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No presente projeto, foi estudada a viabilidade do purê de manga (Mangifera indica Linn.), variedade 'Haden', para pronto consumo. Inicialmente foi feito o acompanhamento do processo de amadurecimento das mangas para determinar o estágio de maturação adequado para o processamento do purê. Foram feitas análises de firmeza, pH, acidez titulável expressa em porcentagem de ácido cítrico, sólidos solúveis e teor de pectina da polpa das frutas. Os resultados mostraram que a coloração da casca foi um bom indicador do estágio de maturação das mangas. Após acidificação, foram alicados no purê quatro tratamento térmicos diferentes: 25,5 minutos a 65°C; 16,0 minutos a 75°C; 4,0 minutos a 80°C e 2,5 minutos a 95°C. Purê tratado e não tratado termicamente foi mantido sob refrigeração durante 36 dias e análises de pH e acidez titulável, além da contagem de bolores e leveduras, foram realizadas no purê na freqüência de 7 dias. Apesar da análise estatística indicar diferenças significativas entre os valores de pH e acidez titulável em função do tempo de armazenamento e do tratamento térmico, o purê apresentou valores dentro dos limites estabelecidos pela legislação para purê de manga destinado ao consumo como bebida (valor de pH entre 3,3 e 4,5 e acidez titulável mínima de 0,32% de ácido cítrico). Em relação à contagem de bolores e leveduras, o purê tratado termicamente mostrou-se estável, apresentado contagem zero dos microrganismos citados durante todo o período de armazenamento. Estudo do comportamento reológico do purê tratado e não tratado termicamente indicou o seu caráter não-newtoniano, de natureza pseudoplástica. Apesar dos tratamentos térmicos apresentarem valores de F bem distintos, as análises físico-químicas, a contagem de bolores e leveduras e o estudo reológico mostraram que não houve diferença entre os produtos finais. Isso indica que a estabilidade físico-química e microbiológica do purê pode ser alcançada com o tratamento térmico que apresentou o menor valor de F, no caso, o tratamento conduzido a 65ºC durante 25,5 minutos. Em um teste de aceitação do consumidor, o purê tratado nestas condições apresentou um alto indice de aceitação, o que reforça a viabilidade do produto pronto para consumo. / In this research project, the viability of 'Haden' mango puree (Mangifera indica Linn.) as a ready-to-serve product was studied. The ripening process of the fruti was studied to determine the adequate stage for the puree production. Firmness, pH, total acidity expressed as citric acid percentage, soluble solids and pectin content of the fruti pulps were analyzed. results showed that color of skin is a good parameter to indicate the mangoes ripening stage. Four different heat treatments were applied to the acidified puree: 25.5 minutes at 65°C; 16.0 minutes at 75°C; 4.0 minutes at 80°C and 2.5 minutes at 95°C. Non treated and treated puree were maintained under refrigeration for 36 days. pH, titrable acidity, molds and yeast analyses were carried out weekly. Although statistical analyses indicate significant difference among pH and acidity values in relation to storage time and heat treatment, the puree presented acceptable values by Brazilian legislation for mango puree consumed as beverage (pH between 3,3 and 4,5 and mininum total acidity of 0,32% of citric acid). Heat treated puree showed microbiological stability, presenting zero count of these microorganisms during the storage time. The study of rheological behavior of treated and non treated purees revealed non Newtonian character of shear thinning nature. Even though the heat treatments presented very distinct F values, the physical chemical analyses, the mold and yeast counts and the rheological behavior showed that there was difference among the final products. This indicates that the stability os the puree can be achieved applying the heat treatment with the smallest F value, that is 25.5 minutes at 65°C. Consumer acceptance test of puree treated in these conditions presented high level of acceptance, which reinforces the viability of this puree as a ready-to-serve product.

