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This thesis includes two studies: The first examined developmental changes that take place in the physiology of aspen (Populus tremuloides Michx.) and to characterize developmental influences on patterns of phenotypic trait variation among different aged ramets within the aspen clones. We surveyed eight clones, each with 8 distinct age classes ranging from 1 to 170 yrs in age. Using regression analysis we examined the relationships between ramet age and expression of functional phenotypes. Eight of the phenotypic traits demonstrated a non-linear relationship in which large changes in phenotype occurred in the early stages of ramet development and stabilized thereafter. Water and nutrient concentration, leaf gas exchange and phenolic glycosides tended to decrease from early to late development, while sucrose and condensed tannin concentrations and water use efficiency increased with ramet age. We hypothesize that ontogenetically derived phenotypic variation leads to fitness differentials among different aged ramets, which may have important implications for clone fitness. Age-related increases in phenotypic diversity may partially underlie aspen's ability as a species to tolerate the large environmental gradients that span its broad geographical range. Fire is an essential component of many forest ecosystems and fire exclusion policies and other anthropogenic factors have significantly altered disturbance regimes, which has lead to increased aspen succession to conifers. The second study examined how post-fire aspen regeneration success is influenced by increasing conifer abundance under longer fire return intervals. 66 sites were selected from the Sanford prescribed fire complex located in the Dixie National Forest. Slope, aspect, sucker regeneration heights, soil samples, and post and prefire stand densities were measured. Results from this study demonstrated that pre-disturbance conifer abundance and aspen densities are good predictors of aspen sucker regeneration success. Results also found that although conifer densities don't change across aspects, aspen densities are different on north facing slopes. We hypothesize the high levels of aspen regeneration came from a large disturbance size which overwhelmed the high levels of herbivores.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of this research was to evaluate tree pasture-based systems (PS) with elephant grass (EG) + spontaneous growing species (SGS), ryegrass (RG), for PS1; EG + SGS + forage peanut, for PS2; and EG + SGS + RG + red clover, for PS3. EG was planted 4 m spaced rows. In the cool-season, ryegrass was sowed between rows of EG; red clover was sowed and the forage peanut was preserved in respectively PS. Experimental design was completely randomized with tree treatments (SF), two replicates (paddocks) in completely split-plot time (grazing cycles). Holstein cows receiving 5.5 kg-daily and a complementary concentrate feed were used in the evaluation. The herbage mass parameters, botanical composition, forage production and stocking rate were evaluated. Samples were collected by the hand-plucking method to analyze the organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and organic matter in situ digestibility (OMISD) of pasture; phenols and tannins on legumes. Nine grazing cycle were performed during the experimental period (341 days). The mean values of forage production, stocking rate, crude protein and digestibility were 17.14; 16.80; and 19.47 t/ha; 3.28; 3.34; and 3.60 UA/ha; 13.86; 15.39; and 14.78%; 78.33; 79.23; and 79.94% on the respective PS. SGS increased significantly (P≤0,05) relation to the PS without forage legume. Similar results were observed for forage production OM an NDF in comparison to PS. Nutritive value was similar between forage legumes. Differences (P≤0,05) on condensed tannin tenors were observed between forage legumes. Considering the forage production, stocking rate and nutritive value, the PS mixed to forage legumes showed better performance. / O objetivo desta pesquisa foi avaliar três sistemas forrageiros (SF) com capim elefante (CE), espécies de crescimento espontâneo (ECE), azevém anual (AZ), como SF1; CE + ECE + AZ + amendoim forrageiro (AF), como SF2; e CE + ECE + AZ + trevo vermelho (TV), como SF3. O capim elefante foi estabelecido em linhas afastadas a cada 4 m. No período hibernal fez-se o estabelecimento do AZ entre as linhas do capim elefante; o trevo vermelho foi semeado e o amendoim forrageiro foi preservado, considerando os respectivos tratamentos. O delineamento experimental foi o inteiramente casualizado, com três tratamentos (SF), duas repetições (piquetes) em parcelas subdivididas no tempo (pastejos). Para avaliação foram usadas vacas da raça Holandesa que receberam complementação alimentar com concentrado à razão de 5,5 kg/dia. Foram avaliados parâmetros da massa de forragem pré-pastejo, a composição botânica, a produção de forragem e a lotação. Para analisar a matéria orgânica (MO), a fibra em detergente neutro (FDN), proteína bruta (PB) e digestibilidade in situ da MO (DISMO) da pastagem e os teores de fenóis e taninos das leguminosas, foram coletadas amostras de pastejo simulado. Durante o período experimental (341 dias) foram efetuados nove ciclos de pastejo. Os valores médios de produção de forragem, lotação, PB e de DISMO foram 17,14; 16,80; e 19,47 t/ha; 3,28; 3,34; e 3,60 UA/ha; 13,86; 15,39; e 14,78%; 78,33; 79,23; e 79,94% nos respectivos SF. Houve aumento significativo (P≤0,05) para espécies de crescimento espontâneo na pastagem sem leguminosa. Resultados similares foram observados entre SF para MO e FDN. O valor nutritivo foi similar entre as leguminosas forrageiras. Foram observadas diferenças (P≤0,05) entre as leguminosas para os teores de taninos condensados. Considerando a massa de forragem, a lotação e o valor nutritivo, as pastagens consorciadas com leguminosas forrageiras apresentaram melhor desempenho.

