O presente trabalho teve como objetivo estudar diferentes tecnologias na extração de óleo da semente de gergelim e de compostos fenólicos e proteínas da torta de gergelim. Este estudo está dividido em quatro partes. O objetivo da primeira parte do trabalho foi extrair compostos fenólicos de diferentes tortas de nozes e sementes nas mesmas condições e comparar o teor de tais compostos e a atividade antioxidante dos extratos. Nessa fase, foram utilizadas nos experimentos tortas das sementes de girassol, linhaça e gergelim, e das nozes amêndoa, pecã, macadâmia e avelã. O extrato da torta de noz pecã apresentou o maior teor de todos os compostos fenólicos analisados, seguido pelo extrato da torta de semente de girassol e de avelã. Essas amostras também apresentaram as maiores atividades antioxidantes. As etapas seguintes do trabalho focaram-se no gergelim. A segunda parte do trabalho teve como objetivo a otimização da extração, pela metodologia convencional, de fenólicos totais e lignanas da torta de gergelim. Inicialmente, um modelo polinomial de segunda ordem foi utilizado para predição dos resultados, mediante a variação da temperatura, concentração de etanol e razão, sólido/solvente. As variáveis de resposta foram as concentrações de fenólicos totais, de sesamina e de sesaminol triglicosídeo e a atividade antioxidante dos extratos obtidos. Entre os compostos analisados, o sesaminol triglicosídeo está presente em maior quantidade na torta de gergelim. A razão sólido/solvente e a concentração de etanol foram os fatores que mais afetaram a extração, enquanto a temperatura demonstrou uma influência reduzida. Na terceira etapa, o escopo da pesquisa foi a avaliação de metodologias alternativas na extração desses mesmos compostos e, também, de proteínas. As tecnologias usadas foram as de campo elétrico pulsado (CEP) e de descargas elétricas de alta tensão (DEAT). A análise da aplicação de CEP e de DEAT foi realizada usando essas tecnologias como pré-tratamentos ao processo de extração com solvente. Os resultados demonstraram que as técnicas foram eficazes e aumentaram os rendimentos do processo para fenólicos totais, lignanas e proteínas da torta. O uso de diferentes porcentagens de etanol também se mostrou significativo nessa etapa, entretanto, esse efeito foi reduzido quando utilizadas as tecnologias elétricas. Da mesma forma, o efeito da temperatura na etapa difusiva foi menor quando os pré-tratamento foram utilizados. Os comportamentos observados sugerem que a aplicação de CEP e DEAT aumenta a eficiência da extração de compostos de interesse. Por fim, na quarta parte do trabalho, objetivou-se melhorar a eficiência do processo de extração do óleo de gergelim aplicando as tecnologias previamente citadas. Esses experimentos demonstraram um efeito significativo dos tratamentos de CEP e DEAT e um aumento na quantidade de óleo extraído com o aumento da energia aplicada às sementes. O uso de DEAT gerou um aumento maior na quantidade de óleo extraído, se comparado à tecnologia de CEP. / The goal of the present work was to study different technologies in the extraction of oil from sesame seed and phenolic compounds and proteins from sesame cake. This study is divided in four parts. The first part aimed to extract water-soluble compounds from different seed and nut cakes under the same conditions and compare the phenolic content and antioxidant activity of the extracts. For the first portion of the study, seed cakes of sunflower, pumpkin, flaxseed and defatted sesame, and nut cakes of almond, pecan, macadamia and hazelnut were used in the experiments. The extract from pecan nut cake presented the highest amounts of all compounds analyzed, followed by sunflower seed and hazelnut cake extracts. These samples also had the highest antioxidant activities. The following steps of the work focused on sesame only. The second part of the work aimed to optimize the extraction of total phenolics and lignans from sesame seed cake. Initially, a second-order polynomial model was set up to predict the responses in different temperatures, solid/solvent ratios and ethanol concentrations. The response variables were the concentrations of total phenolics, sesamin, sesaminol triglucoside and antioxidant activity of the extracts. Among the analyzed compounds, ST is presented in the highest quantity in sesame cake. Solid to liquid ratio and ethanol concentration where the most important factors affecting extraction, whereas temperature showed reduced influence. In the third part of this work, the aim was to evaluate alternative methodologies in the extraction of phenolics and proteins. The technologies used were pulsed electric fields (PEF) and high voltage electric discharges (HVED). These methods were used as pre-treatments, prior to diffusion. Result show that PEF and HVED were efficient and increased the extraction yield for phenolic compounds, lignans and proteins from the cake. The use of different percentages of ethanol was also significant in this stage; however, the effect of this parameter was reduced when the electrical treatments were used. In the same way, temperature also showed a smaller influence on the results when the pre-treatments were used. The observed behaviors suggest that the use of PEF and HVED increases extraction efficiency. Finally, the goal of the last part of the work was to improve oil expression from sesame seeds, using the aforementioned technologies. These experiments show a significant effect of both PEF and HVED. It was observed an increase of the amount of oil extracted with the energy input applied to the seeds. When compared both technologies, HVED showed a more expressive effect then PEF.

