Neste trabalho é apresentado um estudo sobre o rejuvenescimento de membranas de poliamida de osmose reversa utilizando ácido tânico como agente de rejuvenescimento. Em uma primeira etapa foram estudadas oxidações de membranas por cloro livre catalisadas por ferro e alumínio, e degradações promovidas por procedimentos de limpeza química. Posteriormente, testes de rejuvenescimento foram realizados para encontrar as melhores condições para a recuperação da eficiência das membranas. Parâmetros operacionais de procedimentos de rejuvenescimento, tais como: pressão, pH e concentração de ácido tânico da corrente de alimentação foram variados a fim de otimizar a eficiência do tratamento químico na superfície das membranas. Os experimentos foram realizados em um sistema de osmose reversa (OR) em bancada, que pode operar com dois tipos de módulos para membrana, um para membrana plana e outro para membrana em espiral. As performances das membranas foram avaliadas medindo-se a retenção de NaCl e sílica, utilizando-se soluções contendo 2000 ppm de NaCl e também água de alimentação do sistema de OR da empresa AZ. Os resultados obtidos com os experimentos demonstraram que o alumínio e o ferro catalisaram oxidações por cloro livre nas superfícies das membranas utilizadas Também, o agente de limpeza química lauril sulfato de sódio degradou membranas que tinham suas superfícies previamente oxidadas por cloro livre. O tratamento de rejuvenescimento melhorou a retenção de NaCl e de sílica de membranas previamente oxidadas e degradadas por cloro livre e lauril sulfato de sódio, respectivamente. Este trabalho é complementado por um estudo sobre as condições operacionais e de performance das membranas do sistema de osmose reversa da empresa AZ, a fim de verificar e/ou confirmar algumas dúvidas relacionadas com o decréscimo na performance do sistema de OR.

L’objectif de cette thèse est de mettre en évidence le comportement à l’échelle microscopique des composés organiques au cours des procédés de traitement de mélanges complexes, en particulier les procédés membranaires. Pour cela des outils expérimentaux et de modélisation ont été mis au point. Les méthodes de caractérisation expérimentale des mélanges complexes et de l’état de surface des solides utilisés sont entre autres la construction d’isothermes d’adsorption et la mesure des tensions interfaciales par la méthode de la goutte posée. Le cas étudié ici est celui de la filtration de solutions modèles de tensioactifs par osmose inverse. Nous avons montré que le comportement des composés organiques (tensioactifs) influence la performance du procédé membranaire et les propriétés de membranes. L’outil de simulation du comportement des composés en phase liquide et à l’interface liquide-solide permettant une description à une échelle plus fine que celle atteignable expérimentalement est la DPD (Dissipative Particle Dynamics). Une première étape a permis de simuler l’agrégation des tensioactifs en solution et de retrouver les valeurs expérimentales des concentrations micellaires critiques et nombres d’agrégation de tensioactifs anioniques. L’étude de l’adsorption des tensioactifs sur une membrane d’osmose inverse a été initiée, avec pour objectif de mettre en évidence l’organisation des composés à l’échelle locale. L’apport des outils développés a été démontré et leur utilisation pourra être approfondie dans des travaux ultérieurs. / The aim of this work is a better understanding of the microscopic behavior of organic matters during the wastewater treatment of complex mixtures, especially during the membrane processes. Both experimental and simulation methods were developed in this work. Experimentally, adsorption isotherms were built to study the adsorption of organic matters on the membrane surface during the filtration. The sessile drop measurement allowed investigating the surface properties (interfacial tensions) of the membrane. After the filtration of surfactants by reverse osmosis (RO), we found that the surfactants played an important role in the performance and the surface properties of the RO membrane. The DPD (Dissipative Particle Dynamics) simulation method was used to model the behavior of anionic surfactants in solution and at the solid/liquid interface from a more detailed aspect than experiments. Firstly, the micellization of three anionic surfactants in aqueous solution was simulated and the model was validated by comparing the equilibrium properties (the critical micelle concentration and aggregation number) of micelle solutions obtained from simulation to the experimental values in literature. Then the model was extended to simulate the adsorption of surfactants on the RO membrane. The construction of a system with a membrane was initiated, and the study on the organizations of surfactants at the membrane surface opens a door to further active research.