• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 65
  • 35
  • 34
  • 29
  • 8
  • 5
  • 4
  • 4
  • 1
  • 1
  • Tagged with
  • 196
  • 196
  • 43
  • 29
  • 28
  • 27
  • 23
  • 20
  • 18
  • 17
  • 17
  • 17
  • 16
  • 15
  • 15
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Effects of Horticultural Oils on Photosynthesis, Fruit Maturity, and Yield of Wine Grapes

Finger, Sarah Adine 26 May 2000 (has links)
In field experiments conducted in northern Virginia during 1998, oils reduced photosynthesis, fruit maturity, and crop yield. Three applications of a 1.5% (v/v) oil/water emulsion were made to Chardonnay and Cabernet Sauvignon vine canopies at 6200 L/ha (Chardonnay) and 2440 L/ha (Cabernet Sauvignon). Net assimilation rate (NAR), soluble solids concentration (SSC), and berry size were reduced by oil treatments when compared to an untreated control. Also in 1998, a 1.5% (v/v) oil/water emulsion at 5550 L/ha and 4680 L/ha was applied to 23 wine grape cultivars. Eleven cultivars had significant foliar injury but injury was not related to reductions in fruit maturity. Experiments conducted in 1999 determined if reduced spray volumes or applications to only the fruit zone minimize reductions in NAR and SSC. Chardonnay and Cabernet Sauvignon were treated with JMS Stylet oil (1.5%) using 5600 L/ha or 1870 L/ha applied to the whole canopy or 930 L/ha applied to the fruit zone. The NAR of 5600 L/ha treated Cabernet Sauvignon was significantly lower than the NAR of control and other oil treatments on three measurement dates. The NAR of Chardonnay in the 5600 L/ha treatment was significantly lower than the NAR of control treatments in three measurements. Cabernet Sauvignon SSC was reduced by the 5600 L/ha and 1870 L/ha treatments, relative to the water treated control, on three sample dates but not at harvest. The SSC of Chardonnay in the 5600 L/ha treatment was reduced at harvest as compared to all other treatments. The SSC of Chardonnay in the 1870 and 930 L/ha treatments was reduced relative to the water control. Low volumes of oil caused less reduction in NAR and SSC; however, there are concerns about the efficacy of oils used at low volumes due to poor coverage. / Master of Science
22

Effects of Pruning Level and Canopy Management Practices on Berry Maturation Rate and Harvest Parameters of Syrah Wine Grapes

Landolt, Jeffery S. 01 March 2011 (has links) (PDF)
Syrah is an important wine grape in California but is potentially difficult to manage in the vineyard due to its excessive vigor. Vigorous grapevines require more labor for canopy management and tend to create excess shade, decreasing fruit quality. Winter pruning level, shoot thinning and leaf removal influence the overall density of the canopy and the subsequent degree of shade in the fruit zone. An experiment was conducted to assess the effects of two pruning levels with three degrees of labor-intensive canopy management techniques on berry maturation rate and harvest berry parameters for two growing seasons. In 2008, repeated measures analysis showed no significant effects of severe pruning, shoot thinning or both sides leaf removal on maturation rate of performance indicators. At harvest 2008, severe pruning caused a decrease in yield/meter trellis and Ravaz index. In 2009, repeated measures analysis showed significant effects of severe pruning increasing brix, pH and sugar to acid ratio while shoot thinning and both sides leaf removal had no significant effects on maturation rate of performance indicators. At harvest 2009, severe pruning increased brix, pH, tannin, anthocyanins, phenolics, color density, potassium, amino acid % of yeast assimilable nitrogen (YAN), and the following ratios: sugar/acid, amino acid/ammonium, tannin/anthocyanins and malic/tartaric acid. Additionally, severe pruning decreased tartaric acid, yield/meter trellis, ammonium % of YAN and Ravaz index. The findings presented in this thesis suggest that severe pruning could be used as a tool in viticultural areas with short growing seasons because of the increased ripening speed observed. However, because severe pruning generally increases berry size which is negative for vinification, it should be studied further with irrigation and management practices that decrease berry size.
23

Influence de la date de vendange sur les composés phénoliques de la baie de raisin : conséquences pour la typicité du vin / Influence of the harvest date on the phenolic compounds of the grape berries : consequences for the wines typicality

