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Registros recuperados: 14
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Análise e identificação das antocianinas de couve rôxa (Brassica spp.) IPB - Escola Superior Agrária
Lopes, Dulce; Jesus, Benvinda; Cabrita, Luís.
A couve rôxa é uma espécie comestível com uma composição em antocianinas rica e complexa. Sabe-se que contem antocianinas poliglicosiladas, aciladas com um ou mesmo dois grupos acilo aromáticos, nomeadamente com ácidos coumárico e caféico. Este padrão de acilação é particularmente interessante, porque confere estabilidade às antocianinas e aumenta o seu potencial de utilização em aplicações famacêuticas, alimentares e cosméticas. Este estudo tem por objectivo determinar a estrutura das antocianinas de variedades de couve rôxa cultivadas em Portugal, com vista ao seu aproveitamento industrial.
Tipo: ConferenceObject Palavras-chave: Anthocyanins; HPLC; NMR; Brassica spp; Red cabbage.
Ano: 2004 URL: http://hdl.handle.net/10198/3865
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Análise e identificação das antocianins do mirtilo da Madeira (Vaccinium padifolium) e do mirtilo dos Açores (Vaccinium cillyndraceum) IPB - Escola Superior Agrária
Cabrita, Luís; Neves, Higuinaldo Chaves das.
Analisaram-se as antocianinas dos mirtilos da Madeira e dos Açores. Os pigmentos foram isolados por cromatografia líquida preparativa bi-dimensional (exclusão molecular vs fase reversa), e identificados por RMN (1H, CAPT, COSY, HSQC, HMBC). Em V. padifolium isolou-se e identificou-se a malvidina 3-rhamnósido, um pigmento muito raro, elevando para 26 o total de antocianinas já descritas nesta espécie (3 tri-glicósidos, 6 di-glicósidos e 17 monoglicósidos, das quais 5 são pigmentos novos. Há ainda alguns pigmentos que não puderam ser identiifcados, ou porque foram isolados em baixíssimas quantidades, ou porque se degradaram. Com base em dados cromatográficos e espectroscópicos, conclui-se que os frutos de V. cillyndraceum apresentam as mesmas antocianinas...
Tipo: ConferenceObject Palavras-chave: Antocianinas; HPLC; Mirtilo; Vaccinium padifolium; Vaccinium cillyndraceum; Ericaceae.
Ano: 2003 URL: http://hdl.handle.net/10198/3212
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Anthocyanin stability: a chemometrical approach IPB - Escola Superior Agrária
Cabrita, Luís; Fossen, Torgils; Flåten, Geir R.; Andersen, Øyvind M..
The stability of cyanidin 3-glucoside towards five different factors (pH, anthocyanin concentration, sodium chloride concentration, ascorbic acid concentration, Oxygen) was studied during 60 days storage at room temperature using a 2^4-1 reduced factorial design. The influence of each individual parameter on anthocyanin stability was found to vary as a function of time. Sodium chloride and ascorbic acid were, respectively, the variables most contributing to and against anthocyanin stability. Results suggest there may be some degree of interaction between anthocyanin/ascorbic acid, and between pH/Oxygen, affecting anthocyanin degradation.
Tipo: ConferenceObject Palavras-chave: Anthocyanins; Colour stability; HPLC; UV-Vis; Chemometrics; Reduced factorial design.
Ano: 2002 URL: http://hdl.handle.net/10198/3210
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Anthocyanin trisaccharides in blue berries of Vaccinium padifolium IPB - Escola Superior Agrária
Cabrita, Luís; Frøystein, Nils Åge; Andersen, Øyvind M..
Delphinidin 3-O-alfa-rhamnoside, malvidin 3-O-(6''-O-alfa-rhamnopyranosyl-beta-glucopyranoside) and the 3-O-(6''-O-alfa-rhamnopyranosyl-2''-O-beta-xylopyranosyl-beta-glucopyranosides) of cyanidin, petunidin and peonidin were isolated by various chromatographic techniques from the edible berries of Vaccinium padifolium. Their complete structures were elucidated mainly by one- and two-dimensional nuclear magnetic resonance spectroscopy. Together they account for 7% of the anthocyanin content in this species. No anthocyanidin 3-triglycoside, 3-rutinoside or 3-rhamnoside had previously been found in the genus Vaccinium. The 3-O-(6''-O-alfa- rhamnopyranosyl-2''-O-beta-xylopyranosyl-beta-glucopyranosides) of petunidin and peonidin are novel compounds.
