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Biblioteca Digital do IPB (53.442 recursos)

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PTV - Resumos em Proceedings Não Indexados ao ISI

Mostrando recursos 1 - 20 de 360

  1. Qualidade do azeite e sua relação com a cultivar e o clima em Portugal

    Melo-Abreu, J.P.; Maia, F.B.; Vasconcelos, P.; Ribeiro, A.C.; Barba, N.G.; Barros, F.; Cordeiro, A.M.; Neves, A.
    A qualidade do azeite pode ser um elemento diferenciador, permitindo a prática de melhores preços num mercado cada vez mais competitivo. Os constituintes que mais têm sido apontados como tendo propriedades benéficas para a saúde são a composição acídica elevada em monoinsaturados, os valores elevados de tocoferóis, nomeadamente do atocoferol (vitamina E), e de polifenóis. A cultivar, a temperatura e o índice de maturação são variáveis que influenciam alguns dos parâmetros que estão associados à qualidade do azeite. No âmbito do projeto Futurolive, financiado pela FCT, as cultivares Arbequina, Cobrançosa, Galega, Picual e Verdeal foram ensaiadas em Mirandela, Santarém, Elvas e/ou Moncarapacho (Algarve) durante 2 anos. Fizeram-se medições...

  2. The response of rapeseed cultivar hydromel to nitrogen fertilization: chemical composition and antioxidant capacity

    Costa, Dina; Santos, Clementina M.M.; Silva, Artur; Rodrigues, M.A.
    Winter rapeseed (Brassicanapus L.) is a species of the Brassicaceae family and an important agricultural crop in many cold temperate countries, where most of other plants do not grow. It is mainly cultivated in Europe, Asia, North America and Australia, but has a limited acreage in Portugal. The growing demand from rapeseed is dueto a progressive increase in its quality for human and animal consumption and mainly because is being promoted throughout the world as energy crop for the production of biofuels. Many studies have shown that both growth and yield of rapeseed are enhanced significantly by high doses of applied nitrogen. However,...

  3. Synthesis of 2-{2-[5(4)-aryl-2H-[1,2,3]-triazol-4(5)-yl]vinyl}chromen-4-ones

    Albuquerque, Hélio; Santos, Clementina M.M.; Silva, Artur; Cavaleiro, José
    Chromones are a family of oxygen-containing heterocyclic compounds that have been shown particular relevant biological activity. In what concerns to 2-methylchromones, their reactivity is well-known and allowed to exploit many different kinds of chemical reactions. The acidic character of the 2-methyl group, due to the low electron density at C-2 caused by carbonyl group enable this class of compounds to undergo oxidation, photolysis, cycloaddition and condensation reactions

  4. Synthesis of (E)-2-(4-Arylbut-1-en-3-ynyl)-4H-chromen-4-ones

    Albuquerque, Hélio; Santos, Clementina M.M.; Silva, Artur; Cavaleiro, José
    Chromones are a well-known class of naturally occurring oxygencontaining heterocyclic compounds; many of them playing important biological functions in nature [1]. Although 2-methylchromones are one of the scarcest classes of natural chromones, their synthesis and reactivity is well studied. They can participate in several chemical transformations such as oxidation, thiation, hydrogenation, photolysis, cycloaddition and condensation reactions, being useful targets in the synthesis of novel heterocyclic compounds [2]. The acidity of the 2- methyl group, due to the low electron density at C-2 caused by oxygen atom and the α,β-unsaturated ketone system, led us to explore the condensation of 2-methylchromones [3] with propargyl aldehydes [4].

  5. Estudos cinéticos da extração de antioxidantes presentes em cascas de castanha (Castanea sativa Mill.)

    Delgado, Teresa; Pereira, J.A.; Casal, Susana; Ramalhosa, Elsa
    A produção de castanha (Castanea sativa Mill.) é de extrema importância para Portugal, rondando as 22105 toneladas e contribuindo para a balança comercial em cerca de 17 Milhões de Euros [1]. A zona de Trás-os-Montes é uma das mais importantes para a produção deste fruto, contribuindo em cerca de 85% da produção nacional. A nível industrial a castanha é vendida em fresco ou congelada após descasque. Nesta situação a produção de resíduos, designadamente de películas e cascas, é bastante significativa. Até ao momento uma parte é utilizada na compostagem, sendo a restante rejeitada. Alguns estudos apontam para a existência de...

