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Manufacturing industries are facing major challenges in terms of improving product quality and increasing throughput while sustaining production costs to acceptable levels. Product-oriented processes, both legacy and new, are poorly monitored and controlled on the basis of distributed loop controllers that are aiming to maintain critical process variables within acceptable bounds. Thus, poor quality product results when such processes are subjected to large disturbances - operational failures, environmental changes, and changes in loading conditions. In this research, product quality modeling and control based on a vision inspection methodology is proposed to improve product quality and increase productivity. The main contributions of this research are twofold. First, this research introduces a product quality modeling methodology that combines both physical-based modeling and data-driven modeling. The quality model is the link between information coming from the inspection of product features and the specification of process control strategies. It is essential to control and optimize the process. Physical-based modeling is used to model the product temperature profile, and data-driven modeling is used to train the mapping from the product temperature profile to each quality metric. The break down of the sub models increase the flexibility of model development and reduce the effort to change the model when the quality metrics change. The second contribution is the development of a novel approach to control product quality based on vision inspection, which is developed as part of a hybrid, hierarchical architecture. The high-level control module involves scheduling of multiple plant processes, diagnostics of the failure condition in the process, and the supervision of the whole process. The mid-level control module, which is the focus of the work presented here, takes advantage of baking product quality indicators and oven parameter measurements to optimize zone temperature and conveyor speed set points so that the best product quality is achieved even in the presence of disturbances. The low-level control module consists of basic control loops. Each of them controls parameters of each operation in the process separately. They are generally simple and easy to implement.

La conception de procédé agroalimentaire est une activité complexe, caractérisée par la grande diversité des produits et des procédés étudiés, ainsi que par la disparité des contextes de production (artisanale ou industrielle). La conception de systèmes de transformation alimentaire adaptés est animée par d'importants enjeux humains, sanitaires, économiques, environnementaux et même culturels. Dans le cas des Pays du Sud, l'explosion démographique et l'urbanisation croissante impliquent de développer un système de production industriel capable de valoriser des produits issus de savoir-faire traditionnels, tout en répondant à des contraintes de coût et de productivité.Pour prévenir toute perte de temps causée par des analyses de type « essai-erreur », et afin d'éviter des coûts de développement superflus, il existe des outils spécifiques à l'analyse décisionnelle multicritères (MCDA) pouvant être déployé dès les phases préliminaires de la conception. En particulier, il est possible d'analyser le potentiel et les limites technologiques d'un concept défini dans un contexte donné, par l'analyse de l'ensemble de solutions les plus performantes, dites Pareto-optimales. Ces solutions se distinguent par les valeurs de leurs variables de conception, qui sont autant de degrés de liberté pour le dimensionnement du concept (géométrie, matériaux, conditions opératoires).Notre cas d'étude concerne l'évaluation d'un concept de fumage à chaud à plaques radiantes, pour la production de poisson fumé, traditionnellement consommé en Afrique Centrale et de l'Ouest. En effet, avant de prétendre à la diffusion de cette technologie déjà brevetée, il faut s'assurer que le procédé puisse satisfaire des objectifs de production et de performances énergétiques, tout en maintenant une qualité du produit satisfaisante. Ainsi, un outil d'optimisation multiobjectif spécifique a été développé en se basant sur la modélisation du comportement du procédé. Une première étude expérimentale a permis de construire un modèle de séchage du poisson dans des conditions d'air variables (température, vitesse et humidité), qui représente à la fois les flux d'évaporation et les flux liés aux écoulements gravitaires de graisses et d'eau. Dans un second temps, un outil de simulation existant a été amélioré afin de représenter des phénomènes ayant un impact significatif sur les performances du procédé, tels que l'aéraulique des fumées, le recyclage de l'air et la régulation thermique. Ainsi, un modèle d'observation a été établi. Il permet de prédire le comportement de différentes solutions possibles, définies par huit variables de conception, et d'évaluer leurs performances sur la base de six variables d'observation.Dans un dernier volet, la formalisation des préférences et de la connaissance experte du procédé permet d'interpréter les performances en termes de désirabilités (satisfaction), qui sont agrégées en un indice de satisfaction global (fonction objectif) par un principe de précaution. Un algorithme génétique permet alors de trouver une solution optimale qui maximise cette fonction objectif, en explorant l'espace des solutions possibles de manière combinatoire. Cette démarche de conception a été fructueuse car elle a permis de proposer un dimensionnement permettant d'obtenir des performances très satisfaisantes. Il a aussi été possible de proposer des améliorations ciblées pour redéfinir le concept actuel du fumoir à plaques. Par ailleurs, il est à noter que le modèle de comportement peut