No presente projeto, foi estudada a viabilidade do purê de manga (Mangifera indica Linn.), variedade 'Haden', para pronto consumo. Inicialmente foi feito o acompanhamento do processo de amadurecimento das mangas para determinar o estágio de maturação adequado para o processamento do purê. Foram feitas análises de firmeza, pH, acidez titulável expressa em porcentagem de ácido cítrico, sólidos solúveis e teor de pectina da polpa das frutas. Os resultados mostraram que a coloração da casca foi um bom indicador do estágio de maturação das mangas. Após acidificação, foram alicados no purê quatro tratamento térmicos diferentes: 25,5 minutos a 65°C; 16,0 minutos a 75°C; 4,0 minutos a 80°C e 2,5 minutos a 95°C. Purê tratado e não tratado termicamente foi mantido sob refrigeração durante 36 dias e análises de pH e acidez titulável, além da contagem de bolores e leveduras, foram realizadas no purê na freqüência de 7 dias. Apesar da análise estatística indicar diferenças significativas entre os valores de pH e acidez titulável em função do tempo de armazenamento e do tratamento térmico, o purê apresentou valores dentro dos limites estabelecidos pela legislação para purê de manga destinado ao consumo como bebida (valor de pH entre 3,3 e 4,5 e acidez titulável mínima de 0,32% de ácido cítrico). Em relação à contagem de bolores e leveduras, o purê tratado termicamente mostrou-se estável, apresentado contagem zero dos microrganismos citados durante todo o período de armazenamento. Estudo do comportamento reológico do purê tratado e não tratado termicamente indicou o seu caráter não-newtoniano, de natureza pseudoplástica. Apesar dos tratamentos térmicos apresentarem valores de F bem distintos, as análises físico-químicas, a contagem de bolores e leveduras e o estudo reológico mostraram que não houve diferença entre os produtos finais. Isso indica que a estabilidade físico-química e microbiológica do purê pode ser alcançada com o tratamento térmico que apresentou o menor valor de F, no caso, o tratamento conduzido a 65ºC durante 25,5 minutos. Em um teste de aceitação do consumidor, o purê tratado nestas condições apresentou um alto indice de aceitação, o que reforça a viabilidade do produto pronto para consumo. / In this research project, the viability of 'Haden' mango puree (Mangifera indica Linn.) as a ready-to-serve product was studied. The ripening process of the fruti was studied to determine the adequate stage for the puree production. Firmness, pH, total acidity expressed as citric acid percentage, soluble solids and pectin content of the fruti pulps were analyzed. results showed that color of skin is a good parameter to indicate the mangoes ripening stage. Four different heat treatments were applied to the acidified puree: 25.5 minutes at 65°C; 16.0 minutes at 75°C; 4.0 minutes at 80°C and 2.5 minutes at 95°C. Non treated and treated puree were maintained under refrigeration for 36 days. pH, titrable acidity, molds and yeast analyses were carried out weekly. Although statistical analyses indicate significant difference among pH and acidity values in relation to storage time and heat treatment, the puree presented acceptable values by Brazilian legislation for mango puree consumed as beverage (pH between 3,3 and 4,5 and mininum total acidity of 0,32% of citric acid). Heat treated puree showed microbiological stability, presenting zero count of these microorganisms during the storage time. The study of rheological behavior of treated and non treated purees revealed non Newtonian character of shear thinning nature. Even though the heat treatments presented very distinct F values, the physical chemical analyses, the mold and yeast counts and the rheological behavior showed that there was difference among the final products. This indicates that the stability os the puree can be achieved applying the heat treatment with the smallest F value, that is 25.5 minutes at 65°C. Consumer acceptance test of puree treated in these conditions presented high level of acceptance, which reinforces the viability of this puree as a ready-to-serve product.

