Percorrer por autor "Nunes, Fernando M."
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- Antimicrobial and antioxidant activities of aqueous extracts of Lentinula edodes var Donko and KoshinPublication . Afonso, Ana Cristina; Fernandes, Conceição; Garcia, Juliana; Marques, Guilhermina; Nunes, Fernando M.; Saavedra, Maria JoséAntimicrobial resistance is recognizes by the WHO as a serious Public Health problem, representing a global challenge for medicine.
- Aplicação de revestimentos na castanhaPublication . Ramalhosa, Elsa; Pereira, Ermelinda; Laranjo, José Gomes; Ferreira-Cardoso, Jorge; Gomes, A.; Vilela, Alice; Sampaio, Ana; Nunes, Fernando M.No presente capítulo pretende-se descrever as atividades realizadas no âmbito do Projeto ValorCast ao nível da aplicação de revestimentos hidrofílicos e hidrofóbicos com o intuito de reduzir a desidratação das castanhas após a colheita. Para a avaliação de revestimentos hidrofílicos foram realizados quatro estudos, nos quais se avaliou a aplicação dos seguintes compostos: (i) alginato, quitosano e proteína do soro, a 2% (m/v); (ii) quitosano (0,5, 1 e 2%, m/v) e farinha de mandioca (3 e 5%, m/v); (iii) revestimentos comerciais da empresa DOMCA, designadamente o FOOD-COAT®, PROALLIUM® e ambos em conjunto. Na aplicação de revestimentos de resíduos hidrofóbicos utilizou-se a parafina, parafina aditivada com timol e a cera de abelha. Através da realização do primeiro estudo verificou-se que os melhores resultados em termos da qualidade microbiológica do fruto foram obtidos com o quitosano. No segundo estudo observou-se que a aplicação de farinha de mandioca a 5% acarretou o aparecimento de bolores visíveis após 6 meses de armazenamento. Pelo contrário, a aplicação de quitosano a 1 e 2% e farinha de mandioca a 3% forneceram resultados promissores ao nível da redução do desenvolvimento microbiano, principalmente quando se consideram armazenamentos longos (> 3 meses). No terceiro estudo verificou-se que em relação à perda de peso, após o armazenamento durante 4 meses, o FOOD-COAT® foi o revestimento que mostrou o melhor desempenho, com a menor perda de peso (5 a 6%). No entanto, em relação aos microrganismos mesófilos aeróbios e bolores e leveduras, o PROALLIUM® foi o mais eficiente durante dois a três meses. Assim, a junção PROALLIUM®+ FOOD-COAT® pode ser vantajosa para se retardar a perda de peso e o desenvolvimento microbiano até três meses de armazenamento, perdendo a sua eficácia após esse período. Relativamente aos revestimentos hidrofóbicos à base de parafina e cera de abelha foram muito eficientes na prevenção da perda de água quando as castanhas foram armazenadas em condições forçadas. As castanhas revestidas com parafina ou com cera de abelha em termos sensoriais foram idênticas às castanhas antes do armazenamento, exceto com a adição do timol no tratamento da parafina pois conferiu aromas desagradáveis à castanha, provavelmente devido ao odor pungente do timol, mas em termos microbiológicos o timol teve uma ação essencial, pois permitiu diminuir a podridão das castanhas após o armazenamento.