O presente trabalho teve como objetivo estudar diferentes tecnologias na extração de óleo da semente de gergelim e de compostos fenólicos e proteínas da torta de gergelim. Este estudo está dividido em quatro partes. O objetivo da primeira parte do trabalho foi extrair compostos fenólicos de diferentes tortas de nozes e sementes nas mesmas condições e comparar o teor de tais compostos e a atividade antioxidante dos extratos. Nessa fase, foram utilizadas nos experimentos tortas das sementes de girassol, linhaça e gergelim, e das nozes amêndoa, pecã, macadâmia e avelã. O extrato da torta de noz pecã apresentou o maior teor de todos os compostos fenólicos analisados, seguido pelo extrato da torta de semente de girassol e de avelã. Essas amostras também apresentaram as maiores atividades antioxidantes. As etapas seguintes do trabalho focaram-se no gergelim. A segunda parte do trabalho teve como objetivo a otimização da extração, pela metodologia convencional, de fenólicos totais e lignanas da torta de gergelim. Inicialmente, um modelo polinomial de segunda ordem foi utilizado para predição dos resultados, mediante a variação da temperatura, concentração de etanol e razão, sólido/solvente. As variáveis de resposta foram as concentrações de fenólicos totais, de sesamina e de sesaminol triglicosídeo e a atividade antioxidante dos extratos obtidos. Entre os compostos analisados, o sesaminol triglicosídeo está presente em maior quantidade na torta de gergelim. A razão sólido/solvente e a concentração de etanol foram os fatores que mais afetaram a extração, enquanto a temperatura demonstrou uma influência reduzida. Na terceira etapa, o escopo da pesquisa foi a avaliação de metodologias alternativas na extração desses mesmos compostos e, também, de proteínas. As tecnologias usadas foram as de campo elétrico pulsado (CEP) e de descargas elétricas de alta tensão (DEAT). A análise da aplicação de CEP e de DEAT foi realizada usando essas tecnologias como pré-tratamentos ao processo de extração com solvente. Os resultados demonstraram que as técnicas foram eficazes e aumentaram os rendimentos do processo para fenólicos totais, lignanas e proteínas da torta. O uso de diferentes porcentagens de etanol também se mostrou significativo nessa etapa, entretanto, esse efeito foi reduzido quando utilizadas as tecnologias elétricas. Da mesma forma, o efeito da temperatura na etapa difusiva foi menor quando os pré-tratamento foram utilizados. Os comportamentos observados sugerem que a aplicação de CEP e DEAT aumenta a eficiência da extração de compostos de interesse. Por fim, na quarta parte do trabalho, objetivou-se melhorar a eficiência do processo de extração do óleo de gergelim aplicando as tecnologias previamente citadas. Esses experimentos demonstraram um efeito significativo dos tratamentos de CEP e DEAT e um aumento na quantidade de óleo extraído com o aumento da energia aplicada às sementes. O uso de DEAT gerou um aumento maior na quantidade de óleo extraído, se comparado à tecnologia de CEP. / The goal of the present work was to study different technologies in the extraction of oil from sesame seed and phenolic compounds and proteins from sesame cake. This study is divided in four parts. The first part aimed to extract water-soluble compounds from different seed and nut cakes under the same conditions and compare the phenolic content and antioxidant activity of the extracts. For the first portion of the study, seed cakes of sunflower, pumpkin, flaxseed and defatted sesame, and nut cakes of almond, pecan, macadamia and hazelnut were used in the experiments. The extract from pecan nut cake presented the highest amounts of all compounds analyzed, followed by sunflower seed and hazelnut cake extracts. These samples also had the highest antioxidant activities. The following steps of the work focused on sesame only. The second part of the work aimed to optimize the extraction of total phenolics and lignans from sesame seed cake. Initially, a second-order polynomial model was set up to predict the responses in different temperatures, solid/solvent ratios and ethanol concentrations. The response variables were the concentrations of total phenolics, sesamin, sesaminol triglucoside and antioxidant activity of the extracts. Among the analyzed compounds, ST is presented in the highest quantity in sesame cake. Solid to liquid ratio and ethanol concentration where the most important factors affecting extraction, whereas temperature showed reduced influence. In the third part of this work, the aim was to evaluate alternative methodologies in the extraction of phenolics and proteins. The technologies used were pulsed electric fields (PEF) and high voltage electric discharges (HVED). These methods were used as pre-treatments, prior to diffusion. Result show that PEF and HVED were efficient and increased the extraction yield for phenolic compounds, lignans and proteins from the cake. The use of different percentages of ethanol was also significant in this stage; however, the effect of this parameter was reduced when the electrical treatments were used. In the same way, temperature also showed a smaller influence on the results when the pre-treatments were used. The observed behaviors suggest that the use of PEF and HVED increases extraction efficiency. Finally, the goal of the last part of the work was to improve oil expression from sesame seeds, using the aforementioned technologies. These experiments show a significant effect of both PEF and HVED. It was observed an increase of the amount of oil extracted with the energy input applied to the seeds. When compared both technologies, HVED showed a more expressive effect then PEF.