facilement être réadapté pour d'autre type de produits. Dans la perspective d'étendre l'utilisation de cette démarche à d'autres cas d'étude, un effort devra être mené pour la collecte de données fonctionnelles issues de l'expertise. / Food process design is a complex activity, given the wide diversity of existing product and processes, and the plurality of production contexts. Designer must meet the requirements derived from the critical stakes from human, sanitarian, economic, environmental and cultural point of views. In southern countries, the rapid growth of population drives the need of more industrial processes able to valorize traditional products.The savings of development time and extra-expenses are mainly determined by the quality of design choices from the early stage of the designing process, called embodiment design. Multiple criteria decision analysis (MCDA) techniques are used in this purpose, which enable to evaluate and criticize any technological concept. In a specific context, it is possible to generate the Pareto-set of a concept, which is composed of the most efficient possible alternatives. Indeed, every design alternative is defined by some design (or decision) variables which are the degree of freedom for the dimensioning of the system considered. Our case study focuses on a technological innovation to perform hot-smoking using radiant plates (for sanitarian purpose). It is aimed to be developed for the production of traditional hot-smoked catfish widely consumed in West and Central Africa. This is a multicriteria design problem since many objectives have to be satisfied, and concern the product quality, production and energetic performances.In a first work, the mass reduction of catfish dried in hot air conditions was modeled from empirical measurements. In particular, this model takes into account the influence of the drying air conditions (Temperature, Velocity and Relative Humidity) on the calculation of the mass fluxes of evaporation and drips. After that, a global simulation model of the radiant plate hot-smoking process was developed from a previous work. Some key phenomena were described (pressure losses, air recycling, thermal regulation) as they could strongly impact the process performances. The resulting observation model allows predicting the performances of any design alternative defined by a set of 8 design variables.In a final work, expert knowledge and preference were mathematically introduced in a multiobjective optimization tool, meaning some desirability functions. Therefore, every performance variable is converted into desirability indices (traducing the level of satisfaction) and then aggregated into a single global desirability index (thus defining a global objective function). The optimal design of the concept is found using a genetic algorithm.This multiobjective optimization method enabled to find very satisfactory design solution for the radiant plate hot smoking process. More to the point, the analysis of a wide range of Pareto-optimal solutions enabled to better understand what were the strengths and weaknesses, so it was possible to suggest some targeted improvement to the current radiant plate smoking technology. Also, it is noticeable that the current simulation model can be easily adapted to other products. For the purpose of a generalization of the use of such multiobjective methods for the design of food processes, it has been pointed out that efforts should be made to gather expert criteria other relevant functional data.

Ao avaliar parâmetros de qualidade de carne de peito de frango com a intenção de verificar se são afetados pelo estresse térmico severo pré-abate (35°C, 75% umidade relativa, por 2 horas), observou-se que o gasto intenso de energia do animal, no momento do estresse, resultou em pequena extensão da glicólise, gerando como respostas na carne, principalmente, características de escurecimento e alto valor de pH. O uso da marinação com o objetivo de restaurar carnes com propriedades funcionais prejudicadas pelo estresse resultou na padronização da aparência e em pH igualado entre os tratamentos (carnes de animais "estressados" e "não estressados"). No capítulo referente à classificação de carnes pelo uso da cor, foi possível observar a existência de alta correlação entre a luminosidade e outros atributos de qualidade e que o valor L* pode ser usado como uma ferramenta de classificação (com nota de corte L*=53, mensurada 24 horas post mortem). Com relação ao processo de marinação, observou-se que a técnica restaura parcialmente a qualidade da carne pálida, promovendo uma melhora visual da cor, contudo, sem corrigir a funcionalidade das proteínas em reter água ao nível de carnes normais. / In evaluating the quality of chicken breast meat regarding the effects of pre-slaughter severe heat stress (35°C, 75% relative humidity, for 2 hours), it was observed that the intense energy expenditure of the animal at the moment of stress resulted in a slight extension of glicolysis, generating as a consequence, mainly, characteristics of darkening and high levels of pH, on the meat. The use of marination in an attempt to restore meat with damaged functional properties due to stress resulted in the standardization of appearance and in leveling of pH between the treatments (stressed and non-stressed animal meat). In the last chapter, it was possible to observe the existence of strong correlation between the color and the other quality attributes and that the lightness can be used as a classification tool (minimum level L*=53, measured 24 hours postmortem). As for the marination process, it was observed that the technique partly restores the quality of pale meat, promoting a visual improvement of the color, however, it does not correct the proteins functionality to retain water at the same level of normal meat.