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-14T11:24:52Z No. of bitstreams: 1 paulanunesmendes.pdf: 574355 bytes, checksum: 47b4be1086b650071084cf920b4da38c (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2016-07-19T14:16:35Z (GMT) No. of bitstreams: 1 paulanunesmendes.pdf: 574355 bytes, checksum: 47b4be1086b650071084cf920b4da38c (MD5) / Made available in DSpace on 2016-07-19T14:16:36Z (GMT). No. of bitstreams: 1 paulanunesmendes.pdf: 574355 bytes, checksum: 47b4be1086b650071084cf920b4da38c (MD5) Previous issue date: 2011-08-22 / O leite condensado é um dos produtos que apresenta maior crescimento em produção no Brasil, favorecendo o desenvolvimento de novas tecnologias e a adaptação de indústrias de médio e pequeno porte para fabricação deste produto. O objetivo central do presente trabalho foi avaliar os atributos de dois processos de fabricação distintos, sendo o primeiro utilizando-se leite padronizado com aproximadamente 12 % de sólidos totais e o segundo leite pré-concentrado por osmose reversa, identificando a diferença entre os produtos e o impacto do processo de concentração por membrana em suas características desejáveis. Os experimentos foram realizados numa indústria da Zona da Mata Mineira, com avaliações físico-químicas e sensoriais. Os produtos foram analisados com 1, 30, 60 e 120 dias de fabricação. Concluiu-se que o leite condensado com osmose não apresentou diferença estatisticamente significativa em comparação ao leite condensado sem osmose quanto aos atributos avaliados e foi possível estabelecer relações entre constituintes, com aplicação prática, permitindo definir o teor mínimo de sólidos solúveis para obtenção de uma viscosidade mínima. / Condensed milk is a product that presents the highest growth in production in Brazil, favoring the development of new technologies and the adaptation by industries small and medium sized for manufacturing this product. The main objective of this study was to evaluate the attributes of two different manufacturing processes, the first using standardized milk with approximately 12 % total solids and milk pre-concentrated by reverse osmosis the second, identifying the difference between the products and impact for process the membrane concentration in their desirable characteristics. The experiments were conducted in an industry in the Zona da Mata Mineira, with assessments physicochemical and sensory. The products were analyzed with 1, 30, 60 and 120 days of manufacture. It was concluded that the condensed milk with osmosis had no difference statistically significant compared to the condensed milk without osmosis about the attributes evaluated and it was possible to establish relationships between constituents, with practical purpose, such as analytical references like minimum soluble solids content to obtain the minimum viscosity.

Submitted by Marcele Costal de Castro (costalcastro@gmail.com) on 2017-12-14T12:54:22Z No. of bitstreams: 1 LUCINDA FERNANDES DA SILVA D.pdf: 3356063 bytes, checksum: 5edb0cf43049602a3c220ded128a6406 (MD5) / Made available in DSpace on 2017-12-14T12:54:22Z (GMT). No. of bitstreams: 1 LUCINDA FERNANDES DA SILVA D.pdf: 3356063 bytes, checksum: 5edb0cf43049602a3c220ded128a6406 (MD5) Previous issue date: 2013-02 / Membranas compostas de osmose inversa (OI) comerciais (BW30-Dow Filmtec) foram modificadas através do recobrimento com membrana de poli(álcool vinílico) (PVA) reticulado com glutaraldeído (GA) e membrana compósita contendo carvão ativado em pó (CAP) em matriz de PVA para aumento de sua resistência ao cloro. Esse estudo compara o desempenho da membrana comercial original e as modificadas em meio oxidante de cloro (NaClO 300 mg/L, NaCl 2,000 mg/L, pH 9.5). O tempo de exposição e a concentração do cloro foram monitorados em termos de ppm.h (concentração da solução de cloro em ppm exposta a membrana por um tempo fixo em h). Análises de ATR-FTIR e TGA confirmaram a reação de reticulação entre o GA e o PVA além da influência do CAP na matriz da membrana compósita de PVA. Imagens do MEV relativas às membranas original e modificada foram empregadas para avaliação do cobrimento da superfície das membranas. A