A β-galactosidase (E.C 3.2.1.23) é uma das enzimas mais empregadas na indústria de alimentos sendo utilizada na hidrólise da lactose. Neste trabalho foram utilizadas duas metodologias para imobilização desta enzima. Na primeira delas foi empregado como suporte um material híbrido à base de sílica que possui um grupo orgânico catiônico covalentemente ligado. A adsorção da enzima a este material apresentou eficiência que variou de 74 a 53% com o aumento da quantidade de enzima aplicada ao suporte. A baixa estabilidade térmica da enzima imobilizada obtida e as prováveis fracas interações envolvidas na sua adsorção a este suporte podem explicar o decréscimo de atividade observada durante as sucessivas bateladas de hidrólise da lactose. Na primeira batelada o grau de hidrólise foi de 90,9% e no final da última batelada (4ª), a enzima foi capaz de converter apenas 13% do substrato. A segunda metodologia utilizada foi imobilização covalente da enzima em um filme de celulose/líquido iônico modificado com uma poliamina e ativado com glutaraldeído. A presença da poliamina foi confirmada por análises de infravermelho. Após a imobilização, a enzima reteve 60% de sua atividade inicial. Bons resultados de hidrólise da lactose em batelada foram obtidos tanto a 7ºC como a 35ºC e foi possível reutilizar a enzima imobilizada por 16 ciclos consecutivos, a 7ºC, sem mudanças significativas na atividade enzimática. O valor de Km para a enzima imobilizada no material híbrido à base de sílica foi de 9,17 mM e para a enzima imobilizada nos filmes de celulose foi de 11,22 mM, ambos apresentaram um acréscimo quando comparados ao Km enzima livre (1,25 mM), devido à dificuldade de acesso do substrato ao sítio ativo da enzima. Não houve mudança no pH e temperatura ótimos da enzima imobilizada em relação à enzima livre em nenhum dos métodos testados. / β-galactosidase (E.C 3.2.1.23) is the most widely used enzymes in the food industry and its employed in the lactose hydrolysis process. In this study, two methodologies were used to test their immobilization. In the first, the enzyme was immobilized by adsorption in one silica based hybrid material that contains a cationic organic group covalently linked. The efficiency of immobilization showed a decrease of 74 to 53% by increasing the protein load applied to the support. The low thermo stability of the immobilized enzyme and the probable weak interactions involved in their adsorption, could explain the decrease in enzyme activity observed in the successive batch hydrolysis of lactose. In the first run, the degree of lactose hydrolysis was 90.9% and, at the end of the last run (4th), the enzyme was able to convert only 13% of the substrate. The second methodology used was the covalent immobilization of the enzyme on a cellulose/ionic liquid film, modified with a polyamine and activated using glutaraldehyde. The presence of a polyamine was confirmed by infrared analysis. After immobilization, the enzyme retained 60% of its initial activity. Highly efficient lactose conversion was achieved in a batch process at 7ºC and 35ºC and was possible to reuse the immobilized enzyme in 16 repeated cycles, at 7ºC, without any drastic decrease in enzyme activity. Km value for the immobilized enzyme in silica based hybrid material was 9.17 mM and for the enzyme immobilized in the film of cellulose/ionic liquid was 11.22 mM, both showing an increase compared with the Km value for free enzyme (1.25 mM), due to the difficulty of access of the substrate to the active sites of the enzyme. The immobilized enzyme did not show any changes in the optimal pH and temperature when compared to the free enzyme in both methods tested.

