Type 2 diabetes is a worldwide and costly disease that requires complex cellular metabolic breakdown for its development. The onset of this disease is indicated by an abnormal elevated blood glucose level (hyperglycemia) and coexistence with hypertension. Apple and blueberry are the two popular fruits in the U.S. that are high in bioactive phenolic compounds. The objectives of this thesis were to investigate the synergistic health benefits of apple cider and blueberry juice for potential management of early stages of type 2 diabetes using in vitro enzyme assay models and enhance their synergistic effects through fermentation using probiotic strains of lactic acid bacteria. Apple cider and whole blueberry juice were combined at 5 different ratios. Synergistic interaction of the phenolic bioactives between the two juice sources was observed in all assays. For maintenance of high α-glucosidase, α-amylase and ACE inhibition activities, a proportion of 80% apple cider and 20% whole blueberry juice was selected as the optimum combination reflecting maximum health benefits to potentially manage hyperglycemia and hypertension associated with type 2 diabetes. The 80/20 apple cider and blueberry juice combination was fermented at 24 and 48 h using Lactobacillus helveticus R0052 and Bifidobacterium longum isolate. High inhibition of α-glucosidase, α-amylase and ACE enzymes was observed in apple cider/blueberry juice combination. Strong antimicrobial activity against H. pylori was exerted by L. helveticus- and B. longum-fermented sample at 48 h. A possible mode of action through the synergy between lactic acid and proline oxidation pathway was suggested.

Filled hydrogel particles consisting of emulsified oil droplets encapsulated within a hydrogel matrix were fabricated based on the phase separation of proteins and polysaccharides through aggregative and segregative mechanisms. A 3% (wt/wt) pectin and 3% (wt/wt) caseinate mixture at pH 7 separated into an upper pectin-rich phase and a lower casein-rich phase. Casein-coated lipid droplets added to this mixture partitioned into the lower casein-rich phase. When shear was applied, an oil-in-water-in-water (O/W1/W2) emulsion consisting of oil droplets (O) contained within a casein-rich dispersed phase (W1) suspended in a pectin-rich continuous phase (W2) was formed. Acidification from pH 7 to 5 promoted adsorption of pectin onto casein-rich W1 droplets, forming filled hydrogel particles. Particles were then cross-linked using transglutaminase. Particles were assessed for stability to changes in pH, increasing levels of salts (sodium chloride and calcium chloride), and susceptibility to lipid oxidation. Both cross-linked and not cross-linked particles were stable at low pH (pH 2-5). At high pH, cross-linked particles maintained their integrity while not cross-linked particles disintegrated. Particles were stable to sodium chloride (0-500 mM). Calcium chloride levels above 4 mM resulted in system gelation. The rate of lipid oxidation for 1% (vol/vol) fish oil encapsulated within filled hydrogel particles was compared to that of oil-in-water emulsions stabilized by either Tween 20 or casein. Emulsions stabilized by Tween 20 oxidized faster than either filled hydrogel particles or casein stabilized emulsions, while filled hydrogel particles and casein stabilized emulsions showed similar oxidation rates. Using an in-vitro digestion model, the digestion of lipid encapsulated within filled hydrogel particles was compared to that of a casein stabilized oil-in-water emulsion. Results showed similar rates of digestion for both hydrogel and emulsion samples. Attempts to fabricate particles using free oil (rather than emulsified oil) were unsuccessful and resulted in the formation of large non-encapsulated oil droplets (d ~10 μm). By controlling particle concentrations of biopolymer, water, and oil, it was possible to fabricate particles that were highly resistant to gravitational separation which was attributed to the equivalent density of the continuous and particle phases. Results highlight the potential applications and versatility of this delivery system.