rejeição salina (NaCl) e a permeabilidade hidráulica foram avaliadas durante um período maior que 100 h. Ambas as modificações de superfície demonstraram com eficiência o aumento da resistência ao cloro da membrana comercial de OI de 1,00 ppm.h para mais de 15.000 ppm.h. / Commercial thin-film composite reverse osmosis (RO) membranes (BW30-Dow Filmtec) were modified by covering it with a poly(vinyl alcohol) (PVA) membrane crosslinked with glutaraldehyde (GA) and a composite membrane containing powdered activated carbon (PAC) in a matrix of PVA to improve its resistance to chlorine. This study compares the performance of the original commercial membrane and the modified ones in an oxidant chlorine medium (NaClO 300 mg/L, NaCl 2,000 mg/L, pH 9.5). The exposure time and the chlorine concentration were monitored and taken in terms of ppm.h (ppm chlorine concentration solution exposed to membrane for a fixed time in h). ATR-FTIR and TGA analysis confirmed the crosslinking reaction between GA and PVA besides the influence of PAC in the PVA matrix of the composite membrane. SEM images of the original and modified membranes were used to evaluate the surface coating of the membranes. The salt rejection (NaCl) and water permeability were measured during more than 100 h period. Both surface modifications have effectively demonstrated the increase for the chlorine resistance of the commercial RO membrane from 1,000 ppm.h to more than 15.000 ppm.h.

Orientador: Fernanda Elizabeth Xidieh Murr / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T18:27:51Z (GMT). No. of bitstreams: 1 Alves_DeniseGomes_D.pdf: 7580530 bytes, checksum: db12199d14d28ee9a851ac02dd6b4351 (MD5) Previous issue date: 2003 / Resumo: O presente trabalho teve a finalidade de obter acerola em passa utilizando processos combinados de desidratação osmótica e secagem. Foi estudada a influência da desidratação osmótica utilizando soluções binária (água+sacarose) e ternária (água+sacarose+sal) na secagem convectiva de acerola (Malpighia punicifolia L.). Para os pré-tratamentos foram avaliadas as influências do tempo (30 e 90 minutos), temperatura (25 e 60°C) e concentração de sacarose (30 e 60 % p/p) para a solução binária e concentração de sacarose (20 e 50% p/p) para a solução ternária (10% de sal), nas respostas perda de peso, perda de água, ganho de sólidos e na relação ganho de sólidos/perda de água. Para cada solução foi escolhida uma condição para proceder à secagem convectiva e essa condição foi determinada pelo menor valor da relação ganho de sólidos/perda de água. As condições escolhidas foram: solução binária com 60% de sacarose e solução ternária com 50% de sacarose e 10% de sal, ambas na mesma temperatura de 60°C e mesmo tempo de imersão (90 minutos). Foram avaliadas as influências da temperatura (43, 50, 60, 70 e 77°C) e velocidade do ar de secagem (0,50; 0,65; 1,00; 1,35 e 1,50 m/s) nas respostas atividade de água (aw), perda de vitamina C (PC) e tempo de secagem (ts). A acerola desidratada osmoticamente com solução ternária apresentou menores valores de aw, PC e ts. A acerola congelada apresentou os maiores valores de aw, PC e ts, enquanto que a desidratada osmoticamente com solução binária apresentou valores intermediários entre as outras duas condições. Para a análise sensorial foram escolhidos amostras com menores valores de aw, PC e ts. A acerola congelada não foi avaliada sensorialmente por apresentar valores de aw muito elevados, próximos aos valores apresentados pela fruta in natura. A acerola desidratada osmoticamente com solução binária foi a mais aceita pelos provadores situando-se entre as categorias "gostei ligeiramente" e "gostei moderadamente" / Abstract: In the present work it was studied the influence of the osmotic dehydration process using binary (sucrose+water) and ternary (sucrose+salt+water) solutions in the convective drying of acerola fruit (Malpíghía punícífolía L.). Pretreatments were evaluated by influences of immersion time (30 and 90 minutes), temperature (25 and 60°C) and sucrose concentration (30 and 60% w/w) for binary solution and sucrose concentration (20 and 50% w/w) for the ternary solution (10% of salt), on responses of weight loss, water loss, solid gain and solid gain/water loss ratio. For each solution, a condition was stablished to proceed to the convective drying and that condition was determined by the smallest value of the solid gain/water loss ratio. The chosen conditions were: binary solution with 60% of sucrose and ternary solution with 