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| Registros recuperados: 68 | |
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| Vilas-Boas, Miguel; Henderson, M.J.; Freire, C.; Hillman, A.R.; Vieil, E.. |
| The oxidative polymerization of the complex2,3-dimelhyl-N,N-bis( salicylidene)butane-2,3-diaminatonickel( n), [Ni(saltMe)], was monitored by the electrochemical quartz microbalance (EQCM) and crystal impedance techniques. Polymerisation efficiency was maintained throughout deposition of a film, which behaved rigidly, on the electrode. |
| Tipo: Article |
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| Ano: 2000 |
URL: http://hdl.handle.net/10198/5889 |
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| Falcão, Soraia; Freire, C.; Vilas-Boas, Miguel. |
| The study of botanical extracts used in traditional medicinal have always captured researchers attention. Propolis (bee glue) is a sticky dark-colored material that honeybees collected from parts of plants, buds and exudates, mix it with wax and other secretions and use it as construction and defense material in the hive. Because its biological and pharmacological properties, is extensively used in foods and beverages with the purpose of maintain or improve human health. |
| Tipo: ConferenceObject |
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| Ano: 2010 |
URL: http://hdl.handle.net/10198/5029 |
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| Vilas-Boas, Miguel. |
| Actualmente, a única forma eficaz de controlo desta doença passa pela incineração da colónia com graves prejuízos para o apicultor. Ao contrário, a sua disseminação é facilmente negligenciada durante o maneio apícola, pois uma colónia contaminada poderá não evidenciar os sintomas visíveis para o apicultor, e a propagação pode ocorrer através dos utensílios apícolas |
| Tipo: Article |
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| Ano: 2010 |
URL: http://hdl.handle.net/10198/5266 |
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| Fonseca, S.; Garção, H.; Vilas-Boas, Miguel. |
| There is a growing demand of natural products in human diet, both due to the possible negative effects of synthetic food additives on human health and to the increased consumer perception of these products benefits. Among them we find honey, one of the most complex foodstuffs produced by nature and certainly the only sweetening agent that can be used by humans without processing. Honey characteristics are directly dependent on the flora visit by bees, and this is reflected on its composition, Physico-chemical analysis is used routinely to classifY different types of honeys and evaluate their quality. With this work we present a general idea on the chemical properties of Portuguese honeys and contribute to their classification. |
| Tipo: ConferenceObject |
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| Ano: 2006 |
URL: http://hdl.handle.net/10198/5681 |
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| Dias, L.G.; Peres, António M.; Vilas-Boas, Miguel; Rocha, Maria A.; Estevinho, Leticia M.; Machado, A.A.S.C.. |
| An electronic tongue system was developed based on 20 all-solid-state potentiometric sensors and chemometric data processing, with polymeric membranes applied on solid conducting silver-epoxy supports and a Ag=AgCl reference electrode. The sensor array was applied to 52 commercial honey samples obtained randomly from different regions of Portugal. These samples were analysed independently for their pollen profiles by biological techniques and the data collected with the tongue were evaluated for discrimination of the samples with multivariate statistical methods (principal component analysis and linear discriminant analysis), to investigate whether the device may provide an analytical alternative for classification of honey samples with respect to pollen... |
| Tipo: Article |
Palavras-chave: Honey; Pollen; Electronic tongue; Multivariate analysis. |
| Ano: 2008 |
URL: http://hdl.handle.net/10198/1027 |
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| Dias, L.G.; Peres, António M.; Veloso, Ana C.A.; Reis, F.S.; Vilas-Boas, Miguel; Machado, A.A.S.C.. |
| An electronic tongue with 36 cross-sensibility sensors was built allowing a successful recognition of the five basic taste standards, showing high sensibility to acid, salty and umami taste substances and lower performance to bitter and sweet tastes. The taste recognition capability was afterwards tested in the detection of goat milk adulteration with bovine milk, which is a problem for the dairy industry. This new methodology is an alternative to the classical analyticalmethods used to detect caprine milk adulterations with bovine milk, being a simpler, faster and economical procedure. The different signal profiles recorded by the e-tongue device together with linear discriminant analysis allowed the implementation of a model that could distinguish... |
| Tipo: Article |
Palavras-chave: Electronic tongue; Taste standards; Milk adulteration; Cow milk; Goat milk; Principal component analysis; Linear discriminant analysis. |
| Ano: 2009 |
URL: http://hdl.handle.net/10198/1029 |
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| Barros, Lillian; Falcão, Soraia; Baptista, Paula; Freire, C.; Vilas-Boas, Miguel; Ferreira, Isabel C.F.R.. |
| The antioxidant activity of five Agaricus sp. mushrooms was screened through chemical, biochemical and electrochemical techniques. The chemical assays allowed an evaluation of their reducing power and radical scavenging activity, while biochemical assays evaluated the lipid peroxidation inhibition capacity, using erythrocytes and brain cells as models; the electrochemical characterization of the mushrooms extracts were performed by cyclic voltammetry and differential pulse voltammetry. All the species proved to have antioxidant activity and particularly, by the electrochemical techniques, it has been shown that mushroom extracts revealed similar electrochemical responses, suggesting similar electroactive chemical composition, and oxidation potentials more... |
| Tipo: Article |
Palavras-chave: Agaricus sp mushrooms; Electrochemical assays; Lipid peroxidation inhibition. |
| Ano: 2008 |
