Browsing by Author "Dias, Teresa"
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- An assessment of the processing and physicochemical factors contributing to the microbial contamination of salpicão, a naturally-fermented Portuguese sausagePublication . Cadavez, Vasco; Gonzales-Barron, Ursula; Pires, P.; Fernandes, E.; Pereira, Ana Paula; Gomes, Aline; Araújo, José Pedro; Lopes-da-Silva, M.F.; Rodrigues, Paula; Fernandes, Conceição; Saavedra, Maria José; Butler, Francis; Dias, TeresaComplete microbiological, physicochemical and environmental longitudinal data were obtained from factory surveys in order to elucidate risk factors leading to the survival of Enterobacteriaceae, Staphylococcus aureus and Listeria monocytogenes in salpicão sausage. A total of six batches were surveyed from two factories; one added nitrite and polyphosphates in their formulation (Factory II). The addition of polyphosphates slowed down fermentation, which favoured the increase in Enterobacteriaceae (∼0.5 log CFU/g), S. aureus (∼0.5 log CFU/g) and L. monocytogenes (∼70 CFU/g) until maceration. Maceration should be regarded as a critical stage in the control of S. aureus in salpicão, as longer maceration (p = 0.033), higher temperatures of maceration (p = 0.018) and pH of macerated meat (p = 0.079) led to higher S. aureus counts in the final product. The main hurdle controlling S. aureus in salpicão is the pH. For L. monocytogenes and Enterobacteriaceae, at least three hurdles hinder their viability: low Aw (p = 0.010; 0.012), smoking (p < 0.0001; 0.020) and nitrite (p = 0.158; 0.105). Cross-contamination, especially during mixing, should be avoided as it is an important factor explaining the increase in Enterobacteriaceae (p = 0.041), S. aureus (p = 0.015) and L. monocytogenes (p = 0.082) on a batch basis. There is a need to optimise the acidification process and reinforce good hygiene practices
- Análise sensorial de vários tipos de hidromelPublication . Gomes, Teresa; Dias, Teresa; Andrade, João Verdial; Cadavez, Vasco; Morais, Jorge Sá; Ramalhosa, Elsa; Estevinho, Leticia M.A região de Trás-os-Montes e uma das grandes produtoras de mel no pais. No entanto, existe dificuldade em escoar a produção surgindo o hidromel como uma alternativa possível para ultrapassar este problema. Com base em resultados obtidos pela nossa equipa, este trabalho teve como objective avaliar as características sensoriais do hidromel produzido a escala piloto. Resultados anteriores indicam que a levedura Saccharomyces cerevisiae Fermol® Reims Champagne (Pascal Biotech®) á a mais indicada para a fermentação do hidromel. As condições ideais para a produção de hidromel obtidas com base no desenho experimental foram: temperatura entre os 24°C e os 29°C e concentração de sais entre 85 e 100 g/hL.
- Antioxidant and chealting activities of fermentation broths containing fructooligossacharidesPublication . Lama, Aelina; Dias, Teresa; Peres, António M.Fructooligossacharides are present in plants and fruits at low concentrations and with varying individual relative proportions. So, for industrial application, fructooligossacharides extraction from natural sources may not be economically viable. Recently, several works have been published within this field of research usually aiming to establish the best experimental conditions to maximizing fructooligossacharides yield/synthesis [1-3]. However, although it is known that these compounds may have a great health impact, it is also reported that beneficial health effects may depend on the relative fructooligossacharides composition, seeming that nystose-rich diet is preferable compared to a kestoserich preparation, exhibiting a higher anti-hydroxyl radical activity [4,5]. So, in this work it is reported the results regarding a screening study concerning the bioactivity activity of the fermentation broth extracts obtained using fungi with potential for producing fructooligossacharides. The potential use of five fungi (i.e., A. aculeatus, A. japonicus, A. opinicosulum, P. thoumii and P. cornyphipum) was evaluated. Batch fermentation were carried out during 96 hours, at constant temperature (27 ºC) and agitation (100 rpm), being the initial sucrose concentration fixed at 30 g/L. Samples were taken at 24-h intervals and the radical scavenging activity as well as the iron binding ability of chelators, of the different broth extracts, were determined using the DPPH and ferrozine. The overall results obtained showed that although the extracts possessed relatively low bioactive activity; it was possible to set some preliminary insights that allowed selecting the most promissory(s) mold(s), which could enable achieving, in a near future, a final fructooligossacharides formulation with the greatest antioxidant capacity.