Master of Science / Food Science Institute, Human Nutrition / Delores H. Chambers / Fresh mangoes are highly perishable, and therefore, they are often processed to extend shelf-life and facilitate exportation. Studying the transformation that mango cultivars undergo throughout processing can aid in selecting appropriate varieties for products. In the 1st part of this study, the flavor and texture properties of 4 mango cultivars available in the United States (U.S.) were analyzed. Highly trained descriptive panelists in the U.S. evaluated fresh, purée, and sorbet samples prepared from each cultivar. Purées were made by pulverizing mango flesh, passing it through a china cap, and heating it to 85 °C for 15 s. For the sorbets, purées were diluted with water (1:1), sucrose was added, and the bases were frozen in a batch ice cream freezer. Much of the texture variation among cultivars was lost after fresh samples were transformed into purées, whereas much of the flavor and texture variation among cultivars was lost once fresh mangoes and mango purées were transformed into sorbets. Compared to the other cultivars, Haden and Tommy Atkins underwent greater transformations in flavor throughout sorbet preparation, and processing reduced the intensities of some unpleasant flavors in these cultivars. Tommy Atkins was the only cultivar that had flavor differences from other cultivars when it was in sorbet. Results suggest that cultivar variation is generally not detectable in mango sorbet unless the cultivar has a distinct initial flavor. In the 2nd part of this study, descriptive panelists in Thailand evaluated the flavor and texture properties of fresh samples and purées prepared from 6 cultivars grown in Thailand. Thermal processing had unique effects on the flavor of each cultivar, especially Nam Dok Mai and Chok Anun; Nam Dok Mai significantly decreased in mango identity and peach flavors after processing, whereas Chok Anun significantly increased in sweet, mango identity, and pineapple flavors. Although a slight amount of flavor variation among cultivars was lost because of thermal processing, most of the texture variation was eliminated. Because of significant changes in flavor and texture after heat treatment of mango cultivars, manufacturers should select cultivars for mango purées based on their properties after thermal processing.

Jerusalem artichoke has been cultivated in various regions without any special breeding technique. On the other hand, in food industry it does not have a wide usage area. Hence, in food industry its use as a potato substitute in some products is believed to be increasing its economical value. As a first attempt chips and crisps produced from Jerusalem artichoke was analyzed for texture, sensory, color, oil and moisture content. Jerusalem artichoke chips were fried in a bench top deep fat fryer for 120s, 180s and 240s at 160&deg / C, 170&deg / C, 180&deg / C and 190&deg / C. When microwave oven was used samples were cooked for 60s, 75s, 90s, 105s, 120s, 135s and 150s at 600 Watt and 900 Watt. Rheological properties of Jerusalem artichoke puree were investigated and Xanthan gum (2%wb) and sodium metabisulphite (1%wb) added for the desired puree consistence and color. After the production of puree Jerusalem artichoke flour was produced and water added to this flour then dough obtained again. Rheological behaviour of the original puree and these prepared from the containing 1- 4.5 and 1 - 5.0 part water were quite similar. In the light of the experimental results obtained as frying temperature and treatment time increased, moisture content and lightness of the Jerusalem artichoke products have decreased but a*and b* values, hardness, fracture and oil content increased. The best results for frying of Jerusalem artichoke seem to be 180&deg / C with about 240s treatment time for the chips and the same temperature for 180s for the crisps. As microwave power level and duration of treatment increased, moisture content and lightness of the microwave cooked Jerusalem artichoke products have decreased, but a* and b* values increased. Hardness and fracturability values of the products first increased with time and then decreased. When microwave oven was used, the best results were obtained for about 105s treatment time at 600W for the Jerusalem artichoke chips and about 60s processing time at 900W for the crisp. Since treatment time for cooking was significantly reduced when microwave cooking was used, this method could be recommended as an alternative to conventional deep fat frying, as oil is not used as well.