50% of sucrose and 10% of salt, both in the same temperature of 60°C and same immersion time (90 minutes. Influences of temperature (43, 50,60, 70 and 77OC) and air velocities (0,50; 0,65; 1,00; 1,35 and 1,50 m/s) on responses water activity (aw), vitamin C loss (PC) and drying time (ts). Osmotically dehydrated acerola fruit with ternary solution presented smaller values of aw, PC and ts. Frozen acerola fruit presented the largest values of aw, PC and ts, while osmotically dehydrated acerola fruit with binary solution presented intermediate values as compared to other conditions. For sensorial analysis they were chosen samples with smaller values of aw, PC and ts. The frozen acerola fruit was not evaluated in sensorial analysis because presented very high values of aw, close to the values presented by fresh fruit. Osmotically dehydrated acerola fruit with binary solution was more acceptable, with acceptance values in the categories "Iiked lightly" and "liked moderately." / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

Orientador: Fernanda Elizabeth Xidieh Murr / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:39:35Z (GMT). No. of bitstreams: 1 Araujo_EderAugustoFurtado_D.pdf: 3550124 bytes, checksum: 4ae4c9ab1e30f5794d31594fe6304ecd (MD5) Previous issue date: 2005 / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

Orientador: Nelson Horacio Pezoa Garcia / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T01:19:17Z (GMT). No. of bitstreams: 1 Lima_AntonioCalixto_D.pdf: 1805819 bytes, checksum: ea139fe6e1ab6890ae9fa0148511ea3b (MD5) Previous issue date: 2004 / Resumo: A pesquisa objetivou contribuir para a redução das perdas do pseudofruto de caju, estimadas em 1 bilhão kg/ano. Realizou-se a desidratação osmótica a vácuo do pseudofruto de caju do clone CCP 76, empregando-se suco de caju clarificado e concentrado a vácuo com 65°Brix como agente osmótico. A partir da Metodologia de Superfície de Respostas foram definidas as combinações do binômio tempo*temperatura que permitem a obtenção dos melhores rendimentos do processo: 40°C/100min e 36°C/140min. Nestas condições obteve-se, respectivamente, perda de peso da ordem de 32,67 e 31,50%, incorporação de sólidos de 5,37 e 6,20% e perda de umidade de 38,58 e 36,37%. Na desidratação osmótica à pressão ambiente de rodelas de pedúnculos de caju, foram testados os fatores tempo (90, 112, 165, 218 e 240min), temperatura (30; 35; 40; 45 e 50°C) e concentração do suco de caju (55, 60, 65, 70 e 75°Brix). Verificou-se aumento da perda de peso, da perda de umidade, de sólidos totais e da incorporação de sólidos com a elevação dos níveis das variáveis independentes. Foram realizados testes de aceitação sensorial de nove formulações que permitiram selecionar três barras de caju cujos pedúnculos foram desidratados por processos de liofilização, em secador solar e por ar quente em estufas, após terem sido submetidos à desidratação osmótica. As três barras de caju selecionadas foram estocadas por 360 dias, e a intervalos de 45-60 dias foram realizadas análises que demontraram serem estáveis física, química e microbiológicamente. As características sensoriais de todas as barras se mantiveram sem alterações e apresentaram boa aceitação ao longo de todo o período de avaliação, recebendo notas para intenção de compra acima de quatro (4) e médias superiores a sete (7) para os atributos textura, aparência, sabor e aceitação global / Abstract: The aim of this research was to contribute to reduction of cashew apple losses, estimated at 1 billion kg/year. Vacuum osmotic dehydration of the cashew apple clone CCP 76 was done using clarified cashew juice concentrated to 65oBrix as the osmotic agent. Response Surface Methodology was used to define the best time temperature combinations: 40°C/100min and 36°C/140min. Under these conditions the following results were obtained, respectively, 32.67 and 31.50% weight loss, 5.37 and 6.20% solids incorporation, 38.58 and 36.37% moisture loss. For the osmotic dehydration at ambient pressure of cashew apple discs, the factors tested were time (90, 112, 165, 218 and 240min), temperature (30, 35, 40, 45 and 50°C) and cashew juice concentration (55, 60, 65, 70 and 75°Brix). Increases in the levels of the independent variables resulted in increases in weight loss, moisture loss and total solids and solids incorporation. Acceptance tests were performed for nine formulations allowing for the selection of three cashew bars, whose peduncles were dried by freeze drying, solar drying and hot air, after being osmotically dried. The three cashew bars selected were stored and analyzed every 45-60 days for their physical, chemical and microbiological stability. The sensoriy characteristics of all the bars remained unchanged and presented good acceptability throughout the period studied, receiving scores for purchase intent above four (4) and averages above seven (7) for the the attributes of texture, appearance, flavor and overall acceptability / Doutorado / Doutor em Tecnologia de Alimentos