- Application of anti-hail net in apple orchards: effects on fruits chemical characteristicsPublication . Martins-Gomes, Carlos; Pinto, Luís; Silva, Ermelinda; Martins, Sandra; Gonçalves, Alexandre; Brito, Cátia; Moutinho-Pereira, José; Rodrigues, M.A.; Correia, Carlos M.; Nunes, Fernando M.Apple production in Portugal, over the last 15 years, has been subjected to increasing crop damage due to hailstorms and related meteorological extreme conditions. This problem has led farmers and researchers to find practical solutions to protect the orchards, such is the case of netting devices. The application of anti-hail nets in apple tree orchards looks to provide protection against the roughest meteorological events (such as hail, strong winds, and sunburn), while avoiding to upset the development of the plant and or, if possible, helping to improve the plant’s productivity. During 2016, this work was carried out in Carrazeda de Ansiães, a northeast Portuguese plateau zone that is a primary location for apple production, and the application of a grey anti-hail net, which reduces photosynthetically active radiation by 12 %, was tested in an orchard with the cultivars Golden delicious and Fuji of apple tree (Malus domestica Borkh). Control without screen net applied was also used. In order to understand the effects of the net, apples were collected and analysed for their chemical characteristics (total phenols, ortho-diphenols and flavonoids content, ABTS and polyphenolic profile). The obtained results in apple peel revealed, in both cultivars, a decrease in total phenols, ortho-diphenols and flavonoids concentration, whereas in the Fuji cultivar the antioxidant activity, determined by the ABTS assay, was maintained. Pulp results showed little difference with lower (P<0.001) ortho-diphenols content in Fuji cultivar and slightly lower (P<0.05) ABTS activity in Golden delicious cultivar. Peel and pulp methanolic extracts were analysed by HPLC-DAD. The phenolic profile was similar for both cultivars, with the exception of anthocyanins, being identified chlorogenic acid and derivatives of quercetin. The antihail net did not affect the phenolic profile, only decreased the polyphenols concentration. The use of a grey anti-hail net on apple orchards is a suitable alternative for the protection of apple trees against hail ensuring the production of the crop without compromising fruit quality.
- Avaliação do efeito da aplicação de manoproteínas comerciais no incremento da qualidade de vinhos brancosPublication . Ribeiro, Tânia; Fernandes, Conceição; Filipe-Ribeiro, Luis; Nunes, Fernando M.; Cosme, FernandaFace à exigência dos consumidores atuais, as características sensoriais de um vinho, assim como a sua estabilidade, são fatores determinantes para a sua aceitabilidade no mercado. A instabilidade proteica do vinho e consequente desnaturação/precipitação das proteínas depende de fatores (intrínsecos e extrínsecos) e é responsável pelo aparecimento de turvação nos vinhos brancos. Para prevenir a instabilidade proteica são usados vários produtos enológicos, com objetivo de remover as proteínas instáveis, no entanto com várias limitações, tais como eficiência e modificação das características físico-químicas e sensoriais no vinho. Nos últimos anos têm surgido diversos aditivos comerciais à base de manoproteínas, já que as mesmas podem ser uma via alternativa para a estabilização proteica do vinho. Neste trabalho foram selecionadas onze manoproteínas comerciais para avaliar o seu efeito na estabilização proteica, bem como o seu efeito na composição fenólica e nas características cromáticas e sensoriais num vinho branco. Os resultados obtidos mostraram que 9 das 11 manoproteínas testadas apresentaram efeito positivo na estabilização proteica do vinho. Além disso, todas as manoproteínas diminuíram o potencial de acastanhamento dos vinhos, e de um modo geral conduziram a um aumento da luminosidade. Na análise sensorial, apesar de não haver diferenças significativas relativamente ao vinho controlo, tendencialmente os vinhos mais pontuados foram os tratados com manoproteínas, nomeadamente ao nível da diminuição da cor, equilíbrio gustativo e na componente aromática, frutado e floral. Pelos resultados obtidos neste trabalho, podemos concluir que as manoproteínas parecem ser uma alternativa eficiente na estabilização proteica de vinhos brancos e que podem simultaneamente melhorar as características sensoriais do vinho, porém, convém salientar que estes resultados devem ser encarados como preliminares, sendo necessário realizar mais estudos com outros tipos de vinhos.
- Avaliação do efeito da aplicação de manoproteínas comerciais no incremento da qualidade de vinhos brancosPublication . Ribeiro, Tânia; Fernandes, Conceição; Filipe-Ribeiro, Luis; Nunes, Fernando M.; Cosme, FernandaA estabilidade e as características sensoriais dum vinho são fatores determinantes para a sua aceitabilidade. Neste trabalho testaram-se manoproteínas comerciais, verificando-se que estas podem ser uma alternativa eficiente na estabilização proteica de vinhos brancos, melhorando simultaneamente as suas características sensoriais.