Red seaweeds are reported to represent the largest group of algae, with more species accounted for than the combination of brown and green seaweeds. Due to the high amount of polysaccharides in red seaweeds, they are mainly utilized for commercial agar and carrageenan production in industry. However, increasing studies indicate other valuable compounds such as lipids and polyphenols could be potential utilized for multiple human needs (e.g., drug development) (1, 2). With increasing studies demonstrating the potential health benefits of seaweed components, two red seaweed species commonly consumed in Asia, hong qı´ lı´n c a`i (HQL), Eucheuma sp and zhe` gu¯ ca`i (ZGC), Caloglossa leprieurii, were investigated on to determine the anti-inflammatory effects of their extractable lipophilic bioactives (ELB) and bound lipophilic bioactives (BLB) in lipopolysaccharide( LPS)-treated RAW 264.7 macrophages. The chemical composition of ELB and BLB was characterized in terms of total phenolic content (TPC), total flavonoid content (TFC), total tannin content (TTC), oxygen radical absorbance capacity (ORAC), and etc. Six phenolic compounds were identified in ZGC extracts and one was detected in HQL. All extracts inhibited the nitric oxide (NO) production in LPS-induced macrophages, which was associated with downregulation of iNOS and COX-2 protein expression and up-regulation of HQ-1 and NQO1 protein expression. Overall, our results showed that both ELB and BLB in HQL and ZGC seaweeds presented potential anti-inflammatory activities. These results warrant future investigations to determine the mode of actions of red seaweed bioactives and their efficacy in humans.

A crescente demanda por fontes de energia limpas e sustentáveis tem impulsionado a busca por matérias-primas alternativas para a produção de biocombustíveis. Dentre as fontes vegetais não utilizadas para a alimentação, a mamona, o pinhão-manso e o caroço de algodão apresentam elevados teores de óleo para produção de biodiesel e potencial para utilização dos resíduos na alimentação de ruminantes. Entretanto, para que esses \"resíduos\" adquiram status de coprodutos, é necessário avaliar sua toxicidade, para administrá-los em níveis seguros ou realizar sua destoxificação. Este estudo teve por objetivo mensurar o teor das moléculas biotivas gossipol, ricina e ésteres de forbol em tortas de caroço de algodão, mamona e pinhão-manso, respectivamente, a fim de avaliar o potencial de utilização desses subprodutos na alimentação de ruminantes, considerando a ação dessas biomoléculas na fermentação ruminal in vitro em diferentes níveis de substituição ao farelo de soja do concentrado. O delineamento experimental foi totalmente casualizado, utilizando três níveis de adição de biomoléculas extraídas das tortas, simulando a substituição da soja do concentrado em 33,3 66,6 e 100% e adicionadas sobre uma dieta base (controle), e um nível de torta em substituição a 22,2% ao farelo de soja do concentrado da mesma dieta base dos demais tratamentos, a fim de avaliar possíveis diferenças de ação da biomolécula in natura na torta ou extraída. Os dados foram analisados por regressão linear e quadrática, ANOVA e teste de Dunnett para comparação das médias dos tratamentos em relação ao controle. As metodologias em CLAE (HPLC) para quantificação das biomoléculas foram adaptadas e validadas. As concentrações das biomoléculas nas tortas analisadas estiveram dentro da faixa citada pela literatura, sendo que o gossipol e a ricina poderiam ser adicionados na alimentação de ruminantes nos teores propostos neste estudo, proporcionando níveis de ingestão inferiores aos citados como tóxicos pela literatura. Da mesma forma, a produção de gases na fermentação ruminal in vitro não demonstrou ocorrência de efeitos destas biomoléculas sobre a microbiota ruminal. Os níveis de adição de pinhão-manso propostos poderiam ocasionar toxicidade pela ingestão de ésteres de forbol. No bioensaio com pinhão-manso, foram observados efeitos com 22,2% de adição de torta sobre a taxa de eficiência de conversão do metano, sugerindo que os ésteres de forbol estejam bioativos apenas na torta in natura ou ainda que a presença de outro composto tóxico, sozinho ou sinergia com os ésteres de forbol, possa ter interferido na microbiota ruminal. A viabilidade da inclusão das tortas de caroço de algodão e mamona in natura não foi negada por este estudo, entretanto, é necessário considerar a concentração de suas biomoléculas e o manejo animal correto. Para a utilização de pinhão-manso in natura em qualquer nível de adição, ainda são necessários novos estudos sobre a toxicidade dos