ESAV - DIA - Artigo em revista científica, não indexada ao WoS/Scopus
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- Adaptation and validation to Portuguese of the Reasons for Higher Education Dropout ScalePublication . Ferreira, Manuela; Duarte, João; Abrantes, J.L.; Cabral, Lídia Rosário; Guiné, Raquel; Campos, Sofia Margarida; Cardoso, Ana PaulaEnquadramento: O abandono escolar é um problema com que os sistemas educacionais se debatem, colocando em causa a qualidade da instituição escolar e do próprio sistema de ensino. Objetivos: Adaptar e avaliar as qualidades psicométricas da Escala de Motivos de Intenção de Abandono do Ensino Superior para os estudantes do ensino superior português. Metodologia: Estudo quantitativo, transversal, descritivo e correlacional. Foi aplicado um questionário de caracterização sociodemográfica e a Escala de Motivos de Intenção de Abandono do Ensino Superior a uma amostra de 891 estudantes, maioritariamente feminina (68,2%), com uma idade média de 19,68 anos. Recorreu-se à análise fatorial exploratória e confirmatória. Resultados: A escala composta por 30 itens, organizados em 4 dimensões: Organizacional; Gestão de vida; Profissional e Relacional. Apresenta uma variância explicada de 46,5%, e um alfa de Cronbach de 0,959. Conclusão: Os resultados apoiam a adequação psicométrica da escala para a população portuguesa, indicando que poderá ser utilizada em ensaios futuros neste âmbito e permitir a implementação de medidas que o contrariem.
- Adsorption isotherms of maria biscuits from different brandsPublication . Guiné, Raquel; Barroca, Maria João; Pereira, Daniela; Correia, PaulaThis study aimed to determine the adsorption curves of Maria biscuits from dif- ferent brands at temperatures of 25 and 40C. The equilibrium between the sample and the atmosphere was achieved by placing the samples inside flasks containing saturated salts, at the temperatures studied for 5 days, to allow reaching equilibrium.From the results, it was possible to observe that by increasing the tem- perature, the stability of the product is augmented, as for the same moisture content the water activity is greatly reduced. Four sorption models were fitted with the adsorption data, but the Guggenheim–Anderson–deBoer and Henderson were better than the other models tested. In addition, the monolayer moisture content at temperature of 25C ranged between 0.0495 and 0.1981 g water/g dry basis, and at the temperature of 40C this parameter varied between 0.0529 and 0.1960 g water/g dry basis.
- Amido resistente em diversas fontes não convencionais de amidoPublication . Fontinha, C.; Correia, PaulaAmido resistente (AR) é aquele que não é digerido no intestino delgado, conduzindo a efeitos benéficos para a saúde, tal como a fibra dietética faz. Procedeu-se à determinação do AR em farinhas e amidos extraídos de duas variedades de castanha (Castanea sativa Mill), Longal e Martainha, da bolota de azinheira (Quercus rotundifolia) e da glande do sobreiro (Quercus suber). As farinhas foram obtidas por moenda dos frutos após secagem a diferentes temperaturas, 40º C, 50º C, 60ºC e 70ºC. Posteriormente, procedeu-se ao isolamento dos amidos das farinhas, através da aplicação de dois métodos de extracção: um físico-químico e outro enzimático. Verificou-se que os teores de AR mais elevados foram os apresentados pelas farinhas dos frutos secos a 60ºC, sendo de 46,8%, 36,5%, 39,9% e 43,9%, respectivamente para as castanhas das variedades Longal e Martainha, para a bolota e para a glande. O método de extracção que apresentou valores mais elevados de AR para os amidos extraídos dos diferentes materiais foi o método físico-químico. Tudo indica que a secagem dos frutos a 60ºC e a aplicação do método de extracção do amido pelo processo físico-químico nas farinhas dos frutos secos a esta temperatura são aqueles que melhor preservam a estrutura dos amidos.