Ao avaliar parâmetros de qualidade de carne de peito de frango com a intenção de verificar se são afetados pelo estresse térmico severo pré-abate (35°C, 75% umidade relativa, por 2 horas), observou-se que o gasto intenso de energia do animal, no momento do estresse, resultou em pequena extensão da glicólise, gerando como respostas na carne, principalmente, características de escurecimento e alto valor de pH. O uso da marinação com o objetivo de restaurar carnes com propriedades funcionais prejudicadas pelo estresse resultou na padronização da aparência e em pH igualado entre os tratamentos (carnes de animais "estressados" e "não estressados"). No capítulo referente à classificação de carnes pelo uso da cor, foi possível observar a existência de alta correlação entre a luminosidade e outros atributos de qualidade e que o valor L* pode ser usado como uma ferramenta de classificação (com nota de corte L*=53, mensurada 24 horas post mortem). Com relação ao processo de marinação, observou-se que a técnica restaura parcialmente a qualidade da carne pálida, promovendo uma melhora visual da cor, contudo, sem corrigir a funcionalidade das proteínas em reter água ao nível de carnes normais. / In evaluating the quality of chicken breast meat regarding the effects of pre-slaughter severe heat stress (35°C, 75% relative humidity, for 2 hours), it was observed that the intense energy expenditure of the animal at the moment of stress resulted in a slight extension of glicolysis, generating as a consequence, mainly, characteristics of darkening and high levels of pH, on the meat. The use of marination in an attempt to restore meat with damaged functional properties due to stress resulted in the standardization of appearance and in leveling of pH between the treatments (stressed and non-stressed animal meat). In the last chapter, it was possible to observe the existence of strong correlation between the color and the other quality attributes and that the lightness can be used as a classification tool (minimum level L*=53, measured 24 hours postmortem). As for the marination process, it was observed that the technique partly restores the quality of pale meat, promoting a visual improvement of the color, however, it does not correct the proteins functionality to retain water at the same level of normal meat.

Tesis por compendio / [ES] La industria alimentaria ha mostrado un enorme interés por desarrollar nuevos productos a base de fruta con el fin de satisfacer la demanda saludable y sostenible de productos alimentarios de los consumidores. En este sentido, un puré de naranja liofilizado podría representar una opción viable. La liofilización del puré da lugar a una torta que puede consumirse directamente como snack, o puede triturarse para obtener un polvo que puede utilizarse para una amplia gama de aplicaciones. Una optimización adecuada de las condiciones de liofilización podría ayudar a reducir su duración sin afectar a las características del producto final. Sin embargo, los alimentos deshidratados pueden presentar problemas de colapso estructural relacionados con su baja temperatura de transición vítrea. En este sentido, una técnica frecuente para la estabilización de estos productos deshidratados es la incorporación de biopolímeros de alto peso molecular. El objetivo de esta Tesis ha sido el diseño del proceso de liofilización para la obtención de un snack de naranja. Para ello se ha estudiado la influencia de diferentes combinaciones de biopolímeros en la estabilidad física del puré de naranja liofilizado (snack de naranja) y en la bioaccesibilidad in vitro de sus compuestos bioactivos. Asimismo, se ha evaluado su efecto en las propiedades de flujo en aire y de rehidratación del polvo de naranja. Se ha trabajado con diferentes combinaciones de goma Arábiga, maltodextrina, almidón sustituido por grupos octenil succínico, almidón nativo de maíz, fibras de guisante y de bambú. Los resultados mostraron la necesidad de incorporar estos biopolímeros para aumentar la actividad de agua crítica y el contenido de agua crítico para la transición vítrea, el cual se ha relacionado con la pérdida de la textura del snack. Si bien ninguna de las mezclas de biopolímeros fue mejor que las otras en higroscopicidad, carácter anti-plastificante, color y propiedades mecánicas del snack, la mezcla GA con FB fue la que mejoró la bioaccesibilidad