O presente trabalho teve como objetivo estudar diferentes tecnologias na extração de óleo da semente de gergelim e de compostos fenólicos e proteínas da torta de gergelim. Este estudo está dividido em quatro partes. O objetivo da primeira parte do trabalho foi extrair compostos fenólicos de diferentes tortas de nozes e sementes nas mesmas condições e comparar o teor de tais compostos e a atividade antioxidante dos extratos. Nessa fase, foram utilizadas nos experimentos tortas das sementes de girassol, linhaça e gergelim, e das nozes amêndoa, pecã, macadâmia e avelã. O extrato da torta de noz pecã apresentou o maior teor de todos os compostos fenólicos analisados, seguido pelo extrato da torta de semente de girassol e de avelã. Essas amostras também apresentaram as maiores atividades antioxidantes. As etapas seguintes do trabalho focaram-se no gergelim. A segunda parte do trabalho teve como objetivo a otimização da extração, pela metodologia convencional, de fenólicos totais e lignanas da torta de gergelim. Inicialmente, um modelo polinomial de segunda ordem foi utilizado para predição dos resultados, mediante a variação da temperatura, concentração de etanol e razão, sólido/solvente. As variáveis de resposta foram as concentrações de fenólicos totais, de sesamina e de sesaminol triglicosídeo e a atividade antioxidante dos extratos obtidos. Entre os compostos analisados, o sesaminol triglicosídeo está presente em maior quantidade na torta de gergelim. A razão sólido/solvente e a concentração de etanol foram os fatores que mais afetaram a extração, enquanto a temperatura demonstrou uma influência reduzida. Na terceira etapa, o escopo da pesquisa foi a avaliação de metodologias alternativas na extração desses mesmos compostos e, também, de proteínas. As tecnologias usadas foram as de campo elétrico pulsado (CEP) e de descargas elétricas de alta tensão (DEAT). A análise da aplicação de CEP e de DEAT foi realizada usando essas tecnologias como pré-tratamentos ao processo de extração com solvente. Os resultados demonstraram que as técnicas foram eficazes e aumentaram os rendimentos do processo para fenólicos totais, lignanas e proteínas da torta. O uso de diferentes porcentagens de etanol também se mostrou significativo nessa etapa, entretanto, esse efeito foi reduzido quando utilizadas as tecnologias elétricas. Da mesma forma, o efeito da temperatura na etapa difusiva foi menor quando os pré-tratamento foram utilizados. Os comportamentos observados sugerem que a aplicação de CEP e DEAT aumenta a eficiência da extração de compostos de interesse. Por fim, na quarta parte do trabalho, objetivou-se melhorar a eficiência do processo de extração do óleo de gergelim aplicando as tecnologias previamente citadas. Esses experimentos demonstraram um efeito significativo dos tratamentos de CEP e DEAT e um aumento na quantidade de óleo extraído com o aumento da energia aplicada às sementes. O uso de DEAT gerou um aumento maior na quantidade de óleo extraído, se comparado à tecnologia de CEP. / The goal of the present work was to study different technologies in the extraction of oil from sesame seed and phenolic compounds and proteins from sesame cake. This study is divided in four parts. The first part aimed to extract water-soluble compounds from different seed and nut cakes under the same conditions and compare the phenolic content and antioxidant activity of the extracts. For the first portion of the study, seed cakes of sunflower, pumpkin, flaxseed and defatted sesame, and nut cakes of almond, pecan, macadamia and hazelnut were used in the experiments. The extract from pecan nut cake presented the highest amounts of all compounds analyzed, followed by sunflower seed and hazelnut cake extracts. These samples also had the highest antioxidant activities. The following steps of the work focused on sesame only. The second part of the work aimed to optimize the extraction of total phenolics and lignans from sesame seed cake. Initially, a second-order polynomial model was set up to predict the responses in different temperatures, solid/solvent ratios and ethanol concentrations. The response variables were the concentrations of total phenolics, sesamin, sesaminol triglucoside and antioxidant activity of the extracts. Among the analyzed compounds, ST is presented in the highest quantity in sesame cake. Solid to liquid ratio and ethanol concentration where the most important factors affecting extraction, whereas temperature showed reduced influence. In the third part of this work, the aim was to evaluate alternative methodologies in the extraction of phenolics and proteins. The technologies used were pulsed electric fields (PEF) and high voltage electric discharges (HVED). These methods were used as pre-treatments, prior to diffusion. Result show that PEF and HVED were efficient and increased the extraction yield for phenolic compounds, lignans and proteins from the cake. The use of different percentages of ethanol was also significant in this stage; however, the effect of this parameter was reduced when the electrical treatments were used. In the same way, temperature also showed a smaller influence on the results when the pre-treatments were used. The observed behaviors suggest that the use of PEF and HVED increases extraction efficiency. Finally, the goal of the last part of the work was to improve oil expression from sesame seeds, using the aforementioned technologies. These experiments show a significant effect of both PEF and HVED. It was observed an increase of the amount of oil extracted with the energy input applied to the seeds. When compared both technologies, HVED showed a more expressive effect then PEF.

