects of a particular nutrient preparation. Pasta with an oily salad dressing was believed to satiate the eater for longer than a pasta with a creamy salad dressing. Breakfast cereal labelled as high in fibre was expected to produce a more prolonged satiating effect than protein and so on in order for starch, fat or sugar. These differences in expected postingestional satiating after-effects of a food or meal may contribute to the planning of meal contents and perhaps timing. Unexpected timing of a meal or a `surprise' in the postingestional effects of a food altered the composition of the next meal of another sort from the participant's usual choice towards one giving the appropriate after-effects.
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Brooks, Joy Lynne. "Sensor systems for the rapid detection of microorganisms in food." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306341.
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Koussissi, Elisabeth. "Sensory character on relation to composition of Greek red wines." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288629.
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Mota, Rui Manuel Nunes. "Designing for the senses through food design and psychophysiology." Master's thesis, ISA/UL, 2018. http://hdl.handle.net/10400.5/17971.
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Wang, Chia-Lin. "Probiotic lactobacilli as a soy yogurt starter culture - microbiological, chemical and sensory analyses /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422974.
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Obinna-Echem, Patience Chisa. "Development of a Nigerian fermented maize food 'Akamu' as a functional food." Thesis, University of Plymouth, 2014. http://hdl.handle.net/10026.1/2983.
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Akamu is a lactic acid bacteria fermented cereal-based food that complements infant diets in most African countries. Uncontrolled fermentation increases the variability in quality and safety of akamu. This study was aimed at the controlled fermentation of akamu with selected lactic acid bacteria (LAB), investigation of the probiotic potential of the LAB and the effect of variation in production method on the product quality and sensory properties. PCR-DGGE analysis of traditional akamu samples revealed LAB community dominated by Lactobacillus fermentum, L. plantarum, L. delbrueckii subsp. bulgaricus and L. helveticus. Isolated yeasts were Candida tropicalis, C. albicans, Clavispora lusitaniae and Saccharomyces paradoxus. The isolated Lactobacillus plantarum strains (NGL5 and NGL7) fermented irradiated ground maize slurries and produced significant levels of lactic acid (>73 mmol L-1) and low pH ≤3.63 displaying inhibitory activity against Salmonella enterica serovar Enteritidis NCTC 5188, Escherichia coli 1077 (NCTC 11560), Bacillus cereus NCIMB 11925, Staphylococcus aureus NCTC 3750 and Listeria monocytogenes NCTC 7973 in MRS agar and E. coli 1077 in maize slurry fermentation. Viability of both strains of L. plantarum at pH 2 after 3 h was reduced from ≥8.26±0.05 to ≤4.94±0.49 Log10 CFU mL-1 while incubation in 0.3% bile allowed growth to 5.73±0.13 and 7.93±0.12 Log10 CFU mL-1 after 6 h for NGL5 and NGL7 respectively. Auto-aggregation of the L. plantarum strains at 37oC (≥25 after 5 h) correlated with adhesion to hydrocarbons (<15, 26, 33 and 64% for Hexane, Hexadecane, Ethyl acetate and Chloroform respectively). The strains failed to exhibit gelatinase or haemolytic activity but adhered to porcine mucin (OD403 nm ≥0.63 with viability ≥6.52 Log10 CFU mL-1) and Caco-2 cells (≥5.13 Log10 CFU mL-1). The ash, mineral (Ca, K, Mg, Na, S and Zn), IDF, SDFP and TDF content of the L. plantarum fermented ground maize slurries were significantly (p≤0.05) higher than that of the traditional akamu but the peak and final viscosities (139.5 and 68.5 cP respectively) were significantly (p≤0.05) the least. The aroma, appearance, colour, flavour and texture of the resultant porridges were liked moderately by 75% of the assessors. This study demonstrated that fermentation with the L. plantarum strains would contribute towards product safety and the L. plantarum strains possessed some probiotic potential that could be beneficial to the consumers particularly in those developing countries were the main staple foods are fermented cereals.
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Borràs, Iglesias Eva. "Instrumental and chemometric methodologies to assess sensory quality of Mediterranean food." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/386446.