Made available in DSpace on 2014-12-17T14:13:23Z (GMT). No. of bitstreams: 1 AlexandreFSQ.pdf: 1970606 bytes, checksum: 5b6e9381595f936a1ed9bffd4f4fef7a (MD5) Previous issue date: 2008-05-12 / A galactose and sucrose specific lectin from the marine sponge Cliona varians named CvL was purified by acetone fractionation followed by Sepharose CL 4B affinity chromatography. Models of leukocyte migration in vivo were used to study the inflammatory activity of CvL through of mouse paw oedema and peritonitis. Effect of CvL on peritoneal macrophage activation was analyzed. Effects of corticoids and NSAIDS drugs were also evaluated on peritonitis stimulated by CvL. Results showed that mouse hind-paw oedema induced by sub plantar injections of CvL was dependent dose until 50?g/paw. This CvL dose when administered into mouse peritoneal cavities induced maxima cell migration (9283 cells/?L) at 24 hours after injection. This effect was preferentially inhibited by incubation of CvL with the carbohydrates D-galactose followed by sucrose. Pre-treatment of mice with 3% thioglycolate increases the peritoneal macrophage population 2.3 times, and enhanced the neutrophil migration after 24h CvL injection (75.8%, p<0.001) and no significant effect was observed in presence of fMLP. Finally, Pre-treatment of mice with dexamethason (cytokine antagonist) decreased 65.6%, (p<0.001), with diclofenac (non-selective NSAID) decreased 34.5%, (p<0.001) and Celecoxib (selective NSAID) had no effect on leukocyte migration after submission at peritonitis stimulated by CvL, respectively. Summarizing, data suggest that CvL shows pro-inflammatory activity, inducing neutrophil migration probably by pathway on resident macrophage activation and on chemotaxis mediated by cytokines / A lectina denominada CvL, com especificidade para D-galactose e sacarose foi purificada da esponja marinha Cliona varians atrav?s de fracionamento com acetona seguido por cromatografia de afinidade em Sepharose CL 4B. No presente trabalho, foi estudada a atividade inflamat?ria de CvL in vivo atrav?s dos modelos de edema de pata e migra??o de leuc?citos em peritonite induzida em camundongos. Foram analisados os efeitos de carboidratos na inibi??o da peritonite, o efeito da lectina na ativa??o de macr?fagos e o efeito de antiinflamat?rios no modelo de peritonite provocada pela CvL. Os resultados mostraram que o edema de pata induzido pela CvL foi dose dependente at? 50 ?g/pata. Essa mesma dose quando administrada na cavidade peritoneal, foi capaz de induzir migra??o celular (9.283 c?lulas/?L) com pico em 24 horas ap?s a administra??o. Este efeito foi inibido quando a CvL foi previamente incubada com os carboidratos D-galactose e sacarose. O pr?-tratamento dos camundongos com 3% de tioglicolato aumentou a popula??o de macr?fagos em 2,3 vezes o que provocou o aumento da migra??o de neutr?filos em 75,58% (p<0,0001) ap?s 24 horas da inje??o da CvL. No entanto, com a inje??o de fMLP n?o foi observado nenhum efeito significativo. O pr?-tratamento dos camundongos com dexametasona (cortic?ide antagonista de citocinas) reduziu a migra??o de neutr?filos em 65,6% (p<0,001), com diclofenaco ( antiinflamat?rio n?o ester?ide n?o seletivo) reduziu em 34,5% (p<0,001) e com Celecoxibe (antiinflamat?rio n?o ester?ide seletivo) n?o apresentou efeito. Os resultados do presente trabalho s?o indicativos de que a CvL possui atividade pr?-inflamat?ria, induzindo a migra??o de neutr?filos, provavelmente atrav?s da indu??o da libera??o de citocinas quimiot?cticas na ativa??o de macr?fagos residentes no perit?nio