Ce travail de doctorat consiste à valoriser les coproduits issus des industries d’agrumes par des technologies innovantes. Le pressage des agrumes produit des millions de tonnes de déchets par an dans le monde. Ces déchets (peaux, pulpes et pépins) sont généralement dédiés à l’alimentation animale ou bien éliminés par compostage ou incinération. Cependant leur contenu en molécules bioactives conduit à plusieurs voies de valorisation. Vu que les peaux constituent à peu près la moitié de la masse des déchets d’agrumes, les études ont été faites sur la valorisation des peaux de différents types d’agrumes. Les méthodes conventionnelles généralement utilisées pour l’extraction des molécules d’intérêt (extraction solide-liquide, hydrodistillation) présentent plusieurs désavantages tels que l’utilisation des solvants coûteux et toxiques, les longues durées d’extraction et la consommation élevée en énergie. Pour cette raison plusieurs technologies innovantes non thermiques telles que les Champs Electriques Pulsés (CEP), les Décharges Électriques de Haute Tension (DEHT) et les ultrasons (US) et thermiques comme les microondes (MO) et les infrarouges (IR) ont été testées dans ce travail de thèse, pour la valorisation des coproduits d’agrumes. Les agrumes entiers (oranges, pomelos, citrons) sont traités par les CEP à une intensité de 3 kV/cm et l’extraction du jus d’agrumes et des polyphénols a été réalisée par pressage. L’étude de la perméabilisation cellulaire induite par les CEP a été réalisée par plusieurs méthodes et a montré que les degrés d’endommagement diffèrent selon le type d’agrumes traités. L’électroporation des cellules, induite par les CEP a permis d’augmenter les rendements en jus après pressage et d’améliorer le passage des polyphénols des peaux d’agrumes dans le jus. Ce qui explique la possibilité d’obtention d’un jus riche en polyphénols en traitant les agrumes par les CEP avant leur pressage. Parmi les solvants testés pour l’extraction des polyphénols à partir des peaux d’agrumes, l’eau est le moins efficace. L’ajout de 20% de glycérol dans l’eau a modifié la polarité du milieu et a amélioré l’extraction des polyphénols. L’utilisation d’un mélange enzymatique a favorisé la libération des polyphénols piégés dans les polysaccharides. Les solvants eutectiques profonds préparés, ont été aussi efficaces que les mélanges hydro éthanoliques. Pour améliorer d’avantages l’extraction dans les différents solvants verts ou dans le mélange enzymatique, les peaux d’agrumes ont été prétraitées par les DEHT dans l’eau. L’effet mécanique des DEHT, capable de fragmenter les peaux a permis d’améliorer l’extraction des polyphénols 6 dans les différents solvants. L’intensification de l’extraction des polyphénols a été aussi réalisée par les IR et les US. L’extraction des polyphénols par les IR a été optimisée en ayant recours à la méthodologie de surface de réponse. Le chauffage par les IR n’a pas altéré les polyphénols extraits qui ont gardé des activités antifongiques et anti-mycotoxinogènes importantes. Le prétraitement des peaux d’agrumes par les IR sans solvant a fragilisé les structures cellulaires, ce qui a permis d’augmenter la diffusion des polyphénols durant le traitement avec les US. / This work consists of the valorization of citrus by-products with innovative technologies. Citrus pressing produces millions of tons of waste per year worldwide. This waste (peels, pulps and seeds) is generally dedicated to animal feed or eliminated by composting or incineration. However its content in bioactive molecules leads to several ways of valorization. Since peels present about half of the citrus waste mass, studies have been focused on the valorization of citrus peels by the extraction of bioactive compounds. Conventional methods generally used for the extraction of bioactive compounds (solid-liquid extraction, hydrodistillation) have several disadvantages such as the use of expensive and toxic solvents, long extraction times and high energy consumption. For this reason, several innovative non-thermal technologies such as Pulsed Electric Fields (PEF), High Voltage Electrical Discharges (HVED) and Ultrasounds (US) and thermal treatments such as microwaves (MO) and infrared (IR) have been tested for the valorization of citrus by-products. Whole citrus fruits (oranges, pomelos, lemons) were PEF treated at an intensity of 3 kV/cm, then citrus juice and polyphenols were extracted by pressing. The study of the PEF-induced cell permeabilization was conducted by several methods and showed that the degree of damage varied according to the type of the treated fruit. The electroporation of the cells induced by the PEF, allowed an increase the juice yields after pressing and improved the liberation of the polyphenols from the citrus peels into the juice. This explains the possibility of obtaining a juice rich in polyphenols by treating the whole fruits with PEF before pressing. Among the solvents tested for the extraction of polyphenols from citrus peels, water is the least effective. The addition of 20% glycerol to water changed the polarity of the medium and improved the extraction of the polyphenols. The use of an enzyme mixture enhanced the release of the polyphenols related to the polysaccharides. Deep eutectic solvents have been as effective as hydroethanolic mixtures. To improve the yields and the kinetics of extractions in the different green solvents and in the enzyme mixture, citrus peels were pretreated with HVED in water. The mechanical effect of HVED, based on the fragmentation of the peels has improved the extraction of polyphenols in the various solvents. The intensification of polyphenols extraction was also conducted by IR and US. The extraction of polyphenols by IR was optimized using the surface response methodology. IR heating did not alter the extracted polyphenols which have significant antifungal and anti-mycotoxinogenic activities. The pretreatment of citrus peels with IR weakened the cell structures, increasing thus the diffusion of polyphenols during US treatment.

