Percorrer por autor "Amaral, J.S."
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- Avaliação da atividade antimicrobiana de óleos essenciais de mentha sppPublication . Artilheiro, Ana Sofia; Amaral, J.S.A maioria das doenças de origem alimentar são causadas por microrganismos, incluindo bactérias, bolores, protozoários e vírus. Com vista a controlar o crescimento microbiano em alimentos, a indústria alimentar frequentemente recorre ao uso de aditivos, nomeadamente antimicrobianos cuja utilização está devidamente autorizada para esta finalidade. Contudo, recentemente tem-se verificado um interesse crescente na exploração de alternativas que permitam prevenir doenças de origem alimentar e promovam a extensão do prazo de validade dos alimentos. Entre estas, destacam-se os óleos essenciais por frequentemente exibirem propriedades antimicrobianas e/ou antifúngicas. Neste estudo foi testada a atividade antimicrobiana de óleos essenciais de plantas aromáticas utilizadas na alimentação humana, nomeadamente Mentha arvensis e Mentha piperita, sobre bactérias Gram-positivas (Bacillus cereus, Staphylococcus aureus) e Gram-negativas (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa). No caso de M. piperita avaliaram-se dois óleos essenciais, um obtido por hidrodestilação em aparelho de clevenger e outro comercial, enquanto para M. arvensis testou-se apenas um óleo comercial. De forma geral, os óleos essenciais revelaram forte capacidade inibitória contra as bactérias gram-positivas e gram-negativas estudadas, à exceção de Pseudomonas aeruginosa que mostrou ser resistente a todos os óleos testados. Comparativamente ao antibiótico utilizado como controlo positivo, penicilina ou canamicina, em alguns casos foram obtidos halos de inibição superiores para os óleos essenciais. Das duas espécies de menta avaliadas, o óleo de M. piperita foi o mais eficaz, apresentando resultados similares para o óleo comercial e o extraído em laboratório.
- Avaliação da autenticidade de Alheiras de caça por identificação específica de espéciesPublication . Amaral, J.S.; Mafra, Isabel; Oliveira, BeatrizA produção de diferentes enchidos tradicionais é uma práti-ca enraizada em várias regiões do país, em particular no Nordeste Transmontano onde é produzido um produto mui-to apreciados por diversos consumidores, nomeadamente a alheira. A alheira é um produto cárneo tradicional, fumado e fermentado, cuja origem remonta ao final do século XV e se relaciona com a presença de comunidades Judaicas nesta região. Naquela data, sendo frequente o consumo de enchi-dos pela população Cristã e sendo o porco uma espécie não consumida pelos Judeus, para evitar serem facilmente iden-tificados pela Inquisição pelos seus diferentes hábitos ali-mentares, estes começaram a produzir um enchido com forma similar à da cozinha Cristã, mas usando carne de aves em vez de porco. A receita foi, eventualmente, passando através de gerações e tornou-se popular também entre os Cristãos, sendo atualmente produzida com base numa mis-tura de carne e gordura de porco, carne de aves, pão de trigo, azeite, alho, sal e especiarias [1]. Dado o seu sucesso, nos últimos anos, têm surgido novas versões deste tipo de enchido, entra as quais se destacam as alheiras de caça. Estas distinguem-se das suas congéneres tradicionais pelo facto de incluírem na sua composição carne de caça, a qual pode ser adicionada total ou parcialmente em relação à car-ne utilizada na sua confeção.
- Avelã: composição química e efeitos benéficos associados ao seu consumoPublication . Amaral, J.S.; Oliveira, BeatrizAmong the different nuts grown worldwide, hazelnut (Corylus avellana L.) is considered one of the most popular and consumed. Hazelnut is mainly used by the food industry in chocolates, cakes and desserts, with only a small part of the world’s produc"on being consumed as table hazelnut. Hazelnut is considered to be a highly nutri"ous food, providing macronutrients (fat, protein and carbohydrates), micronutrients (vitamins and minerals) and several bioac"ve phytochemicals, including phenolic acids, flavonoids, tannins and phytosterols, among others. Despite presen"ng a high content in fat, hazelnut lipids mainly include monounsaturated fa$y acids (MUFA), which have been associated with beneficial health effects, par"cularly regarding the cardiovascular system. Moreover, different interes"ng proper"es, such as an"oxidant, an"-inflammatory, an"-prolifera"ve and hipocholesterolemic ac"vi"es have been ascribed to several micronutrients and phytochemicals present in hazelnuts. To date, some studies have shown that the consump"on of hazelnuts can have a beneficial effect on health, namely by reducing the risk of cardiovascular diseases. Therefore, its inclusion has been recommended as part of a healthy-diet.