Boreal forests are often strongly nitrogen (N) limited. However, human activities are leading to increased N inputs into these ecosystems, through atmospheric N deposition and forest fertilization. N input into boreal forests can promote net primary productivity, increase herbivore and pathogen damage, and shift plant species composition and community structure. Genetic diversity has been suggested as a key mechanism to promote a plant species’ stability within communities in response to environmental change. Within any plant population, specific traits (e.g. growth and defense traits) can vary substantially among individuals, and a greater variation in traits may increase chances for the persistence of at least some individuals of a population, when environmental conditions change. One aspect of plant chemistry that can greatly vary among different genotypes (GTs) are condensed tannin (CTs). These secondary metabolites have been suggested to affect plant performance in many ways, e.g. through influencing plant growth, the interactions of plants with herbivores and pathogens, and through affecting litter decomposition, and hence the return of nutrients to plants. To investigate how genotypic variation in foliar CT production may mediate the effects that anthropogenic N enrichment can have on plant performance and litter decomposition, I performed a series of experiments. For these experiments, aspen (Populus tremula) GTs with contrasting abilities to produce foliar CTs (i.e. low- vs. high-tannin producers) were grown under 3 N conditions, representing ambient N (+0 kg ha-1), upper level atmospheric N deposition (+15 kg ha-1), and forest fertilization rates (+150 kg ha-1). This general experimental set-up was once established in a field-like environment, from which natural enemies were excluded, and once in a field, in which enemies were present. In my first two studies, I investigated tissue chemistry and plant performance in both environments. I observed that foliar CT levels decreased in response to N in the enemy‑free environment (study I), but increased with added N when enemies were present (study II). These opposing responses to N may be explained by differences in soil N availability in the two environments, or by induction of CTs after enemy attack. Enemy damage generally increased in response to N, and was higher in low-tannin than in high-tannin plants across all N levels. Plant growth of high‑tannin plants was restricted under ambient and low N conditions, probably due to a trade-off between growth and defense. This growth constraint for high‑tannin plants was weakened, when high amounts of N were added (study I and II), and when enemy levels were sufficiently high, so that benefits gained through defense could outweigh the costs of defense production (study II). Despite those general responses of low- and high‑tannin producers to added N, I also observed a number of individual responses of GTs to N addition, which in some case were not connected to the intrinsic ability of the GTs to produce foliar CTs. In study III, gene expression levels in young leaves and phenolic pools of the plants that were grown in the enemy‑free environment were studied. This study revealed that gene control over the regulation of the phenylpropanoid pathway (PPP) was distributed across the entire pathway. Moreover, PPP gene expression was higher in high-tannin GTs than in low‑tannin GTs, particularly under ambient N. At the low N level, gene expressions declined for both low- and high-tannin producers, whereas at the high N level expression at the beginning and the end of the PPP was upregulated and difference between tannin groups disappeared. Furthermore, this study showed that phenolic pools were frequently uncorrelated, and that phenolic pools were only to some extent related to tannin production and gene expression. In study IV, I investigated the decomposability of litter from the field plants. I found that N enrichment generally decreased mass loss, but there was substantial genetic variation in decomposition rates, and GTs were differentially responsive to added N. Study IV further showed that CTs only had a weak effect on decomposition, and other traits, such as specific leaf area and the lignin:N ratio, could better explain genotypic difference in mass loss. Furthermore, N addition caused a shift in which traits most strongly influenced decomposition rates. Collectively, the result of these studies highlight the importance of genetic diversity to promote the stability of species in environments that experience anthropogenic change. / Boreala skogar är ofta mycket kväve (N) begränsade. Men mänskliga aktiviteter leder till ökad N tillförsel i dessa ekosystem, både genom depostition av N från atmosfären och skogsgödsling. N-tillförsel i boreala skogar kan främja netto primärproduktionen men även leda till ökade skador från naturliga fiender (herbivorer och patogener) samt skiftningar i växtartsammansättning. Genetisk mångfald har föreslagits som en viktig mekanism för att främja en växtarts stabilitet inom samhällen som upplever miljöförändringar. Inom varje växtpopulation kan specifika egenskaper (t.ex. tillväxt och försvar) varierar kraftigt mellan individer och en större variation i egenskaper kan öka chanserna för att åtminstone några individer från en population överlever ifall miljöförhållandena förändras. En aspekt av växtkemi som i hög grad kan variera mellan olika genotyper (GT) är bladens kondenserade tanniner (KT). Dessa sekundära metaboliter har föreslagits påverka växtens prestationsförmåga på många sätt, t.ex. genom att påverka tillväxt, interaktioner mellan växter och herbivorer eller patogener och genom att påverka förna nedbrytning, och följaktligen återbördandet av näringsämnen till kretsloppet. För att undersöka hur genotypiska variation i KT produktion kan påverka de effekter som antopogent N kan ha på växtens prestationsförmåga och förna nedbrytning, utförde jag en serie experiment. Jag studerade olika asp (Populus tremula) GT med olika förmåga att producera KT (låg- och hög-tannin producenter). Växterna odlades i tre olika N förhållanden, som representerade ambient N nivå (+0 kg ha-1), atmosfärisk N deposition = låg nivå (+15 kg ha-1), och skogsgödsling = hög nivå (150 kg ha‑1). Dessa GT etablerades i en fält-liknande miljö där naturliga fiender uteslutits och i ett fält där naturliga fiender var närvarande. I mina första två studierna undersökte jag vävnadskemi och växternas prestationsförmåga i de båda miljöerna. Jag observerade att KT nivåerna sjönk till följd av N‑tillsats i den fiende-fria miljön (studie I), men ökade med N-tillsats ifall fiender var närvarande (studie II). Dessa motsatta reaktioner på N-tillsats kan förklaras av skillnader i N-tillgång mellan de två odlingsplatserna eller genom ökad KT produktion som respons på angrepp. Skador orsakade av herbivorer och patogener ökade generellt till följd av N‑tillsats och var högre i låg-tannin än i hög‑tannin producerande GT oavsett N‑förhållande. Tillväxten hos växter från hög‑tannin GT begränsades i ambient- och låg N-tillsats förhållanden, troligen på grund av att avvägning mellan tillväxt och försvar förskjutits emot försvar. Den begränsade tillväxten i hög-tannin växter minskade om stora mängder N tillsattes (studie I och II) och om antalet fiender var tillräckligt högt så att nyttan av försvaret kunde uppväga kostnaderna för försvarsproduktionen (studie II). Trots dessa generella respons hos låg- och hög-tannin GT till följd av N‑tillsats observerade jag även ett antal individuella respons hos GT som i vissa fall var orelaterade till växters förmåga att producera KT. I studie III undersöktes genuttrycksnivåer och fenolinnehåll i blad från växter som odladats i en miljö där naturliga fiender exkluderats. Denna studie visade att fenylpropanoidsyntesvägen (FPV) regleras genom kontroll av många av de undersökta FPV-generna. Dessutom var FPV genuttryck högre i hög-tannin GT än i låg-tannin GT, särskilt vid ambient N. Vid låg N-tillsats minskade genuttrycket av FPV-gener i både låg- och hög-tannin producenter, medan hög N-tillgång ledde till att gener i början och slutet av FPV uppreglerades och till att skillnaderna mellan tannin grupperna försvann. Dessutom visade studien att de separata fenol-poolerna ofta var okorrelerade med varandra och att fenol-poolerna bara till viss del var korrelerade med KT produktion och FPV-genutryck. I studie IV undersökte jag nedbrytningshastigheten för förnan från fältodlade aspar. Jag upptäckte att N-tillsats generellt minskade viktförlusten men att det fanns en betydande genetisk variation mellan GT och att dessa även var olika mottagliga för tillsatt N. Studie IV visade vidare att KT endast hade en svag effekt på nedbrytning och att andra egenskaper såsom specifik bladyta och lignin:N ratio kunde bättre förklara den genotypiska skillnaden i viktförlust. Dessutom orsakade N‑tillsats en förskjutning av vilka egenskaper som mest påverkade förnans nedbrytningshastighet. Sammanfattningsvis visar mina studier på vikten av genetisk mångfald för att främja växtartens stabilitet i miljöer som upplever antropogena förändringar.

Tannine sind pflanzliche, polyphenolische Sekundärmetabolite mit Protein-präzipitierenden und –bindenden Kapazitäten, welche offenbar für die antinutritiven und gesundheitsschädlichen Wirkungen der Tannine verantwortlich sind. Jedoch dominieren in der Literatur die gesundheitsfördernden Beschreibungen, für die meist die antioxidative Kapazität verantwortlich gemacht wurde. Der etablierte Modelorganismus Caenorhabditis elegans wurde zur Analyse dieses Kontrastes ausgewählt. Zunächst wurden Lebensdauer und Stressresistenz der mit Tanninsäure und den Tanninbausteinen Gallussäure, Ellagsäure und Catechin behandelten Nematoden ermittelt. Das vermutete Vorliegen eines „Calorie Restriction“ (CR)-Effektes als auch einer hormetischen Dosis-Wirkungs-Beziehung wurde überprüft. Weiterhin wurden antimikrobielle und antioxidative Eigenschaften als potentielle Ursachen der Langlebigkeit untersucht und die Auswirkungen auf die Fitness und Genexpression analysiert. Die Einbeziehung verschiedener Alterungs-Theorien rundete die Analyse der Tanninwirkung ab. Alle Tannin-Substanzen konnten eine Lebensverlängerung erwirken, doch erstaunlicherweise erwiesen sich Langlebigkeit und Stressresistenz als individuelle, nicht zwangsläufig gekoppelte Parameter. Hormesis, CR-nachahmende Eigenschaften, antimikrobielle Kapazitäten als auch verschiedene stressrelevante Gene sind teilweise für die Lebensverlängerung verantwortlich. Die antioxidative Kapazität scheint jedoch irrelevant zu sein. Die differentielle Expression mehrerer hundert Gene durch Tanninsäure unterstreicht zudem die Komplexität der Wirkweise. Hinweise zur Bestätigung der „Disposable Soma Theory“, der „Mitohormesis“-Theorie und der „Green Theory of Ageing“ konnten zum Teil gefunden werden. Diese Arbeit zeigt die individuelle und kontrastreiche Wirksamkeit der Tannine auf. Sie unterstreicht, dass Tannine molekulare Regulatoren sind, welche nicht nur auf ihre antioxidative und antinutritive Kapazität reduziert werden sollten. / The polyphenolic tannins are plant-produced secondary metabolites with protein precipitating and binding capacities. This characteristic is seemingly responsible for antinutritional and harmful effects. However, health benefits have also been extensively described in the literature. Indeed, antioxidant properties are believed to be the reason for these beneficial effects. The established model organism Caenorhabditis elegans was chosen to examine this apparent contradiction. The nematodes were exposed to tannic acid and to the tannin building blocks gallic acid, ellagic acid, and catechin and the lifespan and stress resistance were determined. The presence of a calorie restriction (CR) effect and a hormetic dose-response-relationship was verified. Furthermore, antimicrobial and antioxidative capacities were assessed as possible causes of longevity and the impact on fitness parameters and gene expressions was analysed. The consideration of different ageing theories completed the analysis of the tannin action. All tannin-substances were able to prolong the lifespan but against all expectations, longevity and stress resistance were shown to be independent entities, which are not necessarily linked. Hormesis, CR-mimetic properties, antimicrobial capacities as well as several stress relevant genes are partly responsible for the life-extension. The antioxidant capacities, however, appeared to be irrelevant. The regulation of several hundred gene expressions by tannic acid underlined the complexity of the mode of action. Furthermore, the results partly confirm the “Disposable Soma Theory”, the “Mitohormesis Theory” and the “Green Theory of Ageing”. This work dissects the contrasting efficiency of the tannin family and underlines in particular, that tannins are molecular regulators, which should not be reduced to their antioxidative and antinutritional capacities