de la vitamina C (VC) y de los compuestos fenólicos totales (TP). Además, esta misma combinación fue la que ofreció uno de los tiempos de mojado más cortos y una menor viscosidad del producto rehidratado, deseado para un producto tipo zumo. Por otra parte, se ha estudiado el impacto de las condiciones de liofilización en el consumo de energía del proceso y en la calidad del snack formulado con GA y FB. Las variables del proceso consideradas han sido la velocidad de congelación (convencional y abatidor), la temperatura de bandeja (30, 40, 50 ºC) y presión de trabajo (5, 100 Pa) durante el secado. Menor presión y mayor temperatura promovieron un ligero mayor secado de las muestras, obteniendo un producto más crujiente, con un color amarillo menos intenso, mejor preservación de VC y ß-caroteno (BC), y una reducción significativa, de hasta un 75%, en el consumo de energía total durante el secado, debido a la reducción del tiempo del proceso. La velocidad de congelación no tuvo impacto significativo sobre ninguna de las propiedades evaluadas. Por tanto, las condiciones recomendadas para el secado por liofilización son 5 Pa de presión y 50 ºC como temperatura de bandeja. Por último, se evaluó la estabilidad física y de los compuestos bioactivos y actividad antioxidante del snack almacenado en bolsas zip, a 4 y 20 ºC, durante 6 meses, simulando condiciones domésticas de almacenamiento. Como resultado, la muestra ganó cierta humedad, con la consecuente pérdida en porosidad y carácter crujiente a partir de los 2 meses. Asimismo, la luminosidad del snack almacenado a 20 ºC disminuyó pasados 2 meses, probablemente debido a las reacciones de pardeamiento, que incluyen la degradación de la VC (20%). BC sufrió una gran disminución, desde el inicio del almacenamiento y más cuanto mayor fue la temperatura. Por lo tanto, para este producto se recomienda un almacenamiento en refrigeración para una mejor preservación de los compuestos bioactivos. / [CA] La indústria alimentària ha mostrat un enorme interés per desenvolupar nous productes a base de fruita amb la finalitat de satisfer la demanda saludable i sostenible de productes alimentaris dels consumidors. En aquest sentit, un puré de taronja liofilitzat podria representar una opció viable. La liofilització del puré dona lloc a una coca que pot consumir-se directament com a snack, o pot triturar-se per a obtindre una pols que pot utilitzar-se per a una àmplia gamma d'aplicacions. Una optimització adequada de les condicions de liofilització podria ajudar a reduir la seua duració sense afectar les característiques del producte final. No obstant això, els aliments deshidratats poden presentar problemes de col·lapse estructural relacionats amb la seua baixa temperatura de transició vítria. En aquest sentit, una tècnica freqüent per a l'estabilització d'aquests productes deshidratats és la incorporació de biopolímers d'alt pes molecular. L'objectiu d'aquesta Tesi ha sigut el disseny del procés de liofilització per a l'obtenció d'un snack de taronja. Per a això s'ha estudiat la influència de diferents combinacions de biopolímers en l'estabilitat física del puré de taronja liofilitzat (snack de taronja) i en la bioaccessibilitat in vitro dels seus compostos bioactius. Així mateix, s'ha avaluat el seu efecte en les propietats de flux en aire i de rehidratació de la pols de taronja. S'ha treballat amb diferents combinacions de goma Aràbiga, maltodextrina, midó substituït per grups octenil succínic, midó natiu de dacsa, fibres de pésol i de bambú. Els resultats van mostrar la necessitat d'incorporar aquests biopolímers per a augmentar l'activitat d'aigua crítica i el contingut d'aigua crític per a la transició vítria, el qual s'ha relacionat amb la pèrdua de la textura del snack. Si bé cap de les mescles de biopolímers va ser millor que les altres en higroscopicitat, caràcter anti-plastificant, color i propietats mecàniques del snack, la mescla GA amb FB va ser la que va millorar la bioaccessibilitat de la vitamina C (VC) i dels compostos fenòlics totals (TP). A més, aquesta mateixa combinació va ser la que va oferir un dels temps de mullat més curts i una menor viscositat del producte rehidratat, desitjat per a un producte tipus suc. D'altra banda, s'ha estudiat l'impacte de les condicions de liofilització en el consum d'energia del procés i en la qualitat del snack formulat