ésteres de forbol nas tortas e sua possível sinergia com outros compostos tóxicos. A identificação e quantificação dos ésteres de forbol antes e após o tratamento de destoxificação constituem os principais entraves para que a utilização da torta de pinhão-manso se torne um coproduto da alimentação animal / The growing demand for sustainable and clean energy sources has increased the search of alternative raw materials for the production of biofuels. Castor-oil plant, jatropha and cotton seeds are among the plant resources that are not used for food although they have high level of oil for biodiesel production and might have considerable potential to use their residues to feed ruminants. However, for these \"residues\" to achieve status of co-products it is necessary to evaluate its toxicity before using them at safe levels or to perform its detoxification. This study aimed to measure the content of gossypol, ricin and phorbol esters bioactives molecules in cottonseed, castor and jatropha meals respectively in order to evaluate the potential of the use of these co-products to feed ruminants, considering the action of these biomolecules in ruminal fermentation in vitro into different substitution levels of soybean meal in the concentrate. The experimental design was completely randomized; one level of a meal by replacing 22,2% of soy in its concentrate and three levels by adding biomolecules extracted from meals simulating the replacement of 33,3, 66,6 and 100% of soy in its concentrate in the same diet base (control) of others treatment in order to evaluate differences of effects of biomolecules in natura both in a meal or extracted. The results were analyzed by linear and quadratic regression, ANOVA and Dunnett´s test for comparison of averages of treatments compared to control. The HPLC methodologies to quantify the biomolecules were adapted and validated. The biomolecules\' concentrations were within the values were quoted in the literature and both the gossypol as ricin could be added in the feeding of ruminants at the levels proposed in this report, providing intake levels below those quoted as toxic in literature. Likewise, the gas production in rumen fermentation in vitro showed no effects of biomocules on rumen microbial. According to the literature, the jatropha levels proposed could cause toxicity by the content of phorbol esters ingested. In the bioassay with jatropha, effects on methane efficiency rate were observed when 22,2% of meal were added, suggesting that phorbol esters are bioactives only in meal in natura or even the presence of other toxic compound, alone or in synergy with phorbol esters, might have affected the ruminal microflora. The viability of cottonseed and castor meal in natura inclusion was not denied by this report, however, it is extremely necessary to consider their concentration of biomolecules and correct animal handling. For the use of jatropha in natura at any level of addition further studies are still needed on the toxicity of phorbol esters in meal in natura and its possible synergy with other toxic compounds. The identification and quantification of phorbol esters before and after detoxification treatment has still being a main barrier to jatropha meal becomes a co-product of animal nutrition

Phytochemicals are widely noted for their role in chemoprevention. Potato (Solanum tuberosum L.) is the third most important food crop worldwide and is considered a significant source of antioxidants, providing an ideal delivery system for beneficial compounds. The anti-proliferative and pro-apoptotic properties of potato bioactive compounds have been reported in vitro on human prostate cancer cell lines. However, in vivo studies are limited, and more information is needed to determine the chemopreventive properties of potato in the diet. The objective of this study was to evaluate the effects of potato bioactives on prostate cancer in vivo using a mouse model. Athymic nude mice received xenografts of human prostate cancer cells (PC-3) and were administered extracts of potato bioactives from either the white flesh Solanum bulbocastanum (PI243510) or CO112F2-2P/P (purple-flesh Colorado selection), while control mice received water. Neither potato extract provided a significant reduction in tumor growth nor reduced levels of the pro-angiogenic protein VEGF, but the S. bulbocastanum extract reduced expression of metastasis associated protein 1 (MTA1) in tumors, and both potato extracts reduced MTA1 expression in lungs, suggesting the need for further research on the potential chemopreventive or chemotherapeutic properties of potato bioactives.

