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Biblioteca Digital do IPB (53.442 recursos)

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Mostrando recursos 1 - 20 de 21

  1. PAHs and metals in a coastal lagoon (Esmoriz/Paramos), Portugal

    Salgado, Maria Antónia; Fernandes, Conceição; Teixeira, C.; Cortez, A.

  2. Can fish adopt the same defence strategy in gill and liver to face chronic metal exposure?

    Fernandes, Conceição; Fontaínhas-Fernandes, A.; Carrola, J.S.; Salgado, Maria Antónia

  3. Mead production: comparison of different production scales (preliminary results)

    Gomes, Teresa; Barradas, Carla; Dias, Teresa; Andrade, João Verdial; Morais, Jorge Sá; Ramalhosa, Elsa; Estevinho, Leticia M.
    Mead production represents a possible economic alternative to honey producers that intend to obtain honey products with surplus value. From that the present work aims to study the influence of using different production scales on the quality of the final mead obtained and on the process performance. Increasing the production scale almost ten times (1.5 to 20 L), some differences were observed. Maximum specific growth rates equal to 0.045 and 0.038 h-1 were obtained for fermentations carried out at 1.5 and 20 L, respectively. The time course of glucose and glycerol were similar for both production scales. Nevertheless, slight differences...

  4. Actividade antioxidante e composição em fenóis totais de dez novas variedades de feijão do ITACYL

    Afonso, Sílvia Marlene Esteves; Oliveira, Ivo; Ramalhosa, Elsa; Asensio-S.-Manzanera, M. Carmen; Asensio, Carmen; Bento, Albino; Pereira, J.A.
    O feijão (Phaseolus ltztlgaris L.) é uma leguminosa largamente consumida no mundo, estando-lhe associadas diferentes propriedades nutricionais. Nas últimas décadas o Instituto Tecnológico Agrário de Castela e Leão (ITACyL) tem-se dedicado ao desenvolvimento de novas variedades de feijão. Neste sentido, com o presente trabalho procedeu-se à avaliação do teor em fenóis totais, e da actividade antioxidante através do efeito bloqueador dos radicais livres de DPPH (2,2-difenil-1-picrilhidrazilo) em dez variedades de feijão desenvolvidas naquele organismo (Almonga, Cárdeno, Cardina, Casasola, Corcal, Curruquilla, Moradillo, Tafioga, Tremaya e Tropical). O teor em fenóis totais foi muito diferente entre variedades oscilando entre 4.19±0.18 (variedade Almonga)...

  5. Evaluation of pedotransfer functions for predicting soil water retention in portuguese soils

    Ribeiro, A.C.
    Estimates of soil water retention characteristics using pedotransfer functions (PTFs) are useful in many studies, such as hydrological modelling and soil mapping. Also reliable information about soil hydraulic properties like water retention characteristic and conductivity functions often constitutes an essential precondition to adequately apply protection and remediation techniques to soil related problems in forest ecology. The determination of the parameters for these functions can be obtained from direct laboratory and field measurements. However, these measurements are time consuming which makes it costly to characterize an extensive area of a land. As an alternative, the existing databases of measured soil hydraulic data may be used to...

  6. Influência da rega deficitária na evolução da maturação da variedade Tinta Roriz (Vitis vinifera L.)

    Ribeiro, A.C.; Sá, A.; Andrade, João Verdial
    Na Região Demarcada do Douro, e em particular na sub-região do Douro Superior, a vinha é conduzida, durante uma parte significativa do seu ciclo vegetativo, em condições de défice hídrico acentuado associadas a altas temperaturas, elevado stresse radiativo e elevado défice de pressão de vapor. As práticas culturais implementadas para minimizar as condições adversas, e em particular o regime de rega, podem alterar substancialmente a fisiologia da videira afectando a produção e a composição do bago. O principal objectivo deste estudo foi o de avaliar o curso da maturação na variedade Tinta Roriz de Vitis vinífera L., através da monitorização dos principais parâmetros da maturação,...

  7. Response of grapevine CV. “Tinta roriz” (Vitis vinifera L.) to moderate irrigation in the Douro Region, Portugal

    Ribeiro, A.C.; Andrade, João Verdial
    The behaviour of cv. “Tinta Roriz” (Vitis vinifera L.), was studied when moderate drip irrigation was applied from veraison to harvest. Field studies were conducted during three growing seasons (2006-2008) in a commercial vineyard located in the Douro region, Portugal. Experimental layout consisted in the measurement of physiological and agronomic parameters in vines submitted to three different irrigation treatments: 0R was non-irrigation, 2R and 4R were irrigated with a constant fraction of reference evapotranspiration of 0.2 and 0.4, respectively. The results showed that moderate irrigation improved plant water status, leaf photosynthesis and transpiration. Yield components and pruning weights had a...

