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Item Acesso Aberto Inactivation of Candida albicans in water using advanced oxidation processes2023-10-26 - Gomes, Ana; Sampaio, Ana C.; Silva, Sara; Fernandes, José R.; Peres, José A.; Lucas, Marco S.Pathogenic microorganisms such as bacteria, viruses, fungi and protozoa have played a central role in the safety of drinking water, since they spread easily in the water network, constituting a health risk for humans and animals. Currently in water treatments, advanced oxidative processes (AOPs) have been increasing in importance in the microbiological disinfection of water. The present study aimed to inactivate C. albicans, a commensal yeast species in Vertebrates that can cause disease, using AOPs. To achieve this objective, a powerful oxidant (hydrogen peroxide) was combined with UV radiation to promote the inactivation of C. albicans. Initially, the inactivation capacity of the H2O2 was assessed and it was verified that the application of 2.5 mM, 5 mM and 10 mM H2O2 reached a cell reduction of 3 log after 180, 360 and 300 min, respectively. Subsequently, the combination with UV-A radiation (λ = 365 nm) proved to be even more promising, as the H2O2 + UV-A system, using the same H2O2 concentrations, reached an inactivation of 3 log after 240, 180 and 60 min, respectively. These results support that UV-A radiation promotes the generation of hydroxyl radicals, which have a comparatively higher oxidation potential (2.8 eV) to the H2O2 (1.8 eV), responsible for the inactivation of C. albicans cells. Thus, the UV-A/H2O2 process can reduce this microorganism in an aqueous matrix, avoiding potential hazards to human and animal health.Item Acesso Aberto PHENOLIC AND SENSORY PROFILE OF BLACKBERRIES (Rubus L.) PRODUCED BY CONVENTIONAL AND ORGANIC AGRICULTURAL PRACTICES2018-06-05 - Pinto T; Vilela A; Pinto A; Nunes FM; Cosme F; Anjos RBlackberries are a rich source of polyphenols with high antioxidant activity; nevertheless, the impact of organic versus conventional agricultural practices on the phenolic and sensory profile is unknown. Therefore, the aim of this study was to compare the accumulation pattern of polyphenols (total phenolic compounds and total anthocyanins), soluble solids, antioxidant activity as well the sensory profile of two blackberries varieties "Loch Ness" and "Chester Thornless" grown under organic and conventional agricultural practices, at the same edaphoclimatic conditions. Both blackberry varieties, agricultural practices as well as their interaction, had a significant effect on the amount of soluble solids. For the total phenolic content, there was only a significant difference between the varieties, with no significant differences between the agricultural practices. Concerning to the total anthocyanins, it was observed a significant interaction between the varieties and agricultural practices. The antioxidant activity of the blackberries followed the same trend as that observed for the total phenolic compounds. Significant differences were only observed between varieties, with the “Loch Ness” variety showing the higher antioxidant activity and “Chester Thornless” variety showing the lowest antioxidant activity regardless the agricultural practice used. Results show that the effect of the agricultural practice on the chemical and sensory profile of blackberries was dependent on the genetic background of the variety and cannot be generalized.Item Acesso Aberto Categorical Principal Component Analysis (CATPCA): a statistical method for sensory data treatment applied to the sensory profile of Port wines2017-05-29 - Vilela, Alice; Monteiro, Bebiana; Correia, ElisetePort wine is a fortified wine. After the grape spirit addition the fermentation stops and the wine retains some of the natural sweetness of the grape. Port wine exhibits a variety of different styles, each with its own characteristic flavors. Ruby, Reserve Ports and Late Bottled Vintage Ports (LBV), Tawny Ports and White Ports. Information about the wines sensory characteristics is critical for the successful development and marketing of each new wine brand once brand management in today’s business world is extremely related to the organizations purpose and improvement of their strategies. The two main purposes of this study were to describe a specific sensory method, used by a trained sensory panel including chemical compounds