Browsing by Author "Andrade, Paula B."
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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.
- 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.
- Brassica oleracea var. costata: comparative study on organic acids and biomass production with other cabbage varietiesPublication . Sousa, Carla; Pereira, David M.; Taveira, Marcos; Dopico-García, Sonia; Valentão, Patrícia; Pereira, J.A.; Bento, Albino; Andrade, Paula B.BACKGROUND: A study was undertaken to evaluate the effect of agronomic practices, harvesting time and leaf age on the organic acid composition and biomass production of Brassica oleracea L. var. costata DC (tronchuda cabbage). Samples were cultivated under eight different fertilisation regimes (two levels each of nitrogen, boron and sulfur, an organic fertiliser and no fertiliser) and collected at three different times. RESULTS: Principal component analysis of the data indicated significant differences. Three principal components with an eigenvalue higher than one accounted for 79.0% of the total variance of the data set. Samples obtained with conventional fertilisation were characterised by the highest values of fresh weight. External leaves showed higher total organic acid and malic acid contents than internal leaves,while the latterwere characterised by higher proportions of citric acid. For consecutive harvests, total organic acid concentration decreased in both external and internal leaves. CONCLUSION: The use of a conventional fertilisation regime (nitrogen, boron or sulfur) improved the growth of B. oleracea var. costata without affecting its organic acid profile. However, for consecutive harvests, total organic acid concentration was observed to decrease independently of the agronomic practices tested. Leaf age influenced the quantitative composition of organic acids.
- Caracterização química de azeites varietais das cultivares Cobrançosa, Madural e Verdeal Transmontana obtidos de azeitonas com diferentes índices de maturação.Publication . Matos, Luís C.; Pereira, J.A.; Andrade, Paula B.; Seabra, Rosa M.; Oliveira, BeatrizA qualidade de um azeite depende de diversos factores, nomeadamente das praticas agronómicas, do estado sanitária dos frutos, das fases sucessivas de colheita, de armazenamento e de transformação. A composição química do produto final está directamente relacionada com a estado e composição do fruto do qual é extraído. A maturação das azeitonas é um processo lento que se prolonga durante vários meses, ao longo do qual ocorrem numerosos processos de transformação química e de síntese de substancias orgânicas . Assim, o estabelecimento de uma época óptima de colheita, por forma a obter um rendimento máximo de extracção e as melhores características qualitativas do produto final.