nÃo hà / Lectinas sÃo glicoporteÃnas que interagem de forma reversÃvel e especificamente com carboidratos. A lectina Vatairea macrocarpa (VML) à uma lectina ligadora de galactose pertencente à famÃlia de leguminosas da tribo Dalbergiae. No presente estudo, nÃs investigamos os efeitos da lectina Vatairea macrocarpa (VML) no modelo de rim isolado de rato, bem como as alteraÃÃes histolÃgicas. O rim isolado a partir de ratos Wistar, pesando entre 240 e 280g foram perfundidos com soluÃÃo de Krebs-Henseleit contendo 6% de albumina bovina sÃrica. Os parÃmetros estudados incluem: pressÃo de perfusÃo (PP), resistÃncia vascular renal (RVR), ritmo de filtraÃÃo glomerular (RFG), fluxo urinÃrio (FU), percentual de transporte tubular de sÃdio (%TNa), percentual de transporte tubular de potÃssio (%TK), e percentual de transporte tubular de cloro (%TCl). A lectina Vatairea macrocarpa (10 Âg/ml) aumentou a pressÃo de perfusÃo, a resistÃncia vascular renal, o fluxo urinÃrio e o ritmo de filtraÃÃo glomerular. Por outro lado, a Vatairea macrocarpa (VML) nÃo alterou o percentual de transporte dos Ãons sÃdio, potÃssio e cloro. O complexo Galactose-Lectina (Gal-VML) quando utilizado nÃo causou qualquer alteraÃÃo nos parÃmetros avaliados, ou seja, bloqueou significativamente o aumento dos parÃmetros PP, RVR, UF e RFG, observados pela aÃÃo da lectina Vatareia macrocarpa (VML). No grupo controle a histologia apresentou um pequeno aumento de material proteinÃceo nos espaÃos urinÃrios, no entanto, nÃo foram detectadas alteraÃÃes a nÃvel de tÃbulos renais. A administraÃÃo de galactose sozinha nÃo modificou os parÃmetros funcionais renais. Os rins prÃ-tratados com Gal-VML teve apenas um pequeno acÃmulo de material proteinÃceo nos espaÃos urinÃrios, mas nenhuma anormalidade foi nos tÃbulos renais. Estes resultados sugerem que a lectina obtida a partir de semestres de Vatairea macrocarpa apresenta importante efeito sobre o sistema renal relacionado com o sÃtio carboidrato-ligante, tendo em vista observamos reversÃo dos efeitos renais quando se utilizou o inibidor especÃfico. O presente trabalho à a primeira demonstraÃÃo de atividade biolÃgica da VML em rim isolado de rato. / Lectins are glycoproteins that interact reversibly and specifically with carbohydrates. The Vatairea macrocapa lectin (VML) is a galactose-binding lectin present in the family leguminosae and in the tribe Dalbergieae. ln the present study, we investigated the effect of Vatairea macrocarpa lectin (VML) in the isolated rat kidneys, as well as histological changes. Isolated kidneys from Wistar rats, weighing 240 to 280g, were perfused with Krebs-Henseleit solution containing 6% of bovine serum albumin. The parameters studied included perfusion pressure (PP), renal vascular resistance (RVR), glomerular filtration rate (GPR), urinary flow (UF), percent of sodium tubular transport (%TNa+), percent of potassium tubular transport (%TK+) and percent of chloride tubular transport (%TCl-). The latairea macrocarpa lectin (10 Âg/mL) increased the PP, RVR, UF and GPR. On the other hand, VML did not change the %TNa+, %TK+ and % TCl-. The lectin plus galactose complex (Gal-VML) signihcantly blocked the increase in the PP, RVR, UF and RFG. ln the control group showed a small amount of a proteinaceous material in the urinary space, although no alteration in the renal tubules was detected. The administrated of galactose alone did not modify the functional kidney parameters. The kidneys perfused with /ML showed moderate deposit of proteinaceous material in the tubules and urinary space. ln the kidneys pretreated with Gal-VML had only small amount of a proteinaceous material in the urinary space. But no abnormalities were seen in renal tubules. These results suggest that lectin from Vatairea macrocarpa seeds presents important effect on renal system reported carbohydrate-binding site, taken into account that showed the reversion of renal effects using the inhibitor specific. The current experiments are first demonstration of biological action of VML in the isolated kidney.