- Amino acid profile and Maillard compounds of sun-dried pears. Relation with the reddish brown colour of the dried fruitsPublication . Coimbra, Manuel; Nunes, Cláudia; Cunha, Pedro; Guiné, RaquelThe sun-dried pear of S. Bartolomeu (Pyrus communis L. var. S. Bartolomeu) is a traditional sweet food product of unique elastic properties and reddish brown colour. Alternative drying methodologies to replace the traditional open air sun-drying procedure are under devel- opment, namely the use of greenhouses with and without air convection and a hot air tunnel. To test whether the Maillard reactions can contribute to the colour of this tra- ditional product, the profiles of free and bound amino acids constituents of the pulp of fresh pears as well as pears processed according to different drying methodologies were evaluated. Also, the occurrence of furosine, car- boxymethyllysine (CML) and carboxyethyllysine (CEL), indicative of Maillard reaction, was diagnosed and quan- tified. The drying of the pears affects the free amino acid profile, increasing proline content and decreasing aspartic and glutamic acids. Although the proteic amino acid profile was not significantly modified with the drying process, a loss of the relative content of Lys was observed. This loss was related with the increase in the amount of furosine, CML and CEL formed during the drying of the fruits. Although all drying methods tested promoted the increase in the amount of CML, CEL and furosine, this increase was higher in the case of the traditional sun-drying and green- house processing, where the fruits presented reddish brown colour, and lower for the hot air tunnel processing, where the fruits became less intense. These results allow affirming that the drying process promotes the occurrence of Mail- lard reaction, contributing to the characteristic reddish brown colour of the final product.
- An insight of Romanians’ knowledge about dietary fibers in relationship with cancerPublication . Tarcea, Monica; Fazakas, Zita; Ruta, Florina; Rus, Victoria; Salcudean, M.; Nemes, L.; Serban, Costela; Guiné, RaquelObjectives: To estimate the relationship between socio-demographic characteristics of Romanian population, and their knowledge towards dietary fiber intake, the information sources preferred and perception of cancer related health risks. Methods: We used a convenient cross-sectional survey, and the data were collected using a validated questionnaire, disseminated online. Six different Romanian counties with 57 cities were selected in 2015, with 670 participants, and we used the SPSS program 22.0 for statistical purpose. Results: The knowledge about dietary fibers intake was low in our sample, also was the ingestion of foods rich in fiber (fruits, vegetables and cereals). Compared to men, women agree significantly more frequent that fibers in appropriate amounts can prevent or treat diseases (U=44607, z=-4.66, p<0.001, r=0.18) and separately related to specific diseases, that fibers can prevent and/or treat cardio-vascular diseases, cholesterol, bowel cancer, breast cancer, constipation, and diabetes, but with no differences regarding the deficiency of vitamins and minerals (p=0.774) or obesity (p=0.399). The in-depth analysis of factors that are able to influence Romanian’s knowledge and attitudes towards food fibers, defined the social profile of the respondents with interest on dietary fiber intake, which is: young females, with at least high school education, that considers internet and television like main sources of information regarding fibers. Comparing to other EU countries, Romanian consumers have good information about dietary fibers importance for health but the daily intake is lower. Conclusions: Based on our results, we can elaborate efficient community and school intervention programs, more focused on modern information technology and communication skills, fit to the consumer’s profile in order to promote a healthy nutrition behavior and proper knowledge.
- Análise das características químicas e físicas de pêras secadasPublication . Guiné, RaquelCom o presente trabalho pretendeu-se estudar a possibilidade de utilizar uma variedade de pêras diferente da tradicionalmente usada para a produção de “pêra passa de Viseu”, e ainda avaliar a possibilidade de simplificação do método tradicional de produção por secagem solar, com vista à sua aplicação industrial. Assim, foram estudadas pêras de diferentes variedades (S. Bartolomeu e D. Joaquina) secadas sob diferentes condições de secagem (secagem solar e secagem contínua a temperaturas constantes de 30, 40 e 50ºC), tendo os produtos finais sido comparados através da avaliação das suas propriedades químicas e físicas. Foi então possível concluir que a variedade D. Joaquina constitui uma boa alternativa à variedade tradicionalmente secada, e que o processo artesanal de secagem pode ser significativamente simplificado sem que isso comprometa as características finais do produto.