Cancer is a global risk for human wellness and health. Dietary habits could profoundly affect the risk of certain cancer, such as colorectal cancer (CRC) (Platz, 2000). CRC has listed the third leading cancer among male and female in the United States (Stewart, 2014). Surprisingly, the consumption of dietary fiber has an inverse correlation with the mortality of CRC (Song, 2018). However, most Americans do not consume enough dietary fiber to meet the recommended level of dietary fiber intake (Clemens, 2012; Lee-Kwan, 2017). Hence, it is reasonable to increase the nutrient density, i.e., dietary fiber, of current food model. Xylo-oligosaccharides (XOS), an emerging prebiotics, showed multiple advantages over fructo-oligosaccharides (FOS) and inulin. For example, Hsu et al. (2004) reported XOS are more effective than FOS on increasing Bifidobacterium level in rat cecum (Hsu, 2004). It is also suggested that dietary fiber and phenolic compounds have synergistic effect on promoting gut health (Uehara, 2001; Matsukawa, 2009). Therefore, the application of XOS into a polyphenol-dense food vehicle (strawberry puree) could be a viable way to promote gastrointestinal health and help reduce CRC risk. First, the effect of xylo-oligosaccharides (XOS) incorporation on the quality attributes of strawberry puree was investigated. Rheological properties, color and physicochemical characteristics and composition such as water activity, pH, and total soluble solids, were investigated to determine the maximum XOS content that can be incorporated into the strawberry pure without significantly altering the original properties of samples. Based on the collected data, adding xylo-oligosaccharides greater than 7.5% w/w will significantly change the quality attributes of the strawberry puree including its rheological characteristics, color profile, water activity, and total soluble solids. The addition of XOS at 2.5% and 5% w/w did not significantly alter overall quality attributes of strawberry puree. Second, the effects of heat treatment (HTST, 75℃, 15s and UHT, 121℃, 2s) and storage condition (storage time: 1, 15, and 36 days; storage temperature: 4℃ and 55℃) on the quality attributes of xylo-oligosaccharides enhanced strawberry puree was studied (texture, color water activity, total soluble solids, and pH). In addition, the physicochemical (total phenolic, tannin, flavonoids contents, and antioxidant activity) evolution was studied. A 9-point Hedonic test was conducted to evaluate the sensory properties (overall, texture, color, appearance, sweetness, aroma, flavor) of purees (with and without XOS, 5%w/w) under different thermal treatments. Briefly, all nutritional attributes were retained better under cold storage (4 ℃) as compared to high-temperature storage (55 ℃). The result revealed that thermal treatment and high storage temperature showed an inverse correlation with puree consistency. As for chemical analysis, intense thermal treatment (UHT) caused the most degradation in TPC, TFC and tannin level. However, such treatments (UHT) helped significantly increase the measurable antioxidant level. For other physicochemical properties, processing methods (HTST / UHT) and high storage temperature exhibited more significance in changing the color profiles of the specimen than XOS incorporation. Overall, the addition of XOS up to 5% w/w could increase nutritional value of strawberry puree as well as consumer preference without significantly compromising quality attributes. Based on instrumental and sensory analysis, HTST treated strawberry puree with XOS incorporation (5% w/w) meet the standard of sensorial attributes of fresh puree with improved shelf-life stability and fiber concentration.

Le concept d’Hôpital Promoteur de Santé (HPS) a pris beaucoup d’importance depuis son élaboration vers la fin des années quatre-vingt. Dans le contexte de la dernière réforme, le réseau montréalais des HPS et CSSS a été créé. Le Centre Universitaire de Santé McGill (CUSM) fait partie de ce réseau depuis 2007. Cette étude vise la création d’un milieu hospitalier promoteur de la santé pour les patients et s’adresse à l’expérience d’un repas pour les personnes âgées nécessitant une diète purée. Une étude de cas qualitative a été utilisée pour explorer la perception de patients vis-à-vis les aspects relatifs à leur cabaret, l’assistance qu’ils recevaient et le contexte social de leur repas. Les impressions des professionnels de la santé quant à l’expérience des patients ont aussi été obtenues. Les résultats indiquent que l’identification difficile des aliments en purée, la saveur, l’apparence et la variété sont tous des éléments qui affectent négativement leur expérience repas. Des sentiments d’impuissance ont aussi été rapportés par les patients et les professionnels de la santé. Le contexte social du repas a été souligné comme étant un aspect à cibler pour améliorer l’expérience des patients. Un programme utilisant des purées formées pourrait contrecarrer les effets négatifs de la prescription d’une diète purée. Des changements dans les pratiques infirmières, à savoir la création d’une ambiance sociale agréable au moment des repas, semble être une option peu couteuse qui pourrait améliorer l’expérience repas des patients et diminuer les sentiments d’impuissance relevés par les professionnels de la santé à l’égard de cet aspect de soin. / The Health Promoting Hospital (HPH) concept has gained much momentum since its development in Europe in the late nineteen eighties. The Montreal network of HPH was created in 2005, within the context of the last reform. The McGill University Health Center (MUHC) is a part of this network since 2007. This study focuses on the creation of a health promoting hospital setting for patients and addresses the mealtime experience of older hospitalized patients requiring a puree diet. A qualitative case study design was used to explore patients’ perceptions of aspects of their puree meal tray, assistance provided by staff and the social context in which the meal was taken. Health professionals’ view of the patients’ experience were also obtained. Results indicate that the difficult identification of food items, flavour, appearance and variety were all important factors negatively affecting the mealtime experience. Feelings of loss of control were also reported by patients and staff. The social context in which the meal was taken was highlighted as an area which could be targeted to improve mealtimes. A program using formed puree food items could help lessen the negative impact of the prescription of a puree diet. Changes in nursing practices regarding the creation of a pleasant social atmosphere were identified as an inexpensive option to improve the mealtime experience for patients and decrease feelings of lack of control for staff in this aspect of care.