L’utilisation de l’ultrafiltration (UF) pour la concentration du lait de fromagerie est une pratique courante en industrie laitière. Dépendamment de l’usage de ce type de concentré, plusieurs avantages y ont été associé, tels que des gains de rendements et de productivité. D’autres procédés baromembranaires, tels que l’osmose inverse (RO) et la nanofiltration (NF), actuellement utilisés pour la gestion des effluents de l’industrie laitière, semblent prometteurs pour réaliser cette étape de concentration du lait de fromagerie. En effet, les gains de rendements attendus avec ces deux procédés sont plus élevés qu’avec l’ultrafiltration car tous les composés du lait sont concentrés et peuvent potentiellement être retenus dans le fromage. De plus, le perméat généré ne contient essentiellement que de l’eau et peut être réutilisé au sein de l’usine. Cependant, ces types de concentrés laitiers (NF et RO) ne sont que peu connus et leur utilisation en fromagerie ne peut être envisagée actuellement. Le but de ce projet était donc de caractériser les concentrés laitiers provenant de l’osmose inverse ou de la nanofiltration du lait et de comprendre les facteurs influençant leurs propriétés fromagères. Une première étude a permis de mettre en évidence l’impact des procédés de concentration du lait sur les propriétés physico-chimiques des concentrés. Il a été montré que les équilibres entre les phases soluble et colloïdale n’étaient pas impactés de façon notable par la concentration du lait, que ce soit par UF, NF ou RO. Ces deux derniers procédés ont, en revanche, mené à une diminution du pH et une augmentation de la force ionique et de la viscosité des concentrés. A pH constant et teneur en protéines similaires, les propriétés de coagulation par la présure ont été impactées par le type de concentrés utilisé et globalement un concentré UF avait de meilleures propriétés de coagulation qu’un concentré NF ou RO. Ces différences ont été attribuées à la force ionique élevée et/ou à la viscosité élevée. Cette première partie a donc permis de déterminer l’impact du procédé de concentration sur les caractéristiques des concentrés et de mettre en évidence les différences de propriétés entre plusieurs types de concentrés laitiers. Dans une seconde étude, l’impact du type de concentré et de l’ajustement de pH sur les propriétés de coagulation par la présure a été déterminé. Les résultats obtenus dans la première partie du projet ont montré des différences de temps de coagulation des concentrés UF et RO. Pour mieux comprendre quel paramètre était responsable, les cinétiques d’hydrolyse de la caséine κ par la présure ont été étudiées. Deux résultats majeurs ont pu être mis en évidence. Premièrement, de faibles variations de pH ont permis d’obtenir des cinétiques de coagulation par la présure similaires entre un concentré RO et un concentré UF, malgré les différences importantes de composition. Deuxièmement, à même pH, les cinétiques d’hydrolyse étaient similaires entre ces deux concentrés et ainsi, les temps de coagulation dépendaient du degré d’hydrolyse au point de coagulation. Finalement, la troisième étude réalisée a permis de déterminer la contribution du lactose et des minéraux aux propriétés fromagères des concentrés RO et d’évaluer l’impact d’une modification des équilibres salins (déminéralisation de la micelle de caséines) des concentrés sur leurs propriétés fromagères. Les teneurs importantes en lactose et en minéraux ont été, conjointement, responsables des principales différences observées au niveau des propriétés de coagulation par la présure entre un concentré RO et UF. En revanche, seul le lactose était à l’origine de l’augmentation des rendements fromagers observée avec l’utilisation de concentrés RO. La déminéralisation de la micelle de caséine, via ajout de NaCl, a un impact négatif sur les propriétés fromagères des concentrés avec une perte de matière grasse marquée et une baisse des rendements fromagers, et n’est donc pas un moyen intéressant pour améliorer