Cadot, Yves 08 December 2010 (has links)
L'objectif de la thèse est de contribuer à l'explicitation du lien au terroir, dans le cas de vins d'Appellation d'Origine Contrôlée. À ce lien au terroir correspond une typicité, qui correspond à des propriétés remarquables et partagées pour un groupe humain de référence. Le lien causal entre typicité et terroir a été étudié en prenant comme élément d'étude le chantier de vendange et les vinifications associées. La composition phénolique des vendanges, et leur aptitude à être extraits lors de la vinification ont permis de mieux interpréter le lien causal étudié. La représentation conceptuelle de la typicité, qui engendre des choix techniques, a été mise en évidence, du point de vue des critères sensoriels d'appartenance et des critères sensoriels de distinction. Cette représentation conceptuelle est en générale consensuelle, et les principaux facteurs du terroir, explicatifs du lien, correspondent au milieu physique. La représentation perceptuelle a été étudiée, permettant de mettre en évidence des descripteurs d'appartenance et de distinction, et de les hiérarchiser vis à vis de la perception globale de la typicité. Cette représentation est moins consensuelle. Les principaux facteurs du terroir, explicatifs du lien, correspondent aux actes techniques, en particulier la date de vendanges et la durée de cuvaison.Une évolution de la composition de la vendange en fonction du niveau de maturité a été mise en évidence d'un point de vue histologique, mais son interprétation est incomplète. L'aptitude des proanthocyanidines à être extraits, en fonction du niveau de maturité des baies est fortement corrélé à la perception globale de la typicité. Dans le cas de vins revendiquant un lien au terroir, certaines représentations de la typicité sont partagées, et engendrent des choix techniques (date de vendange, durée de cuvaison). L'importance de ces choix peut être démontré par l'étude de la composition de la vendange en composés phénoliques. Cependant, il existe un écart entre la typicité en tant que concept et la typicité telle qu'elle est sensoriellement perçue. / The aim of this work is to contribute to highlight the terroir effect, in the case of wines from delimited origin. The typicality is the result of the terroir effect and corresponds, to remarkable and shared properties for a human group of reference. The causal link between typicality and terroir was studied by taking into account the harvest date and the associated wine makings. The phenolic composition of the grape at harvest, and their extractability during the wine making made it possible to better interpret the studied causal link. The conceptual representation of the typicality, which generates technical choices, was highlighted, from the point of view of the sensory criteria of similarity and of distinction. This conceptual representation is in general consensual, and the main factors of the terroir, which explain the causal link, correspond to the soil and climate. The perceptual representation was studied, descriptors of similarity and distinction were highlighted, and theses descriptors were organized with respect to the global perception of the typicality. This representation is less consensual than conceptual one. The main factors of the terroir, which explain the causal link, correspond to the technical acts, particularly the harvest date and the vatting duration.Composition of the harvest, according to the level of maturity was highlighted from a histological point of view, but its interpretation was unfinished. The aptitude of the proanthocyanidins for being extracted, according to the level of maturity is strongly correlated for the global perception of the typicality. For wines related to terroir, some typicality representations are shared, and lead to technical choices (harvest date, duration of vatting). These choices are explained by the harvest composition. However, there is a difference between the typicality as a concept and the typicality as sensory perception.
24

Développements méthodologiques en chromatographie de partage : application aux stilbénoïdes / Methodological development in centrifugal partition chromatography : application to stilbenoids

Bisson, Jonathan 20 December 2012 (has links)
Les stilbénoïdes, sont des composés phénoliques majoritairement issus du règne végétal. La Vigne par l’intermédiaire du vin et du raisin est la principale source alimentaire de stilbènes. La mise en évidence de leur rôle dans les mécanismes de défense des plantes et leurs activités biologiques, y compris sur l’Homme, en font un sujet d’étude en plein essor. L’un des objectifs de cette thèse a été de développer un ensemble de stratégies à la fois analytiques et préparatives utilisant la Chromatographie de Partage Centrifuge (CPC) pour l’étude et l’obtention de ces molécules. Dans un premier temps, nous avons développé une approche de couplage entre cette technique et un spectromètre à Résonance Magnétique Nucléaire (RMN) par l’intermédiaire d’un système d’Extraction sur Phase Solide automatisé (EPS). Dans un second temps, nous avons mis au point un ensemble de méthodes et d’approches séparatives permettant d’obtenir ces composés. Nous avons, grâce au développement d’une méthodologie de dosage de solvants par spectrométrie RMN, étudié une gamme dérivée d’une gamme très utilisée en CPC, l’ARIZONA. Nous avons montré que ces systèmes dérivés, peuvent être utilisés au travers de stratégies d’élution telles que des pas et des gradients afin d’optimiser les séparations. L’une des finalités de notre travail est d’offrir des méthodes permettant d’obtenir ces composés dans des quantités et des qualités suffisantes pour pouvoir constituer une chimiothèque interne au laboratoire pouvant prétendre à s’intégrer dans la Chimiothèque Nationale. Une dernière partie fait état du développement d’outils informatiques, dont la création d’une base de donnée Libre pour les chercheurs en Substances Naturelles. / Stilbenoids are phenolic compounds mostly found in the vegetable kingdom. Vine through wine and grape is the main source of stilbenes in the human diet. The involvement of these compounds in plants resistance mechanisms and their diverse biological activities, including on the human health are continuously highlighted. Making this topic a fast-growing one. One of the objectives of this thesis has been to develop a whole set of analytical and preparative strategies using Centrifugal Partition Chromatography (CPC) in order to study and obtain these molecules. Over a first phase, we developed a hyphenated approach between this technique and Nuclear Magnetic Resonance (NMR) through an automated Solid Phase Extraction (SPE) system. Then, we developed a set of separative methods and approaches with the aim of obtaining these compounds. Then, we carried out the development of a solvent quantifications methodology using NMR spectrometry. This allowed us to study a spin-off scale of a widely-used solvent systems collection called ARIZONA. We showed that these systems are good candidates for different elution strategies using steps and gradients with the aim to optimize separations. One of our purpose was to provide methods for effective and efficient purification of these compounds. This would allow, together with a lab-scale compounds library, their integration into the Chimiothèque Nationale, a nationwide chemical library. Last part accounts for computer tools development, including the creation of a Free database system for Natural Substances researcher.
25

Citotoxicidade e ação anti-inflamatória in vitro dos extratos glicólicos de Morus nigra (amora), Ziziphus joazeiro (juá) e Vitis vinifera (uva) / Cytotoxicity and anti-inflammatory action in vitro of the glycolic extracts of Morus nigra (black mulberry), Ziziphus joazeiro (juá) and Vitis vinifera (grape)