Les microarrays, assemblages organisés d'entités chimiques, biologiques ou cellulaires sont en pleine expansion, car ils présentent un potentiel élevé en recherche fondamentale et appliquée. La mise en œuvre de la technologie microarray repose sur trois méthodes essentielles : la chimie de surface pour la fonctionnalisation des supports, l'utilisation de technologies de précision micrométrique pour fabriquer les microarrays et la détection. Parmi toutes les applications, les microarrays visant à détecter l'activité enzymatique ont connus un développement rapide car ils permettent de tester l'efficacité d'un grand nombre de substrats ou d'inhibiteurs en parallèle. Les protéases, enzymes indispensables aux organismes vivants, et cibles thérapeutiques reconnues, sont des modèles biologiques de choix pour les études d'activité enzymatique sur microarray. La synthèse chimique sur puce n'est en revanche pas très développée.<br />La technologie développée au sein du laboratoire nous permet de former sur quelques cm2 des microarrays de centaines de microgouttes constituant chacune un microréacteur indépendant. Le but de cette thèse est d'appliquer pour la première fois cette technologie à la synthèse chimique et à l'étude de l'activité protéolytique, avant de combiner de manière novatrice les deux approches pour réaliser un criblage.<br />L'application de ces microarrays en synthèse chimique a été utilisée avec succès pour la synthèse d'une banque de molécules chimiques et pour la recherche combinatoire de nouveaux fluorophores. En ce qui concerne l'enzymologie, l'observation de la protéolyse a été validée en utilisant trois types de substrats fluorogènes, dans un premier temps avec la papaïne, puis avec une métalloprotéase, et enfin avec la protéase virale NS3 du virus de l'hépatite C. Finalement, l'utilisation séquentielle de la synthèse chimique et de la biochimie sur un même microarray, qui constitue une approche inédite, a été dédiée à la recherche de nouveaux inhibiteurs de la protéase virale NS3. Ce criblage a conduit à la découverte de molécules potentiellement intéressantes comme agents antiviraux.

Submitted by Leonardo Cavalcante (leo.ocavalcante@gmail.com) on 2018-04-27T14:45:53Z No. of bitstreams: 1 Arquivototal.pdf: 1693139 bytes, checksum: 05772ba5cdc4001f007fd50e10adb2b9 (MD5) / Made available in DSpace on 2018-04-27T14:45:54Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 1693139 bytes, checksum: 05772ba5cdc4001f007fd50e10adb2b9 (MD5) Previous issue date: 2017-04-18 / Seeds, rhizomes and tubers are welcomed with sources of bioactive molecules, which are related to health promotion, such as proteins and other components of plant sources. (Dioscorea cayennensis) is part of the Brazilian food habit, it is necessary to study the proteins present in this plant. The objective of this work was to isolate and characterize biochemically the dioscorin proteic fraction (DPF) present in the tubers of D. cayennensis, characterizing the presence of antinutritional compounds and antioxidant, antibacterial and antifungal biological activities. Isolation of DPF was performed with protein extraction in Tris-HCl 0.05M pH 8.3, followed by precipitation in Ammonium Sulfate (F45-75). The molecular weight of DPF was determined by SDS-PAGE and MALDI-ToF, characterized by the presence of a major component with a mass of approximately 28 kDa corresponding to dioscorin. When tested for the presence of phytochemicals and antinutritional compounds (lectins and trypsin inhibitors), the presence of these compounds was not detected in the DPF. The amino acid composition of the fraction was determined and the antioxidant activity estimated by the ABTS and DPPH methods. Glutamic acid, Aspartic acid and Arginine were the amino acids that showed higher levels in DPF, which explains the antioxidant activity, suggesting that the interaction of these amino acids seems to act on reactive molecules making them stable. Finally, in the evaluation of the antibacterial and antifungal activity of the total extract and DPF against different strains of microorganisms, an antibacterial potential was detected between 50-500 μg/mL of protein for inhibition of the growth of strain of L. monocytogenes. / Sementes, rizomas e tubérculos são geralmente boas fontes de moléculas bioativas, as quais estão relacionadas à promoção da saúde, as proteínas e outros compostos oriundos de fontes vegetais, vem ganhando relevância em pesquisas científicas. Considerando que o consumo do tubérculo de inhame (Dioscorea cayennensis) faz parte do hábito alimentar brasileiro, faz-se necessário o