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L'oli d'oliva, el vi o els fruits secs són productes típics de la regió Mediterrània que ofereixen un valor afegit gràcies als seus beneficis per a la salut i excel·lents característiques sensorials. Per aquest motiu és necessari un control de la qualitat i autenticitat d'aquests productes, que són altament susceptibles a fraus i adulteracions. Un aspecte important és l'avaluació de la qualitat sensorial, que descriu paràmetres percebuts pels sentits (gust, visió, olor i tacte) mitjançant panells validats i entrenats d'experts. Aquests panells tendeixen a ser subjectius i requereixen llargs temps d'anàlisi i alts costos. Com a conseqüència hi ha hagut un increment en el desenvolupament de tècniques d'anàlisi capaces de simular les respostes obtingudes amb el panell de tast humà. L'anomenat 'panell electrònic' ofereix respostes objectives mitjançant l'ús de tècniques multivariants que permeten establir correlacions entre els descriptors definits pels humans i els senyals obtingudes instrumentalment.
Aquesta tesi pretén oferir tècniques instrumentals alternatives, ràpides i senzilles per determinar la qualitat sensorial d'aliments com l'oli d'oliva, el vi o les ametlles.
Els estudis duts a terme inclouen el tractament de les respostes sensorials obtingudes mitjançant metodologies de referència (principalment panells de tast humans), l'optimització dels procediments analítics per treballar amb tècniques instrumentals i el desenvolupament d'eines quimiomètriques adequades per construir els models multivariants. També s'han desenvolupat estratègies de fusió de dades per combinar les diferents dades instrumentals que simulen els sentits humans (olor, gust i visió).El aceite de oliva, el vino o los frutos secos son productos típicos de la región Mediterránea que ofrecen un valor añadido gracias a sus beneficios para la salud y excelentes características sensoriales. Por este motivo es necesario un control de la calidad y autenticidad de estos productos, que son altamente susceptibles a fraudes y adulteraciones. Un aspecto importante es la evaluación de la calidad sensorial, que describe parámetros percibidos por los sentidos (gusto, visión, olor y tacto) mediante paneles validados y entrenados de expertos. Estos paneles tienden a ser subjetivos, requieren largos tiempos de análisis y altos costes. Como consecuencia ha habido un incremento en el desarrollo de técnicas de análisis capaces de simular las respuestas obtenidas con el panel de cata humano. El llamado 'panel electrónico' ofrece respuestas objetivas mediante el uso de técnicas multivariantes que permiten establecer correlaciones entre los descriptores definidos por los humanos y las señales obtenidas instrumentalmente. Esta tesis pretende ofrecer técnicas instrumentales alternativas, rápidas y sencillas para determinar la calidad sensorial de alimentos como el aceite de oliva, el vino o las almendras. Los estudios llevados a cabo incluyen el tratamiento de las respuestas sensoriales obtenidas mediante metodologías de referencia (principalmente paneles de cata humanos), la optimización de los procedimientos analíticos para trabajar con técnicas instrumentales y el desarrollo de herramientas quimiométricas adecuadas para construir los modelos multivariantes. También se han desarrollado estrategias de fusión de datos para combinar los diferentes datos instrumentales que simulan los sentidos humanos (olor, gusto y visión).
Olive oil, wine or nuts are typical products of the Mediterranean region that offer added value thanks to its health benefits and excellent sensory characteristics. Therefore, the control the quality and authenticity of these products is necessary, mainly because they are highly susceptible to fraud and adulterations. An important aspect is the evaluation of sensory quality that describe parameters perceived by the senses (taste, sight, smell and touch) using validated and trained panels of experts. These panels tend to be subjective, requiring long-time analysis and high costs. As a result there has been an increase in the development of analytical techniques capable to simulate the responses obtained with the human taste panel. The so-called 'electronic panel' provides objective responses using multivariate techniques, which establish correlations between descriptors defined by humans and signals obtained instrumentally. This thesis aims to offer fast and simple alternative instrumental techniques to determine the sensory quality of foods such as olive oil, wine and almonds. Studies carried out include the treatment of sensory responses obtained by reference methodologies (mainly human taste panels), optimization of analytical procedures to work with instrumental techniques and the development of appropriate chemometric tools to build multivariate models. Data fusion strategies have also been studied by combining different instrumental data that simulate the human senses (smell, taste and sight).
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Han, Liqing. "Physical and sensory properties of oat cakes /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418026.
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Elam, Jhaelynn. "Comparison of liking scores and panelist engagement when evaluating beverages in traditional booths and virtual or actual dining facility scenarios." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512038890525137.
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Jung, Hoon. "Effects of Micrococci on Improving Sensory Acceptability of Mutton Summer Sausage." DigitalCommons@USU, 1986. https://digitalcommons.usu.edu/etd/5331.