URL: http://hdl.handle.net/10198/814 |
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| Ferreira, Isabel C.F.R.; Baptista, Paula; Vilas-Boas, Miguel; Barros, Lillian. |
| Reactive oxygen species are formed during normal cellular metabolism, but when present in high concentration they become toxic. Mammalian cells possess intracellular defenses such as superoxide dismutase, catalase or glutathione peroxidase in order to protect the cells against excessive levels of free radicals. Also exogenous addition of compounds such as vitamins (A, E, .carotene), minerals (selenium, zinc), or proteins (transferring, ceruleoplasmin, albumin) can provide additional protection'. These natural antioxidants or other sources that can neutralize free radicals may be of central importance in the prevent ion of vascular diseases, some forms of cancer and oxidative stress responsible for DNA, protein and membrane damage.'.3 The northeast of... |
| Tipo: ConferenceObject |
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| Ano: 2005 |
URL: http://hdl.handle.net/10198/3722 |
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| Cabrita, Luís; Carvalho, Ana Maria; Vilas-Boas, Miguel; Ferreira, Isabel C.F.R.. |
| A actividade antioxidante de extractos metanólicos de plantas aromáticas e medicinais silvestres referidas em inventários etnobotânicos realizados na região de Trás-os-Montes foi avaliada in vitro através de técnicas electroquímicas, nomeadamente, por Voltametria Cíclica (CV) e por Voltametria Diferencial por Pulso (DPV). Utilizaram-se eléctrodos de carbono vítreo (diam = 3 mm) e NaClO4 como electrólito. Foram analisadas 24 amostras de 18 espécies, que correspondem a 13 famílias botânicas: Sambucus nigra (Adoxaceae), Cistus ladanifer (Cistaceae), Bryonia dioica (Cucurbitaceae), Cupressus lusitanica (Cupressaceae), Tamus communis (Dioscoreaceae), Arbutus unedo (Ericaceae), Glechoma hederaceae, Origanum vulgare e Thymus mastichina (Lamiaceae), Cytisus... |
| Tipo: ConferenceObject |
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| Ano: 2011 |
URL: http://hdl.handle.net/10198/6088 |
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| Falcão, Soraia; Vilas-Boas, Miguel; Freire, C.; Domingues, M.R.M.; Cardoso, Susana M.. |
| Propolis is a resinous substance collected by honeybees from tree buds, comprising plant exudates, secreted substances from bee metabolism, pollen and waxes. This product is widely used in traditional medicine [I] and it has recently gained popularity as a health food supplement. Currently, it is extensively used in foods and beverages, and it is claimed to improve health and prevent diseases such as inflammation, heart disease, diabetes and cancer. |
| Tipo: ConferenceObject |
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| Ano: 2009 |
URL: http://hdl.handle.net/10198/5682 |
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| Falcão, Soraia; Vilas-Boas, Miguel; Freire, C.; Domingues, M.R.M.; Cardoso, Susana M.. |
| This research outlines an extensive characterization of the phenolic composition of a propolis sample from the northeast of Porto gal. For that, ao ethanolic extract was prepared, fractionated by HPLC and the identification of the phenolic compounds was done by electro spray mass spectrometry in the negative mode. This technical approach allowed the identification of 37 phenolic compounds in the Portoguese propolis sample, including seven that were described for the first time. Two of these new compounds had [M-Hr ions at mlz 403, aod the others had [M-Hr ions at mlz 433, mlz 461, mlz 417, mlz 475, and mlz 565. In general, the molecular weight of these compounds was higher thao the common phenolic compounds of propolis aod their fragmentation pattern... |
| Tipo: ConferenceObject |
Palavras-chave: Propolis; Phenolic compounds; Mass spectrometry; Electrospray ionization. |
| Ano: 2009 |
URL: http://hdl.handle.net/10198/5265 |
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| Barros, Lillian; Cabrita, Luís; Vilas-Boas, Miguel; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.. |
| Plants are a source of compounds that may be used as pharmacologically active products. Cytisus multiflorus, Filipendula ulmaria and Sambucus nigra have been used as important medicinal plants in the Iberian Peninsula for many years, and are claimed to have various health benefits. Herein, the phytochemical composition and antioxidant activity of the mentioned wild medicinal plants were evaluated in vitro, based on chemical, biochemical and electrochemical methods. F. ulmaria was found to be richest in antioxidant phytochemicals, such as phenolics (228 mg GAE/g DW), flavonoids (62 mg CE/g DW), ascorbic acid (2700 lg/g DW) and tocopherols (497 lg/g DW). The antioxidant activity was found to vary in the order: F. ulmaria > S. nigra > C. multiflorus,... |
| Tipo: Article |
Palavras-chave: Cytisus multiflorus; Filipendula ulmaria; Sambucus nigra; Antioxidants; Phytochemicals; Electrochemistry. |
| Ano: 2011 |
URL: http://hdl.handle.net/10198/4104 |
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| Vilas-Boas, Miguel. |
| O mel é produto alimentar que aufere da sociedade um reconhecimento como "produto natural". Este é efectivamente um "rótulo” que lhe confere vantagens comerciais e que todos os agentes do sector devem potenciar através de um trabalho rigoroso nas metodologias de produção, garantindo a qualidade do produto final |
| Tipo: Article |
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| Ano: 2005 |
URL: http://hdl.handle.net/10198/5881 |
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| Vilas-Boas, Miguel. |
| O mel e produto alimentar que aufere da sociedade um reconhecimento como produto natural". Este e efectivamente um "rótulo” que lhe confere vantagens comerciais e que lodos as agentes do sector devem potenciar através de um trabalho rigoroso nas metodologias de produção, garantindo a qualidade do produto final. |
| Tipo: ConferenceObject |
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| Ano: 2005 |
URL: http://hdl.handle.net/10198/5692 |
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| Registros recuperados: 68 | |
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