L'objectif de cette thèse a été de mesurer comment les modifications des régimes hydrologiques, plus particulièrement les exondations, régissent 1) certains aspects du fonctionnement des zones humides, 2) l'organisation et la dynamique à court terme des communautés végétales aquatiques et 3) la survie et la réponse plastique des végétaux aquatiques. Cette thèse aborde les questions à des échelles spatio-temporelles différentes. Premièrement, à l'échelle de la décennie, j'ai mesuré la conséquence de la baisse de la hauteur d'eau des zones humides péri-fluviales sur leur physico-chimie. Deuxièmement, à l'échelle de la saison, j'ai mesuré l'influence des caractéristiques sédimentaires des zones humides sur la réponse à court terme des communautés végétales à l'exondation. Enfin, à l'échelle de quelques semaines, je me suis intéressée à l'aptitude des espèces d'angiospermes aquatiques à mettre en place un ajustement plastique face à l'exondation, en conditions expérimentales de laboratoire et in situ, j'ai recherché les déterminismes de cette réponse (écologiques, morphologiques, phylogénétiques). En termes de caractéristiques physico-chimiques des eaux de surface, l'étude sur 15 ans de la dynamique de zones humides péri-fluviales subissant des exondations, ne conclue pas, comme cela est habituellement décrit dans la littérature, à une augmentation de la teneur en nutriments de la masse d'eau, mais plutôt des changements suggérant des variations du fonctionnement hydrogéologique des zones humides, en faveur d'une plus grande influence de la nappe de versant dans leur alimentation. La réponse in situ des communautés végétales à l'exondation diffère selon le type de sédiment. La résistance et la résilience des communautés décroissent toutes deux avec la capacité de rétention d'eau du sédiment. La capacité des plantes aquatiques à tolérer l'exondation, en conditions expérimentales, semble différer selon leur position phylogénétique, mais pas selon leur forme de croissance (rosettes ou caulescentes) / The objective of this thesis was to measure how changes in hydrological regimes, particularly dewatering govern 1) aspects of the functioning of wetlands, 2) the organization and short-term dynamics of aquatic plant communities and 3 ) survival and plastic response of aquatic plants. This thesis addresses issues at different spatial and temporal scales. First, at the decade scale, I measured the effect of water-level decreases in riverine wetlands on their physico-chemistry characteristics. Second, at the season scale, I measured the influence of sedimentary characteristics of wetlands on short-term response of plant communities to dewatering. Finally, at the scale of a few weeks, I was interested in the ability of aquatic angiosperm species to develop a plastic adjustment to dewatering, in experimental laboratory conditions and in situ, and I looked determinism of this response (ecological, morphological, phylogenetic). In terms of physico-chemical characteristics of surface waters, the 15- year study of the dynamics of riverine wetlands undergoing dewatering, not reached, as is usually described in the literature, with an increase of water body nutrient contents, but rather changes suggesting variations of the hydrogeological functioning of wetlands in favor of a greater influence of the hillslope groundwater table in their water supply. In situ response of plant communities to dewatering differs according to sediment type. Both, resistance and resilience of communities decrease with the sediment water retention capacity. The ability of aquatic plants to tolerate dewatering, in experimental conditions, seems to differ according to their phylogenetic position, but not according to their growth form (rosettes or caulescentes). Species tolerating dewatering show phenotypic adjustments such as denser aerial organs and high plasticity of the leaves, which may explain the maintenance of a similar growth rate in terrestrial and aquatic conditions in these species