estudo das proteínas presentes neste vegetal. O objetivo deste trabalho foi isolar e caracterizar bioquimicamente a fração proteica dioscorina (FPD) presente nos tubérculos de D. cayennensis, detectando a presença de compostos antinutricionais e atividades biológicas antioxidante, antibacteriana e antifúngica. O isolamento do FPD foi realizado com a extração proteica em Tris-HCl 0,05M pH 8,3, seguido de precipitação em Sulfato de Amônio (F45-75). A massa molecular da FPD foi determinada por SDS-PAGE e MALDI-ToF. Caracterizado pela presença de um componente majoritário com massa de aproximadamente 28 kDa, correspondente a dioscorina. Quando submetida a testes de avaliação da presença de fitoquímicos e compostos antinutricionais (lectinas e inibidores de tripsina), não foi detectada na FPD a presença destes compostos avaliados. A composição aminoacídica da fração foi determinada e a atividade antioxidante estimada pelos métodos de ABTS e DPPH. Ácido glutâmico, Ácido Aspártico e Arginina foram os aminoácidos que apresentaram maiores teores na FPD, o que explica a atividade antioxidante verificada, sugerindo que a interação destes aminoácidos parece atuar em moléculas reativas tornando-as estáveis. Por fim, na avaliação da atividade antibacteriana e antifúngica do extrato total e FPD frente a diferentes cepas de micro-organismos, foi detectado potencial antibacteriano entre 50-500 μg/mL de proteína para inibição do crescimento da cepa L. monocytogenes.

A crescente demanda por fontes de energia limpas e sustentáveis tem impulsionado a busca por matérias-primas alternativas para a produção de biocombustíveis. Dentre as fontes vegetais não utilizadas para a alimentação, a mamona, o pinhão-manso e o caroço de algodão apresentam elevados teores de óleo para produção de biodiesel e potencial para utilização dos resíduos na alimentação de ruminantes. Entretanto, para que esses \"resíduos\" adquiram status de coprodutos, é necessário avaliar sua toxicidade, para administrá-los em níveis seguros ou realizar sua destoxificação. Este estudo teve por objetivo mensurar o teor das moléculas biotivas gossipol, ricina e ésteres de forbol em tortas de caroço de algodão, mamona e pinhão-manso, respectivamente, a fim de avaliar o potencial de utilização desses subprodutos na alimentação de ruminantes, considerando a ação dessas biomoléculas na fermentação ruminal in vitro em diferentes níveis de substituição ao farelo de soja do concentrado. O delineamento experimental foi totalmente casualizado, utilizando três níveis de adição de biomoléculas extraídas das tortas, simulando a substituição da soja do concentrado em 33,3 66,6 e 100% e adicionadas sobre uma dieta base (controle), e um nível de torta em substituição a 22,2% ao farelo de soja do concentrado da mesma dieta base dos demais tratamentos, a fim de avaliar possíveis diferenças de ação da biomolécula in natura na torta ou extraída. Os dados foram analisados por regressão linear e quadrática, ANOVA e teste de Dunnett para comparação das médias dos tratamentos em relação ao controle. As metodologias em CLAE (HPLC) para quantificação das biomoléculas foram adaptadas e validadas. As concentrações das biomoléculas nas tortas analisadas estiveram dentro da faixa citada pela literatura, sendo que o gossipol e a ricina poderiam ser adicionados na alimentação de ruminantes nos teores propostos neste estudo, proporcionando níveis de ingestão inferiores aos citados como tóxicos pela literatura. Da mesma forma, a produção de gases na fermentação ruminal in vitro não demonstrou ocorrência de efeitos destas biomoléculas sobre a microbiota ruminal. Os níveis de adição de pinhão-manso propostos poderiam ocasionar toxicidade pela ingestão de ésteres de forbol. No bioensaio com pinhão-manso, foram observados efeitos com 22,2% de adição de torta sobre a taxa de eficiência de conversão do metano, sugerindo que os ésteres de forbol estejam bioativos apenas na torta in natura ou ainda que a presença de outro composto tóxico, sozinho ou sinergia com os ésteres de forbol, possa ter interferido na microbiota ruminal. A viabilidade da inclusão das tortas de caroço de algodão e mamona in natura não foi negada por este estudo, entretanto, é necessário considerar a concentração de suas biomoléculas e o manejo animal correto. Para a utilização de pinhão-manso in natura em qualquer nível de adição, ainda são necessários novos estudos sobre a toxicidade dos ésteres de forbol nas tortas e sua possível sinergia com outros compostos tóxicos. A identificação e quantificação dos ésteres de forbol antes e após o tratamento de destoxificação