89 research outputs found

    Role of p-Coumaric Acid and Micronutrients in Sulfur Dioxide Tolerance in Brettanomyces bruxellensis

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    Sulfite is a common preservative in wine, but the spoilage yeast Brettanomyces bruxellensis can produce volatile phenols even with the recommended sulfite dose. The purpose of this study was to examine how wine components, p-coumaric acid (a precursor of volatile phenols), and micronutrients influence culturability, viability, and volatile phenols production by B. bruxellensis under sulfite stress. In red wine, a high sulfite dose (potassium metabisulfite, 100 mg L1) led to an immediate death phase followed by growth recovery after two weeks. However, 4-ethylphenol (4-EP) was continuously produced by dead or nonculturable cells. Nonetheless, an event of growth recovery could not be observed in the case of the model wine. However, when the model wine was supplemented with minerals and vitamins, both growth recovery and 4-EP production were noticed, suggesting that the minerals and vitamins played an important role in maintaining the viability of cells under the sulfite stress. The yeast could also utilize the p-coumaric acid (p-CA) as an energy source, showing a specific growth rate of 0.0142 h1 with 1 mM of p-CA in model wine. Furthermore, the sulfite-stressed cells exhibited ATP production by means of proton efflux while utilizing the p-CA. This work highlights the novel finding that the conversion of p-CA into 4-EP provides sufficient energy for the cell to remain metabolically active under the sulfite stress.info:eu-repo/semantics/publishedVersio

    Relação entre a sintomatologia psicopatológica, adesão ao tratamento e qualidade de vida na infecção pelo HIV e Aids = Relationship among psychopathological symptoms, treatment adherence and quality of life in HIV/AIDS Infection

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    O presente estudo observou a existência de relações significativas entre sintomatologia psicopatológica (BSI), adesão ao tratamento (CEAT-VIH) e qualidade de vida (WHOQOL-Bref) em 125 pessoas HIV-positivo/AIDS em tratamento antirretroviral, atendidos em um hospital do Porto (Portugal). A sintomatologia psicopatológica correlacionou-se negativamente com adesão ao tratamento e qualidade de vida, e a adesão ao tratamento associou-se positivamente com a qualidade de vida. O modelo preditor de adesão ao tratamento, mediante análise de regressão múltipla, incluiu a ausência de sintomatologia psicopatológica, o comportamento de retirada dos medicamentos na farmácia hospitalar e a presença de efeitos colaterais do tratamento (R² =0,30). Ademais, observou-se um efeito mediador de sintomatologia psicopatológica entre a adesão ao tratamento e a qualidade de vida das pessoas com HIV/AIDS.The study shows evidence of statistical association among psychopathological symptoms (BSI), treatment adherence (CEAT-VIH) and quality of life (WHOQOL-Bref) in 125 HIV-positive/AIDS patients followed at Porto Hospital (Portugal). The psychopathological symptoms present a negative correlation with treatment adherence and quality of life. On the other hand, adherence was positively correlated with quality of life. The model of adherence to the antiretroviral treatment using multiple regression analysis includes absence of psychopathological symptoms, an adherence behavior (i.e. to get the medication at the hospital's pharmacy) and the experience of side effects because of medication (R² = 0.30). Besides, psychopathological symptoms have a mediation effect between adherence and quality of life in people with HIV/AIDS

    Innovative and Healthier Dairy Products through the Addition of Microalgae: A Review

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    ReviewIn recent years, the development of healthier foods, richer in nutraceutical or functional compounds, has been in great demand. Microalgae are attracting increasing attention, as their incorporation in foods and beverages can be a promising strategy to develop sustainable foods with improved nutritional profiles and a strong positive impacts on health. Despite the increasing market demand in plant-based foods, the popularity of fermented dairy foods has increased in the recent years since they are a source of microorganisms with health-promoting effects. In this context, the incorporation of microalgae in cheeses, fermented milks and other dairy products represents an interesting approach towards the development of innovative and added-value hybrid products based on animal proteins and enriched with vegetable origin ingredients recognized as extremely valuable sources of bioactive compounds. The effect of the addition of microalgal biomass (Chlorella vulgaris, Arthrospira platensis, Pavlova lutheri, and Diacronema vlkianum, among others) and its derivates on the physicochemical composition, colorimetric and antioxidant properties, texture and rheology behavior, sensory profile, and viability of starter cultures and probiotics in yogurt, cheese and ice cream is discussed in the current work. This review of the literature on the incorporation of microalgae in dairy products aims to contribute to a better understanding of the potential use of these unique food ingredients in the development of new sustainable products and of their beneficial effects on health. Considering the importance of commercialization, regulatory issues about the use of microalgae in dairy products are also discussedinfo:eu-repo/semantics/publishedVersio

