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Consulta: creatorFacets:"Soares, Maria Elisa" Registros recuperados: 12 Data/hora: 09/06/2017 07:12:48 A utilização do cobre na protecção fitossanitária da oliveira e implicações na segurança alimentar dos produtos do olival. Provedor de dados: 188 Autores: Pereira, J.A.; Soares, Maria Elisa; Pavão, Francisco; Bastos, Maria de Lurdes; Bento, Albino. Na protecção fitossanitária da oliveira, especialmente na luta contra doenças fúngicas, são utilizados pesticidas com diferentes formulações de cobre. A utilização destes produtos e permitida nos diferentes sistemas de protecção do olival, quer seja em produção convencional, em produção integrada ou no modo de produção biológico, o que os torna de utilização praticamente generalizada. Neste sentido, o presente trabalho teve por objectivos estudar a persistência do cobre, aplicado sob diferentes formas - calda bordalesa, hidróxido de cobre e oxicloreto de cobre - em folhas de oliveira e azeitonas durante um período de 44 dias após a aplicação e no azeite obtido em azeitonas processadas em final desse período. Tipo: ConferenceObject Ano: 2009 URL: http://hdl.handle.net/10198/5137 Antioxidant activity and phenolic contents of Olea europaea L. leaves sprayed with different cooper formulations Provedor de dados: 188 Autores: Ferreira, Isabel C.F.R.; Barros, Lillian; Soares, Maria Elisa; Bastos, Maria de Lourdes; Pereira, J.A. The presence of cooper can catalyse oxidation of fatty acid chains, exerting a deleterious influence over shelf life. Transition metals, which possess two or more valence states with a sui tab le redox potential, act as pro-oxidants even at concentrations lower than 0.1 ppm, and could affect the speed of autoxidation and the direction of hydroperoxide breakdown to volatile le compounds. Being copper a transition metal that even, in small concentration, is a very potent oxidation catalyst, can enter a redox reaction, giving rise to consequent lipid peroxidation phenomenon due to the free radicals producing. Tipo: ConferenceObject Ano: 2006 URL: http://hdl.handle.net/10198/3549 Antioxidant activity and phenolic contents of Olea europaea L. leaves sprayed with different copper formulations Provedor de dados: 188 Autores: Ferreira, Isabel C.F.R.; Barros, Lillian; Soares, Maria Elisa; Bastos, Maria de Lourdes; Pereira, J.A. Olive trees (Olea europaea L. Cv. Cobranc¸osa) from the northeast of Portugal were sprayed with three different copper formulations [bordeaux mixture (copper sulphate + calcium hydroxide - 20% Cu), copper hydroxide (40% Cu) and copper oxychloride (50% Cu)] to control olive fungal diseases. The residues of copper in olive leaves, harvested at different times, were evaluated by atomic absorption spectrometry. At all the collection times, treated olive leaves had significantly higher copper contents, compared to the control. The different copper amounts in pesticide formulations lowered the leaves contents in total phenols and hence their antioxidant properties. Olive leaves sprayed with copper oxychloride possessed the highest copper levels and the lowest... Tipo: Article Palavras-chave: Olea europaea; Olive leaves; Copper; Phenols; Antioxidant activity. Ano: 2007 URL: http://hdl.handle.net/10198/749 Copper and lead residues in olives after olive tree treatments with three different copper formulations. Provedor de dados: 188 Autores: Soares, Maria Elisa; Pereira, J.A.; Bastos, Maria de Lurdes. Tipo: ConferenceObject Ano: 2005 URL: http://hdl.handle.net/10198/5575 Copper residues in olives after olive tree treatments with three different copper formulations. Provedor de dados: 188 Autores: Soares, Maria Elisa; Pereira, J.A.; Bastos, Maria de Lurdes. Tipo: ConferenceObject Ano: 2004 URL: http://hdl.handle.net/10198/5512 Extracção de nutrientes minerais do solo, de povoamentos de Castanea sativa