Le concept d’Hôpital Promoteur de Santé (HPS) a pris beaucoup d’importance depuis son élaboration vers la fin des années quatre-vingt. Dans le contexte de la dernière réforme, le réseau montréalais des HPS et CSSS a été créé. Le Centre Universitaire de Santé McGill (CUSM) fait partie de ce réseau depuis 2007. Cette étude vise la création d’un milieu hospitalier promoteur de la santé pour les patients et s’adresse à l’expérience d’un repas pour les personnes âgées nécessitant une diète purée. Une étude de cas qualitative a été utilisée pour explorer la perception de patients vis-à-vis les aspects relatifs à leur cabaret, l’assistance qu’ils recevaient et le contexte social de leur repas. Les impressions des professionnels de la santé quant à l’expérience des patients ont aussi été obtenues. Les résultats indiquent que l’identification difficile des aliments en purée, la saveur, l’apparence et la variété sont tous des éléments qui affectent négativement leur expérience repas. Des sentiments d’impuissance ont aussi été rapportés par les patients et les professionnels de la santé. Le contexte social du repas a été souligné comme étant un aspect à cibler pour améliorer l’expérience des patients. Un programme utilisant des purées formées pourrait contrecarrer les effets négatifs de la prescription d’une diète purée. Des changements dans les pratiques infirmières, à savoir la création d’une ambiance sociale agréable au moment des repas, semble être une option peu couteuse qui pourrait améliorer l’expérience repas des patients et diminuer les sentiments d’impuissance relevés par les professionnels de la santé à l’égard de cet aspect de soin. / The Health Promoting Hospital (HPH) concept has gained much momentum since its development in Europe in the late nineteen eighties. The Montreal network of HPH was created in 2005, within the context of the last reform. The McGill University Health Center (MUHC) is a part of this network since 2007. This study focuses on the creation of a health promoting hospital setting for patients and addresses the mealtime experience of older hospitalized patients requiring a puree diet. A qualitative case study design was used to explore patients’ perceptions of aspects of their puree meal tray, assistance provided by staff and the social context in which the meal was taken. Health professionals’ view of the patients’ experience were also obtained. Results indicate that the difficult identification of food items, flavour, appearance and variety were all important factors negatively affecting the mealtime experience. Feelings of loss of control were also reported by patients and staff. The social context in which the meal was taken was highlighted as an area which could be targeted to improve mealtimes. A program using formed puree food items could help lessen the negative impact of the prescription of a puree diet. Changes in nursing practices regarding the creation of a pleasant social atmosphere were identified as an inexpensive option to improve the mealtime experience for patients and decrease feelings of lack of control for staff in this aspect of care.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-25T11:56:53Z No. of bitstreams: 1 MARCOS ANTÔNIO AMARAL LINS - TESE (PPGEP) 2013.pdf: 2840885 bytes, checksum: 13b6f2695a2ffd6be9d615430752bc2d (MD5) / Made available in DSpace on 2018-09-25T11:56:53Z (GMT). No. of bitstreams: 1 MARCOS ANTÔNIO AMARAL LINS - TESE (PPGEP) 2013.pdf: 2840885 bytes, checksum: 13b6f2695a2ffd6be9d615430752bc2d (MD5) Previous issue date: 2013-07-05 / Para muitos gêneros alimentícios, o processo de transferência de calor é essencial para se chegar à condição de consumo humano. O presente trabalho teve como objetivo estudar o fenômeno da difusão transiente de calor em alimentos pastosos contidos em recipientes cilíndricos. O estudo apresenta soluções para a equação de difusão com condição de contorno do primeiro tipo. Foram desenvolvidas ferramentas analíticas (otimizador acoplado à solução analítica) para a descrição da difusão de calor em produtos pastosos com as formas mencionadas. As ferramentas analíticas foram validadas através de dados obtidos por simulação numérica tanto para o cilindro infinito quanto para o finito. Os erros cometidos com as ferramentas desenvolvidas no cálculo da difusividade térmica aparente para os dados simulados são aceitáveis quando o sensor de temperatura é colocado na região mais interna do cilindro. Os resultados obtidos