Botan, Andresa Graciutti 03 May 2018 (has links)
Submitted by Andresa Graciutti Botan (andresabotan@yahoo.com.br) on 2018-06-06T18:58:46Z No. of bitstreams: 1 Dissert Andresa G Botan.pdf: 1532972 bytes, checksum: af162b8b131f0fd6e440d9ae810290fc (MD5) / Approved for entry into archive by Silvana Alvarez null (silvana@ict.unesp.br) on 2018-06-06T19:37:16Z (GMT) No. of bitstreams: 1 botan_ag_me_sjc.pdf: 1532972 bytes, checksum: af162b8b131f0fd6e440d9ae810290fc (MD5) / Made available in DSpace on 2018-06-06T19:37:16Z (GMT). No. of bitstreams: 1 botan_ag_me_sjc.pdf: 1532972 bytes, checksum: af162b8b131f0fd6e440d9ae810290fc (MD5) Previous issue date: 2018-05-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As plantas medicinais e seus extratos têm sido utilizados na medicina tradicional para fins terapêuticos e como uma atrativa fonte de pesquisa em diversas vertentes ciêntíficas, dentre elas, a atividade anti-inflamatória. O objetivo deste estudo foi analisar a citotoxicidade e ação anti-inflamatória in vitro dos extratos glicólicos das plantas medicinais Morus nigra (amora), Ziziphus joazeiro (juá) e Vitis vinifera (uva) em macrófagos de camundongo RAW 264.7. A citotoxicidade dos extratos foi analisada pelo teste de viabilidade celular MTT em dois períodos de tratamento, 5 min e 24 h. A ação anti-inflamatória dos extratos foi avaliada em macrófagos RAW 264.7 estimulados pelo lipopolissacarídeo (LPS) por meio da quantificação das citocinas pró-inflamatórias fator de necrose tumoral (TNF-α) e interleucina-6 (IL-6) pelo teste imunoenzimático (ELISA), e da quantificação do óxido nítrico pela reação de Griess. Os valores obtidos foram submetidos à análise estatística ANOVA ou Kruskal-Wallis com comparação múltipla de Tukey ou Dunn, com nível de significância de 5%. Concentrações não citotóxicas foram observadas após exposição por 5 min e 24 h, respectivamente, para os extratos de M. nigra (≤ 50 mg/mL e ≤ 1,56 mg/mL), Z. joazeiro (≤ 6,25 mg/mL e ≤ 3,12 mg/mL) e V. vinifera (≤ 25 mg/mL e ≤ 3,12 mg/mL). Em relação à resposta anti-inflamatória, 0,78 e 1,56 mg/mL do extrato de M. nigra e 3,12 mg/mL de V. vinifera apresentaram inibição significativa na produção da citocina TNF-α, e o extrato de Z. joazeiro suprimiu de modo significativo a expressão da citocina TNF-α (3,12 mg/mL) e do óxido nítrico (1,56 e 3,12 mg/mL). O presente trabalho demonstrou que os extratos glicólicos de M. nigra, Z. joazeiro e V. vinifera apresentaram concentrações não citotóxicas em ambos os tempos de tratamento e exerceram efeito anti-inflamatório em macrófagos de camundongo RAW 264.7. / Medicinal plants and theirs extracts have been used in traditional medicine for therapeutic purposes and as a source of research in several scientific aspects, e.g. the anti-inflammatory activity. This study aimed to analyze the in vitro cytotoxicity and anti-inflammatory action of the glycolic extracts of the medicinal plants Morus nigra (black mulberry), Ziziphus joazeiro (juá) and Vitis vinifera (grape) in mouse macrophages cells RAW 264.7. The cytotoxicity of the extracts was analyzed by MTT cell viability assay in two periods, 5 min and 24 h. The anti-inflammatory action of the extracts was evaluated in lipopolysaccharide (LPS) stimulated RAW 264.7 cells by quantifying the pro-inflammatory cytokines tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) by enzyme-linked immunosorbent assay (ELISA) and nitric oxide by Griess reagent. The values obtained were submitted to statistical tests ANOVA or Kruskal-Wallis with post-test Tukey or Dunn multiple comparisons with the significance level of 5%. After exposure for 5 min and 24 h, respectively, non-cytotoxic concentrations were observed for M. nigra (≤ 50 mg/mL and ≤ 1.56 mg/mL), Z. joazeiro (≤ 6.25 mg/mL and ≤ 3.12 mg/mL) and V. vinifera (≤ 25 mg/mL and ≤ 3.12 mg/mL) extracts. Concerning the anti-inflammatory response, 0.78 and 1.56 mg/mL of M. nigra extract and 3.12 mg/mL of V. vinifera extract showed significant inhibition of TNF-α cytokine production. Z. joazeiro extract suppressed significantly the TNF-α cytokine (3.12 mg/mL) and the nitric oxide (1.56 and 3.12 mg/mL) expression. In conclusion, the glycolic extracts of M. nigra, Z. joazeiro, and V. vinifera presented non-cytotoxic concentrations in both treatment periods and showed an anti-inflammatory effect in RAW 264.7 cells.
26

Qualidade, maturação e vida útil pós-colheita de duas cultivares de videiras produzidas sob três porta-enxertos no município de Mossoró/RN / Quality, maturation and shelflife post-harvest of two vine cultivars produced wiht three rootstocks in municipality of Mossoró/RN