As folhas de Maytenus ilicifolia são amplamente utilizadas na medicina tradicional brasileira no tratamento de distúrbios gástricos. Após a comprovação de sua eficácia e segurança, a referida droga vegetal tem sido objeto de diversos estudos com a finalidade de estabelecer parâmetros para o controle de qualidade. Neste sentido, foi avaliada a viabilidade do desenvolvimento de um método analítico fundamentado na precipitação de taninos empregando povidona como agente seqüestrante. Os dados revelaram que a remoção de taninos em solução é satisfatória quando empregada a povidona insolúvel. Foi observado que o polímero também é capaz de precipitar outros polifenóis além dos taninos presentes na solução extrativa de M. ilicifolia. Entretanto, as interações do polímero ocorrem preferencialmente com os derivados catéquicos. Adicionalmente foi desenvolvido e validado um método por CLAE para separação e quantificação de catequina e epicatequina em produtos derivados de M. ilicifolia. Não foram detectadas variações nas áreas dos picos ou nos tempos de retenção durante os ensaios de avaliação do método, sugerindo que as condições cromatográficas empregadas são satisfatórias. Para viabilizar a preparação de produto seco por aspersäo (PSA) em torre de secagem piloto munida de aspersor rotatório, foi necessária a concentração da solução extrativa. A operação foi realizada sob pressão reduzida até alcangar um teor de sólidos mínimo de 15 % (m/m). A operação de secagem da solução concentrada apresentou rendimento de 90 % e o PSA obtido apresentou partículas esféricas, com superfície rugosa e tamanho médio de 22,5 um. A caracterização tecnológica do material revelou que as suas propriedades tecnológicas, tais como, densidades, compressibilidade e fluxo, foram incrementadas quando comparados com o produto preparado em equipamento de bancada. Entretanto, estas modificações não foram suficientes para viabilizar sua compressão direta. Assim sendo, o material foi compactado em máquina de comprimir e em rolos para produção de grânulos. A análise do perfil compressional do PSA e dos granulados, empregando o modelo de Heckel, revelou que o aumento da força de compactação durante a operação de granulação foi o principal responsável pela diminuição no potencial de deformação plástica dos grânulos. Como conseqüência, a recompressão dos grânulos em máquina de comprimir originou compactos com dureza inferior àqueles preparados diretamente do complexo farmacêutico. Enquanto o PSA apresentou reduzida tendência ao rearranjo particular nos estágios iniciais da compressão, os grânulos sofreram intensa reacomodação decorrente da fragmentação e formação de novas pontes, assumindo comportamento plástico em pressões de compressão mais elevadas. Por fim, comprimidos contendo teor elevado de granulado de PSA foram preparados utilizando como adjuvantes a celulose microcristalina, o dióxido de silício coloidal e a croscarmelose sódica. A influência da concentração de dióxido de silício coloidal e croscarmelose sódica na formulação, sobre as respostas de dureza, friabilidade e tempo de desintegração dos comprimidos foram avaliadas através de um Desenho Composto Central. Os dados experimentais foram analisados estatisticamente, utilizando os modelos matemáticos para gerar superfícies de resposta. Os resultados indicaram que a concentração de dióxido de silício coloidal foi inversamente relacionada às respostas de dureza e friabilidade, enquanto que a concentração de croscarmelose sódica foi a principal responsável pela redução no tempo de desintegração. As condições ótimas foram selecionadas através da sobreposição dos gráficos, buscando uma formulação com menor tempo de desintegração, menor friabilidade e o máximo de dureza. A formulação eleita deve conter 1,2 % (m/m) de dióxido de silício coloidal e 5,0 % (m/m) de croscarmelose sódica. Nestas condições os comprimidos apresentaram dureza de 107,9 N, friabilidade de 0,56 % (m/m) e desintegração máxima em 6,8 min. / The leaves of Maytenus ilicifolia are widely used within the traditional Brazilian medicine due to its properties against gastric disorders. Once proved its efficacy and safety, this vegetable drug has been the object of several studies to establish the basis for quality control. Taking this into consideration, it was necessary to evaluate the feasibility of developing an analytical method based on the precipitation of tannins, by using polyvinylpyrrolidone for precipitation. The data have shown that the removal of the tannins in solution was successful when insoluble polyvinylpyrrolidone was used. Hereby it was observed that the polymer has also the ability to precipitate other polyphenols besides the tannins from the aqueous solution of M. ilicifolia. However, the interactions of the polymer happened mostly with the condensed tannins. Further it was developed and also validated an HPLC method to separate and quantify catechin and epicatechin present in aqueous extracts of M. ilicifolia. No significant variations of peak areas or retention times were observed when the evaluation of the method was executed, showing satisfactory chromatographic conditions. In order to make a spray dried extract (SDE) using a spray-drier fitted out with a rotary atomizer, it was necessary to concentrate the extractive solution. This operation had been performed under reduced pressure until a content of 15 % solids was achieved. The drying of the concentrated solution lead to a yield of 90 %, and the obtained SDE presented spherical particles, which have a rough surface and a mean particle size of 22,51.1.m. The technological characterization of the SDE showed that attributes such as densities (tap and bulk), compressibility and flow, have been improved when compared to the product prepared using a mini