Mill., pela colheita de cogumelos silvestres comestíveis Provedor de dados: 188 Autores: Baptista, Paula; Meirinhos, Julieta; Martins, Anabela; Soares, Maria Elisa. No nordeste de Portugal, na última década tem-se assistido a uma intensificação da colheita e comercialização de cogumelos silvestres comestíveis. Apesar da grande diversidade de cogumelos existentes, os colectores, apenas procedem à colheita de algumas espécies, nomeadamente Hydnum rufescens, Boletus edulis, Cantharellus cibarius, Tricholoma acerbum, Xerocomus chrysenteron e em menor quantidade Clitopilus prunulus. Todos estes cogumelos são micorrizicos de Castanheiro. Com o presente trabalho pretendeu-se conhecer os teores de macronutrientes (Azoto – amoniacal e nítrico, fósforo e potássio total) e de alguns micronutrientes (cálcio e magnésio) mobilizados por estes fungos e por conseguinte retirados à cultura de Castanea sativa Mill.. Para tal,... Tipo: ConferenceObject Palavras-chave: Cogumelos silvestres comestíveis; Composição mineral; Fungos micorrízicos; Castanea sativa Mill. Ano: 2004 URL: http://hdl.handle.net/10198/5719 Metal composition of table olives from the portuguese market. Provedor de dados: 188 Autores: Soares, Maria Elisa; Bento, Albino; Bastos, Maria de Lurdes; Pereira, J.A. Olive tree (Olea europaea L.) is one of the most important fruit trees in the Mediterranean countries. Their products, olive oil and also table olives, are important components of the Mediterranean diet and are largely consumed in the world. Table olives are well-known sources of compounds with important biological properties. The preparation of table olives follows three main trades, namely green or Spanish-style olives (Green Olives in Brine - GOB), black ripe or Californian-style olives (Black Ripe Olives), and naturally fermented olives (Direct Brined Olives – DBO). Heavy metals can be present in olive fruits for several reasons: endogenous, depending on the mineral constitution of the soils where the olive trees are located, or exogenous, resulting... Tipo: ConferenceObject Ano: 2007 URL: http://hdl.handle.net/10198/5344 Tolerance and stress response of Macrolepiota procera to nickel Provedor de dados: 188 Autores: Baptista, Paula; Ferreira, Sílvia; Soares, Maria Elisa; Coelho, Valentim; Bastos, Maria de Lourdes. Nickel (Ni) is an essential element for many organisms; however, it is very toxic at high concentrations and also depending on the species. In macrofungi the mechanisms underlying their Ni tolerance are poorly documented. This study examines, for the first time, the participation of the antioxidative system in Macrolepiota procera exposed to different Ni2+ concentrations and their relation with Ni tolerance. The effect of the pH on Ni tolerance was also evaluated. The fungus was cultivated on solid medium with different NiCl2 concentrations (0.05, 0.2, 0.8 mM) at pH 4, 6, and 8, and fungi growth and Ni uptake were determined. The antioxidative enzymes catalase (CAT) and superoxide dismutase (SOD) and the production of hydrogen peroxide (H2O2) were... Tipo: Article Palavras-chave: Macrolepiota procera; Nickel; Stress; Ni2+ tolerance; Ni2+ accumulation; Hydrogen peroxide; Antioxidant enzymes. Ano: 2009 URL: http://hdl.handle.net/10198/4473 Tolerance and stress response of the saprobe macrofungi Macrolepiota procera to nickel Provedor de dados: 188 Autores: Baptista, Paula; Ferreira, Sílvia; Soares, Maria Elisa; Bastos, Maria de Lourdes. Nickel (Ni) is an essential element for many organisms however it is very toxic at high concentrations and also depending on the species. In macrofungi the mechanisms underlying their Ni-tolerance are poorly documented. We examined, for the first time, the participation of the antioxidative system in the Macrolepiota procera exposed to different Ni2+ concentrations and their relation with Ni-tolerance. The effect of the pH on