- Clinoptilolite zeolite foliar application on rainfed olive trees: effects on physiology, biochemistry, growth, yield and olive oil qualityPublication . Martins, Sandra; Gonçalves, Alexandre; Silva, Ermelinda; Brito, Cátia; Pinto, Luís; Arrobas, Margarida; Rodrigues, M.A.; Nunes, Fernando M.; Correia, Carlos M.With the advances of climate change, it is expected harmful consequences to olive tree (Olea europaea L.). Therefore, it is necessary to develop cost-effective practices to reduce the vulnerability of olive crops to the adverse impacts of environmental stresses. Rainfed olive trees were sprayed with zeolites, natural crystalline aluminosilicates, and its effects on photosynthetic activity, phenolic composition, antioxidant activity, leaf minerais concentrations, plant growth, yield, and olive oil quality were assessed. Zeolites application enhanced photosynthetic activity, as well the concentrations of N, Mg, Cu, Zn and Mn in leaves, and changed the secondary metabolism, with decrease oftotal phenols, ortho-diphenols and total antioxidant activity, signs of lower oxidative stress. As consequence, zeolites boosted plant growth, crop yield, and size and weight of fruits. The foliar spray did not significantly affect the oil quality indices free acidity, peroxide value and Km and K270 coefficients. This study strongly suggests that folial' zeolites might be an effective strategy to mitigate the adverse environmental conditions.
- Combining zeolites with early-maturing annual legume cover crops in rainfed orchards: effects on yield, fatty acid composition and polyphenolic profile of olives and olive oilPublication . Martins, Sandra; Silva, Ermelinda; Brito, Cátia; Pinto, Luís; Martins-Gomes, Carlos; Gonçalves, Alexandre; Arrobas, Margarida; Rodrigues, M.A.; Correia, Carlos M.; Nunes, Fernando M.Under climate change threats, there is a growing need to adapt the conventional agronomic practices used in rainfed olive orchards by sustainable practices, in order to ensure adequate crop yield and olive oil quality and to preserve soil health. Therefore, for two years, the effects of conventional tillage practice (T) and two sustainable soil management strategies, a leguminous cover crop (LC) and its combination with natural zeolites (ZL), on the yield, fatty acid composition, polyphenolic profile and quality indices of olive fruits and oil were evaluated. Crop yield was significantly increased by LC and ZL in the first year. Although in the second year no significant differences were verified, the cumulative yield increased significantly by 31.6% and 35.5% in LC and ZL trees, respectively. LC enhanced the moisture and size of olives, while ZL increased, in general, the concentrations of oleuropein, verbascoside, caffeic acid and epicatechin, as well the oleic/linoleic ratio in fruits and the levels of 3,4-dihydroxyphenylglycol, tyrosol, verbascoside and caffeic acid in olive oil. Despite the higher concentration of total phenols in the fruits and oil from T trees in the warmer and dryer year, the quality of the oil decreased, mainly when compared with ZL, as evidenced by the peroxide value and K232 and K270 coefficients. In short, both sustainable soil management strategies appear to be promising practices to implement in olive orchards under rainfed conditions, but the innovative strategy of combining zeolites with legume cover crops, first reported in the present study, confers advantages from a nutritional and technological point of view. Nevertheless, studies subjected to the long-term use of these practices should be conducted to ensure the sustainability of the crop yield and olive oil quality.