This study evaluated the possible uses for a custom-made Capillary Electrophoresis Contactless Conductivity Detector (CE-CCD). One of the key objectives was to determine whether measurements of conductivity with the device could replace UV-spectroscopy to analyze a range of samples, in particular PVA-MB and monosaccharides. Furthermore, to determine the feasibility of using the specific device as a substitute for UV-spectroscopy analysis, two commercial reference devices were used: one contact based conductivity detector and one potentiostat. Changes in resistance and voltage drops of samples containing the analytes were used to determine whether the analysis with the custom made CE-CCD could replace analysis with UV-spectroscopy. The signal from the PVA-MB compared to variation in the signal of the background electrolyte was discovered to be too great for CE-CCD to be applied as a substitute for UV-spectroscopy.  However both monosaccharides analyzed in the study, glucose and galactose could be detected. Glucose could accurately be detected down to 50 μM and galactose down to 25 μM. A semi-empirical calculation estimated a lower limit of 5 μM for glucose and roughly 8 μM for galactose. PVA-MB could not be detected with the custom made CE-CCD while the monosaccharides can be detected in a range low enough to allow the detector to replace UV-spectroscopy for analysis. The best measurements taken with the detector were not as low as the best data found for UV-spectroscopy, but similar electrochemical applications were found to have reached similar or better values. Further development of the detector may lower its limit of detection to approach and possibly exceed the better measurements taken with UV-spectroscopy.

No description available.

No description available.

Les glucides représentent une classe de molécules importante non seulement dans l'industrie alimentaire pour leur apport énergétique, mais aussi en médecine puisqu'ils sont impliqués dans de multiples procédés biologiques. Toutefois, les monosaccharides sont des molécules hautement hydrophiles, ce qui explique leurs piètres propriétés pharmacocinétiques. Il est donc nécessaire de pallier ce problème par la conception de glycomimétiques, soit des dérivés de glucides. Sachant que la fluoration des molécules organiques peut engendrer des composés aux propriétés uniques, l'une des méthodes qui connait un intérêt croissant est la désoxyfluoration des glucides. Néanmoins, l'évaluation biologique de glucides fluorés est souvent difficile, surtout si ces derniers contiennent plusieurs atomes de fluor, car l'installation stéréosélective d'atomes de fluor demeure un défi synthétique de taille. Afin d'apporter notre contribution pour l'avancement des connaissances dans la préparation de fluoroglucides, nous avons proposé de nouveaux chemins synthétiques. Plus précisément, la préparation des analogues 3-désoxy-3-fluoro et 4-désoxy-4-fluoro du D-galactopyranose à partir du lévoglucosan en suivant une approche chiron est décrite dans cette thèse. Ultérieurement, ces composés ont été employés dans des études biologiques afin de vérifier leur potentiel en tant qu'inhibiteurs de protéines galactophiles. À la suite de l'expertise acquise avec le lévoglucosan et voulant déterminer l'influence que peut avoir la présence d'atomes de fluor sur les propriétés physico-chimiques des molécules, nous nous sommes penchés sur la préparation de saccharides polyfluorés. Notamment, les synthèses des dérivés trifluorés du mannose et du talose ainsi que celles de divers hexitols polyfluorés sont décrites dans cette thèse. Néanmoins, des obstacles ont été rencontrés lors de l'installation de l'atome de fluor en C-4 sur les deux trifluorohexopyranoses. Pour remédier à cette situation, une méthode de désoxyfluoration alternative au trifluorure de diéthylaminosulfure (DAST) qui emploie le trihydrofluorure de triéthylamine (Et₃N.3HF) a été développée. La lipophilie de tous les composés a été mesurée et comparée. Également, la conformation dominante en solution de certains composés a été déterminée par RMN et par cristallographie. Les résultats mettent en lumière l'influence de l'atome de fluor sur les propriétés des glucides tout en ouvrant le chemin à de nouvelles molécules d'intérêt en chimie médicinale. / Carbohydrates are an essential class of molecules for living organisms. Besides serving as both a major energy source and structural component, they are also involved in numerous biochemical processes of interest for the pharmaceutical