Percorrer por autor "Veiga, Mariana"
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- Agro-food byproducts as a new source of natural food additivesPublication . Faustino, Margarida; Veiga, Mariana; Sousa, Pedro; Costa, Eduardo M.; Silva, Sara; Pintado, ManuelaNowadays, the agro-food industry generates high amounts of byproducts that may possess added value compounds with high functionality and/or bioactivity. Additionally, consumers' demand for healthier foodstuffs has increased over the last years, and thus the food industry has strived to answer this challenge. Byproducts are generally secondary products derived from primary agro-food production processes and represent an interesting and cheaper source of potentially functional ingredients, such as peptides, carotenoids, and phenolic compounds, thus promoting a circular economy concept. The existing body of work has shown that byproducts and their extracts may be successfully incorporated into foodstuffs, for instance, phenolic compounds from eggplant can be potentially used as a mulfitunctional food additive with antimicrobial, antioxidant, and food colorant properties. As such, the aim of this review is to provide insights into byproducts and their potential as new sources of foodstuffs additives.
- Antiadhesive and antibiofilm effect of Malvidin -3- glucoside and Malvidin -3- glucoside/neochlorogenic acid mixtures upon staphylococcusPublication . Silva, Sara; Costa, Eduardo; Veiga, Mariana; Morais, Rui; Calhau, Conceição; Pintado, Manuela
- Antioxidant-loaded nanocarriers for drinksPublication . Veiga, Mariana; Costa, Célia; Carvalho, Maria João; Costa, Eduardo; Silva, Sara; Pintado, Manuela
- Are olive pomace powders a safe source of bioactives and nutrients?Publication . Ribeiro, Tânia B.; Oliveira, Ana; Coelho, Marta; Veiga, Mariana; Costa, Eduardo M.; Silva, Sara; Nunes, João; Vicente, António A.; Pintado, ManuelaBACKGROUND Olive oil industry generates significant amounts of semi-solid wastes, namely the olive pomace. Olive pomace is a by-product rich in high-value compounds (e.g. dietary fibre, unsaturated fatty acids, polyphenols) widely explored to obtain new food ingredients. However, conventional extraction methods frequently use organic solvents, while novel eco-friendly techniques have high operational costs. The development of powdered products without any extraction step has been proposed as a more feasible and sustainable approach. RESULTS The present study fractionated and valorised the liquid and pulp fraction of olive pomace obtaining two stable and safe powdered ingredients, namely a liquid-enriched powder (LOPP) and a pulpenriched powder (POPP). These powders were characterized chemically, and their bioactivity was assessed. LOPP exhibited a significant amount of mannitol (141 g/ kg), potassium (54 g/ kg) and hydroxytyrosol/ derivatives (5 mg/g). POPP exhibited high amount of dietary fibre (620 g/ kg) associated to significant amount of bound phenolics (7.41 mg GAE/ g fibre DW) with substantial antioxidant activity. POPP also contained an unsaturated fatty acids composition similar to olive oil (76% of total fatty acids) and showed potential as a reasonable source of protein (12 %). Their functional properties (solubility, water‐holding and oil‐holding capacity), antioxidant capacity and antimicrobial activity were also assessed, and their biological safety was verified. CONCLUSION The development of olive pomace powders to apply in the food industry could be a suitable strategy to add-value to olive pomace and obtain safe multifunctional ingredients with higher health-promoting effects than dietary fibre and polyphenols itself.
- Biocompatibility of salix viminalis, salix atrocinerea and salix fragilisPublication . Silva, Sara; Veiga, Mariana; Costa, Eduardo; Costa, Célia; Faustino, Margarida; Ramos, Patricia A. B.; Santos, Sónia A. O.; Freire, Carmen S. R.; Silva, Artur M. S.; Silvestre, Armando J. D.; Pintado, M. Manuela
- Chitosan as an effective inhibitor of multidrug resistant acinetobacter baumanniiPublication . Veiga, Mariana; Costa, Eduardo; Silva, Sara; Pintado, ManuelaBackground: Acinetobacter baumannii is a multidrug resistant pathogen often associated with nosocomial outbreaks, with an innate ability to evade nearly all traditional antibiotics and a capacity to adhere and colonize medical devices. Chitosan is a biocompatible and non-toxic polymer which has been shown to have a strong antimicrobial activity against antibiotic resistant microorganisms, with potential to become an alternative to traditional antimicrobials. Method: Chitosan’s biological activity was assessed upon two A. baumannii strains (one clinical multidrug resistant strain (MDR) and one reference strain CCUG 61012) in planktonic and sessile environments. From a planktonic standpoint minimal inhibitory concentration (MIC) and the minimal bactericidal concentrations (MBC) were determined while from a sessile perspective minimal biofilm inhibitory concentration (MBIC), adhesion and biofilm formation were assayed through biomass and metabolic activity inhibition. Results & Conclusions: Results showed that the chitosan molecular weights tested were effective in inhibiting A. baumannii’s planktonic and sessile growth. For the first MICs and MBCs were obtained at relatively low concentrations (0.5–2 mg/mL). For the latter, MBICs varied between 1 and 8 mg/mL and chitosan effectively inhibited both A. baumannii’s adhesion and biofilm formation, with this inhibitory activity being more pronounced from a biomass formation standpoint. Analyzing the differences observed between the reference and the MDR A. baumannii’s strains, the MDR strain was, in general, as susceptible as the reference strain to chitosan’s activity. Overall, chitosan showed high potential as a possible natural alternative to the treatment of multidrug resistant A. baumannii infections with the high antibiotic resistance profile of this microorganism not being an impediment to chitosan’s activity both in planktonic and sessile settings.