constituem os principais entraves para que a utilização da torta de pinhão-manso se torne um coproduto da alimentação animal / The growing demand for sustainable and clean energy sources has increased the search of alternative raw materials for the production of biofuels. Castor-oil plant, jatropha and cotton seeds are among the plant resources that are not used for food although they have high level of oil for biodiesel production and might have considerable potential to use their residues to feed ruminants. However, for these \"residues\" to achieve status of co-products it is necessary to evaluate its toxicity before using them at safe levels or to perform its detoxification. This study aimed to measure the content of gossypol, ricin and phorbol esters bioactives molecules in cottonseed, castor and jatropha meals respectively in order to evaluate the potential of the use of these co-products to feed ruminants, considering the action of these biomolecules in ruminal fermentation in vitro into different substitution levels of soybean meal in the concentrate. The experimental design was completely randomized; one level of a meal by replacing 22,2% of soy in its concentrate and three levels by adding biomolecules extracted from meals simulating the replacement of 33,3, 66,6 and 100% of soy in its concentrate in the same diet base (control) of others treatment in order to evaluate differences of effects of biomolecules in natura both in a meal or extracted. The results were analyzed by linear and quadratic regression, ANOVA and Dunnett´s test for comparison of averages of treatments compared to control. The HPLC methodologies to quantify the biomolecules were adapted and validated. The biomolecules\' concentrations were within the values were quoted in the literature and both the gossypol as ricin could be added in the feeding of ruminants at the levels proposed in this report, providing intake levels below those quoted as toxic in literature. Likewise, the gas production in rumen fermentation in vitro showed no effects of biomocules on rumen microbial. According to the literature, the jatropha levels proposed could cause toxicity by the content of phorbol esters ingested. In the bioassay with jatropha, effects on methane efficiency rate were observed when 22,2% of meal were added, suggesting that phorbol esters are bioactives only in meal in natura or even the presence of other toxic compound, alone or in synergy with phorbol esters, might have affected the ruminal microflora. The viability of cottonseed and castor meal in natura inclusion was not denied by this report, however, it is extremely necessary to consider their concentration of biomolecules and correct animal handling. For the use of jatropha in natura at any level of addition further studies are still needed on the toxicity of phorbol esters in meal in natura and its possible synergy with other toxic compounds. The identification and quantification of phorbol esters before and after detoxification treatment has still being a main barrier to jatropha meal becomes a co-product of animal nutrition

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.

La spectroscopie RMN alliée à l’utilisation de solvants cristal-liquide fortement et faiblement orientants est une stratégie efficace pour élucider les structures et distributions conformationnelles de petites molécules organiques rigides et flexibles en solution, et déterminer les ordres orientationnel et positionnel des solutés comme des solvants orientés. Dans une première partie, afin d’explorer les différentes contributions aux couplages dipolaires d’un soluté donné, la très faible amplitude de l’ordre orientationnel d’une molécule quasi-sphérique, le tetramethylallène, dissoute dans un nématique thermotrope est exploitée. Dans cette situation limite, le caractère prédominant des mécanismes de réorientation et de vibration moléculaire est mis en évidence, et estimé. Dans une seconde partie, les données RMN obtenues à partir de solutés de petites tailles dissous dans des solvants smectiques sont combinées aux résultats de calculs reposant sur des concepts de thermodynamique statistique et de la théorie de la fonctionnelle de densité. L’efficacité de cette méthode dans la détermination des paramètres d’ordres positionnel du solvant et orientationnel des molécules-sondes est démontrée aussi bien dans le cas de phases conventionnelles smectiques A que celui plus délicat de smectiques interdigitées Ad. La stratégie d’analyse proposée est ensuite étendue à l’investigation des structures tridimensionnelles et équilibres conformationnels