Nascimento, Paula Lidiane de Oliveira Fernandes do 01 August 2016 (has links)
Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-02-20T12:52:08Z No. of bitstreams: 1 PaulaLOFN_TESE.pdf: 1872841 bytes, checksum: c64fbcf4778cab52059b79b31b0f26ad (MD5) / Rejected by Vanessa Christiane (referencia@ufersa.edu.br), reason: Corrigir CPF do prof. Glauber on 2017-02-23T15:27:57Z (GMT) / Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-02-23T15:30:07Z No. of bitstreams: 1 PaulaLOFN_TESE.pdf: 1872841 bytes, checksum: c64fbcf4778cab52059b79b31b0f26ad (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-03-21T15:01:32Z (GMT) No. of bitstreams: 1 PaulaLOFN_TESE.pdf: 1872841 bytes, checksum: c64fbcf4778cab52059b79b31b0f26ad (MD5) / Made available in DSpace on 2017-03-21T15:01:42Z (GMT). No. of bitstreams: 1 PaulaLOFN_TESE.pdf: 1872841 bytes, checksum: c64fbcf4778cab52059b79b31b0f26ad (MD5) Previous issue date: 2016-08-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The viticulture has been expanding its cultivation in many regions of the country. Considering his success in the Northeast, in the Vale do São Francisco, research must be done to stimulate the development of this culture in new regions. The objective of this research was to evaluate the development of two grapevine cultivars produced in three rootstocks in Mossoró/RN, assessing maturity, quality and postharvest life of fruit. The experiment was conducted at the Experimental Farm Rafael Fernandesfrom 2013 to 2015. We used the design of randomized blocks with split plots for the three experiments. The first experiment evaluated the quality of the fruit in four crop cycles, with the rootstock (IAC 766, IAC 572 and IAC 313) in the plots and crop cycles subplots. In the second experiment, the treatments were three rootstocks (IAC 766, IAC 572 and IAC 313) and four maturity stages (14, 19, 24 and 28 days after the start of the color change of the berry) with five repetitions for Isabel Precoce. In the third experiment, we evaluated the shelflife of vine cultivars stored under refrigeration (4 ± 2 ° C and 95 ± 5% RH), where plots were assigned to rootstocks (IAC 766, IAC 572 and IAC 313) and time storage were assigned to the subplots. In third experiment for cultivar Isabel Precoce, storage times were 10, 20, 30, 40 and 50 days after harvest; to cultivar Itália Melhorada, were 8, 16, 24 and 32 days of storage after harvest. The characteristics evaluated for the three experiments were: mass of the bunch, number and berry mass, peel mass, berry length, berry diameter, color Berry (L, A * and B *), firmness (N) mass loss, wilting index stalk and injuries, soluble solids (SS), titratable acidity (TA), pH, SS/AT ratio, total and reducing sugars, anthocyanins, flavonoids, phenolic compounds and antioxidant activity. For the cycles of Isabel cultivar, the bunch weight and the number of berries were higher in the 3rd and 4th cycles; but the physical and chemical characteristics, as soluble solids, SS/AT ratio and sugar, were higher in the 1st cycle; as the bioactive compounds, phenolic and antioxidant activity was higher in the 4th harvest (first semester 2015). For cultivar Itália Melhorada, the 1st cycle gave higher soluble solids and SS/AT ratio, and the rootstock 766 shown superiority; in the second cycle, the mass of the bunch and number of berry was greater, and the rootstock 572 most massive result of the bunch. The ideal point of Isabel Precoce grape harvest is 28 days after the beginning of the maturation. The rootstock had a significant effect only for the SS/AT ratio, and highlight the IAC 766; for bioactive compounds, there was an increase with the maturation only for the phenolic content in the peel and pulp and anthocyanins, the other compounds did not vary throughout the maturation. Regarding storage the cultivar Isabel Precoce had a Shelflife relatively long, 50 days of storage at 4 ° C ± ± 2ºC and 90 ± 5% RH; the cultivar Itália Melhorada had a limited shelf life to 24 days of storage (4 ° C ± 2ºC and 90 ± 5% RH). As for the rootstocks used, the 766 and 572 had higher soluble sugar content for Isabel Precoce cultivar and higher soluble solids and total sugars to cultivar Itália Melhorada / A viticultura vem expandindo seu cultivo por várias regiões do país. Diante do seu sucesso na região nordeste, no Vale do São Francisco, pesquisas devem ser feitas visando estimular o desenvolvimento desta cultura em novas regiões. O objetivo do trabalho foi avaliar a qualidade, maturação e potencial de conservação dos frutos de duas cultivares de videira, produzidas sob três porta-enxertos no município de Mossoró/RN. O experimento foi realizado na Fazenda Experimental Rafael Fernandes, da UFERSA, no período de 2013 a 2015. Utilizou-se para os três experimentos o delineamento em blocos ao acaso com parcelas subdivididas. O primeiro experimento avaliou a qualidade dos frutos em quatro ciclos da cultura, com os porta-enxertos (IAC 766, IAC 572 e IAC 313) nas parcelas e os ciclos da cultura nas subparcelas. No segundo experimento, os tratamentos foram três porta-enxertos (IAC 766, IAC 572 e IAC 313) e quatro estádios de maturação (14, 19, 24 e 28 dias após o início da mudança de cor das bagas) com cinco repetições para Isabel Precoce. No terceiro experimento, foi avaliada a vida útil das cultivares de videira armazenadas sob refrigeração (4 ± 2º C e 95 ± 5% UR), onde as parcelas foram atribuídas aos porta-enxertos (IAC 766, IAC 572 e IAC 313) e tempo de armazenamento, às subparcelas. As características avaliadas para os três experimentos foram: massa do cacho, número de bagas, massa das bagas, massa da casca, comprimento da baga, diâmetro da baga, cor da baga (L, a* e b*), firmeza (N), perda de massa, índice de murchamento do engaço e injurias, sólidos solúveis (SS), acidez titulável (AT), pH, relação SS/AT, açúcares totais e redutores, antocianinas, flavonoides, compostos fenólicos e atividade antioxidante. Para os ciclos da cultivar Isabel, o peso do cacho e número de bagas foram superiores no 3º e 4º ciclos, mas as características físico-químicas como sólidos solúveis, relação SS/AT e açúcar foram superiores no 1º ciclo; quanto aos compostos bioativos, os fenólicos e a atividade antioxidante foram maiores no 4º ciclo. Para a cultivar Itália Melhorada, o 1º ciclo proporcionou maiores teores de sólidos solúveis e relação SS/AT, tendo o porta-enxerto IAC-766 mostrado superioridade; já no segundo ciclo, foram maiores a massa do cacho e número de bagas, tendo o porta-enxerto IAC-572 maior resultado de massa do cacho. O ponto ideal de colheita de uvas Isabel Precoce é aos 28 dias após o início da maturação. O porta-enxerto teve efeito significativo apenas para a relação SS/AT, tendo destaque o IAC-766; para os compostos bioativos, houve aumento com a maturação apenas para os teores de fenólicos na casca e polpa e para as antocianinas, os demais compostos não variaram ao longo da maturação. Com relação ao armazenamento, a cultivar Isabel Precoce teve vida útil relativamente longa, 50 dias de armazenamento a 4º C ± 2ºC e 90 ± 5% UR; a cultivar Itália Melhorada teve sua vida útil limitada aos 24 dias de armazenamento (4º C ± 2ºC e 90 ± 5% UR). Quanto aos porta-enxertos utilizados, o IAC-766 e IAC-572 proporcionaram maiores teores de açúcares solúveis para a cultivar Isabel Precoce e maiores teores de sólidos solúveis e açúcares totais para a cultivar Itália Melhorada / 2017-02-20
27