Ce projet de thèse est dédié à l’étude de l’intensification de l’extraction des polymères d’hémicelluloses à partir du bois d’épicéa par l’application de prétraitements physicochimiques : microondes (MO), décharges électriques de hautes tension (DEHT) et explosion à la vapeur (STEX). L’extraction des hémicelluloses est souvent réalisée par autohydrolyse ou par des traitements chimiques. Dans ce travail de thèse, nous avons étudié un procédé basé sur l’extraction des hémicelluloses en combinant des prétraitements physiques aux prétraitements chimiques et à l’autohydrolyse. Ce couplage a permis d’avoir des hémicelluloses avec des poids moléculaires moyens en masse (Mw) élevés allant jusqu’à 70 kDa, 66 kDa et 55 kDa lors des extractions en milieu basique par STEX, MO et DEHT respectivement. Les performances des prétraitements en termes de rendement d’extraction sont plus élevées que pour l’autohydrolyse seule pour les mêmes conditions de température et de temps d’extraction. La caractérisation des hémicelluloses extraites a révélé une sélectivité d’extraction en fonction du pH du milieu d’imprégnation. L’imprégnation en milieu neutre favorise la solubilisation des galactoglucomannanes (GGM) et l’imprégnation en milieu basique favorise la solubilisation des arabinoglucoronoxylanes (ARX). L’analyse du degré d’acétylation (DA) a montré que la STEX a permis d’extraire des acetyl-GGM avec des DA (~0,35) proches de celui des hémicelluloses à l’état natif. Les films élaborés à partir des hémicelluloses extraites présentent des barrières intéressantes vis à vis de l’oxygène (0,83 cm3.μm-1.jour-1.kPa au maximum) et du rayonnement UV. / This thesis project is specifically dedicated to the study of the intensification of the extraction of hemicellulose polymers from spruce wood by the application of physicochemical pretreatments: Microwave (MW), High Voltage Electrical Discharge (HVED) and Steam Explosion (STEX). Extraction of hemicelluloses is often carried out by an autohydrolysis or by chemical treatments. In this work, we have developed an original process for extracting hemicelluloses polymers by combining physical pretreatments (MW, HVED and STEX) with chemical pretreatments and autohydrolysis. This combination allowed us to recover hemicelluloses with average molecular weights (Mw) highs up to 70 kDa, 66 kDa and 55 kDa when STEX, MW and HVED were applied in basic medium respectively. The performance of the pretreatments in terms of extraction yield is higher than the autohydrolysis alone for the same extraction temperatures. The characterization of the extracted hemicelluloses revealed an extraction selectivity as a function of the pH of the medium of impregnation. Impregnation in neutral medium promotes the solubilization of galactoglucomannans (GGM) and impregnation in a basic medium promotes the solubilization of arabinoglucoronoxylans (ARX). The analysis of the degree of acetylation (AD) showed that STEX pretreatment allowed the extraction of acetyl-GGM with an AD of approximately 0.35 which is close to that in native hemicelluloses.The characterization of films made from extracted hemicelluloses showed that these films are good barrier to oxygen with oxygen permeability near to 0.83 cm3 μm-1 day-1 kPa-1 and to UV radiations.