Tipo: Article Palavras-chave: Anthocyanins; Vaccinium padifolium; Ericaceae; Berries; Chemotaxonomy.
Ano: 2000 URL: http://hdl.handle.net/10198/3204
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Anthocyanin-rich extract decreases indices of lipid peroxidation and DNA damage in vitamin E-depleted rats IPB - Escola Superior Agrária
Ramirez-Tortosa, Carmen; Cabrita, Luís; Andersen, Øyvind M.; Gardner, P.T.; Morrice, P.C.; Wood, S.G.; Duthie, S.J.; Collins, A.R.; Garry, G.G..
Anthocyanins are secondary plant metabolites responsible for the blue, purple, and red color of many plant tissues. The phenolic structure of anthocyanins conveys marked antioxidant activity in model systems via donation of electrons or hydrogen atoms from hydroxyl moieties to free radicals. Dietary intakes of anthocyanins may exceed 200 mg/day, however, little is known about their antioxidant potency in vivo. Consequently, the aim of this study was to establish whether anthocyanins could act as putative antioxidant micronutrients. Rats were maintained on vitamin E-deficient diets for 12 weeks in order to enhance susceptibility to oxidative damage and then repleted with rations containing a highly purified anthocyanin-rich extract at a concentration of 1...
Tipo: Article Palavras-chave: Anthocyanins; Polyphenols; Lipid peroxides; DNA damage; Antioxidants; Free radicals.
Ano: 2001 URL: http://hdl.handle.net/10198/3368
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Anthocyanins from pomegranate (Punica granatum L.) IPB - Escola Superior Agrária
Cabrita, Luís; Neves, Higuinaldo Chaves das.
The anthocyanin contents in the fruits from three cultivars of Punica granatum L. (asseria, mollar and negral) was studied. Six anthocyanins were isolated from the red seeds of pomegranate fruits using a combination of Sephadex LH-20 column chromatography and reverse-phase semi-preparative HPLC. On the basis of chromatographic and spectroscopic techniques, they were identified as the 3-monoglucosides and 3,5-diglucosides of delphinidin, cyanidin and pelargonidin. Total anthocyanin content in fruits of the different cultivars varied in order mollar > negral > asseria. The relative order of aglycone occurrence was cyanidin > delphinidin >> pelargonidin. The 3-monoglucoside and 3,5-diglucoside anthocyanin derivatives occurred in similar...
Tipo: ConferenceObject Palavras-chave: Anthocyanins; HPLC; Punica granatum L.; Pomegranate; Punicaceae; Natural food colorants.
Ano: 2002 URL: http://hdl.handle.net/10198/3211
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Anthocyanins in blue berries of Vaccinium padifolium IPB - Escola Superior Agrária
Cabrita, Luís; Andersen, Øyvind M..
Twenty anthocyanins were isolated from the extract of the edible blue berries of Vaccinium padifolium (Uveira) by a combination of chromatographic techniques. Mainly on the basis of nuclear magnetic resonance techniques (1H, COSY, TOCSY, HSQC, HMBC, SEFT) they were identified as the 3-O-beta-glucopyranosides, 3-O-beta-galactopyranosides, 3-O-beta-arabinopyranosides and 3-O-sambubiosides (2'-O-beta-xylopyranosyl-O-beta-glucopyranosides) of delphinidin, cyanidin, petunidin,malvidin and peonidin. Anthocyanidin disaccharides have not been identified in the genus Vaccinium previously, and the 3-sambubiosides of peonidin, petunidin and malvidin are novel compounds.
Tipo: Article Palavras-chave: Anthocyanins; Vaccinium padifolium; Ericaceae; Berries.
Ano: 1999 URL: http://hdl.handle.net/10198/3203
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Avaliação da actividade antioxidante de extractos de plantas medicinais e aromáticas de Trás-os-Montes por métodos electroquímicos IPB - Escola Superior Agrária
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
Ano: 2011 URL: http://hdl.handle.net/10198/6088
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Chemical, biochemical and electrochemical assays to evaluate phytochemicals and antioxidant activity of wild plants IPB - Escola Superior Agrária
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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Colour and stability of pure anthocyanins in aqueous solutions at high pH values IPB - Escola Superior Agrária
Andersen, Øyvind M.; Fossen, Torgils; Cabrita, Luís.