amb GA i FB. Les variables del procés considerades han sigut la velocitat de congelació (convencional i abatedor), la temperatura de safata (30, 40, 50 °C) i pressió de treball (5, 100 Pa) durant l'assecat. Menor pressió i major temperatura van promoure un lleuger major assecat de les mostres, obtenint un producte més cruixent, amb un color groc menys intens, millor preservació de VC i ß-caroté (BC), i una reducció significativa, de fins a un 75%, en el consum d'energia total durant l'assecat, a causa de la reducció del temps del procés. La velocitat de congelació no va tindre impacte significatiu sobre cap de les propietats avaluades. Per tant, les condicions recomanades per a l'assecat per liofilització són 5 Pa de pressió i 50 °C com a temperatura de safata. Finalment, es va avaluar l'estabilitat física i dels compostos bioactius i activitat antioxidant del snack emmagatzemat en bosses zip, a 4 i 20 °C, durant 6 mesos, simulant condicions domèstiques d'emmagatzematge. Com a resultat, la mostra va guanyar una certa humitat, amb la conseqüent pèrdua en porositat i caràcter cruixent a partir dels 2 mesos. Així mateix, la lluminositat del snack emmagatzemat a 20 °C va disminuir passats 2 mesos, probablement a causa de les reaccions de enfosquiment, que inclouen la degradació de la VC (20%). BC va patir una gran disminució, des de l'inici de l'emmagatzematge i més com més gran va ser la temperatura. Per tant, per a aquest producte es recomana un emmagatzematge en refrigeració per a una millor preservació dels compostos bioactius. / [EN] Food industries have showed a huge interest in developing new fruit-based products to satisfy the healthy and sustainable demand of food products by consumers. In this sense, offering a freeze-dried orange puree could represent a feasible option. Freeze-drying the puree results in a cake that can be consumed directly as a snack, or it can be crushed to obtain a powder that can be used for a wide range of applications. A suitable optimisation of the freeze-drying conditions could help to reduce its duration without affecting the characteristics of the final product. However, dehydrated foods may present problems of structural collapse related to its low glass transition temperature. In this sense, an approach for the stabilisation of dehydrated products is the incorporation of high molecular weight biopolymers. The aim of this Thesis has been the design of the freeze-drying process to obtain an orange snack. The influence of different combinations of biopolymers on the physical stability of the freeze-dried orange puree (orange snack) and on the in vitro bioaccessibility of its bioactive compounds has been studied. Their effect on the air flow and rehydration properties of an orange powder obtained after crushing the snack has also been evaluated. Different combinations of gum Arabic, maltodextrin, starch substituted with octenyl succinic groups, native corn starch, pea and bamboo fibres were used. The results showed the need to incorporate these biopolymers to increase the critical water activity and the critical water content for the glass transition, which has been related to the loss of snack texture. Although none of the biopolymer combinations was better than the others in terms of hygroscopicity, anti-plasticising character, colour, and mechanical properties of the snack, the GA mixed with FB was the one that improved the bioaccessibility of vitamin C (VC) and total phenolic compounds (TP). This same combination offered the shortest wetting times and a lower viscosity of the rehydrated product, which is desirable for a juice-type product. Also, the impact of the freeze-drying conditions on the energy consumption of the process and on the quality of the snack formulated with GA and FB has been studied. The process variables considered were freezing rate (conventional and blast freezer), shelf temperature (30, 40, 50 ºC) and working pressure (5, 100 Pa) during drying. Lower pressure and higher temperature promoted a slightly higher drying of the samples, which resulted in a crispier product, as well as a less intense yellow colour. However, at the sensory level, there was no significant preference for any of the samples processed under the different conditions studied. In addition, VC and ß-carotene (BC) were better preserved under these conditions, conditions which significantly