- Análise SWOT à produção da pêra passa de ViseuPublication . Guiné, Raquel; Peres, Gabriela; Ferreira, DulcineiaO presente trabalho consistiu na realização de inquéritos, junto dos operadores da pêra de São Bartolomeu e respectivo fruto secado, que são a Cooperativa Agrícola de Fruticultores da Beira Alta CRL e a Cooperativa Agrícola de Mangualde CRL, no sentido de conhecer as características de produção e comercialização deste produto regional. Foi ainda realizada uma análise SWOT, ou seja, uma análise dos pontos fortes, pontos fracos, oportunidades e ameaças, com vista ao estabelecimento de um plano de acção.
- Analysis of drying kinetics of eggplant through thin layer models and evaluation of texture and colour propertiesPublication . Ferrão, Ana Cristina; Guiné, Raquel; Correia, Telma; Rodrigues, RosaEggplant is a food with unique characteristics. However, due to its high moisture content it is very perishable. Thus, to increase its shelf life it can be applied the drying process. This work aimed at studying the effects of drying on eggplant, namely on the physical properties of colour and texture, as well as the analysis of drying kinetics by thin layer models. The drying was carried out using a convection chamber with a temperature of 80ºC and an air velocity of 0.5 m/s. The texture profile analysis was done with a texturometer equipped with a 75 mm probe and the colour measurement was performed with a calorimeter in the CIELab coordinates. For both texture and colour, all analysis were done in triplicate, before and after drying. The results showed that there were clear differences in colour, with the difference being higher in the case of the dried sample (E = 25.95) when compared to the fresh sample analysed 10 minutes after the cut (E = 9.69).Regarding the texture, drying caused alterations in the eggplant structure, with an increase in elasticity and chewiness and a decrease in hardness, resilience and cohesiveness. As for the kinetics, the sample took 2.5 hours to reach a moisture content of approximately 10%. Four thin layer models were tested, being the Wang & Singh model the one that proved to be the most suitable to fit the experimental data, with a correlation coefficient equal to 0.9902.
- Analysis of moisture content and density of pears during drying.Publication . Guiné, Raquel; Castro, JoséSolar dried pears of the “S. Bartolomeu” variety are a very much appreciated and preferred dried food product in Portugal. Nevertheless, the traditional solar drying is carried out at open air during the months of July and August, and this nowadays is a disadvantage for larger productions. This work is to evaluate the possibility of producing dried pears from this and other varieties, maintaining the characteristics of the traditional dried pears. In this study four different types of pears were studied, including “S. Bartolomeu” as a basis for comparison and the drying method employed was the traditional one. From the results it was concluded that, although the behaviour of the four varieties do not vary significantly, one particular variety (“D. Joaquina”) is a good alternative to the “S. Bartolomeu” pear.
- Analysis of the drying kinetics of chestnuts.Publication . Guiné, Raquel; Fernandes, RaquelChestnuts are widely produced in Portugal and have an unquestionable economic interest, allowing a multiplicity of potential industrial applications, either in their natural form or after dehydration. In this work the experimental dehydration behaviour of three different varieties of chestnuts (Castanea Sativa) was investigated, and the experiments were carried out under isothermal conditions, using ventilated driers at 70, 80 and 90 ºC. The experimental data obtained for the variations of water content along the drying time was fit to a two-term exponential model with success. The experimental drying rate points were calculated by approximating the derivatives to finite differences, and the drying rate versus moisture content and time curves were fit respectively to a sigmoid function and a first order kinetics, with relatively good results. Moreover, it was possible to conclude that the varieties Longal and Martainha show better drying features than the variety Viana, and thus seem to be more suitable for industrial purposes. The influence of temperature on the drying rates was evidenced, with higher drying temperatures corresponding to faster processes, which represents an advantage when evaluating production costs. Finally, the experimental data was used to predict effective diffusivity according to Fick’s second law equation, assuming that the variation of diffusivity with temperature could be expressed by an Arrhenius type function, and the values of diffusivity obtained ranged from 4.45e-9 to 7.65e-9 m2/s, respectively for chestnuts of the variety Longal at 70 ºC and Viana at 90 ºC.