spray-drier supplied with a pneumatic nozzle. However, these modifications were not enough to enable its direct compression. Therefore, the material was compacted to produce granules after slugging or roller compaction, The compressional analysis of the SDE and each granule batch using the Heckel equation proved that the increase in the compaction force once processing the granulation was the main factor to reduce the material's ability to undergo plastic deformation. Consequently, the recompression of the granules in a tablet press led to compacts with a lower crushing strength compared to that prepared by direct compression of the pharmaceutical complex. Whereas the SDE has shown a reduced tendency to particle rearrangement at early stage of compression, the granules showed an intense fragmentation and rebound behavior, presenting a plastic behavior when higher compaction pressures were used. Finally, tablets containing a high dose of granulated spray dried extract of M. ilicifolia were prepared by using the following excipients: microcrystalline cellulose (filler/binder), colloidal silicon dioxide (glidant and moisture adsorber) and cross-linked carboxymethylcellulose (disintegrant). The influences of colloidal silicon dioxide (CSD) and cross-linked carboxymethylcellulose (CMC-Na) on the tablet hardness, disintegration time and friability were evaluated by a central composite design. The data were analyzed statistically and mathematical models were used to create response surfaces. The results have indicated that the concentration of CSD shows an inverse relation to the responses of hardness and friability, while the concentration of CMC-Na was the most important factor that caused a reduction of the time necessary for total disintegration. The optimal conditions for processing were chosen by the overlapping of graphics, taking into consideration that the formulation should present a minimum of disintegration time, lower friability and a maximum of hardness. Thus, it was found that the best formulation should have a content of 1.2% (w/w) of CSD and 5.0% (w/w) of CMC-Na. Regarding these conditions, the tablets have shown a hardness of 107.9 N, friability of 0.56% (w/w) and a disintegration time of 6.8 min.

L’intégration des fibres naturelles cellulosiques de plantes annuelles ou de résidus agricoles ou agro-industriels dans l’élaboration de matériaux de structures composites et le développement de nouveaux liants biosourcés sont aujourd’hui un domaine de recherche d’intérêt croissant. La thèse s'est déroulée dans le cadre du programme « Eco-panneaux », dont les deux objectifs principaux furent tout d'abord de valoriser les fibres végétales d’origine tunisienne comme l’alfa, le jonc et les folioles de palme et ensuite d'évaluer le potentiel d'espèces végétales tunisiennes dont les écorces sont riches en tannins (fruit de grenade, racines du sumac et tronc de pin d’Alep). Les études de caractérisation des fibres ont montré que leurs masses volumiques sont inférieures à 1. Le calcul du point de saturation des fibres (FSP) montre des valeurs majoritairement comprises entre 60 et 100 %. Nous avons également pu caractériser la cinétique d'imprégnation d'eau pour chacune des fibres. L’imprégnation se stabilise après 24 h d’immersion. Riches en minéraux (concentrations supérieures à 1 %), les fibres ont montré des teneurs en cellulose, en lignines et en hémicellulose comparables à celles généralement rencontrées avec les fibres de bois. L’analyse thermogravimétrique (ATG) a permis de constater que les matrices végétales étudiées sont thermiquement stables pour des températures inférieures à 200°C. Le dosage colorimétrique pour étudier la composition en polyphénols des matrices tannifères, l’analyse infrarouge et l’étude structurale de l’extrait des tanins, ainsi que le calcul du « Stiasny number » , montrent la forte teneur de l’écorce de grenade en tanins hydrolysables et la richesse des écorces du tronc de pin d’Alep et des racines du sumac en tanins condensés. L’étude des propriétés thermiques des extraits de tanins par ATG montre que les tanins de pin d’Alep et du sumac sont thermiquement plus stables que ceux de la grenade. La colle formulée à partir d’hexamine et de tanins de pin d’Alep présente un module d’élasticité élevé. Alors que la colle à base de tanins de grenade forme le réseau le moins dense. Ces résultats ont été confirmés par l’étude de la résistance au cisaillement. L'étude réalisée sur les composites fibres-plâtre (mise en œuvre et caractérisation physico mécanique des composites) a montré que les fibres locales pourraient constituer une alternative aux fibres d'importation utilisées actuellement. Une première caractérisation de la conductivité thermique des panneaux isolants élaborés à partir des fibres locales et de colles de tanins montre une conductivité thermique moyenne de 0,106w/K.m. / The integration of natural cellulosic fibers from annual plants and agricultural residues and agro-industrial materials in the development of composite structures and the development of new bio-based adhesives, are now a research field with growing interest. The thesis was conducted within the framework of "Eco-panels" program, which its two main objectives were firstly, to enhance plant fibers of Tunisian origin as alfa, rush and palm leaflets and then to evaluate the potential of Tunisian plant species whose bark is rich in tannins (pomegranate fruit, sumac roots and Aleppo pine trunk). The characterization studies of fibers showed that their densities are less than 1. The calculation of the fiber saturation point (FSP) shows values mostly between 60 and 100 %. We were also able to characterize the impregnation kinetics of water for each of these fibers. The impregnation stabilizes after 24 h of immersion. Rich in minerals (concentrations greater than 1 %), the fibers showed levels of cellulose, lignin and hemicellulose comparable to those generally encountered with wood fibers. The thermogravimetric analysis (TGA) shows that the plant matrices are thermally stable for temperatures below 200 ° C. The colorimetric assay of the polyphenolic composition of tanniferous matrices, the infrared analysis and the structural study of the tannins extract, as well as the calculation of "Stiasny number" show the high content in hydrolysable tannins for pomegranate barks and richness of Aleppo pine trunk barks and sumac roots barks in condensed tannins. The study by TGA of the thermal properties of tannins extracts shows that Aleppo pine and sumac tannins are thermally more stable than those of pomegranate. The formulation made from hexamine and Aleppo pine tannins has the greatest elasticity modulus. While the formulation prepared from pomegranate tannins forms the least dense network. These results were confirmed by the study of the shear strength. The study conducted on fiber-plaster composites (implementation and physico-mechanical characterization of composites) showed that local fiber could be an alternative to imported fibers used currently. A first characterization of the thermal conductivity of insulation panels made from local plant fibers and tannins adhesives shows an average conductivity of 0,106 W / Km.

