Browsing by Author "Lopes, Pedro"
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- Compostos fenólicos das peras de S. Bartolomeu.Publication . Silva, Lizete; Lopes, Pedro; Domingues, Maria do Rosário; Guiné, Raquel; Coimbra, ManuelPyrus communis L. var. S.Bartolomeu é uma pêra usada para produzir a pêra passa de Viseu, um produto tradicional português produzido por secagem ao sol. O produto final é um fruto pequeno, de cor castanha-avermelhada, com propriedades elásticas. As propriedades organolépticas que influenciam a qualidade do produto final são a cor, o sabor e a textura, tendo os compostos fenólicos uma função importante nestes atributos. As procianidinas são os principais compostos fenólicos da pêra de S. Bartolomeu. Com o processamento a Pêra Passa de Viseu, o conteúdo em compostos fenólicos diminui 64%, verificando-se que as procianidinas aumentam o seu grau de polimerização, com diminuição da sua extractabilidade. Com o objectivo de desenvolver uma metodologia capaz de substituir a secagem solar tradicional, foram processadas peras utilizando uma estufa solar estufa de convecção forçada e, em alternativa, um túnel de ar quente, a 40 ºC, sem exposição solar. Estas peras assim processadas foram comparadas com as obtidas pelo método tradicional e com as peras não processadas. Os compostos fenólicos de cada uma das amostras foram extraídos com soluções de metanol e de acetona/água (6:4, v:v) e a sua identificação e caracterização foi feita por espectrometria de massa (ESI-MS e ESI-MS/MS). A extractabilidade das procianidinas com grau de polimerização entre 2 e 6 (DP2-DP6) é muito afectada pelo processo de secagem e varia com o processo utilizado. Os polímeros das amostras não processadas e processadas em túnel foram extraídos em maior quantidade pelo metanol do que os das amostras que foram sujeitas à exposição solar, tendo estes compostos sido extraídos em maior quantidade com a solução de acetona/água. Para além das procianidinas, o composto fenólico mais abundante nos extractos foi o ácido clorogénico. Foram também identificados, principalmente nos extractos das amostras expostas à luz solar, isorhamnetina-3-Hex, canferol-3-Hex e quercetina-3-Hex.
- Continuing Teacher Education: Informal Collaborative Teacher Network as a Response to the Emergency Context Created by COVID-19Publication . Mota, Miguel Ângelo Sousa Dias Ferreira da; Cabo, Isabel; Valéria, Cátia; Guedes, Damiana; Lopes, PedroThe COVID-19 pandemic posed unprecedented challenges to the education sector, necessitating a rapid transition to emergency distance learning and highlighting the need to train teachers to maintain educational continuity under lockdown restrictions. In response, initiatives such as “Online Pedagogical Sharing” emerged, comprising short-term training activities aimed at educators and teachers at all levels of education in Portugal. This case study, conducted within a qualitative paradigm, explores how training organised by this informal collaborative network contributed to the continuous professional development and adaptation of teaching practices during the pandemic. It utilised digital technologies to meet the demands of distance learning and improve the pedagogical use of new technologies. The sessions, which took place between June and July 2020, were widely accessible, facilitating a meaningful collaborative approach in the teaching environment. By analysing data collected during these sessions, the study highlights the network’s effectiveness in facilitating collaborative learning and the impact of educational technologies during a time of significant pedagogical change. This work not only documents the immediate response to the crisis but also suggests avenues for future use of similar practices in post-pandemic contexts, emphasising the need for further analysis of the resilience and effectiveness of these adapted pedagogical strategies.