industry, such as molecular recognition. However, native carbohydrates are highly polar molecules having poor pharmacokinetic properties. Therefore, glycomimetic compounds are being developed to tackle this problem. Deoxyfluorination of carbohydrates has emerged as a popular approach to generate glycomimetic tools since the presence of fluorine on organic compounds can lead to molecules with unique properties. Nevertheless, stereo selective syntheses of fluorinated carbohydrates can be quite challenging, especially if there is more than one fluorine incorporated into the carbohydrate scaffold. To bring our own contribution to the field of fluorinated carbohydrates, we proposed new synthetic pathways to prepare 3-deoxy-3-fluoro and 4-deoxy-4-fluoro analogues of D-galactopyranose. The alternative procedures to the decade-long known methods use a chiron approach starting from affordable levoglucosan. These fluorinated galactosides were evaluated as lectin inhibitors and investigated as antiproliferative agents. Following this work, levoglucosan was further used to study the impact of fluorine on the physicochemical properties of carbohydrates. Thus, the preparations of various polyfluorinated compounds such as trifluorinated derivatives of mannose and talose as well as multiple fluorohexitols, are described in this thesis. Lipophilicity of all fluorinated carbohydrates reported in this document has been assessed. In addition, the conformation of some new compounds has been determined both by NMR spectroscopy and by X-ray crystallographic analyses. Moreover, a simple synthetic approach using triethylamine trihydrofluoride (Et₃N.3HF) was developed as an alternative to the diethylaminosulfur trifluoride (DAST) reagent. These results highlight the effect of the fluorine on physical properties of carbohydrates. Furthermore, the different studies could provide tools to help expand research in glycobiology and related fields.

A major challenge in hepatic tissue engineering is that liver cells rapidly lose their phenotype in in vitro cell culture systems. For this reason, it is necessary to design biomaterials that can support and enhance hepatic functions. Hepatocytes have a surface protein, called the asialoglycoprotein receptor (ASGP-R), which interacts with galactose via a specific receptor-ligand interaction. Polyelectrolyte multilayers (PEMs) were prepared by the layer by layer method, which is based on electrostatic attractions between oppositely charged polyelectrolytes (PEs). Anionic (hyaluronic acid) and cationic (chitosan and galactosylated chitosan) PEs were used in the fabrication of detachable, free-standing PEMs. The main focus of this study is the design of PEMs comprised of 50 bilayers of PEs. PEMs that contained galactose functional groups were assembled with either 5 or 10 bilayers of galactosylated chitosan (5 - 10 % of galactosylation). Optical properties, solvent stability and surface topography of the PEMs were measured. / Master of Science

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / As lectinas sÃo proteÃnas que contÃm pelo menos um domÃnio nÃo catalÃtico que lhes permite reconhecer seletivamente e se ligar de uma forma reversÃvel a glicanos especÃficos. A Frutalina à uma lectina obtida a partir das sementes de Artocarpus incisa, conhecida popularmente como fruta-pÃo. O isolamento foi realizado por cromatografia de afinidade em coluna de Agarose-D-Galactose e sua caracterizaÃÃo demonstrou que a Frutalina à uma glicoproteÃna, principalmente &#945;-D-galactose ligante, mas que tambÃm reconhece &#945;-D-Manose. Possui 2,1% de carboidratos e apresenta, em seu perfil de SDS-PAGE, duas bandas protÃicas com massas moleculares aparentes de 12 e 15 kDa, sendo uma proteÃna oligomÃrica, encontrando-se como tetrÃmero apenas em pH alcalino, com massa molecular aparente de 60 kDa. Massas diversas em torno de 16 kDa foram observadas nos espectros deconvoluÃdos em espectrometria de massas, o que corrobora a presenÃa de isoformas. Este trabalho mostra a cristalizaÃÃo e anÃlises dos dados obtidos por difraÃÃo de raios-x para determinaÃÃo da estrutura tridimensional desta lectina, e para isso foram realizados ensaios de cristalizaÃÃo da Frutalina isolada a partir das sementes maduras, na presenÃa do ligante (&#945;-D-galactose) e na sua forma apo (sem ligantes). Os cristais de Frutalina cresceram principalmente em poÃos de pH 8,5 contendo PEG como precipitante e etileno-glicol e os melhores cristais apareceram apÃs uma semana de maturaÃÃo, sendo difratados a