  6. The effect of legume cover crops on soil phosphorus availability

    Arrobas, Margarida; Pereira, Ermelinda; Ferreira, I.Q.; Rodrigues, M.A.
    Legume can fix atmospheric N and sequester carbon. Some legumes are able to uptake sparingly soluble soil phosphorus. Additionally, all those effects may contribute to a beneficial increase in soil microbial activity. In this work three ground-cover treatments were imposed to an olive orchard located in NE Portugal: Natural vegetation (Nat veg); Natural vegetation fertilized with 60 kg N ha-1 yr-1 (Nat veg +N); and a mixture of self-reseeding annual legumes (Legumes). Three years after the establishment of the ground-cover treatments, soil samples were taken from the 0- 10 and 10-20 cm depths. Extractable soil P was determined by the Olsen and Egner-Riehm methods, the acid phosphatase...

  7. The nutritional status and olive yield after three years of the cultivation of legume species as a cover crop in an olive orchard

    Rodrigues, M.A.; Ferreira, I.Q.; Dimande, Paulo; Pereira, Ermelinda; Arrobas, Margarida
    Growing self-reseeding annual legumes in olive orchards may increase the sustainability of the cropping system by increasing soil organic carbon and reducing the use of nitrogen fertilizers. In thls work, results are presented on the nitrogen nutritional status of trees and olive yields three years after the introduction of different ground-cover treatments in an olive orchard located in NE PortugaL The experimental design included three ground-cover treatments: Natural vegetation (Nat veg); Natural vegetation fertilized with 60 kg N ha'1 yr·1 (Nat vet +N); and a mixture of eleven self-reseeding annual legumes (Legumes). The experiment started in October 2009. The nutritional statUs of olive trees was assessed by...

  8. The effect of legume cover crops grown in an olive orchard on soil microbial activity

    Pereira, Ermelinda; Arrobas, Margarida; Ferreira, I.Q.; Rodrigues, M.A.
    Microbial biomass and soil respiration are major indicators of the soil biological fertility which can be affected by soil management practices. The aim of this study was the evaluation of the effect of three ground-cover treatments, imposed to an olive orchard, on soil microbial biomass and activity. The ground-cover treatments were: Natural vegetation (Nat veg); Natural vegetation fertilized with 60 kg N ha-1 (Nat veg +N); and a mixture of eleven annual legumes (Legumes) grown as a cover crop. The experiment was carried out in a rainfed olive orchard located in Mirandela, NE Portugal. Three years after the experimental set-up had been installed, random samples of...

  9. Retardation in seed germination and induction of oxidative stress in lettuce plants upon spent coffee grounds exposure

    Gomes, Teresa; Pereira, J.A.; Ramalhosa, Elsa; Casal, Susana; Baptista, Paula
    Over the past years, several strategies have been tentatively applied to reuse spent coffee grounds (SCG). This residue, obtained after the brewing process, has a global production around 6 million tons per year. The use of SCG in domestic agriculture is an increasing popular practice. However, scientific evidences about their effect on plants remain unknown. Caffeine present in SCG (about 0.2%) together with tannins and chlorogenic acids could have a toxic effect on soil microorganisms and plants. In this study, we intended to verify the relation between seed germination and the antioxidative system in Lactuca sativa L. cv. “Wonder of...

  10. Effect of fresh and composted espresso spent coffee on soil and Lactuca sativa L. mineral composition

    Gomes, Teresa; Cruz, Rebeca; Pereira, J.A.; Ramalhosa, Elsa; Casal, Susana; Baptista, Paula
    Espresso spent coffee grounds (ESC) comprises solid residues obtained after espresso coffee preparation, which are massively generated worldwide, being unfortunately disposed together with common garbage. Still, there are several references about its application as organic fertilizer in domestic cultivation, due to their richness on mineral compounds, especially potassium. However, their effect or safety on agriculture remains unknown. In this study, a greenhouse experiment was undertaken to examine the potential of using ESC either in fresh or in composted form to enhance mineral composition of the soil and of Lactuca sativa L. plants. With this purpose, lettuce plants cv. “Four seasons”...