Cette étude a deux objectifs principaux : l’extraction de tanins condensés d’écorces de pin maritime et la formulation de colles tanin-lignosulfonate. Deux méthodes d’extraction ont été étudiées. La première est une extraction à l’eau chaude ; c’est une technique simple, peu coûteuse, sans solvant. La deuxième est une extraction assistée par micro-ondes ; c’est une technique innovante, rapide et peu consommatrice en solvant. L’optimisation des conditions d’extraction à l’eau chaude a été réalisée. Les extraits ont été caractérisés par des dosages colorimétriques, leur réactivité au formaldéhyde, par infrarouge à transformée de Fourier (IRTF), par chromatographie en phase liquide à haute pression, par 1H RMN et 2D HSQC RMN. L’impact de la granulométrie sur l’extraction de polyphénols et particulièrement de tanins condensés par extraction assistée par micro-ondes a été étudié pour la première fois. Les deux types d’extraction ont été comparés. L’extraction assistée par micro-ondes a un rendement en extractibles inférieur à l’extraction à l’eau chaude. Mais elle extrait plus de tanins condensés, de flavonoïdes simples et plus de sucres. Quelle que soit la méthode d’extraction, les tanins condensés majoriatires extraits de l’écorce de pin maritime sont de la catéchine, de l’épicatéchine, de l’épicatéchine gallate et de l’épigallocatéchine. Des colles tanin-lignosulfonate ont été produites en utilisant l’héxaméthylènetetramine comme durcisseur. Dans un premier temps, des tanins de mimosa ont été utilisés avec des lignosulfonates de sodium et des lignosulfonates d’ammonium. Les lignosulfonates ont subi deux traitements au glyoxal qui ont été comparés par analyse thermogravimétrique (ATG), par calorimétrie différentielle à balayage (DSC), par les propriétés thermiques et mécaniques de colles et de panneaux de particules avec des lignosulfonates ayant subi les deux traitements ont également été étudiées. L’optimisation du ratio tanin de mimosa-lignosulfonate glyoxalé a été menée et les propriétés thermiques des colles mesurées. L’optimisation des conditions de pressage de panneaux de particules a été réalisée. Des panneaux de particules avec de bonnes performances mécaniques ont été fabriqués. Des colles à base de tanins d’écorce de pin maritime et de lignosulfonates ont été réalisées avec 40% de tanins et 60% de lignosulfonates. Ces colles ont été caractérisées par IRTF, analyse thermomécanique, ATG et DSC. Ces colles sont rentrées dans la fabrication de panneaux de particules. Les émissions de formaldéhyde et la cohésion interne des panneaux ont été mesurées et comparées à des panneaux encollés avec une colle tanin de mimosa-lignosulfonate et une résine urée-formaldéhyde. Grâce à ces résultats, il a été possible de montrer que les panneaux de particules fabriqués à partir de colles bio-sourcées n’émettaient pas de formaldéhyde. / This study has two main objectives: the extraction of condensed tannins from maritime pine bark and the preparation of tannin-lignosulfonate adhesives. Two extraction methods were studied. The first is hot water extraction which is a simple, cheap method without the use of an organic solvent. The second is microwave-assisted extraction which is a fast, innovative method using only a small amount of solvent. Optimum extraction conditions were determined for hot water extraction. The extracts were characterised by their reaction to formaldehyde and by using colorimetric tests, Fourier Transformed Infrared spectroscopy (FTIR), high pressure liquid chromatography, 1H NMR and heteronuclear single quantum correlation 2D NMR.. The two types of extraction were compared. It was found that microwave-assisted extraction produced a lower yield of extractibles than the hot water method but that it produced more condensed tannins, simple flavonoids and sugars. The condensed tannins extracted from maritime pine bark are catechin, epicatechin, epicatechin gallate and epigallocatechin, whatever the extraction method used. Tannin-lignosulfonate adhesives were produced using hexamethylenetetramine as a hardener. First, mimosa tannins were used with sodium lignosulfonates and ammonium lignosulfonates. The lignosulfonates underwent two glyoxal treatments which were compared using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and by determining the thermal and mechanical properties of the adhesives and of the particle boards made using the lignosulfonates resulting from the two treatments. The optimum mimosa tannin-glyoxalated lignosulfonate ratio was determined and the thermal properties of the adhesives were measured. The optimum conditions of pressing the particle boards were determined. Particle boards which recorded a good mechanical performance were produced. Adhesives using maritime pine bark tannins and lignosulfonates were prepared with 40% tannins and 60% lignosulfonates. These adhesives were characterised using FTIR, thermomechanical analysis, TGA and DSC. These adhesives were used to produce particle boards. The emission of formaldehyde and the internal bond of the boards were measured and compared to those of boards made with a mimosa tannin-lignosulfonate adhesive and to those of boards made with a urea-formaldehyde resin. Thanks to these results, we were able to produce particleboards with bio-based adhesives that didn’t emit formaldehyde.