- Cereal bars functionalised with tempeh: nutritional composition, isoflavone content and consumer acceptancePublication . Melo, Priscila F. de; Kalschne, Daneysa Lahis; Silva-Buzanello, Rosana; Amaral, J.S.; Torquato, Alex S.; Corso, Marinês Paula; Falcão, Heloisa G.; Colla, Eliane; Ida, Elza I.; Canan, CristianeThe aim of this study was to produce cereal bars (CB) added with tempeh flour (TF) and evaluate the nutritional composition, fatty acids profile, isoflavone content and sensory acceptance. Tempeh was produced from organic soya beans cotyledons fermented by Rhizophus oligosporus followed by freeze-drying and milling in order to obtain the TF. The addition of 10%, 15% and 20% TF to CB resulted in both protein and lipid content increase and a higher polyunsaturated/saturated fatty acids ratio. The content of isoflavone aglycones, the forms considered to have higher biological activity, was higher in TF than in soya bean, which was also reflected in the CB chemical composition. An acceptance test showed that CB added with TF (up to 15%) were sensory accepted. Overall results suggest that the addition of TF as an ingredient in cereal bars allows improving the chemical and functional characteristics of this type of ready-to-eat foods.
- Classification PDO olive oils on the basis of their sterol composition by multivariate analysisPublication . Alves, M. Rui; Cunha, Sara C.; Amaral, J.S.; Pereira, J.A.; Oliveira, BeatrizThe sterol compositions (GLC/FID/capillary column) of monovarietal olive oils (51 samples) from the most important cultivars of northeastern Portugal (Cvs. Cobranc¸osa, Madural and Verdeal Transmontana) and 27 commercial samples of olive oils with protected denomination of origin (PDO) from the same region and cultivars were evaluated. Δ-sitosterol, Δ5-avenasterol and campesterol were the most representative sterols. Cholesterol, stigmasterol, clerosterol and Δ7-stigmastenol were also found in all samples. All studied samples respected EC Regulation N. 2568, and in all cases total sterols were remarkably higher than the minimum limit set by legislation, ranging from 2003 to 2682 mg/kg. Results were analysed with the help of several statistical techniques, including reduction of dimensionality by principal component analysis with cross-validation of the number of components, followed by the use of canonical variate predictive biplots for model development and canonical variate interpolative biplots for approximate classification of monovarietal and PDO olive oils. These biplots proved to be a very interesting solution in the present case study, overcoming the problems of interpretation and classification that arise whenever different multivariate analyses are coupled together.
- A neural network based fall detectorPublication . Rodrigues, Pedro João; Amaral, J.S.; Igrejas, GetúlioIn this project we present an intelligent fall detector system based on a 3-axis accelerometer and a neural network model that allows recognizing severaI possible motion situations and performing an emergency call only when a fall situation occurs, with low false negatives rate and low false positives rate. The system is based on a two module platform. The first one is a Mobile station (MS) and should be carried always by the person. An accelerometer is implemented in this module and its information is transferred via a radio-frequency channel (RF) to the Base station (BS). The BS is fixed and is connected to a GSM (Global system for Mobile communication) module. A neural network model was built in to the BS and is able to identify falls from other possible motion situations, based on the received information. According to the neural network response the system sends a SMs (short Message service) to a destination number requesting for assistance.
- A neural network based fall detectorPublication . Rodrigues, Pedro João; Amaral, J.S.; Igrejas, GetúlioIn this project we present an intelligent fall detector system based on a 3-axis accelerometer and a neural network model that allows recognizing several possible motion situations and performing an emergency call only when a fall situation occurs, with low false negatives rate and low false positives rate. The system is based on a two module platform. The first one is a Mobile Station (MS) and should be carried always by the person. An accelerometer is implemented in this module and its information is transferred via a radio-frequency channel (RF) to the Base Station (BS). The BS is fixed and is connected to a GSM (Global System for Mobile communication) module. A neural network model was built into the BS and is able to identify falls from other possible motion situations, based on the received information. According to the neural network response the system sends a SMS (Short Message Service) to a destination number requesting for assistance.
- Nutritional composition and bioactivity of Umbilicus rupestris (Salisb.)Dandy: An underexploited edible wild plantPublication . Iyda, Júlia Harumi; Fernandes, Ângela; Calhelha, Ricardo C.; Alves, Maria José; Ferreira, Flávio Dias; Barros, Lillian; Amaral, J.S.; Ferreira, Isabel C.F.R.The inclusion of edible wild plants in human diet has been receiving an increasing attention, as they represent an easily accessible source of nutrients, vitamins and antioxidants. In this work, the leaves of Umbelicus rupestris (Salisb.) Dandy, an edible species for which only scarce data is available in literature, were thoroughly evaluated for its nutritional profile, chemical characterization and bioactive properties. Being considered a succulent plant, the leaves revealed a very high content of moisture, with several beneficial compounds, including omega-3 polyunsaturated fatty acids, tocopherols and different polyphenols. A total of twelve flavonoids, three phenolic acids and one phenylpropanoid glucoside were identified in the decoction and/or hydroethanolic extracts, with most of them being described for the first time in this plant. Both extracts showed antioxidant activity and potential to inhibit some of the assayed bacteria, while not presenting cytotoxic effects on a non-tumour primary cell culture.