Percorrer por autor "Morais, Rui M."
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- 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.
- Health promoting properties of blueberries: a reviewPublication . Silva, Sara; Costa, Eduardo M.; Veiga, Mariana; Morais, Rui M.; Calhau, Conceição; Pintado, ManuelaWith the strengthening of the link between diet and health, several foodstuffs have emerged as possessing potential health benefits such as phenolic rich fruits and vegetables. Blueberries, along with other berries, given their flavonoid and antioxidant content have long since been considered as a particularly interesting health promoting fruit. Therefore, the present work aimed to compile the existing evidences regarding the various potential benefits of blueberry and blueberry based products consumption, giving particular relevance to in vivo works and epidemiological studies whenever available. Overall, the results demonstrate that, while the evidences that support a beneficial role of blueberry and blueberry extracts consumption, further human based studies are still needed.
- Impact of a purified blueberry extract on in vitro probiotic mucin-adhesion and its effect on probiotic/intestinal pathogen systemsPublication . Silva, Sara; Costa, Eduardo M.; Oliveira, Hélder; Freitas, Vitor de; Morais, Rui M.; Calhau, Conceição; Pintado, ManuelaSeveral arguments have been made to substantiate the need for natural antimicrobials for the food industry. With blueberry extracts, the most compelling are both their healthy connotation and the possibility of obtaining a multipurpose solution that can be an antioxidant, colorant, and antimicrobial. From an antimicrobial perspective, as blueberry/anthocyanin-rich extracts have been associated with a capacity to inhibit harmful bacteria while causing little to no inhibition on potential probiotic microorganisms, the study of potential benefits that come from synergies between the extract and probiotics may be of particular interest. Therefore, the present work aimed to evaluate the effect of an anthocyanin-rich extract on the adhesion of five different probiotics as well as their effect on the probiotics’ capacity to compete with or block pathogen adhesion to a mucin/BSA-treated surface. The results showed that, despite some loss of probiotic adhesion, the combined presence of extract and probiotic is more effective in reducing the overall amount of adhered viable pathogen cells than the PROBIOTIC alone, regardless of the probiotic/pathogen system considered. Furthermore, in some instances, the combination of the extract with Bifidobacterium animalis Bo allowed for almost complete inhibition of pathogen adhesion
- On the Utilization of Microalgae for Brewery Effluent Treatment and Possible Applications of the Produced BiomassPublication . Raposo, M. Filomena de J.; Oliveira, Susana E.; Castro, Paula M.; Bandarra, Narcisa M.; Morais, Rui M.The effluent of a brewery, complete or diluted with deionised water or with normal culture medium, was used as the growth nutrient medium for Chlorella vulgaris and for a consortium obtained from the autochthonous flora of that effluent (microalgae, cyanobacteria and bacteria). The cultures were exposed to continuous light and aeration, at 25°C, and growth was evaluated by direct counting (C. vulgaris) or by chlorophyll determination (autochthonous flora). Total protein and lipid content, and amino acid and fatty acid profiles in the produced biomass were determined. The highest removal rate of nutrients present in the effluent was obtained when the complete effluent was used as the culture medium for the autochthonous flora – up to 5,855 g kg–1 biomass d–1 of nitrogen and up to 805 g kg–1 biomass d–1 of phosphate. A reduction of up to 27% in biological oxygen demand (BOD5, initial level of 2,172 mg O2 L–1) and up to 15% in chemical oxygen demand (COD, initial level of 1,340 mg O2 L– 1) was observed in cultures of the autochthonous flora grown in different loads of effluent. A significant increase in aspartic acid, glutamic acid and valine content, and a higher level of the ramified fatty acids, of the 14:0isobr, 18:4ω3, and the eicosapentaenoic acid, were found in the final biomass obtained from cultures grown with different loads of effluent, compared with the results obtained for the cultures grown in normal nutrient medium. The final microalgae biomass obtained, considering its protein and fatty acid content and the absence of heavy metals in significant amount, can be appropriate for use as animal feed or for biofuel production.