les propriétés fromagères des concentrés. Ce projet a permis d’apporter de nouvelles connaissances sur les concentrés laitiers produits par osmose inverse, et dans une moindre mesure par nanofiltration, et de mettre en évidence l’impact de ces procédés de concentration sur les propriétés fromagères des concentrés. La meilleure compréhension de ces systèmes laitiers et des facteurs affectant leurs caractéristiques permet de fournir des pistes à envisager pour optimiser leur utilisation en fromagerie. / The use of pressure-driven membrane processes is a common practice in the dairy industry, and ultrafiltration (UF) is widely used for the concentration of cheesemilk. Depending on how the UF concentrate is used, several advantages have been claimed, such as yield and productivity gains. Other membrane processes, such as reverse osmosis (RO) and nanofiltration (NF), are currently used for the management of effluents in the dairy industry and could be promising for cheesemilk concentration. Indeed, they are expected to lead to higher yield gains than UF concentrates, due to the concentration of all milk compounds and the retention of some of them in the cheese. In addition, the permeates generated contain essentially water and can be reused within the plant. However, only little information can be found about these types of milk concentrates and more knowledge is needed to consider their use for cheesemaking. The purpose of this project was therefore to characterize the milk concentrates from reverse osmosis and nanofiltration and to study their cheesemaking properties. A first study highlighted the impact of the milk concentration process on the physicochemical properties of the concentrates. It has been shown that the equilibria between the soluble and colloidal phases were not significantly affected by the concentration of milk, using UF, NF or RO. The latter two processes, on the other hand, have led to a decrease in pH and an increase in ionic strength and viscosity of the concentrates. At constant pH and similar protein content, rennet coagulation properties were affected by the type of concentrates used and, overall the UF concentrate had better coagulation properties than NF or RO concentrates. These differences were attributed to their high ionic strength and/or high viscosity. This first part, therefore, allowed us to have an overview of the impact of the concentration process on the concentrates characteristics and to highlight the differences in properties between various types of milk concentrates. A second study investigated the impact of the type of concentrate and pH adjustment on the rennet coagulation properties. The results obtained in the first part of the project showed the differences in coagulation times of UF and RO concentrates. To understand which parameter was responsible for those differences, the kinetics of κ- casein hydrolysis by rennet were studied. Two major results were highlighted. First, small pH variations allowed to obtain similar rennet coagulation kinetics between RO and UF concentrates, despite the significant differences in composition. Secondly, at the same pH, the hydrolysis kinetics were similar between these two concentrates and the differences in coagulation time were due to variation in the degree of hydrolysis at the coagulation point. Finally, the third study carried out highlighted the contribution of the high lactose and salts contents on the impaired cheesemaking properties of RO concentrates. Furthermore, the impact of a change in salt equilibrium (reduced micellar salt content) on the cheesemaking properties of milk concentrates was also studied. The high contents of lactose and salts were both responsible for the impaired rennet gelation properties of RO concentrates. However, the high lactose content alone was accountable for the increased cheese yields with the use of RO concentrates. Reducing the mineral charge of the micelles, via addition of NaCl, had a negative impact on the cheesemaking properties of concentrates with marked fat losses and decreased cheese yields. This approach is then not suitable to improve the cheesemaking properties of milk concentrates. This project provided new knowledge on milk concentrates produced by reverse osmosis, and to a lesser extent by nanofiltration, as well as on the impact of these concentration processes on the cheesemaking properties of the concentrates. The better understanding of these concentrates is necessary to optimize their use in cheesemaking.