  8. Polysaccharide composition of Fraxinus angustifolia Leave infusions

    Martins, Vitor Manuel Ramalheira; Coimbra, Manuel A.
    The use of plant infusions with medicinal purposes, such as the ones from members of the Fraxinus genus, is an ancient practice that has been reported by popular medicine [1]. The health benefits are associated with the presence of phenolic compounds and polysaccharides, among others [2]. Although phenolic compounds have been studied in detail for more than two decades, the characterization of the polysaccharides present in plant infusions and their involvement in the health benefits is still incipient. The polysaccharides of F. angustifolia dried leaves were recovered by dialysis (12-14 kDa cut-off). The high molecular weight material comprised approximately 2% of...

  9. Polysaccharides from the infusions of P. tridentatum, F. angustifoliaand M. suaveolens

    Martins, Vitor Manuel Ramalheira; Coimbra, Manuel A.
    The use of plant infusions for medicinal purposes is present in secular traditions of all civilizations. In Portugal, in Trás-os-Montes region, the small shrub (Pterospartum tridentatum), the narrow-leafed ash (Fraxinus angustifolia), and the apple mint (Mentha suaveolens) are plants used for such purposes. According to the popular tradition, the infusions of P. Tridentatum, F. Angustifolia, and M. suaveolens protect against diabetes, high blood pressure, high levels of cholesterol, and uric acid [1].These health benefits are associated with the presence of phenolic compounds, essential oils, and polysaccharides, among others. Although phenolic compounds and essential oils have been studied in detail for...

  10. Monomeric composition and linkage analysis of the polysaccharides present in the infusions of Fraxinus angustifolia leaves

    Martins, Vitor Manuel Ramalheira; Coimbra, Manuel A.
    In the Trás-os-Montes region, the use of infusions of Fraxinus angustifolia dried leaves as a protection against high levels of cholesterol, blood pressure and uric acid is widespread. Pectic polysaccharides isolated from the infusions of some medicinal plants have been reported as biologically active [1,2]. Pectic poly-saccharides have been described as structurally complex polymers, exhibiting different polymeric building blocks: homogalacturonans (HG), rhamnogalacturonans-I (RG-I), rhamnogalacturonans-II (RG-II) and xylogalacturonans (XG) [3]. The backbone of RG-I can be partly substituted with various side chains, such as arabinans, type-I and type-II arabinogalactans (AG-I and AG-II). The aim of this work is to provide a...

  11. Medição do fluxo de calor no solo num pomar de macieiras através de um método simples e de baixo custo

    Ribeiro, A.C.; Melo-Abreu, J. Paulo de
    O fluxo de calor no solo é um dos componentes do balanço de energia à superfície do solo. A sua medição é fundamental em várias aplicações micrometeorológicas que requerem a quantificação dos componentes do balanço energético como por exemplo a determinação da taxa de evaporação do solo, da taxa de arrefecimento nocturno, entre outras. A determinação do fluxo de calor no solo pode ser efectuada através de métodos que se baseiam na medição da temperatura do solo, utilizando placas de fluxo de calor ou através da combinação dos dois métodos. Além da precisão, a simplicidade e o custo são factores determinantes na selecção do método...

  12. Modelling apple flower and fruit damage to frost

    Melo-Abreu, J. Paulo de; Ribeiro, A.C.; Snyder, R.L.
    Good quality apples are grown in relatively cold areas. However, frost frequently causes damage to flowers and small fruits. When the percentage of frost damage losses is higher than the thinning requirement of the cultivar, production is reduced. In addition to reducing yield, frost damage to the skin and malformation of the fruits often devalues the quality and reduces profits. Critical temperature tables in relation to phenological stage are available for apples and other deciduous crops (Ballard and Proebsting, 1978; Proebsting and Mills, 1978). Some of the data came from field observations using temperatures from standard shelters and some came from excised branch chamber...

  13. A ventilação forçada na protecção contra a geada de fruteiras caducifólias

    Ribeiro, A.C.; Melo-Abreu, J. Paulo de; Gonçalves, D.A.
    A geada em Portugal e particularmente nas regiões do interior norte e centro provoca, frequentemente, danos em fruteiras caducifólias importantes como a macieira, cerejeira e amendoeira. O rendimento dos agricultores é severamente afectado e a não estabilização das produções tem igualmente consequências ao nível das empresas e cooperativas do sector. Além da redução da produção, a geada provoca deformações e outros defeitos nos frutos, diminuindo consequentemente o seu valor comercial. A minimização de potenciais prejuízos pode fazer-se através da implementação de medidas preventivas (protecção passiva) e actuando imediatamente antes ou durante a noite de geada (protecção activa) (Snyder & de Melo-Abreu, 2005). Nos métodos indirectos ou passivos – de carácter preventivo...