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The effects of micrococci on sensory characteristics of different batches of summer sausages were determined. Sixty four salt-tolerant indigenous isolates were selected from beef or mutton treated with 1.5 or 3.0% sodium chloride and 120 ppm sodium nitrite, and held at 5 or 10 C for 5 days. These isolates (61/64) were identified as staphylococci and micrococci. Summer sausages were made from several lamb, ewe, and ram carcasses which were hand deboned and blended after grinding to contain 22% fat. Six summer sausage treatments were prepared using two different sources of commercial starter cultures including Micrococcus species or Micrococcus varians and Lactobacillus plantarum, an indigenous Micrococcus isolate, a microbial lipase, or encapsulated lactic acid.
Three sensory panel sessions rated these products for consumer acceptability. Sensory panel results indicated that starter culture treatments did not improve sensory characteristics of the summer sausage over the treatment containing encapsulated lactic acid. Lipase addition caused a general reduction in sensory panel ratings for flavor, texture, appearance, and overall acceptability of the summer sausage (p = 0.05).
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Kurt, Esra. "Associations between lipid composition, shelf life and sensory quality in ruminant meats." Thesis, University of Bristol, 1999. http://hdl.handle.net/1983/a77d9a0c-f888-4650-b6b8-7c1b8f5cee45.
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Rosengren, Maja. "Sensorisk optimering av en musselsoppa för äldre konsumenter i Europa : ett delarbete i utvecklingen av hållbara rätter från havet." Thesis, Högskolan Kristianstad, Fakulteten för naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-21222.
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Färdiglagade måltider för specifika målgrupper ställer höga krav på både utseende av maten och förpackningsalternativ så råvaror tillagas så bästa och mest näringsrika vis. Detta arbete studerar skillnaden i smak och textur mellan två olika konserveringsmetoder av en färdiglagad musselsoppa genom att förpacka i en mikrovågsförpackning och en ångförpackning. Enkäter för att undersöka skillnad i utseende på soppan gällande musslor med och utan skal genomförs även och där också en jämförelse av kulturell påverkan i våra matval, hur noga man är med hygien när det kommer till mat och deltagarnas generella matintresse för att göra en jämförelse av svenska och franska deltagare. Syftet är att genomföra en sensorisk optimering av en musselsoppa som utvecklats för äldre konsumenter.There are high demands on readymade meals when it comes to both the look of the food and the way the meal is packaged to ensure the produce is cooked in the best and most nutritious way. This rapport is about seeing if there is a difference in taste and texture between two different conservation methods for a premade mussel soup. A survey to see if the soup is more appealing if served with the mussels in their shell or deshelled was made and also an comparison of a cultural input on the food choices, how important the hygiene is when it comes to food and the participants overall food interest to get an overall comparison of Swedish and French participants the aim is to complete a sensory optimization of a mussel soup which was developed for old aldults.
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Hartman, John Sommer H. J. "Evaluation of a foot-mounted slip sensor." [University Park, Pa.] : Pennsylvania State University, 2009. http://honors.libraries.psu.edu/theses/approved/WorldWideIndex/EHT-16/index.html.
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Liu, Yu-Hui. "Multivariate methods for relating different sets of variables with applications in food research." Thesis, University of Bristol, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303768.
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CAMARGO, RITA J. de. "Estudo do tratamento combinado de radiacao ionizante e cobertura de quitosana em mamao papaia (Carica papaya L.)." reponame:Repositório Institucional do IPEN, 2004. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11250.
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Made available in DSpace on 2014-10-09T12:49:56Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:03:08Z (GMT). No. of bitstreams: 1 10190.pdf: 8026659 bytes, checksum: a56ea24c48876e3cb2903f4a35974cf3 (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Monroe, Ellen. "School-Based Speech-Language Pathologist's Perceptions of Sensory Food Aversions in Children." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etd/3735.
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Sensory Food Aversions occur frequently in children who are likely to appear on Speech-Language Pathologist’s (SLP’s) caseloads. The lack of research regarding intervention for Sensory Food Aversions in schools and the assertion of a gap in school-based services for children with feeding disorders was a significant indicator for the need of the study. A quantitative, descriptive, exploratory research design was selected using a self-developed questionnaire in order to exploreschool-based SLP’s perceptions of their knowledge and skills related to Sensory Food Aversions, as well as determine resources available for working with this population. Findings from the study suggest a need for educational training, emphasize the advocacy role of an SLP, and shed light on the challenges/barriers SLPs face in regard to treating Sensory Food Aversions in schools. This study may be useful for SLPs in order to meet the needs of children with Sensory Food Aversions.
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Deans, Gillian A. "Design and analysis of sensory evaluation experiments." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240734.
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