Browsing by Author "Seabra, Rosa M."
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- Analysis and quantification of flavonoidic compounds from Portuguese olive (Olea europeae L.) leaf cultivarsPublication . Meirinhos, Julieta; Silva, Branca M.; Valentão, Patrícia; Seabra, Rosa M.; Pereira, J.A.; Dias, Alberto; Andrade, Paula B.; Ferreres, FredericoTwenty three samples of 18 Portuguese olive leaf cultivars were analysed by a reversed-phase HPLC/DAD procedure and eight flavonoidic compounds were identified and quantified (luteolin 7,40-O-diglucoside, luteolin 7-O-glucoside, rutin, apigenin 7-O-rutinoside, luteolin 40-O-glucoside, luteolin, apigenin and diosmetin). Luteolin 7,40-O-diglucoside and luteolin 40-O-glucoside were identified by HPLC/DAD/MS/MS – ESI. The studied olive leaf samples showed a common phenolic pattern, in which luteolin 40-O-glucoside was almost always the major compound
- Analysis of phenolic compounds from hazelnut (Corylus avellana L.) leavesPublication . Amaral, Joana S.; Ferreres, Frederico; Santos, Alberto; Pinheiro, Cristina; Andrade, Paula B.; Seabra, Rosa M.Hazelnut leaf has been used in folk medicine in varicose veins and haemorrhoidal symptomatology for its vasoconstrictor and antihaemorrhagic properties. Slight antidysenteric, antifungal and healing properties have also been described
- Antioxidant potential and relation with chemical composition of wild edible mushrooms cap and stipePublication . Ribeiro, Bárbara; Lopes, Rosário; Andrade, Paula B.; Seabra, Rosa M.; Gonçalves, Rui; Baptista, Paula; Valentão, PatríciaA comparative study of the organic acids and phenolics composition and of the total alkaloids content of entire wild edible mushrooms (Russula cyanoxantha, Amanita rubescens, Suillus granulatus and [Boletus edulis) and correspondent cap and stipe was performed. All species presented oxalic, citric, malic and fumaric acids. Phenolic compounds were present in all of the analyzed species, beingp-hydroxybenzoic acid identified in A. rubescens and S. granulatus species. It seems that this compound may have a propensity to accumulate in the cap of A. rubescens. B. edulis was the species that presented the highest total alkaloids amounts. All species revealed DPPH radical scavenging activity, being B. edulis the most effective one.
- Antioxidative properties of tronchuda cabbage (Brassica oleracea L. var. costata DC) external leaves against DPPH, superoxide radical, hydroxyl radical and hypochlorous acidPublication . Vrchovska, Vendula; Sousa, Carla; Valentão, Patrícia; Ferreres, Frederico; Pereira, J.A.; Seabra, Rosa M.; Andrade, Paula B.The ability of the aqueous extract of tronchuda cabbage (Brassica oleracea L. var. costata DC) external leaves to act as a scavenger of DPPH- and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid) was investigated. A phytochemical study was also undertaken, and thirteen phenolic compounds and five organic acids were identified and quantified. Tronchuda cabbage extracts exhibited antioxidant capacity in a concentration-dependent manner in all assays, although some pro-oxidant effect was also noticed. The samples with higher phenolic and organic acid contents displayed the major antioxidant potentials.
- Aroma compounds in eleven edible mushroom species: relationship between volatile profile and sensorial characteristicsPublication . Pinho, P. Guedes de; Ribeiro, Bárbara; Gonçalves, Rui; Baptista, Paula; Valentão, Patrícia; Seabra, Rosa M.; Andrade, Paula B.Wild edible mushrooms are consumed a lot in many countries, being cooked or eaten in salads. Their culinary and commercial value is mainly due to their organoleptic properties, namely aroma and flavour. In addition, the aroma is very characteristic for each mushroom species, which determines the distinction between them. Despite the high consumption of mushrooms, little work is available concerning their volatile composition. Trás-os-Montes region (north-eastern Portugal) is known for the variety of its soils and diversity of climate conditions. This variability assumes an important role in mushroom production, which is why this region is recognised as one of the richest regions in wild edible species. In this work eleven wild edible mushrooms collected in this region were studied: Suillus bellini, Suillus luteus, Suillus granulatus, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica and Cantharellus cibarius. With the exception of B. edulis, F. hepatica, C. cibarius and S. luteus, there is no knowledge of volatile characterisation of these species. The volatile and semi-volatile constituents were determined by headspace solid-phase microextraction (HS-SPME) and by liquid extraction combined with gas chromatographymass spectrometry (GC-MS). A total of 49 volatiles and 17 semi-volatile components were identified. Using sensorial analysis, the descriptors “mushroom-like”, “farmfeed-like”, “floral”, “honey-like”, “hay-herb” and “nutty” were obtained. The multivariate analysis (principal component analysis and agglomerative hierarchic cluster analysis) of sensorial and chemical data revealed a correlation between sensory descriptors and volatiles. The studied mushroom species can be divided in three groups: one rich in C8 derivatives, like 3-octanol, 1-octen-3-ol, trans-2-octen-1-ol, 3-octanone and 1-octen-3-one; another with high amounts of terpenic volatile compounds; and a third one rich in methional. The presence and contents of these compounds gives a considerable contribution to their sensory characteristics.