  14. Polymeric biophenols in olive mill wastewaters

    Cardoso, Susana M.; Falcão, Soraia; Peres, António M.; Pereira, Olívia R.; Domingues, M.R.M.
    Olive mill wastewater (OMW), the effluents generated in the olive oil extraction industry operating in three-phases mode, are phytotoxic mainly due to its high phenolic content [1]. On the other hand, attending to the potential healthbenefits of some of their phenolic compounds, OMW are now regarded as a potent source of biophenols for food and pharmaceutical industries. An important portion of the OMW biophenols include the secoiridoids found in olive pulp and their derivatives formed along the olive oil extraction process [2]. Still, due to the complex composition of OMW, many phenolic compounds remain unknown. Their structural identification can encourage the search of new bioactive compounds in OMW and...

  15. A hybrid electronic tongue for direct classification of baby liquid foods with or without gluten

    Peres, António M.; Dias, L.G.; Veloso, Ana C.A.; Sousa, Mara E.B.C.; Machado, A.A.S.C.

  16. Phytochemical composition and antioxidant properties of portuguese kale and portuguese tronchuda cabbage produced in a sustainable agriculture production system are affected by climate conditions

    Aires, A.; Carvalho, R.; Fernandes, Conceição; Saavedra, M.J.; Rosa, E.

  17. Probabilistic simulation of children exposure to migrants from packaging: photoinitiators from printing inks

    Machado, Carla; Fernandes, Conceição; Pereira, Joel; Poças, Maria de Fátima
    The present work presents an exercise to simulate exposure of Portuguese consumers to benzophenone, a photoinitiator used in packaging printing inks. The simulation model combined experimental data of benzophenone concentration found in packages collected from market and food consumption and packaging usage data obtained from a database. The model followed a probabilistic approach: the distribution of occurrence data was combined with food consumption data in a probabilistic simulation with the Monte Carlo sampling method. The values found indicate that benzophenone levels of exposure are of no health concern according to the tolerable daily intake defined by EFSA.

  18. Adsorption equilibrium of fructose, glucose and sucrose for cationic resins in the sodium and potassium form

    Nobre, Clarisse; Santos, M.J.; Dominguez, Ana; Torres, Duarte; Peres, António M.; Rocha, Isabel; Ferreira, Eugénio C.; Rodrigues, Lígia R.; Teixeira, José A.
    Separation of glucose from mixtures of fructose and sucrose in molasses is a major challenge in industrial sugar chromatographic separations. The efficiency of a chromatographic process is largely dependent on the adsorbent used. Sulfonated poly(styrene-co-divinylbenzene) (PS-DVB) ion exchange resins are the most frequently used for sugars separation, generally in a cationic form. The cation will complex with the hydroxyl group of the sugar leading to a selective adsorption according to the orientation of the hydroxyl group. Thus, the conformation of the sugar determines its relative affinity for the resin and its distribution coefficient. Consequently, fructose forms the more stable sugar-cation complex being preferentially adsorbed in the...

  19. Equilibrium studies of the adsorption of fructo-oligosaccharides from a pure mixture and a fermentative broth on a dowex monosphere calcium resin

    Nobre, Clarisse; Vaňková, K.; Peres, António M.; Polakovič, M.; Teixeira, José A.; Rodrigues, Lígia R.
    Fructo-oligosaccharides (FOS) namely, kestose, nystose and fructofuranosylnystose, are prebiotics that can be obtained by fermentation. The resulting fermentative broth is a complex mixture consisting also of salts and other sugars that must be removed. Adsorption equilibrium studies were conducted using the static method in batch mode onto Dowex Monosphere calcium resin, at 60ºC, for FOS contained in a fermentative broth and pure mixtures. Experimental isotherms data were analyzed using linear, Langmuir/anti-Langmuir, Freundlich, Redlich & Peterson, and Toth models. Isotherm parameters were determined using linear and nonlinear correlations for the minimization of several error functions. The nonlinear correlations were found to provide the best isotherm parameters for the models. FOS contained...

  20. New biophenols in olive mill wastewaters

    Cardoso, Susana M.; Falcão, Soraia; Peres, António M.; Domingues, M.R.M.
    Olive mill wastewaters (OMW) have been attracting the attention of food and pharmaceutical industries, as it is a potential source of biophenols with a wide range of biological activities. This effluent produced in the olive oil industry contains approximately half of the total phenolic compounds of the olive fruit and it is currently exploited for industrial extraction of hydroxytyrosol [1]. Still, the phenolic composition of OMW is extremely complex, and many compounds are yet unidentified. In this context, the identification of unknown phenolic compounds can encourage the search of new bioactive compounds in OMW and contribute to further valorize this waste. In the present work, six new phenolic compounds...

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