Ce travail de thèse concerne l’utilisation des électrotechnologies pour une valorisation optimisée de la betterave à sucre conformément au concept de bioraffinerie. Les électro-technologies appliquées sont les champs électriques pulsés (CEP) et les décharges électriques de haute tension (DEHT). L’étude s’attache d’une part à l’optimisation d’un procédé alternatif pour l’extraction du sucre par pressage alcalin à froid assisté par CEP. D’autre part, elle propose des nouvelles voies pour la valorisation de deux coproduits de l’industrie betteravière qui sont les radicelles et la pulpe de betterave. Dans la première partie, le traitement électrique par CEP couplé au chaulage permet une meilleure désintégration du tissu betteravier. Il permet d’accélérer les cinétiques du pressage, d’améliorer le rendement ainsi que la qualité du jus et d’alléger la procédure de purification en aval de l’extraction. Une étude paramétrique d’optimisation a permis d’identifier le meilleur itinéraire d’application de ce nouveau procédé d’extraction. Les cossettes fraîches de betterave sont prétraitées par CEP à 600 V/cm pour 10 ms (Q = 2,7 Wh/kg). Les cossettes électroporées sont ensuite pressées à froid pour extraire 75 % du jus. Les cossettes pressées subissent un pressage alcalin avec 10 % du lait de chaux. Afin d’extraire le sucre résiduel dans le gâteau de pressage obtenu, deux étapes de pressage supplémentaires avec une étape intermédiaire d’hydratation sont nécessaires. Ce procédé optimisé permet de bien épuiser les cossettes en sucre (perte en sucre de 0,23 % et matière sèche de pulpes de 39 %) pendant une courte durée d’extraction (30 min) avec un faible soutirage (108 %) par rapport au procédé de diffusion. Il permet ainsi des économies significatives de matière et d’énergie surtout pour les étapes d’extraction du jus et de séchage de pulpes. Par rapport au procédé conventionnel, le gain énergétique s’élève à 91,96 × 106 kWh pour une usine traitant 10 000 t/j de betteraves pendant une campagne de 110 jours. De plus, le procédé proposé permet de simplifier la procédure de purification et de réduire de 50 à 60 % la quantité de chaux utilisée. Dans la deuxième partie de cette étude, deux procédés de transformation ont été proposés et optimisés à l’échelle laboratoire pour la valorisation des radicelles et de la pulpe de betterave à sucre. Les radicelles ont été utilisées pour produire du bioéthanol. Le jus brut de radicelles a été extrait par pressage à froid assisté par CEP. La production du bioéthanol a été achevée par fermentation alcoolique. Le prétraitement par CEP (450 V/cm, 10 ms) a permis d’accélérer la cinétique de pressage, d’augmenter le rendement en solutés (79,85 % vs. 16,8 %) et d’obtenir un jus plus concentré (10 % vs. 5,2 %). Le procédé optimisé permet de produire environ 41,75 L de bioéthanol par tonne de radicelles lorsque l’on applique un prétraitement par CEP contre seulement 8,2 L de bioéthanol sans prétraitement électrique confirmant ainsi le potentiel de ce nouveau schéma de valorisation. La pulpe de betterave déshydratée ayant une matière sèche de 92,8 % a été utilisée pour l’extraction de pectines. L’étude réalisée a montré que l’application d’un prétraitement par DEHT permet d’intensifier l’extraction des pectines. Le gain relatif de rendement en pectines est de 25,3 % pour une énergie consommée de 76,2 kJ/kg. Le schéma de bioraffinage proposé pourra aider au maintien de la filière betteravière en France après la suppression de système de quotas sucriers dans l’Union européen qui entrera en vigueur le 1er octobre 2017. / This work discusses the use of electrotechnologies for an optimized valorization of sugar beet according to the concept of biorefinery. The applied electrotechnologies are pulsed electric fields (PEF) and high-voltage electrical discharges (HVED). The study firstly aims at optimizing an alternative method for sugar extraction by PEF assisted cold alkaline pressing. On the other hand, it proposes new ways for valorizing two by-products of sugar beet industry, which are sugar beet tails and pulps. In the first part, PEF treatment combined with liming leads to a better disintegration of beet tissue. It permits accelerating of pressing kinetics, improvement of juice yield and quality, and reduction of subsequent purification procedure. A parametric optimization study identified the best application itinerary of the proposed extraction process. Fresh sugar beet cossettes are pretreated by PEF at 600 V/cm for 10 ms (Q = 2.7 Wh/kg). The electroporated cossettes are then pressed to extract 75% of intracellular juice. Compressed cossettes are subjected to an alkaline pressing with 10% lime milk. In order to extract the residual sucrose in the obtained press-cake, two additional steps of pressing with an intermediate hydration are required. This optimized process allows well exhausting the sugar cossettes (sugar loss of 0.23% and pulp dry matter of 39%) for a short extraction (30 min) and with low draft (108%) compared to diffusion method. Thus, it allows substantial saving in materials and energy especially for juice extraction and pulp drying. Compared to the conventional method, the energy saving amounted to 91.96 × 106 kWh for a sugar beet factory treating 10 000 tons per day for a campaign of 110 days. In addition, the proposed method simplifies the purification procedure of raw juice and reduces the used amount of lime from 50 to 60%. In the second part of this study, two processing methods were proposed and optimized at lab-scale for valorization of sugar beet tails and pulps. Sugar beet tails were used to produce bioethanol. Raw juice of beet tails was extracted by PEF assisted cold pressing. Bioethanol production was then done by alcoholic fermentation. Pretreatment of beet tails with PEF (450 V/cm, 10 ms) permits accelerating the pressing kinetics, increasing the yield of solutes (79.85% vs. 16.8%), and leads to a more concentrated juice (10% vs. 5.2%). The optimized process permits the production of about 41.75 L of bioethanol per ton of beet tails when PEF pretreatment is applied against only 8.2 L of bioethanol without PEF confirming the potential of this new valorization scheme. Dried beet pulp having a dry matter of 92.8% was used for pectin recovery. The present study showed that the application of HVED pretreatment leads to intensify pectin extraction. The relative gain of pectin yield is 25.3% with an energy consumption of 76.2 kJ/kg. The proposed biorefinery scheme could protect the sugar beet industry in France after the suppression of the sugar quota system in the European Union, which will take effect on 1st October 2017.