- Antioxidant and chealting activities of fermentation broths containing fructooligossacharidesPublication . Lama, Aelina; Dias, Teresa; Peres, António M.Fructooligossacharides are present in plants and fruits at low concentrations and with varying individual relative proportions. So, for industrial application, fructooligossacharides extraction from natural sources may not be economically viable. Recently, several works have been published within this field of research usually aiming to establish the best experimental conditions to maximizing fructooligossacharides yield/synthesis [1-3]. However, although it is known that these compounds may have a great health impact, it is also reported that beneficial health effects may depend on the relative fructooligossacharides composition, seeming that nystose-rich diet is preferable compared to a kestoserich preparation, exhibiting a higher anti-hydroxyl radical activity [4,5]. So, in this work it is reported the results regarding a screening study concerning the bioactivity activity of the fermentation broth extracts obtained using fungi with potential for producing fructooligossacharides. The potential use of five fungi (i.e., A. aculeatus, A. japonicus, A. opinicosulum, P. thoumii and P. cornyphipum) was evaluated. Batch fermentation were carried out during 96 hours, at constant temperature (27 ºC) and agitation (100 rpm), being the initial sucrose concentration fixed at 30 g/L. Samples were taken at 24-h intervals and the radical scavenging activity as well as the iron binding ability of chelators, of the different broth extracts, were determined using the DPPH and ferrozine. The overall results obtained showed that although the extracts possessed relatively low bioactive activity; it was possible to set some preliminary insights that allowed selecting the most promissory(s) mold(s), which could enable achieving, in a near future, a final fructooligossacharides formulation with the greatest antioxidant capacity.
- Application of FTIR-ATR spectroscopy on the bee pollen characterizationPublication . Anjos, Ofélia; Santos, António J.A.; Dias, Teresa; Estevinho, Leticia M.Bee pollen contains almost all nutrients required by the human organism as well as diverse health-promoting substances. However, its composition and nutritional value greatly depend on the botanical origin. As such, it is important to develop a rapid and non-expensive methodology that allows studying its characteristics, making labelling more objective and easier. The FTIR-ATR technique was used to predict some nutritional parameters in 126 bee pollen samples. FTIR-ATR spectrum obtained in the region between 4000 and 400 cm -1 with PLS Regression models were used to correlate spectral information with the data obtained using reference methods. In this first approach with pollen samples, good correlation models with appropriate accuracy were obtained for the evaluated parameters with r 2 varying from 74.8 to 97% and residual prediction deviation between 2.0 and 5.8. These results suggest that FTIR-ATR may be a useful technique for assessing bee pollen’s composition.
- Assessment of physiological conditions in e. Coli fermentations by epifluorescent microscopy and image analysisPublication . Carneiro, Sónia; Amaral, António L.; Veloso, Ana C.A.; Dias, Teresa; Peres, António M.; Ferreira, Eugénio C.; Rocha, IsabelThe development of monitoring methods for assessing the physiological state of microorganisms during recombinant fermentation processes has been encouraged by the need to evaluate the influence of processing conditions in recombinant protein production. In this work, a technique based on microscopy and image analysis was developed that allows the simultaneous quantification of parameters associated with viability and fluorescent protein production in recombinant Escherichia coli fermentations. Images obtained from light microscopy with phase contrast are used to assess the total number of cells in a given sample and, from epifluorescence microscopy, both protein producing and injured cells are evaluated using two different fluorochromes: propidium iodide and enhanced yellow fluorescent protein. This technique revealed the existence of different cell populations in the recombinant E. coli fermentation broth that were evaluated along four batch fermentations, complementing information obtained with standard techniques to study the effects of the temperature and induction time in recombinant protein production processes.