- Production of a food grade blueberry extract rich in anthocyanins: selection of solvents, extraction conditions and purification methodPublication . Silva, Sara; Costa, Eduardo M.; Calhau, Conceição; Morais, Rui M.; Pintado, M. Manuela E.Blueberries are recognized, by the scientific community and consumers, for their health promoting potential. This fact makes blueberries, and blueberry derived products, prime candidates to aid in the development of healthier foodstuffs that are easily recognized as such by consumers. As blueberries health promoting properties are frequently associated with their phenolic, particularly anthocyanins, composition the present work aimed to establish a simple, food safe, approach to extract these compounds. One that, while being food safe also allowed for a relatively easy scale up process. To accomplish this, four different solvents (water, ethanol, methanol and acetone) acidified or not, were evaluated for their extraction capabilities. The results obtained demonstrated that ethanol acidified with 0.01% HCl was an effective extractant of both phenolic compounds and anthocyanins. Acetone was significantly more effective in extracting phenolic compounds but it was almost unable to extract anthocyanins, with the addition of acid allowing for an increase of anthocyanin yield but reducing the overall phenolic yield. The extraction of anthocyanins may be further improved with the addition of an ultrasound treatment to the extraction process, though no significant differences were observed when considering the overall phenolic content. Furthermore, if seeking a condensed extract, purification using solid phase extraction columns allowed the production of an extract comprised of ca. 40% (w w(-1)) anthocyanins.
- Selective activity of an anthocyanin-rich, purified blueberry extract upon pathogenic and probiotic bacteriaPublication . Silva, Sara; Costa, Eduardo M.; Machado, Manuela; Morais, Rui M.; Calhau, Conceição; Pintado, ManuelaBlueberry extracts have been widely recognized as possessing antimicrobial activity against several potential pathogens. However, the contextualization of the interaction of these extracts with beneficial bacteria (i.e., probiotics), particularly when considering the food applications of these products, may be of importance, not only because their presence is important in the regular gut microbiota, but also because they are important constituents of regular and functional foodstuffs. Therefore, the present work first sought to demonstrate the inhibitory effect of a blueberry extract upon four potential food pathogens and, after identifying the active concentrations, evaluated their impact upon the growth and metabolic activity (organic acid production and sugar consumption) of five potential probiotic microorganisms. Results showed that the extract, at a concentration that inhibited L. monocytogenes, B. cereus, E. coli and S. enteritidis (1000 μg mL−1), had no inhibitory effect on the growth of the potential probiotic stains used. However, the results demonstrated, for the first time, that the extract had a significant impact on the metabolic activity of all probiotic strains, resulting in higher amounts of organic acid production (acetic, citric and lactic acids) and an earlier production of propionic acid.
- Variation of anthocyanins and other major phenolic compounds throughout the ripening of four Portuguese blueberry (Vaccinium corymbosum L) cultivarsPublication . Silva, Sara; Costa, Eduardo M.; Coelho, Marta C.; Morais, Rui M.; Pintado, Manuela E.Blueberries are widely recognised as one of the richest sources of bioactive compounds, among which are anthocyanins, though the ripeness of berries has been reported as affecting the phytochemical composition of fruits. Therefore, the present work aimed to evaluate the variation of anthocyanins, and other major phenolics, throughout five ripening stages in four blueberry cultivars. The results showed that the antioxidant capacity and anthocyanin content increased during ripening, reaching the highest values when the blueberries are collected from bunches comprised of 75% ripe blueberries. Antagonistically, the amount of phenolic acid decreases, while the quercetin-3-glucoside levels remain stable. Furthermore, Goldtraube blueberries appear to possess, systematically, higher amounts of phenolic compounds than the other cultivars studied. Thus, when seeking the highest yield of anthocyanins, the preferred harvest should occur in bunches that contain ca 75% of ripe blueberries and, considering the cultivars assayed, the Goldtraube cultivar appears to bethe richest in phenolic compounds.