Adubação potássica em videiras jovens e em produção no sul do Brasil / Potassium fertilization in young vines and production in southern Brazil

Ciotta, Marlise Nara 22 August 2014 (has links)
The application of potassium (K) and lime as a source of Calcium (Ca) and Magnesium (Mg) in soil may affect the growth and nutritional status of young plants of grapevines as well as grape production, must composition and distribution of forms of K in the soil. This study aimed to i) evaluate the growth and nutritional status of young grapevines submitted to the application of K lime in soil ii) evaluate how potassium fertilization affects the grape production, must composition and alterations of forms of K in soil, and iii) evaluate the potential of water in leaves as well as the nutritional status and must composition of grapevines grown with or without irrigation. Four studies were carried out. In study I, two experiments were performed in Campanha Gaucha (RS) in order to assess young plants. In the experiment 1, 0, 30 and 60 kg K2O ha-1were applied. In the experiment 2, 0, 60, 120, and 180 kg K2O ha-1were applied with application of dolomitic and calcitic lime. The K content in leaves, plant height, stem diameter and pruned material weight were evaluated. Studies II, III and IV were carried out for plants in production with the installation of three other experiments. One of the experiments was performed in Serra Catarinense (SC) with 0, 50, 100, 150 and 200 kg K2O ha-1 yr-1. The second experiment was in Campanha Gaucha with five levels of K in the soil. The K content in leaf, berries, grape yield components, and must composition were evaluated in both experiments. The third experiment was carried out in the region of Trento (Italy) with grapevines in production, with or without irrigation the soil, where the water potential of plants as well as the nutrient content in the leaf and berry of grapes were evaluated. In the experiment with young plants, soil potassium fertilization increased the K only in the 0-10 cm layer and influenced the content of K in the leaves in the first season; however, it did not influence the growth of cv. Chardonnay or Pinot Noir. For plants in production in Serra Catarinense there was an increase in the levels of exchangeable, non-exchangeable and total K in soil with the application of potassium fertilizer. The application of K in the soil increased the concentration of K in leaf and petioles of grapevines; however, it did not affect grape production or the must composition. In Campanha Gaucha, the increase of the content of exchangeable K in the soil increased the total K in the leaves in flowering, the K content in the berries and the pH of the must; however, it did not affect grape production. Although providing less negative water potential in grapevine leaves, irrigation did not affect nutritional status or the enological parameters of the berry, showing little interference in its nutrient content. / A aplicação de potássio (K) e calcário, como fonte de Ca e Mg no solo, podem afetar o crescimento e o estado nutricional de plantas jovens de videiras, assim como, pode afetar a produção de uva, composição do mosto e alterar a distribuição das formas de K no solo. O trabalho objetivou (a) avaliar o crescimento e o estado nutricional de videiras jovens submetidas à aplicação de K calcários no solo (b) avaliar como a adubação potássica pode afetar a produção de uva, composição do mosto e alteração das formas de K no solo (c) avaliar o potencial de água em folhas, o estado nutricional e a composição do mosto, de videiras cultivadas com e sem irrigação. Foram realizados quatro estudos. Para avaliar plantas jovens, no estudo I, foram instalados dois experimentos na Campanha Gaucha (RS), onde foi aplicado, no experimento 1: 0,30 e 60 kg de K2O ha-1; e no experimento 2: 0, 60, 120, e 180 kg de K2O ha-1, com aplicação de calcário calcítico e dolomítico. Avaliou-se o teor de K em folhas, a altura de plantas, diâmetro de caule e massa do material podado. Para plantas em produção, Estudos II, III e IV, foram instalados outros três experimentos. Na Serra Catarinense (SC) com 0, 50, 100, 150 e 200 kg de K2O ha-1 ano-1 e outro na Campanha Gaucha com 5 níveis de K no solo, em ambos foram avaliados os teroes de K na folha, nas bagas, componentes de rendimento da uva e composição do mosto. Na região de Trento (Itália) foi instalado um experimento com videiras em produção, com e sem irrigação do solo, onde foi avaliado o potencial hídrico das plantas, além do teor de nutrientes na folha e na baga de uva. No experimento com plantas jovens, a adubação potássica no solo incrementou os teores de K somente na camada de 0-10 cm, influenciou o teor de K nas folhas na primeira safra, porém não influenciou os parâmetros de crescimento nas cv. Chardonnay e Pinot Noir. Para plantas em produção na Serra Catarinense houve incremento nos teores de K trocável, não trocável e total no solo com a aplicação da adubação potássica. A aplicação de K no solo aumentou os teores de K no limbo e pecíolo das videiras, mas não afetou a produção de uva e a composição do mosto. Na Campanha o incremento do teor de K trocável no solo aumentou o K total nas folhas no pleno florescimento, o teor de K nas bagas e o valor de pH do mosto, mas não afetou a produção de uva. A irrigação, apesar de proporcionar potencial de água menos negativo nas folhas da videira, não afetou o estado nutricional, os parâmetros enológicos e pouco interferiu no teor de nutrientes na baga.
28