L’ajustement protéique du lait de fromagerie par ultrafiltration (UF) est une pratique courante, mais très peu d’études ont porté sur l’utilisation de l’osmose inverse (OI) pour la fabrication fromagère. La préconcentration du lait de fromagerie par OI permettrait d’améliorer l’éco-efficience du procédé, ainsi que d’augmenter l’efficacité de production et les rendements. Des travaux récents ont montré que les fromages fabriqués à partir des concentrés d’OI contiennent une teneur importante en lactose et en minéraux et sont plus humides que les autres types de fromages. Dans le cadre de ce projet de recherche, l’ajustement du pH, le lavage du caillé et l’utilisation d’un agent chélateur du calcium sont les leviers qui ont été évalués pour leur potentiel à égoutter et à déminéraliser le fromage. Les propriétés fromagères ont été étudiées en comparaison avec celles des concentrés d'UF. Dans cette étude, il a été possible d’explorer une nouvelle application d’un sel habituellement utilisé pour la fabrication des fromages fondus. Le salage à sec avec le citrate de sodium (TSC) a amélioré la rétention du gras de 4,56 % dans les fromages d’OI, mais des études complémentaires de distribution minérale seront nécessaires pour déterminer s’il s’agit d’un levier d’intérêt. Dans les conditions testées, le lavage du caillé n’a pas amélioré les propriétés des concentrés d’OI. L'acidification a permis d’augmenter les rendements, la rétention du gras et l’égouttage et a diminué la teneur en minéraux et le ratio calcium total / protéines du fromage modèle. Les rendements obtenus lors de la fabrication fromagère à partir des concentrés d’OI étaient de 2 à 3 % supérieurs à ceux obtenus en UF. Cette étude suggère que le pH peut jouer un rôle majeur dans l'amélioration de la qualité des fromages faits de concentrés d'OI et que ce type de concentré peut contribuer à améliorer significativement les rendements fromagers par rapport à l’UF. / The protein adjustment of cheese milk by ultrafiltration (UF) is a common practice, but very few studies have focused on the use of reverse osmosis (RO) for cheesemaking. Milk preconcentration by RO prior to cheesemaking could improve the eco-efficiency of the process, as well as to increase production efficiency and yields. Previous studies have shown that cheeses made from RO concentrates have a high content of lactose, minerals and moisture in comparison to other types of cheeses. As part of this research project, pH adjustment, curd washing and the use of a calcium chelating agent are the levers that have been evaluated for their potential to decrease the level of moisture and minerals in the cheese. Cheesemaking properties of RO concentrates have been studied in comparison with those of UF concentrates and non-concentrated milk. In this study, it was possible to explore a new application of a chelating salt usually used in processed cheese. Dry salting with trisodium citrate (TSC) improved fat recovery by 4.56%, but further studies of mineral distribution will be necessary to determine if it is a lever of interest. In the conditions tested, washing the curd with water or with TSC solution did not improve the properties of RO concentrates. Acidification helped to increase yields, fat recovery and curd drainage and decreased the mineral content and total calcium / protein ratio of model cheese. The yields obtained during cheesemaking from RO concentrates were 2 to 3 % higher than those obtained with UF. This study confirms the importance of controlling pH in cheesemaking and its fundamental impact on cheese mineralization and moisture. It also suggests that pH can play a major role in improving the quality of cheese made from RO concentrates and that this type of concentrate can significantly improve cheese yields compared to UF.

Sous les effets combinés de la surexploitation des ressources marines et du changement climatique la mer Méditerranée se transforme progressivement en un point chaud du changement global. En dépit d’un grand nombre de modèles développés localement ou régionalement en mer Méditerranée, aucun ne s’est encore attelé aux modifications d'assemblages d’espèces à l’échelle du bassin avec une modélisation intégrée des écosystèmes de la physique jusqu’aux prédateurs et représentant explicitement les dimensions à la fois multi-spécifique, spatiale, et trophique. Ces travaux de thèse présentent donc un triple enjeu : (i) mettre en œuvre une telle modélisation de la richesse spécifique en Méditerranée basée sur les traits de vie et représentant l'intégralité du cycle de vie d’espèces en interaction ; (ii) projeter les conséquences des changements physiques et biogéochimiques induits par le changement climatique sur la distribution spatiale des espèces et sur la structure et le fonctionnement trophique de l'écosystème méditerranéen ; (iii) explorer des scénarios de gestion des pêches visant à reconstituer certains stocks d'intérêts commerciaux dans un contexte de changement climatique. Pour répondre à ces enjeux, un modèle end-to-end, OSMOSE-MED, s’appuyant