Ce travail de thèse concerne l'étude et l'évaluation de l'extraction et de la séparation de molécules d'intérêt à partir des résidus de colza. L'impact des différents traitements (broyage, champs électriques pulsés, décharges électriques de hautes tensions et ultrasons) sur l'amélioration de l'extraction des polyphénols et des protéines à partir des tiges de colza a été comparé. Ces traitements permettent d'endommager les membranes et/ou parois cellulaires de manière mécanique, électrique ou acoustique, facilitant ainsi la libération des composés intracellulaires vers le milieu extérieur. La cinétique d'extraction, le rendement en polyphenols totaux et en protéines et la consommation énergétique sont principalement étudiés. De plus, l'efficacité des traitements étudiés pour l'extraction des polyphénols et protéines, en fonction du degré de maturité de la plante a été étudiée. Les méthodes testées pour la séparation des extractibles (polyphénols et protéines) concernent la coagulation, la filtration membranaire ainsi que le couplage de ces deux méthodes afin de réduire la consommation de solvants organiques et la rétention des polyphénols au cours de séparation. La séparation des extractibles a été évaluée par le biais de l'analyse de pureté et du taux de rétention. Enfin, des effets positifs du traitement électrique sur l'étape de séparation des extractibles tels que l'augmentation du flux du perméat et la diminution du colmatage ont été remarqués. / This thesis work concerns the study and the evaluation of the extraction and the separation of valuable compounds from rapeseed residues. The impact of different treatments (grinding, pulsed electric fields, high voltage electrical discharges and ultrasound) on the enhancement of the extraction of polyphenols and proteins from rapeseed stems was compared. These treatments can damage cell membranes and 1 or cell walls mechanically, electrically or acoustically, thus facilitating the release of intracellular compounds to the surroundings. The extraction kinetics, yield of total polyphenols and proteins and energy consumption were mainly studied. In addition, influences of plant maturity on the efficiency of studied treatments for the extraction of polyphenols and proteins have been studied. The methods tested for the separation of extractives (polyphenols and proteins) include coagulation, membrane filtration and the combination of these two methods in order to reduce the consumption of organic solvents and the retention ofpolyphenols during separation. The separation of extractives was evaluated by means of analysis of purity and relative removal. Finally, positive effects of electrical treatment on the extractive separation step such as the increase ofpermeate flux and the decrease of membrane fouling have been observed.

Ce travail de doctorat traite l’optimisation des méthodes d’extraction des composés phénoliques à partir des sous-produits de la viticulture et de la viniculture, à savoir les sarments de vigne et les marcs de raisins. Plusieurs technologies innovantes sont appliquées et comparées : l’extraction accélérée par solvant (EAS), les décharges électriques de haute-tension (DEHT), les ultrasons (US) et les champs électriques pulsés (CEP). Les extractions solide-liquide faites sur les sarments ont montré que, parmi les solvants étudiés, l’eau est le moins efficace. L’ajout de la β-cyclodextrine dans l’eau améliore le procédé d’extraction mais est moins efficace que les mélanges hydroéthanoliques. L’extraction en milieu alcalin donne le meilleur rendement en composés phénoliques. L’intensification de l’extraction des composés phénoliques des sarments est possible grâce aux nouvelles technologies d’extraction. L’efficacité des méthodes testées est la moindre avec les US, moyenne avec les CEP pour atteindre le meilleur rendement phénolique avec les DEHT. La filtrabilité de ces extraits est d’autant plus lente que leur composition est complexe. L’ultrafiltration membranaire permet une très bonne purification et concentration des composés phénoliques. L’étude des mécanismes d’action des DEHT a permis d’identifier les phénomènes favorisant l’extraction des composés phénoliques à partir des sarments. Un effet mécanique des DEHT, capable de fragmenter les sarments, est en majorité responsable de cette amélioration. Le procédé énergivore du broyage pourra alors être omis. Un effet électrique contribuant également à l’intensification du procédé d’extraction est démontré. La formation de peroxyde d’hydrogène durant le traitement par DEHT est quantifiée mais ne semble pas altérer les composés phénoliques qui sont des molécules à capacité antiradicalaire élevée. Quant aux études portées sur les marcs de raisins, la variation simultanée de plusieurs paramètres opératoires a permis l’optimisation de l’extraction aqueuse et hydroéthanolique des composés phénoliques en ayant recours à la méthodologie de surface de réponse (MSR). Le passage d’un milieu aqueux à un milieu hydroéthanolique a permis d’améliorer nettement le procédé d’extraction solide-liquide des composés phénoliques et l’utilisation de l’EAS a permis l’augmentation du rendement en composés phénoliques jusqu’à trois fois par rapport à l’optimum obtenu en milieu hydroéthanolique. / This study deals with the optimization of the extraction