- Comparative antioxidant and antimicrobial properties of Lentinula edodes Donko and Koshin varieties against priority multidrug-resistant pathogensPublication . Garcia, Juliana; Afonso, Ana Cristina; Fernandes, Conceição; Nunes, Fernando M.; Marques, Guilhermina; Saavedra, Maria JoséThe problematic increase in multidrug-resistant bacteria translates into the urgent need to discover novel and effective antimicrobial substances. Herein, mushrooms could be a promising alternative of natural source of new antimicrobials. The present work aimed to compare the phytochemical composition and antimicrobial activity of methanol and aqueous crude extracts of Lentinula edodes var. Koshin and Donko. Disk diffusion method was used to screen the antimicrobial activity and to assess the synergistic effect of the mushroom extracts. Microdilution method was used to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). Phytochemical characterization of mushrooms extracts was achieved by analysis of total phenols, ortho-diphenols content and its antioxidant activity. The results noticed a positive relation between phenolic compounds content, antioxidant activity, and antimicrobial capacity of the mushroom's extracts. The L. edodes var. Koshin aqueous extracts, which contained the highest amount of total phenolic compounds, exhibited the highest scavenging capacity of ABTS which, in turns, exhibited the highest antimicrobial efficacy in inhibiting the growth of methicillin-resistant Staphylococcus aureus. Moreover, the combination between mushrooms extracts and commercial antibiotics showed favorable synergistic effects against tested bacteria. These results suggest that L. edodes var. Koshin may represent an important and valuable therapeutic source of compounds to be used against multidrug-resistant bacteria.
- Comparison of ion exchange resins at industrial scale and enological stabilizers treatments for tartaric stabilization of white Port wine: Impact on wine physicochemical and sensory profilePublication . Moreira, Daniela; Fernandes, Conceição; Borges, Rita; Marques, Celeste; Matos, Carlos; Vilela, Alice; Filipe-Ribeiro, Luis; Nunes, Fernando M.; Cosme, FernandaA frequent cause cause of stability loss in awine is the formation of crystalline salts of potassium bitartrate (KHT) that appears mainly at low temperatures, temperatures, as a consequence of a large decrease in its itssolubility solubility [1,2]. Port wine is a Portuguese fortified wine produced exclusively in the Douro Valley demarcated region. There are only only few few studies regarding white Port wine tartaric stabilization, although its importance for consumers acceptance.
- Comparison of ion exchange resins at industrial scale and enological stabilizers treatments for tartaric stabilization of white Port wine: Impact on wine physicochemical and sensory profile.Publication . Moreira, Daniela; Fernandes, Conceição; Borges, Rita; Marques, Celeste; Matos, Carlos; Vilela, Alice; Filipe-Ribeiro, Luis; Nunes, Fernando M.; Cosme, FernandaA frequent cause of stability loss in a wine is the formation of crystalline salts of potassium bitartrate (KHT) that appears mainly at low temperatures, as a consequence of a large decrease in its solubility [1, 2]. Although important for consumer’s acceptance, there are only few studies regarding white Port wine tartaric stabilization. Therefore, tartaric stabilization has been carried out in a white Port wine by ion exchange resins, at an industrial scale, and by the addition of enological stabilizers, with the main objective of comparing the impact of these treatments on wine physicochemical and sensory profile. Port wine is a Portuguese fortified wine produced exclusively in the Douro Valley demarcated region. In this study, a white Port wine from the 2015 vintage from Gran Cruz winery, Portugal was used and almost 20% from the total wine volume was treated by ion exchange resins (pH-Stab®). The stabilizers used were metatartaric acid and carboxymethylcellulose (CMC1 5%, CMC2 20%; CMC3 solid) with different structural characteristics. Wine tartaric stability was measured by the mini contact test. Wines phenolic composition - total phenols, flavonoid and non-flavonoid compounds, as well as the chromatic characteristics by the CIELab method, were also evaluated. Sensory analysis was performed by a panel of eight trained tasters. Twenty-one attributes were selected and were quantified using a five-point intensity scale. As expected, all treatments assayed stabilized the white Port wine. All the samples presented a slight decrease in total phenolic compounds and non-flavonoid phenolic compounds. Concerning sensory analysis, wine treatment with ion exchange resins was more scored for the visual limpidity attribute and for the aroma attributes citrus and tea.