<p style="text-align: justify; ">Hladno presovano ulje semena uljane tikve je&nbsp;proizvod specifičan za Srbiju, za razliku od zemalja u regionu koje imaju dugu tradiciju proizvodnje&nbsp;devičanskog tikvinog ulja.&nbsp;Tokom postupka hladnog presovanja sirovogosu&scaron;enog&nbsp;semena uljane tikve na pužnoj presi&nbsp;temperatura izdvojenog ulja ne prelazi 50 ^oC, &scaron;to se&nbsp;odražava na fizičko-hemijske, nutritivne i senzorne&nbsp;karakteristike kao i na oksidativnu stabilnost i&nbsp;antioksidativni potencijal ovog ulja.&nbsp;U cilju &scaron;to bolje karakterizacije ovog proizvoda na&nbsp;na&scaron;em trži&scaron;tu, ispitan je kvalitet hladno presovanog&nbsp;tikvinog ulja poreklom iz semena vi&scaron;e različitih&nbsp;slobodnooplodnih sorti i F1 hibrida, golosemenih i&nbsp;uljanih tikvi sa ljuskom, koje uspevaju u na&scaron;oj&nbsp;zemlji.&nbsp;Hladno presovano ulje semena tikve odlikuju&nbsp;specifične senzorne karakteristike: pored izuzetno&nbsp;blage arome, mirisa na sirovo seme tikve i ukusa&nbsp;koji podseća na meso tikve, ovo ulje se posebno&nbsp;izdvaja po boji koja je kod ispitivanog ulja bila&nbsp;svetlo-smedja do crvenkasta. Prema senzornim&nbsp;karakteristikama (naročito boji) izdvojili su se uzorci ulja poreklom iz semena austrijskih hibrida. Na&nbsp;osnovu sastava masnih kiselina ovo ulje pripada olinsko-linolnom tipu, &scaron;to ga svrstava u nutritivno&nbsp;veoma vredna biljna ulja, čemu doprinosi i visok&nbsp;sadržaj gama-tokoferola, koji je dominantan u&nbsp;tikvinom ulju. Određivanje sastava i sadržaja sterola je posebno bilo značajno kada je u pitanju hladno&nbsp;presovano tikvino ulje s obzirom da nema&nbsp;literaturnih podataka na tu temu. U ispitivanim&nbsp;uzorcima su bili dominantni delta-7 steroli, a određen je i izuzetno visok sadržaj skvalena, koji&nbsp;ima veoma važnu biolo&scaron;ku funkciju. Ispitivano ulje je posedovalo dobar antiradikalski potencijal, koji je&nbsp;bio u snažnoj linearnoj zavisnosti sa sadržajem fenolnih materija. Ulje dobijeno ekstrakcijom iz&nbsp;pogače, koja je zaostala nakon hladnog presovanja&nbsp;semena, posedovalo je veći antiradikalski potencijal&nbsp;u odnosu na hladno presovano &scaron;to je rezultat&nbsp;sadržaja fenolnih materija u većem procentu i ne&scaron;to&nbsp;nižeg sadržaja tokoferola u odnosu na hladno<br />presovano ulje.</p> / <p> Cold-pressed pumpkin oil is a product specific<br /> to Serbia, given that other countries in the<br /> region traditionally produce virgin pumpkin oil.<br /> In the process of cold pressing raw-dried<br /> pumpkin seeds by screw press, the<br /> temperature of extracted oil does not exceed<br /> 50oC, which affects physical, chemical,<br /> nutritional and sensory characteristics of this<br /> oil, as well as its oxidative stability and<br /> antiradical capacity.<br /> For the purpose of more precise<br /> characterization of this product in the domestic<br /> market, the quality of cold pressed oil from<br /> seeds of many free breeding varieties and F1<br /> hybrids &ndash; of both naked and husk seed<br /> pumpkins being grown in our country &ndash; was<br /> examined.<br /> Specific sensorial properties: light brown to<br /> reddish color, mild aroma, a smell similar to<br /> that of raw pumpkin seeds and a taste<br /> resembling that of pumpkin pulp are<br /> characteristic for this oil. As for sensory<br /> characteristics, the samples of oil from<br /> Austrian hybrid seeds, stood out. On the basis<br /> of fatty acid content, this oil belongs to the<br /> oleic-linoleic type, meaning it is a highly<br /> nutritional vegetable oil, which is also due to<br /> high levels of dominant gamma-tocopherol. Determination of the types and content of</p> <p> sterols was particularly important, given that<br /> there are no data specific to cold-pressed<br /> pumpkin oil in the literature. Delta-7 sterols are<br /> the most dominant sterols in examined oil<br /> samples and also very high content of<br /> squalene was found, which a compound with<br /> an important biological function is. The oil has<br /> an excellent antiradical capacity, showing a<br /> strong linear correlation with the amounts of<br /> phenolic compounds. Oil extracted from the<br /> cake, left over after the cold pressing of<br /> pumpkin seeds, had greater antiradical<br /> capacity than the samples of cold pressed oil,<br /> due to higher percentage of phenolic<br /> compounds and a slightly lower content of<br /> tocopherols compared to cold pressed oil.</p>

Made available in DSpace on 2016-12-23T13:50:03Z (GMT). No. of bitstreams: 1 Flavia Fracalossi Baioco.pdf: 791854 bytes, checksum: 59f8b324bb88b6f6a6d459366bd121d2 (MD5) Previous issue date: 2013-11-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O yacon é uma raiz tuberosa considerada alimento funcional devido ao alto conteúdo de frutooligossacarídeos (FOS). Por ser um alimento perecível, em razão do alto teor de água, métodos de processamento têm sido propostos para preservar os constituintes nutricionais e propiciar o seu armazenamento. Nesse contexto, o presente estudo teve como objetivo o desenvolvimento e a avaliação de metodologias de processamento das raízes de yacon visando à produção de suco integral, xarope e farinha. Na condução dos experimentos, primeiro foi avaliado o melhor procedimento para extração