sur le couplage d’un modèle de hauts niveaux trophiques OSMOSE à des modèles de physique et de biogéochimie NEMOMED12 et ECO3M-S, a été développé. Avec cent espèces modélisées, représentant près de 95 % des captures effectuées en Méditerranée, il s’agit du premier modèle trophique de ce type intégrant une aussi grande richesse spécifique, sur une échelle spatiale aussi vaste (la mer Méditerranée dans son ensemble) et à fine résolution (20x20 km²). Selon le scénario d'émissions de gaz à effet de serre RCP8.5, les projections réalisées avec le modèle OSMOSE-MED mettent en évidence une augmentation globale de la biomasse et des captures, respectivement de 22% et 7% d'ici la fin du siècle. Ces augmentations masquent néanmoins de grandes disparités géographiques. Le bassin oriental se démarque par une augmentation globale de la biomasse associée aux espèces exotiques. Au regard des captures, le modèle prévoit des augmentations dans le bassin oriental et une diminution importante dans la partie occidentale. Un changement de la composition spécifique des captures pourrait apparaître au cours du 21ème siècle avec l'apparition d'espèces gagnantes (e.g. anchois) et perdantes (e.g. merlu). Les espèces gagnantes seraient principalement les espèces de petits pélagiques, thermophiles et/ou exotiques, de plus petites tailles et de plus bas niveaux trophiques tandis que les espèces perdantes seraient généralement les grands démersaux et pélagiques, pouvant pâtir d'un décalage spatial avec leurs proies potentielles à la suite d'une contraction ou d'un déplacement de leur aire de répartition géographique. Dans ce contexte, les projections de scénarios de gestion des pêches mettent en évidence les avantages d'une plus grande sélectivité ou d'une réduction de la mortalité par pêche pour reconstituer certains stocks d'intérêts commerciaux, en particulier parmi les organismes appartenant au groupe des démersaux, benthiques et grands pélagiques. Une réduction de la mortalité par pêche pourrait en outre inverser les tendances projetées à la baisse de la biomasse et des captures totales en Méditerrannée occidentale. / Under the combined effects of overexploitation of marine resources and climate change the Mediterranean Sea is gradually becoming a hotspot of global change. Despite a large number of models developed locally or regionally in the Mediterranean Sea, no previous studies have addressed changes in species assemblages at the basin scale with an integrated ecosystem modelling from physics to predators and explicitly representing the multi-species, spatial, and trophic dimensions. This thesis work presents a threefold challenge: (i) implementing such a model of the species richness in the Mediterranean Sea based on life history traits and representing the entire life cycle of interacting species; (ii) projecting the consequences of physical and biogeochemical changes induced by climate change on the spatial distribution of species and on the structure and trophic functioning of the Mediterranean ecosystem; (iii) exploring fisheries management scenarios aiming at rebuilding some stocks of commercial interest in a climate change context. To address these challenges, an end-to-end model, OSMOSE-MED, based on the coupling of a high trophic level OSMOSE model with NEMOMED12 and ECO3M-S physical and biogeochemical models, has been developed. With 100 modelled species, representing nearly 95% of the catches made in the Mediterranean Sea, it is the first trophic model of this type to integrate such a large diversity of species, on such a large spatial scale (the Mediterranean Sea as a whole) and at fine resolution (20x20 km²). According to the greenhouse gas emissions scenario RCP8.5, projections made with the OSMOSE-MED model show an overall increase in biomass and catches of 22% and 7% respectively by the end of the century. However, these increases mask large geographical disparities. The eastern basin is characterized by an overall increase in biomass associated with exotic species. With regard to catches, the model projects increase in the eastern basin and a significant decrease in the western part. A change in the species composition of catches could appear during the 21st century with winner (e.g. anchovy) and loser (e.g. hake) species. Winner species would mainly belong to the small pelagics group, are thermophilic and/or exotic, of smaller sizes and of low trophic level while loser species are generally large-sized, some of them of great commercial interest, and could suffer from a spatial mismatch with potential prey subsequent to a contraction or shift of their geographic range. Fisheries management scenario projections highlight the benefits of greater selectivity or reduced fishing mortality for the recovery of certain stocks of commercial interest, particularly among organisms belonging to the demersal, benthic and large pelagic groups. A reduction in fishing mortality could also reverse the projected decline in biomass and total catches in the Western Mediterranean.