- Determinação do poder anti-radicalar dos compostos fenólicos das peras frescas e secadas de S. Bartolomeu.Publication . Silva, Lizete; Lopes, Pedro; Cunha, Pedro; Rocha, Sílvia; Guiné, Raquel; Coimbra, ManuelAs procianidinas são os principais compostos fenólicos da pêra de S. Bartolomeu (Pyrus communis L.). Com o processamento a pêra passa de Viseu, o conteúdo em compostos fenólicos diminui 64%, verificando-se que as procianidinas aumentam o seu grau de polimerização e diminuem a sua extractabilidade. Com o objectivo de avaliar o poder anti-radicalar dos compostos fenólicos presentes nas peras de S. Bartolomeu frescas e secadas e a sua biodisponibilidade ao longo do tracto gastrointestinal, foram analisadas peras secadas pelo método tradicional com exposição solar directa, peras secadas em estufa solar de convecção forçada e peras secadas em túnel a 40 ºC sem exposição solar. Os compostos fenólicos foram extraídos com soluções de metanol e de acetona/água (6:4 v/v). Os testes de avaliação do poder anti-radicalar das amostras foram feitos em soluções simulantes da saliva (1% -amilase, pH 6,5), do suco gástrico (1% pepsina, pH 2) e do meio líquido do duodeno (0,15% sais biliares e 3% pancreatina, pH 7), a 37 ºC. Os testes foram realizados individualmente nas três condições e também de modo sequencial, simulando o percurso pelo aparelho digestivo. A actividade anti-radicalar foi medida pelo teste de DPPH. Cada um dos simulantes, quando analisado individualmente, não apresenta efeitos significativos na actividade anti-radicalar dos extractos. No entanto, a acção sequencial dos três simulantes reduz para metade a capacidade anti-radicalar. Estes resultados permitem inferir que os compostos fenólicos existentes nos vários extractos de pêra fresca e secada apresentam biodisponibilidade, resistindo parcialmente à degradação pela saliva, suco gástrico e meio líquido do duodeno.
- Effcet of ripening stage on the solar drying kinetics and properties of S. Bartolomeu pears (Pirus Communis L.).Publication . Guiné, Raquel; Lopes, Pedro; Barroca, Maria João; Ferreira, DulcineiaPears of the variety S. Bartolomeu (Pyrus communis L.) have been used over the years in Portugal to produce a traditional dried pear known as “pera passa”. The processing comprehends a solar drying performed at open air, with obvious disadvantages, either concerning the drying efficiency or the sanitary quality of the final product, taking into account that the products are exposed to multiple contamination agents. For these reasons, attempts have been made to study alternative production methodologies, including the use of solar stoves, among others. In the present work pears of the variety S. Bartolomeu (Pyrus communis L.), harvested at three different moments, corresponding to three ripening stages, were dried in a solar stove and their drying kinetics were studied, and the evolution of some properties was monitored along the drying process. From the results obtained it was possible to conclude that the equations used to model the drying kinetics fit with accuracy the experimental data, and that the climatic conditions that occurred in each drying period influenced the drying rate, being essay one clearly faster than the other two essays. On the other hand, considering the evolution of the properties of the pears along drying, it was possible to observe that the pears harvested in the two first dates showed quite similar trends through drying, while the pears harvested at the last date revealed a clear distinct behavior, allowing to deduce that the ripening stage at harvest plays an important role in the drying process.
- Influence of drying treatments on the colour of green bell peppers.Publication . Guiné, Raquel; Lopes, Pedro; Barroca, Maria João; Ferreira, DulcineiaPears of the variety S. Bartolomeu have been used over the years in Portugal to produce a traditional dried pear known as “pera passa”. The processing comprehends a solar drying performed at open air, with obvious disadvantages, either concerning the drying efficiency or the sanitary quality of the final product, taking into account that the products are exposed to multiple contamination agents. For these reasons, attempts have been made to study alternative production methodologies, including the use of solar stoves, among others. In the present work pears of the variety S. Bartolomeu which were harvested at three different moments, and therefore correspond to three different ripening stages, were dried in a solar stove and the evolution of some properties was monitored along the drying process. From the results obtained was possible to conclude that the pears harvested in the two first dates show quite similar trends through drying, while the pears harvested at the last date reveal a clear distinct behavior, allowing to infer that the ripening stage at harvest plays an important role in the subsequent drying operation.