    Development and physicochemical characterization of a new grass pea (Lathyrus sativus L.) miso

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    BACKGROUND: Western consumers interest in Eastern fermented foods has been growing, due to their nutritional and healthy properties. In this study, new sweet misos and salty misos were produced using grass pea (Lathyrus sativus L.) – traditional Portuguese legume from local producers – to promote its consumption and preservation. The evolution of the new misos was evaluated in comparison to traditional miso (made from soybean), through analysis of the chemical composition, colour, texture and linear viscoelastic behaviour. RESULTS: Throughout the fermentation process, the ascorbic acid and phenolic compounds content – with important nutritional value – increased in all misos, mainly in misos produced using grass pea, besides, grass pea sweet miso presented the fastest evolution and darkest colour. The texture parameters (firmness and adhesiveness) of misos decreased over time: grass pea sweet miso showed the highest firmness reduction (51.63 N to 6.52 N) and soybean sweet miso the highest adhesiveness reduction (27.76 N to 3.11 N). Viscoelastic moduli also decreased, reflecting a reduction in the degree of internal structuring for all misos. However, grass pea misos presented more structured internal systems with faster maturation kinetics than soybean misos, for which stabilization started earlier. CONCLUSION: Two innovative misos were developed from grass pea. After 4 months, the texture parameters and viscoelastic moduli for grass pea misos, were similar to the control misos made from soybean, showing that grass pea can be used as a raw material to produce a sustainable miso with potentially healthy propertiesinfo:eu-repo/semantics/publishedVersio

    Wine spoilage control: impact of Saccharomycin on Brettanomyces bruxellensis and its conjugated effect with sulfur dioxide

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    The yeast Brettanomyces bruxellensis is one of the most dangerous wine contaminants due to the production of phenolic off-flavors such as 4-ethylphenol. This microbial hazard is regularly tackled by addition of sulfur dioxide (SO2). Nevertheless, B. bruxellensis is frequently found at low levels (ca 103 cells/mL) in finished wines. Besides, consumers health concerns regarding the use of sulfur dioxide encouraged the search for alternative biocontrol measures. Recently, we found that Saccharomyces cerevisiae secretes a natural biocide (saccharomycin) that inhibits the growth of different B. bruxellensis strains during alcoholic fermentation. Here we investigated the ability of S. cerevisiae CCMI 885 to prevent B. bruxellensis ISA 2211 growth and 4-ethylphenol production in synthetic and true grape must fermentations. Results showed that B. bruxellensis growth and 4-ethylphenol production was significantly inhibited in both media, although the effect was more pronounced in synthetic grape must. The natural biocide was added to a simulated wine inoculated with 5 x 10 2 cells/mL of B. bruxellensis, which led to loss of culturability and viability (100% dead cells at day-12). The conjugated effect of saccharomycin with SO2 was evaluated in simulated wines at 10, 12, 13 and 14% (v/v) ethanol. Results showed that B. bruxellensis proliferation in wines at 13 and 14% (v/v) ethanol was completely prevented by addition of 1.0 mg/mL of saccharomycin with 25 mg/L of SO2, thus allowing to significantly reduce the SO2 levels commonly used in wines (150–200 mg/L)info:eu-repo/semantics/publishedVersio

    Grapevine aquaporins: gating of a tonoplast intrinsic protein (TIP2; 1) by cytosolic pH