reference development, to establish the most important descriptive and discriminative sensory attributes of different Port wine styles and brands and to compare the results of PCA with the results of CATPCA, in order to assess the feasibility of both techniques.Item Acesso Aberto Reserve Ruby Port wine: alternatives to gelatine protein fining agents2017-05-29 - Cosme, Fernanda; Jorge, Nuno; Vilela, Alice; M. Nunes, FernandoAnimal protein fining agents are traditionally used in the wine industry. However, in recent years some allergic problems of these protein fining agents have promoted to search for allergen free alternatives. A possible alternative to animal proteins are plant proteins, in particular, pea protein. Therefore, the aim of this study was to compare the effect of gelatine of animal origin (porcine gelatine and fish skin gelatine) with non-allergenic fining agents (association of PVPP, plant protein and silica; pea protein; association of PVPP, calcium bentonite and inert yeast; inert yeast and activated sodium bentonite) on a Reserve Ruby Port Wine chromatic characteristics, phenolic compounds and sensory attributes, at laboratory scale. Colour intensity, hue, coloured anthocyanins and polymeric pigments showed a significant decrease in all fined wines when compared to the unfined wine. The highest decrease in colour intensity, total anthocyanins and polymeric pigments occurred in wines treated with porcine gelatine. The lowest decrease in colour intensity was observed in wines treated with inert yeast, association of PVPP, calcium bentonite and inert yeast and activated sodium bentonite. The most balanced wine and that with the best results on colour intensity was the one treated with association of PVPP, calcium bentonite and inert yeast.Item Acesso Aberto STUDY OF CHEMICAL AND SENSORY PROPERTIES OF LOUREIRO MONOVARIETAL WINES FROM PORTUGUESE VINHO VERDE REGION – A CHEMOMETRIC APPROACH2016-10-23 - Vilela, Alice; Lopes, Cátia; Marques, Catarina; M. Nunes, Fernando; Correia, Elisete; Cosme, FernandaMonovarietal white wines produced in the Demarcated Vinho Verde Region are distinguished by their characteristic flavor and color, revealing the variety that gave rise to them. Thus, the aim of this study was to characterize the chemical composition, namely phenolic composition of Loureiro monovarietal wines, from different Vinho Verde sub-regions (Sousa, Lima, Cávado and Melgaço) of 2014 vintage. It was also performed a Categorical Principal Components Analysis (CATPCA) correlating these data with the sensory profile of the different wines analyzed. A non-parametric MANOVA was used to statistically analyze the results, for there was no assumptions of normality and homogeneity of variance-covariance matrices. To identify significant differences between samples, it was performed the Kruskal-Wallis test, followed by the multiple comparison of means of orders (SPSS software Statistics, version 22.0) considering a probability of error type I () of 0.05. In the monovarietal Loureiro wines, significant differences in relation to the physico-chemical parameters: dry extract, reducing sugars and glucose/fructose ratio were found. Regarding the dry extract, the QLI, QDM and QCL wines present a significantly higher level (25.5 to 23.9 g/L), also being these wines those with a significant content of reducing sugars, 8.71 to 6.51 g/L. Concerning the chemical parameters related to color and phenolic composition, the color ranged from 0.070 - 0.084 u.a., total phenolics from 277 - 371 mg gallic acid/L, flavonoids between 143-201 mg gallic acid/L and non-flavonoids between 132-169 mg gallic acid/L. There were only significant differences in the content of phenolic acids (gallic acid and coutaric acid isomer) and catechin. The sensory profile of the seven Loureiro wines is quite similar, however, one wine –QPLL- shows a lower score in the attributes related to the nasal perception (aroma), ortho-nasal perception (flavor) and mouthfeel. When we correlate these data with the chemical data, the CATPCA clearly shows the detachment of QPLL wine from the other wines. Being this the only wine of Lima Vinho Verde Sub-Region, these differences probably occur due to the different terroir.Item Acesso Restrito A LEXICON FOR DESCRIBING THE ORAL, NASAL AND ORTHO-NASAL SENSATIONS ELICITED BY PORTUGUESE MONOVARIETAL LOUREIRO WINES2016-10-23 - Marques, Catarina; Correia, Elisete; Vilela, AliceThe