Influência de diferentes práticas viticulturais sobre a fermentação alcoólica e a formação de compostos de aroma em cultivares vitis vinifera / Influence of different viticultural practices in the alcoholic fermentation and the formation of aroma compounds in cultivars Vitis vinifera

Rodrigues, Daniele 08 February 2013 (has links)
Orientadores: Helena Teixeira Godoy, Roger Wagner / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-23T09:21:02Z (GMT). No. of bitstreams: 1 Rodrigues_Daniele_D.pdf: 2460072 bytes, checksum: c95a5ef47b314914e0a09d0a616b0186 (MD5) Previous issue date: 2013 / Resumo: O aroma dos vinhos é formado por compostos provenientes das uvas e por compostos formados durante a vinificação, caracterizando a identidade, a tipicidade e a qualidade do vinho. A fermentação alcoólica é o processo de maior importância para a formação desses compostos. Porém, a falta de nutrientes nos mostos, como o nitrogênio, pode resultar em uma fermentação lenta, com a formação insuficiente da biomassa e, consequentemente, a baixa síntese de compostos de aroma. A qualidade de certos vinhos também pode ser prejudicada pela presença de compostos indesejáveis, os offflavours. Dentre esses compostos estão as metoxipirazinas que, em altas concentrações, são responsáveis pelo aroma herbáceo ou de pimentão verde em uvas Cabernet sauvignon, sendo incorporadas no vinho durante o processo de vinificação. Alguns parâmetros têm sido relacionados com as altas concentrações desses compostos, sendo o mais importante a maturação incompleta das uvas na época da colheita, que pode ser influenciada por fatores naturais como a umidade do ar, as precipitações pluviométricas e a temperatura. Diante do exposto, este trabalho foi desenvolvido com o intuito de suprir a falta de nitrogênio no mosto durante a vinificação e de diminuir a concentração de metoxipirazinas nas uvas e nos vinhos. Para isso, diferentes práticas de manejo foram aplicadas nos vinhedos. A pulverização de amônia no solo dos vinhedos das cultivares Merlot, Cabernet franc e Cabernet sauvignon, foi testada para a obtenção de nitrogênio necessário para a fermentação alcoólica e a produção dos compostos de aromas. Para isso, os vinhedos foram divididos em parcelas e receberam diferentes concentrações de amônia (10, 60, 90, 120 e 180 kgN.Hectare-1). Na época da vindima, as uvas foram colhidas e analisadas quanto aos teores de nitrogênio assimilável e de aminoácidos, sendo em seguida vinificadas, e os vinhos analisados quanto aos teores de álcoois superiores e de ésteres. A dupla poda e a cobertura do vinhedo foram realizadas com a cultivar Cabernet sauvignon e testadas para a diminuição de metoxipirazinas na uva e no vinho. Amostras de uvas foram colhidas durante todo o período de maturação, com o intuito de acompanhar as concentrações de metoxipirazinas. Na época da vindima, as uvas foram colhidas e analisadas quanto aos seus teores de metoxipirazinas, sólidos solúveis totais e pH, sendo em seguida vinificadas, e os vinhos analisados quanto aos seus teores de metoxipirazinas. Os resultados mostraram que todas as técnicas de manejo aplicadas nos vinhedos foram eficientes e conseguiram atingir seus objetivos. Com relação à pulverização de amônia, os tratamentos que receberam maiores concentrações desse composto no solo apresentaram concentrações mais elevadas de nitrogênio assimilável (167,163 e 184 mg.L-1) e de aminoácidos (752, 921 e 998 mg.L-1) nos mostos, se comparados com os tratamentos controles (128,103 e 115 mg.L-1 para nitrogênio assimilável e 534, 542 e 601 mg.L-1 para aminoácidos), indicando que as plantas foram capazes de absorver esse composto do solo e utilizá-lo na produção de aminoácidos. A presença de elevadas concentrações de nitrogênio assimilável e de aminoácidos nos mostos influenciou e acelerou a fermentação alcoólica das varietais Merlot e Cabernet sauvignon, cujos tratamentos que apresentaram as maiores concentrações de nitrogênio assimilável tiveram seu tempo de fermentação reduzido de 9 para 7 dias. Adicionalmente, os vinhos elaborados com as uvas oriundas desses mesmos tratamentos apresentaram as maiores concentrações de álcoois superiores (190, 443 e 356 mg.L-1) e de ésteres (6505, 6440 e 6298 ]g.L-1), indicando que a síntese desses compostos foi beneficiada pela presença das altas concentrações de nitrogênio assimilável e de aminoácidos. Sendo assim, conclui-se que a pulverização de amônia no solo foi satisfatória, pois forneceu nitrogênio suficiente para o desenvolvimento da fermentação alcoólica e para a produção de compostos aromáticos. Com relação às metoxipirazinas, os resultados mostraram que elas sofreram degradação ao longo do período de maturação, com valores para a concentração de IBMP (2-metoxi-3-isobutilmetoxipirazina) iniciando em 46 ng.L-1 e finalizando abaixo 2,5 ng.L-1. A cobertura do vinhedo foi a técnica mais eficiente na redução de metoxipirazinas em safras colhidas no verão, apresentando uvas com concentração final máxima para a IBMP de 5,27 ng.L-1, sugerindo que a alta temperatura abaixo da cobertura favoreceu a degradação desses compostos. Porém, a dupla poda inverteu a época da colheita do verão para o inverno,época mais fria e de menor intensidade pluviométrica, contribuindo para o aumento do tempo para as bagas atingirem a