- Properties of pears harvested at different ripening stages.Publication . Guiné, Raquel; Lopes, Pedro; Barroca, Maria João; Ferreira, DulcieniaPears of the variety S. Bartolomeu have been used over the years in Portugal to produce a traditional dried pear known as “pera passa”. The processing comprehends a solar drying performed at open air, with obvious disadvantages, either concerning the drying efficiency or the sanitary quality of the final product, taking into account that the products are exposed to multiple contamination agents. For these reasons, attempts have been made to study alternative production methodologies, including the use of solar stoves, among others. In the present work pears of the variety S. Bartolomeu which were harvested at three different moments, and therefore correspond to three different ripening stages, were dried in a solar stove and the evolution of some properties was monitored along the drying process. From the results obtained was possible to conclude that the pears harvested in the two first dates show quite similar trends through drying, while the pears harvested at the last date reveal a clear distinct behavior, allowing to infer that the ripening stage at harvest plays an important role in the subsequent drying operation.
- Secagem de Pêras em Estufa Solar com Convecção ForçadaPublication . Guiné, Raquel; Lopes, Pedro; Barroca, Maria João; Ferreira Wessel, DulcineiaPara os ensaios relativos à colheita e secagem de pêra de São Bartolomeu no ano de 2007, foram colhidas pêras no pomar de Venda de Galizes, em 3 fases de maturação, considerando como segunda fase a data de colheita para produção de pêra secada de modo tradicional, de acordo com indicações do produtor de pêra passa em Venda de Galizes. As pêras correspondentes a cada lote de maturação foram secadas na estufa solar da Escola Superior Agrária de Viseu, a qual está equipada com um sistema de ventilação regulável. Durante os ensaios foram registadas as condições de temperatura e humidade relativa a intervalos de 10 minutos, e foram sendo feitas análises para verificar a evolução da humidade dos frutos ao longo do processo, e estimar as velocidades de secagem. No ano de 2008 as peras foram colhidas uma única vez, tendo esta colheita sido função da evolução do estado de maturação das pêras no pomar de Ervedal da Beira, já que, por falta de produção, não foi possível continuar a utilizar pêras do pomar de Venda de Galizes. O procedimento de secagem foi o mesmo que foi adoptado para o ano de 2007.
- Solar drying kinetics of pears harvested at different ripening stages.Publication . Guiné, Raquel; Lopes, Pedro; Barroca, Maria João; Ferreira, DulcineiaIn Portugal, pears of the variety S. Bartolomeu have been used to produce a traditional product named “pêra passa de Viseu”. These pears are dried at direct open air sun exposure, following a multi-step procedure. In the last years some investigation around this product and the production method has been carried out to better understand them and establish alternative production techniques. In the present work pears of the variety S. Bartolomeu, harvested at three different moments, corresponding to three ripening stages, were dried in a solar stove and their drying kinetics were studied. From the results obtained it was possible to conclude that all the six equations used to model the drying kinetics fit with accuracy the experimental data, and that the differences found in the three essays result mainly from the climatic conditions that occurred in each drying period.
- Using Artificial Intelligence to Prevent Drowsiness Based on Facial RecognitionPublication . Azevedo, Daniel; Guedes, Damiana; Santos, Gonçalo; Soares, Francisco; Lopes, PedroIn Portugal, in 2017, there were 34,416 accidents on the roads. It is estimated that the second major cause of accidents is driver fatigue. In this way, over the years, legislation has been created to mitigate the problem. In parallel with the European Union, the Fédération Internationale de l'Automobile (FIA) has encouraged the automotive industry to develop systems embedded in vehicles to increase their safety and mitigate this and other problems.This approach is intended to be an intermediate solution, as to be the in-between the security of a system embedded in a vehicle and the accessibility of a mobile system. In this way, the project aims to be as cheap, fast and applicable as possible. Using Face API technology provided by Microsoft, it is possible to have access to a set of features based on artificial intelligence, accomplishing tasks previously unthinkable, or very costly.