para a difusividade térmica aparente de agar gel, purê de tomate e creme custard são compatíveis com os resultados encontrados na literatura para esses produtos. O software Finite Cylinder First Kind foi desenvolvido, validado e aplicado aos dados do purê de tomate, creme custard e agar gel para várias posições no interior do cilindro finito onde estes gêneros alimentícios se encontravam. Todos os resultados obtidos por otimização e simulação tiveram uma excelente concordância com os resultados experimentais. O método numérico se mostrou mais eficiente do que o analítico, na descrição do processo de difusão de calor nos produtos estudados, devido sua versatilidade de permitir a obtenção da solução da equação de difusão considerando a difusividade térmica variável com a temperatura local. / For many foodstuffs, the process of heat transfer is essential to reach the condition human consumption. The present work aims to study the phenomenon of transient diffusion of heat in pasty foodstuffs contained in cylindrical containers. The study presents solutions for the diffusion equation with boundary condition of the first kind. Analytical tools were developed - optimizer coupled to the analytical solution - to describe the diffusion of heat into products with the forms mentioned. Analytical tools were validated using data obtained by numerical simulation for both the cylinder the infinite and finite. The tools developed minimize errors in calculating the thermal diffusivity for the simulated data are acceptable when the temperature sensor is placed in the innermost region of the cylinder. The results obtained for the thermal diffusivity of agar gel, tomato puree and cream custard are consistents with the results found in the literature for these products. The software finite cylinder first kind was developed, validated and applied to data of tomato puree, cream custard and agar gel for various positions within the finite and infinite cylinder filled with these foodstuffs. All results obtained by simulation and optimization had an excellent agreement with the experimental results. The numerical method is more efficient than the analytical description of the heat diffusion process in the products, due to their versatility that allows obtaining the solution of the diffusion equation considering the thermal diffusivity varies with local temperature.

[ES] Existen muchos estudios que relacionan el consumo regular de frutas con importantes beneficios para la salud. Esto es debido a la gran cantidad de fibra, vitaminas y otros compuestos bioactivos presentes en ellas, los cuales pueden ser de gran ayuda en la prevención de algunas enfermedades. En los últimos años, el consumidor se ha decantado por consumir productos con alto valor nutricional y, como consecuencia del estilo de vida actual, existe una alta demanda de productos con fácil manejo para su consumo. Algunos de los principales inconvenientes de las frutas son su estacionalidad y corta vida útil, por lo que resulta interesante ofrecer productos de fruta de alto valor nutritivo y sensorial, estables y fácil manejo. La liofilización es una técnica que permiten obtener productos altamente estables microbiológicamente, debido a su bajo contenido de humedad, y con una máxima calidad sensorial, nutritiva y funcional. Sin embargo, se trata de un proceso largo y energéticamente costoso. Con base a lo anterior, el objetivo de esta tesis ha sido seleccionar las mejores condiciones de liofilización para la obtención de dos productos de naranja, uno la propia torta liofilizada y otro el polvo obtenido por trituración de la misma. Así, la sección uno se centra en evaluar la influencia tanto del contenido de agua como de la composición en solutos de un producto naranja en algunas propiedades de la torta liofilizada y del polvo correspondiente. Las propiedades analizadas se seleccionaron teniendo en cuenta tanto la retención de los compuestos bioactivos, como la porosidad, el color y las propiedades mecánicas de la torta obtenida y del polvo conseguido tras su trituración, además de las propiedades de flujo del polvo y su comportamiento frente a la rehidratación. En base a los resultados obtenidos se ha podido concluir que el puré de naranja es más recomendable a los efectos de obtener un producto tipo snack crujiente y el zumo cuando se desee un polvo para rehidratar, en este caso evitando cualquier tratamiento térmico antes de la liofilización. En la sección dos, se ha