Browsing by Author "Soutinho, Susana"
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- Evolução dos compostos fenólicos e da capacidade antioxidante durante a maturação de frutos vermelhos (framboesa, groselha e mirtilo) de produção biológicaPublication . Soutinho, Susana; Gonçalves, Fernando; Jordão, Antonio; Guiné, RaquelO modo de produção biológico distingue-se de outros métodos de produção pelo seu equilíbrio e ação construtiva nos sistemas agrícolas. Nos últimos anos, tem havido um interesse crescente em alimentos de origem biológica. Ao mesmo tempo, tem crescido a procura por frutos devido à sua composição em compostos biologicamente ativos, associados a efeitos benéficos para a saúde humana. Neste trabalho foram estudados três frutos vermelhos, framboesa, groselha e mirtilo, produzidos em modo biológico. Com a execução do trabalho pretendeu-se estudar a evolução do teor em compostos fenólicos e da capacidade antioxidante destes frutos vermelhos ao longo da maturação. Os resultados mostraram que os compostos fenólicos totais dos três frutos decresceram ao longo da maturação, tanto no extrato de metanol como no de acetona. O teor em compostos fenólicos do extrato de metanol era superior quando comparado com o extrato de acetona. O mirtilo foi, entre os frutos estudados, o que apresentava teores mais elevados de compostos fenólicos. Os teores de taninos e antocianinas totais quantificadas no mirtilo e na groselha aumentaram ao longo da maturação. Pelo contrário, a framboesa continha, no final da maturação, teores mais baixos destes compostos. No final da maturação, os teores mais elevados de taninos e de antocianinas foram observados no mirtilo. Ao longo da maturação verificou-se um decréscimo na percentagem relativa das formas monoméricas das antocianinas. No final da maturação, todos os frutos apresentavam valores semelhantes de capacidade antioxidante quando determinada pelo método DPPH. No caso do método ABTS, o mirtilo mostrou valores mais elevados de capacidade antioxidante.
- Phenolic compounds and antioxidant activity in red fruits produced in organic farming.Publication . Guiné, Raquel; Soutinho, Susana; Gonçalves, FernandoIn this work were studied three red fruits (raspberry, gooseberry and blueberry) produced in organic mode, to evaluate the variations in the content of phenolic compounds and antioxidant capacity along maturation. The phenols were extracted from the fruits with two solvents (methanol and acetone) and were quantified by the Folin-Ciocalteu method. The antioxidant activity was determined with two methods (HPPH and ABTS). Furthermore, HPLC was used to identify and quantify some phenolic compounds present in the fruits analyzed. The results showed that the total phenolic compounds in all fruits decreased along maturation, either in the methanol or acetone extracts (23 % and 20 % reduction, on average, for methanol and acetone extracts, respectively), although in methanol extracts the levels of phenolic compounds were always higher (0.54 and 0.21 mg GAE/g). The blueberry showed higher level of total phenolics in methanol extract (average 0.67 mg GAE/g), while in the acetone extract it was gooseberry (average 0.31 mg GAE/g). At the end of maturation, all fruits studied had similar values of antioxidant capacity as determined by DPPH method (0.52 mmol Trolox/g). For the ABTS method, blueberries showed higher values of antioxidant activity (6.01 mmol Trolox/g against 3.01 and 2.66 mmol Trolox/g, for raspberry and gooseberry, respectively). Furthermore, the HPLC analysis allowed to identify monomeric anthocyanins and phenolic acids in the three fruits studied.
- Phenolic Compounds in Red Fruits Produced in Organic Farming at Maturation StagePublication . Soutinho, Susana; Guiné, Raquel; Jordão, António; Gonçalves, FernandoThe agricultural organic farming is different from conventional farming in a way that is aimed at providing a balanced and constructive action in agricultural systems. With the increase in intensive agriculture, undesirable changes were being observed in ecosystems with irreparable damage being caused to the natural equilibrium. This is the reason for the increasing interest in organic farming as an environment friendly agricultural production method. In the present work three red fruits produced in organic farming were analysed, namely raspberry, gooseberry and blueberry. The samples were harvested in a local farm when at plain maturation. The results obtained allowed to conclude that the blueberry contained higher amounts of phenolic compounds, total tannins and total anthocyanins than raspberry and gooseberry. Furthermore, the HPLC analysis allowed to identify monomeric anthocyanins and phenolic acids in the three fruits studied
- Phenolic Compounds in Red Fruits Produced in Organic Farming at Maturation StagePublication . Soutinho, Susana; Guiné, Raquel; Jordão, Antonio; Gonçalves, FernandoThe agricultural organic farming is different from conventional farming in a way that is aimed at providing a balanced and constructive action in agricultural systems. With the increase in intensive agriculture, undesirable changes were being observed in ecosystems with irreparable damage being caused to the natural equilibrium. This is the reason for the increasing interest in organic farming as an environment friendly agricultural production method. In the present work three red fruits produced in organic farming were analyzed, namely raspberry, gooseberry and blueberry. The samples were harvested in a local farm when at plain maturation. The results obtained allowed to conclude that the blueberry contained higher amounts of phenolic compounds, total tannins and total anthocyanins than raspberry and gooseberry. Furthermore, the HPLC analysis allowed to identify monomeric anthocyanins and phenolic acids in the three fruits studied