diversity of wines of the Demarcated Region of Vinho Verde, Portugal, can be explained by different soil and climate characteristics and the diversity of grape varieties. Among these, the varietal wines are particularly appreciated by consumers because it allows them to identify the characteristics of the respective grape-varieties. Among the set of recommended varieties for Vinho Verde production, there are varieties like Loureiro, with unique aromatic characteristics. Through sensory analysis, we can study the aromatic potential of this variety. This tool has been applied in many food and drinking companies, given its potential in consumers and markets preferences, resulting in the product improvement quality. Thus, this study aimed to select and train a group of people, potential panelists, for Vinho Verde wine tasting in Aveleda S.A. Company, able to trace the sensory profile of Loureiro monovarietal wines. The recruitment of candidates involved sending a questionnaire with questions of interest to the study. After recruitment, training sessions were developed to make it possible to select the candidates, able to belong to a panel of tasters. These sessions were based on a first contact of candidates with solutions and products that would be tasted in a later stage of the study. Some standard sensory analysis tests were used: identification, threshold, ranking and triangular tests. At the end of the training sessions, of the 36 candidates recruited, only 11 (9 men and 2 women) were selected, making now part of the Aveleda S.A. Company's tasting Panel. In order to develop a sensory lexicon for the monovarietal Loureiro wines, the panelists selected some descriptors, with samples of wines from different producers. Tasters were asked to freely describe the sensations that the sample had awakened, according to certain organoleptic parameters. The descriptors were presented and discussed to the panel, so that would be consensual. For the chosen descriptors, references were developed using chemical compounds, natural compounds and, even, some wines. Seven Loureiro monovarietel wines of the Vinho Verde Region were used to develop the sensory lexicon. Nonparametric Multivariate Analysis of Variance (Nonparametric MANOVA), Kruskal–Wallis test, Fisher´s least significant difference (LSD) to compare average orders and CATPCA (Categorical Principal Components Analysis were applied to the results. The choice of a nonparametric test was due to the nature of data (ordinal data) and the number of observations. Moreover, the assumptions of parametric tests are not met on the sample data. Therefore, parametric tests may not be the most appropriate method of analysis because in such cases the statistics may not be a good estimate of the parameter. Regarding Loureiro wines flavor lexicon, the descriptors that best define the sensory profile of this variety are: bitter taste, clean, acid taste, softness; tropical fruits, vegetable, Loureiro, floral, citrus, apple and mineral aromas; sweet taste; sense of persistence, full-bodied and balanced; vegetable, citrus and tropical fruits flavor notes. In relation to the aroma descriptors citrus, apple aroma, mineral aroma and sweet taste, were found to have significant differences between the wines.Item Acesso Aberto Caraterização Sensorial E Fenólica De Vinhos Tintos Monovarietais Produzidos Com Castas Tintas Cultivadas Na Região Demarcada Do Douro2016-05-06 - Vilela, Alice; Liquito, Ângela; Cosme, FernandaAs castas Touriga Nacional, Touriga Franca, Sousão, Pinot Noir e Cabernet Sauvignon são castas importantes cultivadas na Região Demarcada do Douro e características dos vinhos produzidos nessa região. Este trabalho pretende contribuir para uma melhor caracterização sensorial e fenólica dos vinhos monovarietais obtidos dessas cinco castas, recorrendo a descritores e técnicas analíticas apropriadas. Para tal, procedeu-se ao treino de um painel de provadores, com soluções padrão de aromas extraídos de produtos naturais e testes de ordenação dos sabores elementares. O perfil sensorial de cada vinho foi obtido através de uma análise descritiva quantitativa. Dos resultados obtidos na Análise de Clusters e Análise em Componentes Principais, foi possível observar a formação de grupos que distinguem os vinhos monovarietais entre si. Para a formação destes grupos contribuíram o descritor pimento verde, característico dos