de molécules flexibles bioactives ou biomimétiques. Dans une perspective méthodologique, à l’aide d’études expérimentale et théorique portant sur le biphényle, molécule symétrique constituée d’un unique rotor, il est tout d’abord démontré l’intérêt des méthodes de simulations par dynamique moléculaire pour évaluer l’ensemble des couplages dipolaires d’un soluté donné dans une phase thermotrope, ultérieurement utilisés comme paramètres initiaux dans une analyse spectrale itérative, et in fine déterminées précisément. L’analyse spectrale chronophage et dont l’aboutissement est incertain si les paramètres initiaux sont difficiles à estimer, en est ainsi facilitée. Puis, les distributions conformationnelles d’anti-inflammatoires non stéroïdiens de dérivés salicylés et profènes, fluorés ou non, constitués d’un ou deux rotors indépendants sont présentées. Via l’utilisation inédite du modèle AP-DPD dans les solvants nématiques (chiraux) lyotropes faiblement orientants, et à partir des couplages dipolaires homo- et hétéronucléaires notamment obtenus grâce à l’expérience RMN GET-SERF, créée à propos pour permettre l’extraction simple et rapide des couplages 1H-19F, les surfaces d’énergie potentielle de ces biomolécules sont décrites de façon satisfaisante. Enfin, les équilibres conformationnels de deux stilbénoïdes constitués de deux rotors coopératifs sont déterminés dans deux solvants cristal-liquide, l’un fortement, l’autre faiblement orientant. Ces études comparatives permettent de discuter la fiabilité, la précision et l’accessibilité des observables RMN extraites dans les phases, et d’établir la complémentarité des analyses RMN réalisées dans ces solvants. / NMR spectroscopy in weakly and highly orienting media is used as a route for dealing with orientational, positional, structural and conformational problems of a variety of small rigid and flexible organic molecules in solution. First, the very weak orientational order of a quasi-spherical molecule dissolved in a nematic phase is exploited for exploring the role of the different contributions to the observed dipolar coupling. In such a limit condition, a predominant effect of the non-rigid reorientation-vibration coupling term emerges. Then, NMR data obtained from small rigid probes dissolved in smectic solvents are combined with a statistical thermodynamic density functional theory, in order to measure the positional order parameters of both solutes and solvent. The methodology gives good results when applied to a conventional smectic A liquid crystal and to the more delicate case of an interdigitated smectic Ad phase. The strategy is subsequently extended to the investigation of structure, order and conformational equilibrium of flexible bioactive or biomimetic molecules dissolved in various partially ordered NMR solvents. A first experimental and theoretical study is presented on the symmetric single-rotor molecule of biphenyl dissolved in a thermotropic liquid crystal. This test-case indicates molecular dynamics simulations are a promising tool for estimating a set of dipolar couplings of a solute in a thermotropic solvent, to be used as starting set of parameters in a standard operator-mediated NMR spectral analysis. Then, we report the conformational study of some single- and two-rotor nonsteroidal anti-inflammatory drugs, belonging to the families of salicylates and profens, dissolved in weakly orienting chiral nematic PBLG phases. A new pulse sequence, the Gradient Encoded heTeronuclear 1H-19F SElective ReFocusing NMR experiment (GET-SERF), is proposed here for the trivial edition of all 1H-19F couplings in one single NMR experiment, for a given fluorine atom. Starting from homo- and heteronuclear dipolar couplings, difficult to extract in thermotropic solvents because of a too complex spectral analysis, the torsional distributions of such molecules can be satisfactory described by the Additive Potential model combined with the Direct Probability Description of the torsional distribution in terms of Gaussian functions (AP-DPD approach). Finally, the conformational and orientational study of two stilbenoids displaying cooperative torsions is discussed in both a highly and weakly ordering liquid crystal phase. This comparative study allows to draw some conclusions on reliability, accuracy and accessibility of desired data in the two phases. Overall, this work proves NMR in liquid crystals is a flexible and meaningful tool for studying order, structure and conformation and it can greatly benefit from the availability of several aligning media inducing a different degree of order.