uma resoluÃÃo mÃxima de 1,81 Ã. A melhor soluÃÃo para o grupo espacial, considerando eixos e planos de simetria, foi obtida para o grupo espacial I2 com a obtenÃÃo de um Rfactor de 38,6% e LLG de 19,9. A estrutura da Frutalina apresenta, em cada unidade monomÃrica, um &#946; prisma simÃtrico, com trÃs grupos de 4 folhas beta, cada. O sÃtio de reconhecimento a carboidratos, à semelhante ao da Jacalina, e envolve o N-terminal da cadeia &#945;, demonstrando, na regiÃo, um enovelamento caracterÃstico de lectinas da famÃlia Moraceae. O sÃtio de ligaÃÃo da Frutalina consiste numa cavidade prÃxima ao N-terminal da cadeia &#945;, formada por quatro resÃduos-chave: Gly25, Tyr146, Trp147 e Asp149. As bases de interaÃÃo com o ligante sÃo relacionadas ao nÃmero de interaÃÃes, que ocorrem entre a hidroxila do C1 e o resÃduo Tyr146, a hidroxila do C3 e o resÃduo Gly25, a hidroxila do C4 e os resÃduos de Gly25 e Asp149 e a hidroxila do carbono 6 aos resÃduos Tyr146, Trp147 e Asp149. Algumas hidroxilas da &#945;-D-Galactose tambÃm utilizam de interaÃÃes com molÃculas de Ãgua estruturais, para buscar estabilidade no sÃtio de reconhecimento a carboidratos. O grande nÃmero de interaÃÃes corrobora com a grande afinidade que a Frutalina tÃm a galactose e à sua grande capacidade de aglutinaÃÃo, alÃm de proporcionar uma anÃlise das dimensÃes da lectina em relaÃÃo ao ligante, onde se visualiza que o sitio de ligaÃÃo à muito maior que o aÃÃcar, o que pode justificar a preferÃncia que a Frutalina costuma apresentar por glicoconjugados de maior massa molecular, proporcionando maior encaixe, e maior nÃmero de interaÃÃes quÃmicas entre um glicoconjugado maior. / Lectins are proteins containing at least one non-catalytic domain that allows them to recognize and selectively bind a reversible specific glycans. Frutalin is a lectin obtained from Artocarpus incisa seeds, popularly known as breadfruit. The isolation was performed by affinity chromatography on column of Agarose-D-Galactose and their characterization shows that frutalin is a glycoprotein mainly &#945;-D-galactose ligand, because it also recognizes epimers of &#945;-D-mannose. It has 2.1% of carbohydrates and presents, in its SDS-PAGE profile, two protein bands with apparent molecular masses of 12 and 15 kDa, with an oligomeric protein, lying as tetramer only in alkaline pH, with apparent molecular mass of 60 kDa. Several masses around 16 kDa was observed in deconvoluted spectra in Mass Spectrometry, which confirms the presence of isoforms. This work shows the crystallization and analysis of data obtained by x-ray diffraction to determine the three-dimensional structure of this lectin, and that were performed crystallization trials of frutalin isolated from the mature seeds in the presence of ligand (D-galactose) and the way apo (no binders). The frutalin crystals have grown primarily in wells of pH 8.5 containing PEG as precipitant and ethylene glycol and the best crystals appeared after one week of maturation being diffracted to a maximum resolution of 1.81 Ã. The best solution, for the space group, considering axes and planes of symmetry, has been obtained for the I2 space group, with the construction of an Rfactor of 38.6% and LLG = 19.9. The structure of frutalin presents in each monomeric unit, a symmetrical &#946;-prism with three groups of four beta strands each. The carbohydrate recognition site is similar to the jacalin, and involves the N-terminus of the &#945; chain, showing, in the region, a characteristic folding of the Moraceae family. The frutalin binding site cavity is near the N-terminus of the &#945; chain formed by four key residues Gly25, Tyr146, Asp149, and Trp147. The bases of interaction with the binder are related to the number of interactions occurring between the C1 hydroxyl and Tyr146 residue, C3 hydroxyl and Gly25 residue, C4 hydroxyl and Asp149/Gly25 residues, and C6 hydroxyl and Tyr146/Trp147/Asp149 residues. Some hydroxyls of &#945;-D-galactose also utilize interactions called structural waters, to seek stability in the carbohydrate recognition site. The large number of interactions agrees with the high affinity that frutalin has with galactose and its great capacity for agglutination, in addition to providing an analysis of the dimensions of the lectin in relation to the binder, which may justify the preference that frutalin tends to present by higher molecular weight glycoconjugates, and that happens due to the most fitting, and the greatest number of chemical interactions among a larger glycoconjugate.