vinhos monovarietais da casta Cabernet Sauvignon e os descritores aroma floral e aroma frutado característicos dos vinhos monovarietais da casta Touriga Nacional. O vinho da casta Touriga Franca é caracterizado pela sua intensidade aromática enquanto, o vinho da casta Sousão se distingue por apresentar uma cor mais intensa.Item Acesso Aberto Análise Em Componentes Principais Categórica Aplicada Ao Perfil Sensorial De Vinhos Do Porto2016-05-06 - VILELA, Alice; MONTEIRO, Bebiana; CORREIA, EliseteHá muitos anos que a análise estatística multivariada é utilizada para tratamentos de dados sensoriais, nomeadamente a Análise em Componentes Principais (PCA). Trabalhos em vinhos, de diferentes categorias e estilos, têm sido publicados, onde esta técnica é aplicada. No entanto, uma vez que as variáveis escolhidas, por análise descritiva quantitativa, são medidas numa escala ordinal e a dimensão da amostra é reduzida a técnica mais adequada é a Análise em Componentes Principais Categórica (CATPCA). Assim, os principais objetivos deste estudo foram: aplicar um método sensorial específico, usada por um painel de provadores treinado, descrevendo os atributos sensoriais mais importantes para os diferentes estilos e marcas de Vinho do Porto e, comparar os resultados da PCA com os resultados da CATPCA, com o intuito de avaliar a viabilidade de ambas as técnicas. No final do trabalho demonstramos que a análise dos dados CATPCA parece ser mais robusta e explica mais de 15% da variação inicial do que a análise PCA.Item Acesso Aberto Perfil Sensorial e Fenólico De Vinhos Brancos Monovarietais Produzidos Com Castas Brancas Cultivadas Na Região Demarcada Do Douro2016-10-11 - VILELA, Alice; MARTINS, Sílvia; COSME, FernandaOs vinhos monovarietais brancos são particularmente apreciados pelos consumidores, porque lhes permite identificar as características das respetivas castas. Assim, este trabalho teve como objetivo estudar o perfil sensorial e fenólico de nove vinhos brancos monovarietais produzidos com castas brancas cultivadas na Região Demarcada do Douro (Viognier, Viosinho, Touriga Branca, Gewürztraminner, Sauvignon Blanc, Encruzado, Chardonnay, Alvarinho e Verdelho). A avaliação sensorial foi efetuada por um painel de provadores, devidamente treinado, de modo a obter o perfil sensorial de cada vinho através de uma análise descritiva quantitativa. Neste sentido, o vinho que mais se destacou, em quase todos os descritores sensoriais avaliados, foi o vinho monovarietal da casta Gewürztraminner, nomeadamente nos descritores aroma e flavor a frutos tropicais, seguido dos vinhos monovarietais da casta Alvarinho e Encruzado que se destacaram pela cor. O vinho monovarietal da casta Encruzado ainda se destacou pelo aroma herbáceo e sabor amargo. A casta Verdelho apresentou maior teor em compostos fenólicos, ao contrário da casta Gewürztraminner, que apresentou o teor mais baixo.Item Acesso Aberto Estabilização tartárica de um vinho do Porto Ruby Reserva por electrodiálise: Processo alternativo à estabilização tartárica pelo frio2016-10-11 - JORGE, Nuno; VILELA, Alice; BRAGA, António; M. NUNES, Fernando; COSME, FernandaA estabilização tartárica pelo frio é a operação unitária mais frequente em enologia para estabilizar tartaricamente os vinhos. No entanto, esta é uma operação lenta e dispendiosa. A electrodiálise é um processo que pode também estabilizar o vinho quanto à instabilidade tartárica. Assim, o objectivo deste trabalho foi comparar o método de estabilização tartárica pelo frio com o método de electrod iálise, num Vinho do Porto Ruby reserva, quanto à eficiência da estabilização, composição fenólica e características sensoriais. Os resultados mostraram que os vinhos tratados pelo método de estabilização tartárica pelo frio tiveram uma diminuição significativa na intensidade da cor, antocianinas totais, pigmentos poliméricos e totais, compostos fenólicos totais e flavonóides. A análise sensorial mostrou que os vinhos tratados pelo método de electrodiálises foram mais pontuados nos descritores da limpidez, da intensidade da cor, persistência, equilíbrio, intensidade de sabor, qualidade aromática e intensidade. Este estudo fornece informação que poderá ser usado para seleccionar um método alternativo à estabilização tartárica pelo frio.Item Acesso Restrito Assessment and Description of Magnesium Deficiencies in Chestnut Groves2003 - Portela, Ester; Roboredo, Marta; Louzada, José