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    Grapevine (Vitis vinifera L.) is one of the oldest and most important perennial crops being considered as a fruit ligneous tree model system in which the water status appears crucial for high fruit and wine quality, controlling productivity and alcohol level. V. vinifera genome contains 28 genes coding for aquaporins, which acting in a concerted and regulated manner appear relevant for plant withstanding extremely unfavorable drought conditions essential for the quality of berries and wine. Several Vv aquaporins have been reported to be expressed in roots, shoots, berries and leaves with clear cultivar differences in their expression level, making their in vivo biochemical characterization a difficult task. In this work V. vinifera cv. Touriga nacional VvTnPIP1;1, VvTnPIP2;2 and VvTnTIP2;1 were expressed in yeast and water transport activity was characterized in intact cells of the transformants. The three aquaporins were localized in the yeast plasma membrane but only VvTnTIP2;1 expression enhanced the water permeability with a concomitant decrease of the activation energy of water transport. Acidification of yeast cytosol resulted in loss of VvTnTIP2;1 activity. Sequence analysis revealed the presence of a His131 residue, unusual in TIPs. By site directed mutagenesis, replacement of this residue by aspartic acid or alanine resulted in loss of pHin dependence while replacement by lysine resulted in total loss of activity. In addition to characterization of VvTn aquaporins, these results shed light on the gating of a specific tonoplast aquaporin by cytosolic pHinfo:eu-repo/semantics/publishedVersio

    Molecular and functional characterization of grapevine NIPs through heterologous expression in aqy-null Saccharomyces cerevisiae

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    Plant Nodulin 26-like Intrinsic Proteins (NIPs) are multifunctional membrane channels of the Major Intrinsic Protein (MIP) family. Unlike other homologs, they have low intrinsic water permeability. NIPs possess diverse substrate selectivity, ranging from water to glycerol and to other small solutes, depending on the group-specific amino acid composition at aromatic/Arg (ar/R) constriction. We cloned three NIPs (NIP1;1, NIP5;1, and NIP6;1) from grapevine (cv. Touriga Nacional). Their expression in the membrane of aqy-null Saccharomyces cerevisiae enabled their functional characterization for water and glycerol transport through stopped-flow spectroscopy. VvTnNIP1;1 demonstrated high water as well as glycerol permeability, whereas VvTnNIP6;1 was impermeable to water but presented high glycerol permeability. Their transport activities were declined by cytosolic acidification, implying that internal-pH can regulate NIPs gating. Furthermore, an extension of C-terminal in VvTnNIP6;1M homolog, led to improved channel activity, suggesting that NIPs gating is putatively regulated by C-terminal. Yeast growth assays in the presence of diverse substrates suggest that the transmembrane flux of metalloids (As, B, and Se) and the heavy metal (Cd) are facilitated through grapevine NIPs. This is the first molecular and functional characterization of grapevine NIPs, providing crucial insights into understanding their role for uptake and translocation of small solutes, and extrusion of toxic compounds in grapevineinfo:eu-repo/semantics/publishedVersio

    Clean Label “Rocha” Pear (Pyrus communis L.) Snack Containing Juice By-Products and Euglena gracilis Microalgae

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    Original Research“Rocha do Oeste” pear is a Portuguese Protected Designation of Origin variety and one of the country’s most relevant fruits for its nutritional value, production area, and exportation amounts. The recent integration of a pilot-scale juice production line brought to SUMOL+COMPAL company the need to characterize the new resulting fractions and value the new by-products. The objective of this work was to value the juice clarification by-products, producing a clean label and fiber-rich snack, in a circular economy rationale, where the secondary products are upcycled back into the food value chain, by creating another food product that includes those by-products. For the above to be possible, the laboratory conditions to produce pear fractions were optimized. After optimizing the puree centrifugation, using response surface methodology (RSM), and optimizing the turbid juice crossflow filtration, the different fractions were characterized in rheological, nutritional, and physical aspects. Comparison to the pulps revealed an increase in the viscosity of the pomace; an enriching effect on the fructose, glucose, and dietary fiber levels in the pomace, and maintenance of the vitamin C levels after centrifugation; and with no effect on the contents of total phenols during the filtration step. A thick pear snack was developed, incorporating retained fraction, inulin, and Euglena gracilis in the pomace, and optimized regarding its firmness and dietary fiber content. The snack characterization revealed an interesting total phenols content (which was maintained from the raw materials). Compared to the snack without microalgae and a commercial fruit snack, the pear snack with E. gracilis was well-accepted by the sensory panel, mainly in texture and appearance, and can be further improved in aroma and flavor. The snack without microalgae was the favorite among the three samples, in most sensory parameters, and never got the answer “I’m sure I wouldn’t buy it.” Therefore, an innovative, clean label and plant-based snack was developed, in a circular economy rationale, which was relatively well-appreciated by the panel. This snack is rich in dietary fiber, having the possibility of presenting various nutritional claims, and the potential for easy sensory optimizationinfo:eu-repo/semantics/publishedVersio
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