  11. Pine nuts authenticity in the Portuguese market

    Santos, Carla; Porfírio, Bruno; Silva, Anaísa; Faria, Miguel; Cruz, Rebeca; Ramalhosa, Elsa; Pereira, J.A.; Cunha, Sara; Casal, Susana
    Pine nuts, the edible seed of the pine tree (Pinus spp.) are a valuable commodity in the international market, with Portugal attaining the fourth position with the exclusive production of Pinus pinea. Pine nuts from different pine species differ in size, nutritional value, taste and therefore commercial values, making it necessary to grant their authenticity. Following recent reports on pine nut mislabelling in European markets, mainly with those of Asiatic origin, the main objective of the present work was to characterize the quality and authenticity of the pine nuts sold in the Portuguese market. Samples (n=15) were analysed for their main...

  12. Espresso coffee residues in horticultural improvement

    Cruz, Rebeca; Morais, Simone; Mendes, Eulália; Pereira, J.A.; Baptista, Paula; Ramalhosa, Elsa; Casal, Susana
    Spent coffee grounds are usually disposed as common garbage, without specific reuse strategies. Due to its recognized richness in bioactive compounds, the effect of espresso spent coffee grounds on lettuce´s macro- and micro- elements, as well as on its antioxidant and bioactive compounds, was assessed in order to ascertain its potential applicability in agroindustry, minimizing environmental issues and increasing vegetables nutritional features. Therefore, a greenhouse pot experiment with fresh and composted spent coffee (2.5 to 30% v/v) was conducted, using lettuce plants. The plants antioxidant capacity, assessed by radical scavenging effect and reducing power, was enhanced by spent coffee. Total reducing...

  13. Valorização de produtos e sub-produtos de origem vegetal

    Ramalhosa, Elsa; Delgado, Teresa; Fernandes, Luana; Silva, Ana Cândida; Rodrigues, Nuno; Gomes, Teresa; Pereira, Ermelinda; Bento, Albino; Casal, Susana; Baptista, Paula; Pereira, J.A.
    Portugal é um país onde a agricultura assume particular importância, com uma grande riqueza e diversidade de produtos de origem vegetal que interessa caracterizar e valorizar. Por outro lado, durante a sua etapa de produção é originada uma grande quantidade de sub-produtos que interessa aproveitar. Neste sentido, no âmbito das actividades do projecto “AGRINNDIF - Mejora de la competitividad del sector agrario de Castilla y León y Norte de Portugal através de la innovación y el desarrollo de productos diferenciados de alto valor”, financiado pelo POCTEP, têm-se desenvolvido diferentes atividades para a caracterização e valorização de produtos vegetais, tais como...

  14. Efeito do tratamento térmico no perfil de ácidos gordos de alheiras do Nordeste Transmontano

    Pereira, Ermelinda; Fontes, Marta; Pereira, Etelvina; Teixeira, A.; Ramalhosa, Elsa
    O Nordeste Transmontano é uma região onde diversos produtos cárneos tradicionais são produzidos. A alheira é um desses produtos típicos, feita à base de carne de porco, pão e azeite, sendo sujeita a um processo de fumagem. Após esse período, a alheira está pronta para ser vendida ao consumidor final. Este antes de a consumir, sujeita-a a um tratamento térmico, o qual pode provocar alterações no perfil lipídico dos alimentos no que se refere à composição em ácidos gordos. Para estudar o efeito do aquecimento no perfil lipídico de alheiras, no presente trabalho extraiu-se a gordura e determinou-se o perfil...

  15. Caracterização físico-química de formulações de geleia de uva de diferentes castas como forma de valorização de frutos regionais

    Fernandes, Luana; Rodrigues, Nuno; Pereira, J.A.; Ramalhosa, Elsa
    A uva (Vitis vinifera L.) é um fruto que apresenta uma elevada variedade de castas cuja qualidade e tipicidade resultam da diversidade e adaptação às várias regiões em que são cultivadas. Assim, o conhecimento, investimento e preservação dessas castas podem contribuir para o desenvolvimento de produtos diferenciados que, com garantia de qualidade, são uma grande oportunidade para o aumento da competitividade no mercado. Nesse sentido o presente trabalho teve como principal objectivo formular e caracterizar físico-quimicamente geleias de uva de dez castas portuguesas com o intuito dos nossos produtores terem mais uma alternativa de comercialização deste fruto e os consumidores...