reduced, up to 75%, the total energy consumption during drying, due to the reduction of the process time. The freezing rate had no significant impact on any of the properties evaluated. Therefore, the recommended conditions for freeze-drying to maximise the preservation of bioactive compounds, with a lower energy consumption, while providing a snack perceived as a crispy product by consumers, are 5 Pa pressure and 50 ºC as shelf temperature. Finally, the physical stability and the stability of bioactive compounds and antioxidant activity of the snack stored in zip bags at 4 and 20 ºC for 6 months, simulating domestic storage conditions, was evaluated. As a result, a certain moisture gain of the sample was observed, with a consequent loss in porosity and crispness after 2 months. Also, the luminosity of the snack stored at 20°C decreased after 2 months, probably due to browning reactions, including degradation of VC (20%). BC suffered a large decrease, from the beginning of storage and more so the higher the temperature. Therefore, refrigerated storage is recommended for better preservation of the bioactive compounds of this product. / Silva Espinoza, MA. (2021). Design of the process of obtaining a freeze-dried orange puree. Formulation, freeze-drying variables, and storage conditions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/170354 / Compendio

Bakgrund: Över 20 mutagena ämnen har detekterats i tillagade livsmedel. Till dessa räknas heterocykliska aminer. Studier har visat att dessa aminer kan orsaka mutationer och därmed öka risken för att utveckla cancer. Heterocykliska aminer bildas under tillagning av kött i höga temperaturer genom Maillardreaktionen. Syfte: Syftet med denna litteraturstudie var att se om marinering med öl, vin eller örtkryddor kan minska bildningen av heterocykliska aminer vid tillagning av kött. Metod: Denna studie är en litteraturstudie med ett urval av artiklar från databaserna PubMed och Web of Science. Totalt inkluderades 6 artiklar varav 3 artiklar studerade marinering med öl/vin och 3 studerade marinering med örtkryddor och örtextrakt. Resultat: Samtliga studier som undersöktes visade att marinering har en reducerande effekt på mängden heterocykliska aminer som bildas vid tillagning. Den mest troliga hypotesen om mekanismen är att effekten beror på den antioxidativa förmågan hos marinaderna. Ett exempel är en marinad med kombinationen gurkmeja och citrongräs som reducerade koncentrationen heterocykliska aminer med 94,8%. Slutsats: Marinering med öl, vin eller örtkryddor visades effektivt reducera mängden heterocykliska aminer. Stora reducerande effekter detekterades i marinader med gurkmeja, citrongräs, ingefära och mörk lager. Mer forskning behövs för att fastställa om reduktionen är kopplad till den antioxidativa effekten hos marinaderna / Background: Over 20 different mutagenic substances has been detected in cooked food. These include heterocyclic amines. Studies have shown that these amines can create mutations and increase the risk of developing cancer. Heterocyclic amines are formed in meat during the Maillard reaction which occours at high temperature cooking. Aim: The aim of this study was to investigate if the effect of marinating with beer, wine and herbs/spices can reduce the formation of heterocyclic amines found in cooked meat. Method: This study is a literature study with a selection of articles from databases PubMed and Web of Science. Six articles were included in this study. 3 articles involved marinade with beer/wine and 3 articles involved marinade with herbs/spices and extract. Results: All studies examined showed that marinating has a reducing effect on the concentration of heterocyclic amines formed during cooking. The most credible hypothesis of the mechanism is that the effect depends on the antioxidativ capacity of the marinades. For example one marinade with the combination of turmeric and lemon grass reduced the concentration of heterocyclic amines by 94,8%. Conclusion: Marinades containing beer, wine or herbs/spices was shown to effectively reduce the amount of heterocyclic amines. Great reducing effects were found using turmeric, lemon grass, ginger and black beer. More scientific research is needed to determine if the reduction is linked to the antioxidant effect in marinades.

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