Cinque varietà di sorgo (Sorghum bicolor (L.) Moench) provenienti da Nigeria, Senegal, Burkina Faso e due dall’Italia, sono state caratterizzate per il loro profilo nutrizionale, analizzando la modulazione di due marcatori cellulari (contenuto in proteine totali e attività della GPx), il contenuto di fattori chelanti (tannini e fitati), l’attività fitasica e il contenuto, la bioaccessibilità e la biodisponibilità di ferro e zinco e analizzando l’impatto di due importanti processi alimentari, quali fermentazione e cottura. I risultati mostrano che sia la varietà sia il processo influenzano la maggior parte dei parametri. Tannini e fitati, elementi in traccia, contenuto proteico totale e il processo (soprattutto la fermentazione) sono modulati dalla varietà. La fermentazione riduce il contenuto di fattori chelanti e aumenta l’attività fitasica, incrementando, così, la biodisponibilità degli elementi in traccia; mentre la cottura non ha un impatto significativo. D’altra parte, la fermentazione ha un impatto negativo su entrambi i marcatori cellulari, mentre la cottura solo sul contenuto proteico totale. Le varietà africane, soprattutto quella dal Senegal, hanno mostrato il migliore profilo nutrizionale, mentre, globalmente, le italiane il peggiore. I risultati indicano che la selezione di varietà e di adeguati processi alimentari può avere un impatto significativo sul valore nutrizionale del sorgo. / Five sorghum cultivars (Sorghum bicolor (L.) Moench) from Nigeria, Senegal, Burkina Faso and Italy (two), were characterized for their nutritional values by analysing the modulation of cellular functional markers (total protein content and GPx activity), chelating factors (iron-binding phenolic groups and phytates) content and phytase activity, as well as iron and zinc content, bioaccessibility and bioavailability, also considering the impact of food processing methods as fermentation and cooking. The results revealed that both variety and food processing affect most of the tested parameters. Chelating factors, trace elements, cellular total protein content, as well as the effect of processing (mainly fermentation) were modulated by variety. Fermentation decreased chelating factors content, as well as increased phytase activity, leading to enhancement of iron and zinc estimated bioavailability, whereas cooking had no substantial impact. On the other hand, fermentation process had a negative impact on both cellular functional markers while cooking only on the cellular total protein content. The African varieties, particularly the Senegal one, showed the most promising nutritional profile, whereas the two Italian varieties overall showed a poor one. The results indicate that selection of traditional varieties and processing methods can have a significant impact on parameters relevant to sorghum nutritional value.