methods of phenolic compounds from viticulture and viniculture by-products, namely vine shoots and grape pomace. Several innovative technologies were tested and compared: high voltage electrical discharges (HVED), accelerated solvent extraction (ASE), ultrasounds (US) and pulsed electric fields (PEF). The solid-liquid extraction conducted on vine shoots showed that, amongst the studied solvents, water is the least effective. The addition of the β-cyclodextrin to water improves the extraction process but remains less effective than that with hydroethanolic mixtures. The extraction in alkaline medium gives the highest phenolic compound extraction yields. The intensification of phenolic compound extraction from vine shoots was possible thanks to new extraction technologies. The effectiveness of the tested methods was the least with US, followed by PEF to accomplish the highest phenolic yield with HVED. The filterability of the extracts was slower when their composition was complex, and the membrane technology allowed a good purification and concentration of phenolic compounds. The reason behind the high effectiveness of HVED was investigated. The action mechanisms of HVED were studied in details. A mechanical effect of HVED provoked vine shoots fragmentation and particle size reduction. This was the main phenomenon responsible for the intensification of the extraction process. It also suggested that a grinding pretreatment would not be necessary prior to HVED, which considerably diminishes the energy input of the overall process. The presence of a non-mechanical effect and its contribution in the efficiency of HVED were also shown. The formation of hydrogen peroxide during the treatment was observed. However it did not seem to alter vine shoot phenolic compounds since these demonstrated a high radical scavenging capacity. As for the studies conducted on grape pomace, the simultaneous variation of several operating parameters allowed the aqueous and hydroethanolic optimization of phenolic compound extraction from these byproducts by response surface methodology (RSM). The passage from an aqueous to a hydroethanolic medium clearly improved the solid-liquid extraction of phenolic compounds from grape pomace. The use of ASE further increased the phenolic compound yield up to three times as compared to the optimum obtained with a hydroethanolic solvent.

Ce travail de recherche porte sur l’intensification de l’extraction des polyphénols à partir des écorces de chêne pédonculé et d’épicéa commun par des technologies innovantes : les champs électriques pulsés (CEP), les ultrasons (US) et les micro-ondes (MO). Ces prétraitements permettent l’amélioration de l’extraction par endommagement des membranes et/ou parois cellulaires. L’effet de chacune de ces techniques (CEP, US et MO) sur l’extraction des polyphénols a été mis en évidence à travers une étude d’optimisation quantitative et qualitative : suivi du rendement des polyphénols, de l’activité antioxydante et caractérisation chimiques des composés extraits.Une étude comparative des prétraitements (CEP, US et MO) couplés à une diffusion en milieu hydro-alcoolique alcalin, a permis de mieux comprendre les mécanismes mis en jeu lors d’un traitement d’un tissu fibreux. L’étude a prouvé que l’efficacité du procédé est indépendante de la famille d’arbre à laquelle appartiennent les écorces (résineux ou feuillus). De plus, pour valoriser les écorces de bois, l’application d’un prétraitement par CEP (20 kV/cm, 200 impulsions, 3,2 kJ/g bois) suivi d’une diffusion semble être une alternative aux ultrasons, micro-ondes et à l’extraction avec des écorces préalablement broyées. En effet, grâce à l’action électrique et mécanique des CEP, ce prétraitement permet d’obtenir un extrait riche en polyphénols (10,5 g EAG/100g MS pour l’épicéa soit 83 % d’efficacité et 5 g EAG/100g MS pour le chêne soit 82 % d’efficacité). / This research work focuses on the intensification of polyphenols extraction from Quercus robur and Norway spruce barks using innovative technologies : pulsed electric field (PEF), ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE). These pre-treatments enhance the release of intracellular compounds by damaging the membrane and/or cell wall. The effect of each of these technologies (PEF, UAE and MAE) on polyphenols extraction has been highlighted in a quantitative and qualitative optimization analysis by evaluating the polyphenols concentration, antioxidant activity and by the chemical characterization of the extracted compounds.A comparative study of pre-treatments (PEF, UAE and MAE) coupled with an extraction step in an alkaline hydro-alcoholic medium allowed us to better understand the involved phenomena. The induced process efficiency is independent of the tree family to which the bark belongs (coniferous and hardwood). For bark valorization, the application of PEF treatment (20 kV/cm, 200 pulses, 3.2 kJ/g bark) followed by a diffusion step seems to be an alternative to ultrasound and microwave assisted extractions and to the extraction from grinded barks. In fact, the electrical and mechanical effect of PEF treatment allow to obtain an extract rich in polyphenols (10.5 g GAE/100g DM and an efficiency of 83 % for Norway spruce and 5 g GAE /100g DM and an efficiency of 82 % for Quercus robur bark).