do suco das raízes: (i) aplicando o branqueamento a 100 °C por quatro minutos e (ii) não aplicando o tratamento. Definida a melhor forma de obtenção do suco, utilizou-se dessa para produção dos sucos empregados na elaboração do xarope. A porção de suco obtida foi dividida em quatro frações, sendo a elas adicionadas as seguintes quantidades de antioxidantes por quilograma de raiz descascada, respectivamente: (i) ácido cítrico - 0,18 g, (ii) ácido ascórbico - 0,18 g, (iii) combinação de ácido cítrico e ascórbico na proporção de 50% cada - 0,9 g e (iv) sem adição de antioxidante. A farinha foi processada a partir da torta, resultante da obtenção dos sucos, que foi seca a 60 °C e triturado em liquidificador. Foram realizadas análises físico-químicas e de cor dos derivados. Os dados obtidos foram analisados por meio de ANOVA e teste de Tukey a 5% de significância. O tratamento branqueamento foi eficaz na elaboração dos sucos, por inibir o escurecimento, manter constantes as coordenadas de cor e não alterar as características físico-químicas do suco. O emprego do calor na concentração dos sucos para elaboração dos xaropes não promoveu hidrólise dos açúcares complexos em açúcares simples, pois o teor de glicídios redutores não aumentou em nenhum dos tratamentos. Em relação às coordenadas de cor, o xarope com ácido cítrico apresentou maior valor de L*, indicando maior claridade em relação aos demais, e também apresentou valor de h* próximo de 90°, indicando maior proximidade à cor amarela, e maior valor de C*, mostrando maior pureza da cor. A farinha da torta apresentou alto teor de fibra bruta e, juntamente com o xarope controle, o maior teor de cinzas. Os xaropes tiveram menores teores de proteínas, enquanto a farinha da torta apresentou as menores médias de glicídios redutores e não redutores. Desse modo, nos aspectos nutricional e dietético, os xaropes são os preferidos, devido aos maiores teores de glicídios não redutores, tendo o xarope com o antioxidante ácido cítrico apresentado as melhores coordenadas de cor e pH próximo de 4,5, tornando-se o melhor derivado de yacon entre os analisados no presente estudo / The yacon is a tuberous root considered a functional food due to the high content of fructooligosaccharides (FOS). In fact to be a perishable food, because of the high water content, processing methods have been proposed to preserve the nutritional constituents and provide its storage. In reason of this, the present study aimed the development and evaluation methods of yacon root processing in order to produce pulpy juice, syrup and flour. For conducting the experiments, first was estimated the best way to extract juice from the root: (i) apply blanching treatment at 100 °C during four minutes, and (ii) do not apply the treatment. Attested the best way to obtain the juice, it was used for the production of juices used in the syrup preparation. The portion of the juice obtained was divided into four fractions, each of them received the following amounts of antioxidants per kilogram of peeled root, respectively: (i) citric acid - 0.18 g, (ii) ascorbic acid - 0.18 g, (iii) a combination of citric acid and ascorbic acid at ratio of 50% each - 0.9 g, and (iv) without the addition of antioxidant. The flour was processed from marc, resulting of juices processing, which was dried at 60 °C and grounded in a blender. Analyses of physicochemical characteristics and color of yacon products were carried out. Obtained data were analyzed statistically by ANOVA and Tukey s test. The bleaching treatment was effective in the juices preparation, because inhibit browning, maintain constant color coordinates and not change the juice physicochemical characteristics. The use of heat in the juice concentration for the syrup preparation not promoted hydrolysis of complex sugars into simple sugars, because reducing glycids did not increase in any of the treatments. Regarding color coordinates, the syrup with citric acid showed higher L* value, indicating greater clarity in relation to others, and also presented the h* value close to 90°, indicating greater proximity to the yellow color, and higher *C value, showing a greater color purity. Flour of yacon marc showed high crude fiber content and, along with control syrup, the higher ash content. Syrups had lower levels of protein, while the flour of yacon marc had the lowest averages of reducing and non-reducing glycids. Thus, in the nutritional and dietary aspects, syrups are preferred due to higher non-reducing glycids, and the syrup with the citric acid antioxidant presented the best color coordinates and pH next to 4.5, making it the best yacon product analyzed in this study