estudiado el impacto de la temperatura del secado, 30 y 50 °C, sobre los compuestos bioactivos del producto obtenido a partir del zumo de naranja formulado con goma Arábiga y fibra de bambú, así como sobre las mismas propiedades antes descritas de la torta liofilizada y de su correspondiente producto en polvo. En este caso, además, se llevó a cabo una evaluación sensorial de los productos rehidratados. Los resultados obtenidos permiten recomendar 50°C para el secado de este producto por liofilización. Esta temperatura acorta el tiempo del proceso en un 64 %, favorece la extracción de la vitamina C sin afectar al contenido total de fenoles y carotenoides, mejora las propiedades mecánicas de las tortas y no afecta a la fluidez ni a la rehidratación del producto en polvo. Finalmente, en la sección tres, se ha trabajado en la aplicación de una solución analítica basada en la ley de Darcy para modelar la cinética de pérdida de agua durante la liofilización. La solución analítica debe complementarse con una solución numérica de las ecuaciones de Fourier para la transferencia de calor. El modelo se ha ajustado a la dinámica experimental de liofilización de un producto a base de naranja formulado a partir del zumo. La pseudo-permeabilidad de Darcy obtenida fue de 2,0X10-12 con un índice de desviación de la conducta ideal de 0,5. Las ecuaciones propuestas, resueltas con la pseudo-permeabilidad de Darcy ajustada y el índice de desviación ideal, permiten reproducir la dinámica de liofilización experimental del mismo producto a diferentes temperaturas. / [CA] Existeixen molts estudis que relacionen el consum regular de fruites amb importants beneficis per a la salut. Això és degut a la gran quantitat de fibra, vitamines i altres compostos *bioactivos que es troben elles, els quals poden ser de gran ajuda en la prevenció d'algunes malalties. En els últims anys el consumidor s'ha decantat per consumir productes amb alt valor nutricional i, a conseqüència de l'estil de vida actual, existeix una alta demanda de productes amb fàcil maneig per al seu consum. Alguns dels principals inconvenients de les fruites són la seua estacionalitat i curta vida útil, per la qual cosa resulta interessant oferir productes de fruita d'alt valor nutritiu i sensorial, estables i fàcil maneig. La liofilització és una tècnica que permeten obtindre productes altament estables microbiologicament, a causa del seu baix contingut d'humitat, i amb una màxima qualitat sensorial, nutritiva i funcional. No obstant això, es tracta d'un procés llarg i energèticament costós. Amb base a l'anterior, l'objectiu d'aquesta Tesi ha sigut seleccionar les millors condicions de liofilització per a l'obtenció de dos productes de taronja, un la pròpia coca liofilitzada i un altre la pols obtinguda per trituració d'aquesta. Així, la primera part de la Tesi se centra en avaluar la influència tant del contingut d'aigua com de la composició en soluts d'un producte taronja en algunes propietats de la coca liofilitzada i de la pols corresponent. Les propietats a analitzar es van seleccionar tenint en compte tant la retenció dels compostos bioactius, com la porositat, el color i les propietats mecàniques de la coca obtinguda i de la pols aconseguida després de la seua trituració, a més de les propietats de flux de la pols i el seu comportament enfront de la rehidratació. Sobre la base dels resultats obtinguts s'ha pogut concloure que el puré de taronja és més recomanable a l'efecte d'obtindre un producte tipus snack cruixent i el suc quan es desitge una pols per a rehidratar, en aquest cas evitant qualsevol tractament tèrmic abans de la liofilització. En la segona part de la Tesi, s'ha estudiat l'impacte de la temperatura de l'assecat, 30 i 50 °C, sobre els compostos bioactius del producte obtingut a partir del suc de taronja formulat amb goma Aràbiga i fibra de bambú, així com sobre les mateixes propietats abans descrites de la coca liofilitzada i del seu corresponent producte en pols. En aquest cas, a més, es va dur a terme una avaluació sensorial dels productes rehidratats. Els resultats obtinguts permeten recomanar 50 °C per a l'assecat per liofilització d'aquest producte. Aquesta temperatura acurta el temps del procés en un 64%, afavoreix l'extracció de la vitamina C sense afectar el contingut total de fenols i carotenoids, millora les propietats mecàniques de les coques i no afecta a la fluïdesa ni a la rehidratació del producte en pols. Finalment, en la tercera part de