- Bee propolis effect on protection of RBC’s membrane integrityPublication . Moreira, Leandro; Rogão, Mónica; Pereira, Ana Paula; Morais, Margarida; Costa, Bruno; Dias, L.G.; Dias, Teresa; Estevinho, Leticia M.Propolis is a resinous substance collected from plants by bees. The propolis composition depends on the surrounding vegetation, the season, and the area from which derive. This hive product usually contains a variety of chemical compounds such as polyphenols (flavonoids, phenolic acids and esters), steroids, and amino acids. The hereditary spherocytosis (HS) is a congenital hemolytic anemia, with origin in the modification of membrane proteins of erythrocytes, which leads to increased susceptibility to hemolysis and a decrease of the cell over-life. The HS is the most common red blood cell (RBC) membrane disorder in European Caucasians, with a prevalence of roughly 200-300 per 106, and to Japanese population 5.7-20.3 per 106. The aim of the present work was to determine if propolis extracts could affected the red cell membrane integrity and comparing the effect of two propolis extracts from different regions (Bornes - Trás-os-Montes; Fundão - Beira Interior). In this work, two adults were studied, one with the syndrome HS splenectomized and one healthy used as control. Diagnosis of HS was made by clinical features, identification of spherocytes on peripheral blood smears and abnormal osmotic fragility. The results show that the two propolis extracts affected the erythrocyte membrane fragility in both individuals (control and patient with HS).
- Bee propolis effect on protection of RBCs membrane integrityPublication . Moreira, Leandro; Rogão, Mónica; Pereira, Ana Paula; Morais, Margarida; Costa, Bruno; Dias, L.G.; Dias, Teresa; Estevinho, Leticia M.Propolis is a resinous substance collected from plants by bees. The propolis composition depends on the surrounding vegetation, the season, and the area from which derive. This hive product usually contains a variety of chemical compounds such as polyphenols (flavonoids, phenolic acids and esters), steroids, and amino acids. The hereditary spherocytosis (HS) is a congenital hemolytic anemia, with origin in the modification of membrane proteins of erythrocytes, which leads to increased susceptibility to hemolysis and a decrease of the cell over-life.
- Caracterização química do extracto lipofilico do pólen apícola do Parque Natural de Montesinho. Pesquisa da sua actividade biológicaPublication . Barbosa, Sandra; Barros, Lillian; Dias, Teresa; Estevinho, Leticia M.; Silvestre, Armando; Simões, MárioO homem tem comprovado as múltiplas propriedades nutritivas e medicinais dos produtos apícolas, utilizando-os para seu benefício desde os tempos mais remotos, no entanto tem sido durante este século quando os avanços da química lhe permitiram determinar a presença de elementos que justificam plenamente as virtudes que a medicina popular lhe tem atribuído. Exemplo de um destes produtos é o pólen apícola, que dadas as suas características tem sido utilizado em medicina tradicional, em dietética, mais recentemente na industria cosmética e na alimentação artificial de colmeias e de outros insectos polinizadores em períodos de carência alimentar.
- Cloning and expression analysis of glucanase genes from Phytophthora cinnamomiPublication . Martins, Ivone; Meirinho, Sofia G.; Dias, Teresa; Jorge, Lurdes; Martins, Fátima; Choupina, AltinoPhytophthora cinnamomi is one among the most destructive species of Phytophthora associated to the decline of forestry, ornamental and fruit species. Associated with this oomycete is the ink disease of Castanea sativa Mill. Glucan endo-1,3-β-D-glucosidase catalyzes the hydrolysis of 1,3-β-D-glucoside linkages in callose, laminarin and several carbohydrates found in the cell wall of plants and fungi. It is generally thought that glucanases play a role in plant defence by digesting wall components of the fungal pathogen. In oomycetes, glucanases have been studied at biochemical level for their possible role in hyphal tip growth and branching, where there is thought to be a delicate balance between the cell wall synthesis and hydrolysis. Fungal cell wall degrading enzyme production is influenced by a number of factors including the type of strain, the culture conditions and substrate type. The aim of this work was the analysis of homologous expression, in P. cinnamomi, and heterologous expression, in Pichia pastoris, of the endo-1,3-β-D-glucosidase encoding gene ENDO1 produced by P. cinnamomi. The expression was studied during growth in different carbon sources and was also performed a time course of endo-1,3-β-D-glucosidase production. Different plasmids were used to clone the gene on each organism and we used RT-PCR analysis to examine its expression. The major expression levels occurred at the medium with glucose as carbon source. These and other results will be presented.