- Aroma compounds in eleven edible mushroom species: relationship between volatile profile and sensorial characteristicsPublication . Pinho, P. Guedes de; Ribeiro, Bárbara; Gonçalves, Rui; Baptista, Paula; Valentão, Patrícia; Seabra, Rosa M.; Andrade, Paula B.Volatile and semi-volatile components of 11 wild edible mushrooms, Suillus bellini, Suillus luteus, Suillus granulatus, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Fistulina hepatica and Cantharellus cibarius, were determined by headspace solidphase microextraction and by liquid extraction combined with gas chromatographymass spectrometry.
- Aroma compounds in eleven edible mushroom species: relationship between volatile profile and sensorial characteristicsPublication . Pinho, P. Guedes de; Ribeiro, Bárbara; Gonçalves, Rui; Baptista, Paula; Valentão, Patrícia; Seabra, Rosa M.; Andrade, Paula B.Wild edible mushrooms, are consumed a lot in many countries, being cooked or eaten in salads. Their culinary and commercial value is mainly due to their organoleptic properties, namely aroma and flavour. In addition, the aroma is very characteristic for each mushroom species, which determines the distinction between them (1, 2). Despite the high consumption of mushrooms, little work is available concerning· their volatile composition. Tras-os-Montes region (north-east.em Portugal) is known for the variety of its soils and diversity of climate conditions.
- Avaliação nutricional e composição em ácidos gordos de 6 variedades de nozes, sementes de Juglans regia L., cultivadas em Trás-os-MontesPublication . Amaral, Joana S.; Casal, Susana; Pereira, J.A.; Seabra, Rosa M.; Oliveira, BeatrizA dieta mediterrânea, considerada saudável e uma das melhores no que concerne à prevenção das doenças cardiovasculares inclui, como componentes importantes, os frutos secos. No entanto, e talvez devido ao facto deste tipo de alimentos ser rico em lípidos, assistiu-se a um declínio do seu consumo. Actualmente, associa-se o consumo de frutos secos à ingestão de ingredientes com propriedades funcionais. Quando comparadas com a maioria dos outros frutos secos, que contam principalmente ácidos gordos monoinsaturados, as nozes distinguem-se pelos teores elevados em ácidos gordos polinsaturados (omega-3 e omega-6).
- Beefsteak fungus Fistulina hepatica: phenolic compounds and organic acids contents and antioxidative propertiesPublication . Ribeiro, Bárbara; Valentão, Patrícia; Baptista, Paula; Seabra, Rosa M.; Andrade, Paula B.Fistulina hepatica mushroom, commonly known as beefsteak fungus, usually is a saprobic and sometimes a parasitic fungus that lives on the wood of hardwoods (especially oaks and chestnut), during Swnmer and Autumn. As the common name suggests, beefsteak fungus is remarkably similar in appearance to raw meat. In the past, it was often cooked and eaten as a substitute for meat. It is sold in several markets and can be eaten raw in salad or with a sauce of parsley and garlic.
- Benefícios potenciais do consumo de nozesPublication . Amaral, Joana S.; Casal, Susana; Seabra, Rosa M.; Oliveira, BeatrizOs frutos secos, na sua generalidade, apresentam uma composição similar do ponto de vista nutricional sendo, caracteristicamente, alimentos com elevado teor de lípidos. Por este motivo, a generalidade dos consumidores evita o seu consumo, uma vez que associa este tipo de alimentos ao aumento de peso corporal. No entanto, estudos epidemiológicos e clínicos realizados nas últimas décadas sugerem que o consumo frequente de quantidades moderadas de frutos secos pode ter efeitos benéficos para a saúde humana, principalmente a nível do perfil lipídico sanguíneo.13 Quando comparadas com a maioria dos outros frutos secos, os -quais contêm principalmente ácidos gordos monoinsaturados, as nozes destacam-se pelos seus teores elevados em ácidos gordos polinsaturados E -3 e 0-6, nomeadamente em termos dos ácidos gordos essenciais linoleico e 0-linolénico. Para além do seu perfil favorável em ácidos gordos, as nozes contêm ainda vários outros compostos bioactivos, tais como fitoesteróis, tocoferóis e tocotrienóis. Neste trabalho procedeu-se ao estudo da fracção lipídica das nozes em termos do seu perfil em ácidos gordos, triacilgliceróis, fitoesteróis, tocoferóis e tocotrienóis. As composições em ácidos gordos e fitoesteróis foram analisadas por GC/FID, os triacilgliceróis por HPLC/ELSD e os tocoferóis e tocotrienóis por HPLC/DAD/FL. Os detalhes relativos à composição nos referidos compostos serão apresentados bem como a sua relação com possíveis efeitos benéficos para a saúde.