la Tesi, s'ha treballat en l'aplicació d'una solució analítica basada en la llei de Darcy per a modelar la cinètica de pèrdua d'aigua durant la liofilització. La solució analítica ha de complementar-se amb una solució numèrica de les equacions de Fourier per a la transferència de calor. El model s'ha ajustat a la dinàmica experimental de liofilització d'un producte a base de taronja formulat a partir del suc. La pseudo-permeabilitat de Darcy obtinguda va ser de 2,0X10-12 amb un índex de desviació de la conducta ideal de 0,5. Les equacions proposades, resoltes amb la pseudo-permeabilitat de Darcy ajustada i l'índex de desviació ideal, permeten reproduir la dinàmica de liofilització experimental del mateix producte a diferents temperatures. / [EN] There are many studies linking regular fruit consumption with important health benefits. This is due to the large amount of fibre, vitamins and other bioactive compounds found in them, which can be of great help in the prevention of some diseases. In recent years, consumers have become more inclined to consume products with high nutritional value and, as a consequence of today's lifestyle, there is a high demand for products that are easy to handle for consumption. Some of the main disadvantages of fruits are their seasonality and short shelf life, so it is interesting to offer fruit products of high nutritional and sensory value that are stable and easy to handle. Freeze-drying is a technique that makes it possible to obtain highly microbiologically stable products, due to their low moisture content, and with maximum sensory, nutritional and functional quality. However, it is a long and energy-intensive process. Based on the above, the aim of this Doctoral Thesis has been to select the best freeze-drying conditions for obtaining two orange products, one the freeze-dried cake itself and the other the powder obtained by crushing it. Thus, the first part of the Thesis focuses on evaluating the influence of both the water content and the solute composition of an orange product on some properties of the freeze-dried cake and the corresponding powder. The properties to be analysed were selected taking into account the retention of the bioactive compounds, the porosity, the colour and the mechanical properties of the cake obtained and of the powder obtained after grinding, as well as the flow properties of the powder and its behaviour against rehydration. Based on the results obtained, it can be concluded that orange puree is more recommendable for obtaining a crunchy snack-type product and juice when a powder for rehydration is desired, in this case avoiding any heat treatment before freeze-drying. In the second part of the Thesis, the impact of the drying temperature, 30 and 50 °C, on the bioactive compounds of the product obtained from orange juice formulated with gum Arabic and bamboo fibre, as well as on the same properties described above of the freeze-dried cake and its corresponding powdered product, has been studied. In this case, a sensory evaluation of the rehydrated products was also carried out. The results obtained allow to recommend 50°C for the freeze-drying of this product. This temperature shortens the processing time by 64 %, favours the extraction of vitamin C without affecting the total phenol and carotenoid content, improves the mechanical properties of the cakes and does not affect the flowability and rehydration of the powdered product. Finally, in the third part of the Thesis, we have studied the application of an analytical solution based on Darcy's law to model the kinetics of water loss during freeze-drying. The analytical solution must be complemented with a numerical solution of the Fourier equations for heat transfer. The model has been fitted to the experimental dynamics of freeze-drying an orange-based product formulated from the juice. The Darcy pseudo-permeability obtained was 2,0X10-12 with an index of deviation from ideal behaviour of 0,5. The proposed equations, solved with the adjusted Darcy pseudo-permeability and the ideal deviation index, allow to reproduce the experimental freeze-drying dynamics of the same product at different temperatures. / Uscanga Ramos, MA. (2022). Influencia de la composición y de la temperatura de secado en la calidad de un producto de naranja liofilizado. Propuesta de un modelo mecanístico para la modelización de la cinética del proceso [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181238 / TESIS