As folhas de Maytenus ilicifolia são amplamente utilizadas na medicina tradicional brasileira no tratamento de distúrbios gástricos. Após a comprovação de sua eficácia e segurança, a referida droga vegetal tem sido objeto de diversos estudos com a finalidade de estabelecer parâmetros para o controle de qualidade. Neste sentido, foi avaliada a viabilidade do desenvolvimento de um método analítico fundamentado na precipitação de taninos empregando povidona como agente seqüestrante. Os dados revelaram que a remoção de taninos em solução é satisfatória quando empregada a povidona insolúvel. Foi observado que o polímero também é capaz de precipitar outros polifenóis além dos taninos presentes na solução extrativa de M. ilicifolia. Entretanto, as interações do polímero ocorrem preferencialmente com os derivados catéquicos. Adicionalmente foi desenvolvido e validado um método por CLAE para separação e quantificação de catequina e epicatequina em produtos derivados de M. ilicifolia. Não foram detectadas variações nas áreas dos picos ou nos tempos de retenção durante os ensaios de avaliação do método, sugerindo que as condições cromatográficas empregadas são satisfatórias. Para viabilizar a preparação de produto seco por aspersäo (PSA) em torre de secagem piloto munida de aspersor rotatório, foi necessária a concentração da solução extrativa. A operação foi realizada sob pressão reduzida até alcangar um teor de sólidos mínimo de 15 % (m/m). A operação de secagem da solução concentrada apresentou rendimento de 90 % e o PSA obtido apresentou partículas esféricas, com superfície rugosa e tamanho médio de 22,5 um. A caracterização tecnológica do material revelou que as suas propriedades tecnológicas, tais como, densidades, compressibilidade e fluxo, foram incrementadas quando comparados com o produto preparado em equipamento de bancada. Entretanto, estas modificações não foram suficientes para viabilizar sua compressão direta. Assim sendo, o material foi compactado em máquina de comprimir e em rolos para produção de grânulos. A análise do perfil compressional do PSA e dos granulados, empregando o modelo de Heckel, revelou que o aumento da força de compactação durante a operação de granulação foi o principal responsável pela diminuição no potencial de deformação plástica dos grânulos. Como conseqüência, a recompressão dos grânulos em máquina de comprimir originou compactos com dureza inferior àqueles preparados diretamente do complexo farmacêutico. Enquanto o PSA apresentou reduzida tendência ao rearranjo particular nos estágios iniciais da compressão, os grânulos sofreram intensa reacomodação decorrente da fragmentação e formação de novas pontes, assumindo comportamento plástico em pressões de compressão mais elevadas. Por fim, comprimidos contendo teor elevado de granulado de PSA foram preparados utilizando como adjuvantes a celulose microcristalina, o dióxido de silício coloidal e a croscarmelose sódica. A influência da concentração de dióxido de silício coloidal e croscarmelose sódica na formulação, sobre as respostas de dureza, friabilidade e tempo de desintegração dos comprimidos foram avaliadas através de um Desenho Composto Central. Os dados experimentais foram analisados estatisticamente, utilizando os modelos matemáticos para gerar superfícies de resposta. Os resultados indicaram que a concentração de dióxido de silício coloidal foi inversamente relacionada às respostas de dureza e friabilidade, enquanto que a concentração de croscarmelose sódica foi a principal responsável pela redução no tempo de desintegração. As condições ótimas foram selecionadas através da sobreposição dos gráficos, buscando uma formulação com menor tempo de desintegração, menor friabilidade e o máximo de dureza. A formulação eleita deve conter 1,2 % (m/m) de dióxido de silício coloidal e 5,0 % (m/m) de croscarmelose sódica. Nestas condições os comprimidos apresentaram dureza de 107,9 N, friabilidade de 0,56 % (m/m) e desintegração máxima em 6,8 min. / The leaves of Maytenus ilicifolia are widely used within the traditional Brazilian medicine due to its properties against gastric disorders. Once proved its efficacy and safety, this vegetable drug has been the object of several studies to establish the basis for quality control. Taking this into consideration, it was necessary to evaluate the feasibility of developing an analytical method based on the precipitation of tannins, by using polyvinylpyrrolidone for precipitation. The data have shown that the removal of the tannins in solution was successful when insoluble polyvinylpyrrolidone was used. Hereby it was observed that the polymer has also the ability to precipitate other polyphenols besides the tannins from the aqueous solution of M. ilicifolia. However, the interactions of the polymer happened mostly with the condensed tannins. Further it was developed and also validated an HPLC method to separate and quantify catechin and epicatechin present in aqueous extracts of M. ilicifolia. No significant variations of peak areas or retention times were observed when the evaluation of the method was executed, showing satisfactory chromatographic conditions. In order to make a spray dried extract (SDE) using a spray-drier fitted out with a rotary atomizer, it was necessary to concentrate the extractive solution. This operation had been performed under reduced pressure until a content of 15 % solids was achieved. The drying of the concentrated solution lead to a yield of 90 %, and the obtained SDE presented spherical particles, which have a rough surface and a mean particle size of 22,51.1.m. The technological characterization of the SDE showed that attributes such as densities (tap and bulk), compressibility and flow, have been improved when compared to the product prepared using a mini spray-drier supplied with a pneumatic nozzle. However, these modifications were not enough to enable its direct compression. Therefore, the material was compacted to produce granules after slugging or roller compaction, The compressional analysis of the SDE and each granule batch using the Heckel equation proved that the increase in the compaction force once processing the granulation was the main factor to reduce the material's ability to undergo plastic deformation. Consequently, the recompression of the granules in a tablet press led to compacts with a lower crushing strength compared to that prepared by direct compression of the pharmaceutical complex. Whereas the SDE has shown a reduced tendency to particle rearrangement at early stage of compression, the granules showed an intense fragmentation and rebound behavior, presenting a plastic behavior when higher compaction pressures were used. Finally, tablets containing a high dose of granulated spray dried extract of M. ilicifolia were prepared by using the following excipients: microcrystalline cellulose (filler/binder), colloidal silicon dioxide (glidant and moisture adsorber) and cross-linked carboxymethylcellulose (disintegrant). The influences of colloidal silicon dioxide (CSD) and cross-linked carboxymethylcellulose (CMC-Na) on the tablet hardness, disintegration time and friability were evaluated by a central composite design. The data were analyzed statistically and mathematical models were used to create response surfaces. The results have indicated that the concentration of CSD shows an inverse relation to the responses of hardness and friability, while the concentration of CMC-Na was the most important factor that caused a reduction of the time necessary for total disintegration. The optimal conditions for processing were chosen by the overlapping of graphics, taking into consideration that the formulation should present a minimum of disintegration time, lower friability and a maximum of hardness. Thus, it was found that the best formulation should have a content of 1.2% (w/w) of CSD and 5.0% (w/w) of CMC-Na. Regarding these conditions, the tablets have shown a hardness of 107.9 N, friability of 0.56% (w/w) and a disintegration time of 6.8 min.