maturação ideal e, indiretamente, favorecendo a degradação das metoxipirazinas durante este tempo, chegando a valores finais de concentração inferiores a 2,5 ng.L-1, tornando assim a dupla poda o tratamento mais eficaz para a redução das metoxipirazinas nas uvas e, consequentemente, no vinho / Abstract: The aroma of the wine is made by compounds from grapes and compounds formed during the vinification, featuring the identity, typicality and quality of wine. Alcoholic fermentation is the process of greater importance for the formation of these compounds. However, the lack of nutrients in musts, such as nitrogen, can result in a slow fermentation, with the formation of biomass insufficient and the lower synthesis of aromatic compounds. The quality of certain wines may also be impaired by the presence of undesirable compounds, the off-flavours. Among these compounds are the methoxypyrazines that, in high concentrations, are responsible for the flavor herbaceous or green peppers in grapes Cabernet Sauvignon, being incorporated into the wine during the winemaking process. Some parameters have been related to high concentrations of these compounds, the most important is the unripe grapes at harvest time, which can be influenced by natural factors such as humidity, rainfalls and temperature. Given the above, this work has been developed in order to address the lack of nitrogen in musts during vinification and decrease the concentration of methoxypyrazines in grapes and wines. For this, different management practices were applied in the vineyards. Spraying ammonia into the soil vineyards of Merlot, Cabernet franc and Cabernet Sauvignon was tested to obtain nitrogen necessary for the fermentation and production of flavor compounds. For this, the vineyards were divided into plots and received different concentrations of ammonia (10, 60, 90, 120 and 180 kgN.Hectare-1). At the time of harvest, the grapes were harvested and analyzed for the levels of assimilable nitrogen and amino acids, after they were vinified and the wines were analyzed for the levels of higher alcohols and esters. The double pruning and coverage vineyard were conducted with the cultivar Cabernet Sauvignon and tested to decrease methoxypyrazines in grapes and wine. Samples were harvested during all the maturing period in order to monitor the concentrations of methoxypyrazines. At the time of harvest, the grapes were harvested and analyzed for their content of methoxypyrazines, soluble solids and pH, after they were vinified and the wines were analyzed for their content of methoxypyrazines. The results showed that all the management techniques applied in vineyards were efficient and to achieve their objectives. Regarding the addition of ammonia, the treatments that received higher concentrations of this compound in the soil showed higher concentrations of assimilable nitrogen (167, 163 and 184 mg.L-1) and amino acids (752, 921 and 998 mg L-1) in must, when compared to control treatments (128, 103 and 115 mg.L-1 for assimilable nitrogen and 534, 542 and 601 mg.L-1 for amino acids), indicating that the plants were able to absorb the compound of the soil and use it for the amino acid production. The presence of high concentrations of assimilable nitrogen and amino acids in musts influenced and accelerated the alcoholic fermentation of Merlot and Cabernet Sauvignon, the treatments that presented the highest concentrations of assimilable nitrogen had their fermentation time reduced from 9 to 7 days. Additionally, the wines produced with grapes coming from these same treatments had higher concentrations of higher alcohols (190, 443 and 356 mg L-1) and ester (6505, 6440 and 6298 ]g.L-1), indicating that the synthesis of these compounds was benefited by the presence of high concentrations of assimilable nitrogen and amino acids. Therefore, it is concluded that the addition of ammonia in the soil was satisfactory, because it supplied sufficient nitrogen to the development of alcoholic fermentation and the production of aromatic compounds. With respect to methoxypyrazines, the results showed that they undergo degradation during the maturation period, with values for the concentration of IBMP (2-methoxy-3-isobutylpyrazine) starting at 46 ng.L-1 and ending below 2,5 ng.L-1. The coverage vineyard technique was more effective in reducing methoxypyrazines in crops harvested in summer, with grapes with a maximum final concentration of IBMP of 5,27 ng.L-1, suggesting that high temperature below de coverage favored the degradation of these compounds. However, double pruning reversed the harvest season from summer to winter, coldest and least rainfall intensity, contributing to the increase in time for the berries reach optimum ripeness and, indirectly favoring the degradation of methoxypyrazines during this time, reaching a final concentration values below 2,5 ng.L-1, thus making the double pruning the most effective treatment for reducing methoxypyrazines in grapes and wines / Doutorado / Ciência de Alimentos / Doutora em Ciência de Alimentos
29

Identification et validation fonctionnelle de nouveaux gènes impliqués dans la voie de biosynthèse des composés phénoliques / identification and functional validation of new genes involved in the biosynthetic pathway of phenolic components