- Chitosan’s biological activity upon skin-related microorganisms and its potential textile applicationsPublication . Costa, Eduardo M.; Silva, Sara; Veiga, Mariana; Tavaria, Freni K.; Pintado, Maria M.Over the years the body of work relating chitosan and its possible skin-related applications has grown, showing that chitosan is active both as a free compound and as a functional finishing of textiles. As a free molecule chitosan proved itself to be an attractive option as it is biocompatible and has a demonstrated biological activity (e.g. growth inhibition or adhesion inhibition) upon multiple skin pathogens, even upon multidrug resistant species. Furthermore, chitosan has wound healing accelerating properties, which make it a prime candidate for possible control of skin related infections. Almost inconspicuously, textiles have been one the main lines of defense of the skin against foreign threats, acting as a physical barrier to microbial colonization and infection. With the advent of textile functionalization specially designed textiles with enhanced protective characteristics, such as antimicrobial capacity, have come to the forefront. Chitosan functionalized textiles have been shown to be effective inhibitors of microbial growth with even invasive multidrug resistant species, as MRSA, being inhibited. Therefore, chitosan and chitosan functionalized textiles present themselves as both an interesting alternative to traditional antibiotics and as a possible means to enhance current treatment strategies.
- DNA agarose gel electrophoresis for antioxidant analysis: Development of a quantitative approach for phenolic extractsPublication . Silva, Sara; Costa, Eduardo M.; Vicente, Sandra; Veiga, Mariana; Calhau, Conceição; Morais, Rui M.; Pintado, Manuela E.Most of the fast in vitro assays proposed to determine the antioxidant capacity of a compound/extract lack either biological context or employ complex protocols. Therefore, the present work proposes the improvement of an agarose gel DNA electrophoresis in order to allow for a quantitative estimation of the antioxidant capacity of pure phenolic compounds as well as of a phenolic rich extract, while also considering their possible pro-oxidant effects. The result obtained demonstrated that the proposed method allowed for the evaluation of the protection of DNA oxidation [in the presence of hydrogen peroxide (H2O2) and an H2O2/iron (III) chloride (FeCl3) systems] as well as for the observation of pro-oxidant activities, with the measurements registering interclass correlation coefficients above 0.9. Moreover, this method allowed for the characterization of the antioxidant capacity of a blueberry extract while demonstrating that it had no perceived pro-oxidant effect.
- Engineering and health benefits of fruits and vegetables beveragesPublication . Veiga, Mariana; Costa, Eduardo M.; Voss, Glenise; Silva, Sara; Pintado, ManuelaFruits and vegetables are one of the pillars of a healthy diet. However, individuals frequently disregard their importance for the maintenance of health and the homeostatic balance and have considerably lower ingestions of these products than recommended by regulatory bodies. The preparation and/or commercialization of fruit and vegetable beverages (with balanced nutrient and phytonutrient profiles) may be an interesting alternative to the direct consumption of fruits and vegetables as it provides an easy, on the go solution for this problem. Therefore, this chapter aimed to provide a comprehensive evaluation of the possibilities of fruit and vegetable beverages as well as characterize the mains constituents responsible for the health benefits attributed to them.
- Exploring chitosan nanoparticles as effective inhibitors of antibiotic resistant skin microorganisms – from in vitro to ex vitro testingPublication . Costa, Eduardo M.; Silva, Sara; Veiga, Mariana; Tavaria, Freni K.; Pintado, Maria M.Nowadays, nosocomial skin infections are increasingly harder to manage and control. In the search for new, natural compounds capable of being alternatives to traditional antibiotics, chitosan and its nanoparticles, have garnered attention. This work sought to understand the potential of chitosan NPs in the management of infections caused by MDR skin pathogens in planktonic and sessile assays. Additionally, NPs’ capacity to inhibit biofilm quorum sensing and prevent HaCat infections was also evaluated. The results obtained showed that chitosan NPs had an average size and charge of 226.6 ± 5.24 nm and +27.1 ± 3.09 mV. Inhibitory and bactericidal concentrations varied between 1 and 2 mg/mL and 2–7 mg/mL, respectively. Chitosan NPs effectively inhibited biofilm growth for all microorganisms and possessed strong anti-quorum sensing activity. Lastly, chitosan NPs proved to be effective interfere with A. baumannii’s infection of HaCat cells, as they significantly reduced intracellular and extracellular bacterial counts.