This study on anthocyanin colour variation (intensity, lambda max, molar absorbptivity) over the pH range 1-9 during 60 days of storage, was conducted on petunidin 3-[6-O-(4-O-E-p-coumaroyl-O-alfa-L-rhamnopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside (petanin) and cyanidin 3-O-beta-D-glucopyranoside (cy3glc) at 10 and 23ºC. Compared to cy3glc, petanin afforded higher colour intensity and higher or similar stability throughout the whole pH range. At pH 4.0, 84% of petanin was intact after 60 days storage at 10ºC, while the corresponding solution of cy3glc was totally degraded. At pH 8.1 the colour intensity of petanin was even higher than at the lowest pH values. The visible lmax absorption of petanin after 5 days at pH 8.1 at 10ºC was...
Tipo: ConferenceObject Palavras-chave: Anthocyanins; Stability; Colour; Alkaline pH.
Ano: 1998 URL: http://hdl.handle.net/10198/3013
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Colour and stability of pure anthocyanins influenced by pH including the alkaline region IPB - Escola Superior Agrária
Fossen, Torgils; Cabrita, Luís; Andersen, Øyvind M..
This study on anthocyanin colour variation (intensity, lambda max, absorptivity) over the pH range 1-9 during 60 days of storage, was conducted on petunidin 3-[6-O-(4-O-E-p- coumaroyl-O-alfa-L-rhamnopyranosyl)-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside (petanin) and cyanidin 3-O-beta-D-glucopyranoside (cy3glc) at 10 and 23ºC. Compared to cy3glc, petanin afforded higher colour intensity and higher or similar stability throughout the whole pH range. At pH 4.0, 84% of petanin was intact after 60 days storage at 10ºC, while the corresponding solution of cy3glc was totally degraded. At pH 8.1 the colour intensity of petanin was even higher than at the lowest pH values. The visible lambda max absorption of petanin after 5 days at pH 8.1 at 10ºC was...
Tipo: Article Palavras-chave: Anthocyanins; Colour stability.
Ano: 1998 URL: http://hdl.handle.net/10198/3206
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Colour and stability of the six common anthocyanidin 3-glucosides IPB - Escola Superior Agrária
Cabrita, Luís; Fossen, Torgils; Andersen, Øyvind M..
This study on anthocyanin stability and colour variation (lambda max, absorptivity) in the pH range 1-12 during a period of 60 days storage at 10 and 23ºC, was conducted on the 3-glucosides of the six common anthocyanidins. It was mostly in the alkaline region that differences in colour and stability became significant. Although it has been generally accepted that anthocyanins are stable only at low pH values, this study revealed that, for some of the anthocyanin 3-glucosides (e.g. malvidin 3-glucoside), the bluish colours were rather intense and stability relatively high in the alkaline region. Thus, they can be regarded as potential colorants for some slightly alkaline food products.
Tipo: Article Palavras-chave: Anthocyanins; Colour; Stability.
Ano: 2000 URL: http://hdl.handle.net/10198/3208
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Colours of pure anthocyanidin 3-glucosides in aqueous solutions during storage IPB - Escola Superior Agrária
Cabrita, Luís; Fossen, Torgils; Andersen, Øyvind M..
A study on anthocyanin stability and colour variation (intensity, lambda max., molar absorptivity) during storage at 10º and 23ºC over the pH range 1-12 was conducted for the 3-glucosides of the six common anthocyanidins. These results show that some anthocyanins may provide stable and intense bluish colour for extended application in slightly alkaline food products. For instance, there are some Mexican food (varieties of 'tacos') containing anthocyanins under alkaline conditions.
Tipo: ConferenceObject Palavras-chave: Anthocyanins; Colour stability.
Ano: 1999 URL: http://hdl.handle.net/10198/3157
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Polyacylated anthocyanins from Hebe IPB - Escola Superior Agrária
Cabrita, Luís; Justesen, Ulla; Frøystein, Nils Åge; Andersen, Øyvind M..
Four acylated anthocyanins were isolated from flowers of Hebe spp. On the basis of LC-MS (Liquid Chromatography - Mass Spectrometry) and NMR (Nuclear Magnetic Resonance) techniques, they were identified as (1) cyanidin 3-O-[2-O-(6-O-(E-caffeoyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-beta-glucopyranoside, (2) cyanidin 3-O-[2-O-(6-O-(E-p-coumaroyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-beta-glucopyranoside, (3) cyanidin 3-O-[2-O-(6-O-(E-caffeoyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside], and (4) cyanidin 3-O-[2-O-(6-O-(E-p-coumaroyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside]....
Tipo: ConferenceObject Palavras-chave: Anthocyanins; HPLC; LC-MS; NMR; Hebe spp.; Scrophulariaceae.
Ano: 2002 URL: http://hdl.handle.net/10198/3209
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