Ni-tolerance was also evaluated. The fungus was cultivated on solid medium with different Ni concentrations (0.05, 0.2, 0.8 mM) at pH 4, 6 and 8, and fungi growth and Ni uptake was determined. The antioxidative enzymes, catalase (CAT) and superoxide dismutase (SOD) and the production of hydrogen peroxide (H2O2) were evaluated on... Tipo: ConferenceObject Palavras-chave: Macrolepiota procera; Nickel; Stress; Ni-tolerance; Ni-accumulation; Hydrogen peroxide; Antioxidant enzymes. Ano: 2009 URL: http://hdl.handle.net/10198/4488 Validação de uma metodologia por EAA/AE para avaliação dos níveis de crómio total e crómio hexavalente em cogumelos Provedor de dados: 188 Autores: Figueiredo, Ana E.; Soares, Maria Elisa; Baptista, Paula; Castro, Marisa; Bastos, Maria de Lourdes. Os cogumelos têm sido utilizados como bioindicadores da contaminação ambiental provocada por alguns metais pesados, tais como, o cádmio, cobre, chumbo, crómio, mercúrio e zinco. Vários autores referem que foram observadas grandes concentrações de metais pesados nestes macromicetes colhidos em zonas muito poluídas, como sejam, a proximidade de estradas com muito trânsito, zonas industriais onde haja emissão de gases e resíduos, bem como, zonas próximas de fundições e minas. Tipo: ConferenceObject Palavras-chave: Cogumelos; Crómio total; Crómio hexavalente; Espectrometria de Absorção Atómica com Atomização Electrotérmica. Ano: 2007 URL: http://hdl.handle.net/10198/5937 Validation of a method to quantify copper and other metals in olive fruits by ETAAS. Application to the residual metal control after olive tree treatments with different copper formulations Provedor de dados: 188 Autores: Soares, Maria Elisa; Pereira, J.A.; Bastos, Maria de Lourdes. An electrothermal atomization atomic absorption spectrometry method was validated to quantify residues of copper, aluminum, cadmium, chromium, iron, lead, and nickel in olive fruit. The linearity ranges under the optimized conditions were 0.19-20.0, 1.11-50.0, 0.02-2.0, 0.15-20.0, 0.80- 20.0, 0.35-50.0, and 0.60-50.0 íg/L, respectively. The limits of quantification were, expressed in nanograms per gram of dry weight, 12.6, 74.0, 1.34, 10.0, 53.4, 23.4, and 40.0, respectively. For all of the metals the precision of the instrumental method was <6.3% and that of the analytical method was always <10%, except for aluminum, for which the precision was 12%. The accuracy of the method was evaluated according to the standard additions method, the recoveries... Tipo: Article Palavras-chave: Method validation; Atomic absorption spectrometry; Metal residues; Olive fruit; Fungicide residues. Ano: 2006 URL: http://hdl.handle.net/10198/748 Validation of an electrothermal atomization atomic absorption spectrometry method for quantification of total Chromium and Chromium(VI) in wild mushrooms and underlying soils Provedor de dados: 188 Autores: Figueiredo, Ana E.; Soares, Maria Elisa; Baptista, Paula; Castro, Marisa; Bastos, Maria de Lourdes. An ETAAS method was validated to quantify total Cr and CrVI in mushrooms and the underlying soils. The method includes a sample pretreatment for total Cr dissolution using a wet acid digestion procedure and a selective alkaline extraction for CrVI. The limits of detection were, expressed in íg/L, 0.15 and 0.17 for total Cr and CrVI, respectively. The linearity ranges under the optimized conditions were 0.15-25.0 and 0.17-20.0 íg/L for total Cr and CrVI, respectively. The limits of quantification were, expressed in íg/g of dry weight, 0.0163 and 0.0085 for total and hexavalent chromium, respectively. The precision of the instrumental method for total Cr and CrVI was lower than 1.6%, and for the analytical method, it was lower than 10%. The accuracy of the... Tipo: Article Palavras-chave: Mushrooms; Soil; Total Cr; CrVI; Atomic absorption spectrometry. Ano: 2007 URL: http://hdl.handle.net/10198/942