Le caroubier est considéré comme l'un des arbres fruitiers et forestiers qui présente le plus grand potentiel de valorisation puisque toutes les parties de cette plante sont utilisables dans plusieurs applications industriels. Le caroubier est cultivé dans plusieurs régions du Liban mais peu d'études sont disponibles sur les voies de valorisation et sur les propriétés fonctionnelles et structurales des graines et des gousses. Ainsi, dans le cadre d'une démarche qui vise à promouvoir et contribuer à une meilleure valorisation et gestion de cette ressource renouvelable, nous avons entrepris dans cette thèse des travaux consacrés à la caractérisation et à l'évaluation de la valeur nutritive et fonctionnelle des gousses de caroube issues de plusieurs régions libanaise. Ces travaux ont porté notamment sur la caractérisation morphologique et physico-chimique des gousses et sur la purification des gommes extraits des graines. Ces gommes ont fait l'objet d'une étude approfondie portant sur leur comportement rhéologique et la relation entre ce comportement, la variété et le lieu géographique. Nous avons aussi déterminé les isothermes de sorption de ces gommes pour prédire les conditions idéales de leur conservation. Les résultats obtenus à l'issue de cette étude ont démontré clairement la présence des corrélations morphologie, composition chimique et coordonnées géographiques de différents cultivars étudiés. De même, les études structurales et rhéologiques ont montré des différences significatives entre les gommes purifiées. Cette différence semble être liée à une variation du rapport galactose/mannose et de la masse molaire observée selon les variétés. Par ailleurs, les études des isothermes de sorption ont permis de fournir des informations complémentaires sur leurs hygroscopicités et par conséquence sur les conditions idéales de leur conservation / The carob plant is considered as one of the fruit and forester tree that has the greatest potential of valorization since all the parts of this plant can be used in several food and cosmetic applications. The carob is cultivated in several areas of lebanon but few studies are available on the ways of valorization and the functional and structural properties of the different fractions of this tree (seeds and pods). Thus, in view to develop a strategy aims to promote and contribute to a better valorization and management of this renewable resource, we undertook in this thesis of work devoted to the characterization and the evaluation of nutritive and functional properties of the carob pods resulting from several lebanese areas. This work focused particularly on the morphological and physicochemical characterization of the pods and the purified fraction of gum. These gums were the subject of a thorough study relating to their rheological behavior and the relation between this behavior, the variety and the geographical localization of the studied varieties. We also determined the isotherms of sorption of these gums to predict the ideal conditions of their conservation. The obtained results clearly showed the presence of the correlations between morphology, chemical composition and geographical localization of the different studied cultivars. In the same way, the structural and rheological studies showed significant differences between purified gums. This difference seems to be related to a variation of the galactose /mannose ratio and molar mass according to the varieties. These interesting rheological properties open the carob gums a new niches of valorization with added values. In addition, the studies of the isotherms of sorption provided additional information on their hygroscopicities and by consequence on the ideal conditions of their conservation