  16. É possível inovar e valorizar produtos e sub-produtos de origem vegetal tradicionais?

    Ramalhosa, Elsa; Delgado, Teresa; Fernandes, Luana; Silva, Ana Cândida; Rodrigues, Nuno; Gomes, Teresa; Pereira, Ermelinda; Bento, Albino; Casal, Susana; Baptista, Paula; Pereira, J.A.
    A Escola Superior Agrária do Instituto Politécnico de Bragança (Portugal) tem desenvolvido e participado em projetos relacionados com a valorização de produtos e sub-produtos de origem vegetal, tais como o projeto “AGRINNDIF - Mejora de la competitividad del sector agrario de Castilla y León y Norte de Portugal através de la innovación y el desarrollo de productos diferenciados de alto valor”, financiado pelo POCTEP, e o projeto “Borra de café: programa de reconversão hortícola e implicações na qualidade e segurança dos vegetais produzidos” (FCT/PTDC/AGR-AAM/102447/2008). No projeto AGRIINDIF foram realizadas, até ao momento, diversas atividades, tais como: caracterização físico-química e biológica...

  17. Drying behavior of the marketed mushrooms Lactarius deliciosus and Agaricus bisporus

    Silva, Ana Cândida; Baptista, Paula; Ramalhosa, Elsa
    Wild edible mycorrhizal mushrooms have great commercial importance, as well as beneficial properties, linked to their nutritional value, delicacy and flavor. Lactarius deliciosus is appreciated worldwide, being frequently used in the preparation of several culinary dishes. On the other hand, Agaricus bisporus is a commercial mushroom also quite used. However, mushrooms are extremely perishable and shelf life of fresh mushrooms is very short. Therefore, they are frequently processed, being dehydration one of the possible preservation methods. The aim of the present work was to compare the forced convective hot-air drying of L. deliciosus and A. bisporus in respect to their drying...

  18. Drying behavior of two chestnut fruits (Castanea sativa Mill) varieties

    Delgado, Teresa; Pereira, J.A.; Casal, Susana; Ramalhosa, Elsa
    Portugal is an important chestnut fruit (Castanea sativa Mill.) producer. However, its preservation represents a critical problem for both producers and industrials. Fruit weight loss and development of moulds during storage, as well as size variability, are some good examples. In this context, the fruit drying can be regarded as a preservation method, allowing its stabilization and subsequent production of other high value chestnuts based products.In Trás-os-Montes region (NE, Portugal), the most important varieties are Longal and Judia. Thus, in the present work, preliminary studies on the drying behavior of these varieties are reported. Upon harvest, the axial dimensions of...

  19. Chemical and thermal characterization of a portuguese traditional fermented meat sausage

    Fonte, Marta; Pereira, Ermelinda; Pereira, Etelvina; Teixeira, A.; Ramalhosa, Elsa
    In the North of Portugal several traditional fermented meat products are produced. One of these is the alheira that is a smoked sausage, made from the meat of pig, regional wheat bread and olive oil, seasoned with salt, garlic and paprika. This product must be subjected to a thermal process before consumption in order to garantee its safety and reducing the occurrence of foodborne diseases. The aim of the present work was to characterize this product in relation to the chemical composition and thermal behaviour. Alheiras were bought to local producers. pH, water activity, fat and protein contents were determined....

  20. Polyhydroxylated 2-styrylchromones and –xanthones as potent antioxidante agentes

    Santos, Clementina M.M.; Silva, Artur; Pinto, Diana; Cavaleiro, José
    Chromones and xanthones are two classes of oxygenated heterocyclic compounds widely distributed in natureY1 Both natural and synthetic derivatives have been reported to exhibit biological, pharmacological and biocidal properties.11.21 The antioxidant capacity deserves a special mention and the structure-activity studies indicate that a substitution pattern that includes the presence of phenolic and/or catecholic moieties is highly important. 131 Inspired by the chemical structures of natural products we developed new routes for the synthesis of the quite rare family of 2-styrylchromones 1 and challenged us to design novel bioactive derivatives. 141 The reactivity of 3-bromo-2-styrylchromones was explored for the synthesis of unique examples of 2,3-diarylxanthones 2.151 Moreover, we focus our attention...

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