Khater, Fida 12 July 2011 (has links)
Les proanthocyanidines (PA) du raisin jouent un rôle majeur dans les propriétés organoleptiques du vin notamment dans l'astringence et la stabilité de la couleur. Elles sont accumulées principalement dans la pellicule et les pépins pendant les premiers stades du développement de la baie. La biosynthèse des PA commence à être bien décrite, cependant certaines étapes restent à élucider.Une étude transcriptomic avait permis d'indentifier de nouveaux gènes potentiellemnt impliqués dans la biosynthèse des PA (Terrier et al., 2009). Parmi ces gènes figuraient 3 glucosyltransférases et 2 glucose- acyltransférases.Les trois glucosyltransférases VvgGT1, VvgGT2 et VvgGT3 présentent de fortes homologies entres elles et avec d'autres glucosyltransférases capables de catalyser la formation de glucose ester. Les transcrits sont exprimés durant les premiers stades de développement de la baie principalement dans les pépins et la pellicule mais aussi dans la pulpe pour VvgGT2. Les propriétés de ces 3 enzymes (Km, Vm, spécificité de substrat, effet du pH) ont été étudiées in vitro après production de protéines recombinantes. Les 3 VvgGTs sont capables de catalyser la synthèse d'esters de glucose en présence de dérivés d'acide hydroxybenzoique ou d'acide hydroxycinnamique.Deux acyltransférases VvGAT1 et VvGAT2 ont été isolées. Elle présente de fortes similarités avec des acyltransférases glucose-ester dépendantes de type serine carboxypeptidase like. Les transcrits sont exprimés surtout avant la véraison, dans les pépins et la pellicule pour VvGAT1 et dans la pulpe et les pépins pour la VvGAT2. L'expression hétérologue dans différents hôtes n'a pas permis de détecter d'activité enzymatique. Les analyses en microscopie confocale suggèrent que VvGAT1 fusionnée à une GFP est localisée dans des vésicules cytoplasmiques.L'implication successive des VvgGTs et des VvGATs dans la galloylation des PA et dans la synthèse d'esters d'acides hydroxcinnamiques est discutée. / Grape proanthocyanidins (PA) play a major role in organoleptic properties of wine, being involved in astringency and color stability. They are accumulated mainly in skin and seeds during early stages of berry development. Numerous structural genes involved in PA biosynthesis have already been identified even in grape, but some steps are still not documented.A previous transcriptomic study led to identify new genes putatively involved in the PA pathway (Terrier et al., 2009). Among them, 3 glucosyltransferases and 2 glucose acyl transferases were identified. The objective of this work is to clarify the function of these genes in the phenylpropanoid pathway.The three glucosyltransferases called VvgGT1, VvgGT2, VvgGT3 displayed high sequence similarities between them and with other plant glucosyltransferases able to catalyze the formation of glucose esters. The transcripts are expressed in the early stages of grape berry development, mainly in skins and seeds and also in the pulp for VvgGT2. The properties of these 3 enzymes (Km, Vm, substrate specificity, pH sensitivity) were studied in vitro after production of recombinant proteins. The three of them are able to catalyse the synthesis of glucose ester with derivates of hydroxybenzoic acids and hydroxycinnamic acids as substrates and with similar kinetic properties.Two glucose-acyltransferases called VvGAT1 and VvGAT2 were isolated. They displayed high sequence similarity with other Serine carboxypeptidase like acyltransferases-glucose dependent. The transcripts are expressed in early stages of grape berry development mainly in skins and seeds for VvGAT1 and in pulp and seeds for VvGAT2. Heterologous expression of the proteins in different hosts were unsuccessful. The confocal microscopy data suggest that VvGAT1 fused to GFP are localized in cytosolic vesicles.The successive involvement of those VvgGT and VvGAT in the galloylation of PAs and in the synthesis of hydroxycinnamic esters is discussed.
30

Développement de sondes moléculaires appliquées à l’étude de la biosynthèse des flavonoïdes / Molecular probes development for Flavonoid biosynthesis studying

Carrié, Hélène 20 December 2013 (has links)
Les flavonoïdes sont des substances naturelles connues pour leurs propriétés anti-inflammatoires, anti-cancéreuses ou anti-virales chez l'homme. Chez les végétaux, ils participent notamment à leur protection vis-à-vis d'organismes pathogènes. La voie de biosynthèse des flavonoïdes est l'une des plus étudiées chez les plantes et notamment chez la vigne : Vitis vinifera. Cependant, la ou les enzymes impliquées dans les dernières étapes de biosynthèse conduisant aux anthocyanes et aux proanthocyanidines restent, à ce jour, peu ou pas connues. L’étude que nous proposons a pour but de concevoir des sondes moléculaires d’affinité susceptibles d’interagir avec une ou plusieurs enzymes impliquées dans ces dernières étapes de biosynthèse. Ces sondes, basées sur la technologie émergeante de protéomique chimique : « Activity- and affininity Based Protein Profiling » (ABPP), ont été validées à l’aide d’une enzyme modèle : la leucoanthocyanidine dioxygénase (LDOX). Elles ont ensuite été appliquées à des extraits complexes de protéines issus de Vitis vinifera. / Flavonoids are natural substances known for their anti-inflammatory, anti-cancerous and anti-virals properties in humans. In plants, they are one of the molecules responsible for fighting pathogens. The flavonoid biosynthesis pathway as been greatly studied in plants, especially in that of the grapevine: Vitis vinifera. However, detailed studies of the exact function of the enzymes involved in the last steps of the biosynthesis of anthocyanins and proanthocyanidins remains largely lacking.The study that we propose is to synthesize molecular probes designed to specifically interact with enzymes involved in the last stages of flavonoids biosynthesis. Our probes, based on the emerging chemical proteomic technology, activity- and affinity based protein profiling (ABPP), were validated with a model enzyme: leucoanthocyanidin dioxygenase (LDOX). After which, they were used with complex protein mixtures from Vitis vinifera.

Page generated in 0.0737 seconds