Browsing by Author "Costa, Eduardo"
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- Anthocyanin recovery from grape by-products by combining ohmic heating with food-grade solvents: phenolic composition, antioxidant, and antimicrobial propertiesPublication . Coelho, Marta; Silva, Sara; Costa, Eduardo; Pereira, Ricardo N.; Rodrigues, António Sebastião; Teixeira, José António; Pintado, ManuelaUsually, wine-making by-products are discarded, presenting a significant environmental impact. However, they can be used as a source of bioactive compounds. Moreover, consumers’ increasing demand for naturally nutritious and healthy products requires new formulations and food product improvement, together with sustainable, environmentally friendly extraction methods. Thus, this work aimed to compare ohmic heating (OH) with conventional methodology (CONV), using food-grade solvents, mainly water, compared to standard methanol extraction of anthocyanins. No significant differences were found between the CONV and OH for total phenolic compounds, which were 2.84 ± 0.037 and 3.28 ± 0.46 mg/g DW gallic acid equivalent, respectively. The same tendency was found for antioxidant capacity, where CONV and OH presented values of 2.02 ± 0.007 g/100 g and 2.34 ± 0.066 g/100 g ascorbic acid equivalent, respectively. The major anthocyanins identified were malvidin-3-O-acetylglucoside, delphinidin-3-O-glucoside, petunidine-3-O-glucoside, cyanidin-3-O-glucoside, and peonidine-3-O-glucoside. These extracts displayed antimicrobial potential against microorganisms such as Yersinia enterocolitica, Pseudomonas aeruginosa, Salmonella enteritidis, methicillin-sensitive Staphylococcus aureus, a methicillin-resistant Staph. aureus (MRSA), and Bacillus cereus. In conclusion, OH provides similar recovery yields with reduced treatment times, less energy consumption, and no need for organic solvents (green extraction routes). Thus, OH combined with water and citric acid allows a safe anthocyanin extraction from grape by-products, thus avoiding the use of toxic solvents such as methanol, and with high biological potential, including antimicrobial and antioxidant activity.
- 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
- Antibiofilm properties of quercus ilex acorn extracts against MRSA and MSSAPublication . Silva, Sara; Costa, Eduardo; Costa, Maria do Rosário; Pereira, Miguel; Coelho, Marta; Pintado, M. E.Biofilms are complex structures that grant microorganisms some survival advantages namely nutrient availability and antimicrobial resistance. As such, the need to find new antimicrobial compounds that are active against these structures is in great demand. Phenolic compounds are described as capable of interfering with the cellular membrane and interact with both intracellular and extracellular proteins, thus they may present an alternative to traditional biofilm control. Acorns have been reported as a rich source of phenolic compounds, particularly tannins, and thus are likely to exhibit some of the properties that are associated with these compounds, namely antimicrobial properties. As such, the present work aimed to assess the antibiofilm properties of hydroethanolic, phenolic rich, acorn extracts against two Staphylococcus aureus strains, one sensitive (MSSA) and one resistant (MRSA) to methicillin. To do so, both microorganisms were exposed to two different sub-MIC concentrations of extracts produced using acorn shells (fresh and roasted) and cotyledons (fresh or roasted). The amount of biofilm produced in the presence of the extracts, after 48 h, was then determined using the microtiter - crystal violet based assay. The results obtained showed that MRSA was the most sensitive strain, with biomass inhibition percentages ranging from 60 to 70%, while for MSSA all inhibition percentages ranged between 29 to 57%. No significant differences between shell and cotyledon were found when considering the results obtained for MRSA. The same was not observed for MSSA where biomass production was significantly higher for roasted cotyledon (2.5 to 20.6%). For this microorganism, it was interesting to note that lower concentrations of the extracts appeared to possess a higher antibiofilm activity (0.7 times more active for fresh or roasted shell extract and 0.6 times more active for fresh cotyledon extracts). Overall, these results indicate that Quercus ilex acorns possess the potential to be an effective means of biofilm control though further studies are still required to fully ascertain their true potential.
- Antimicrobial and antibiofilm activity of chitosan on the oral pathogen Candida albicansPublication . Costa, Eduardo; Silva, Sara; Tavaria, Freni; Pintado, ManuelaOral candidiasis is particularly evident, not only in cancer patients receiving chemotherapy, but also in elderly people with xerostomy. In general, Candida is an opportunistic pathogen, causing infections in immunocompromised people and, in some cases, when the natural microbiota is altered. Chitosan, a natural derivative of chitin, is a polysaccharide that has been proven to possess a broad spectrum of antimicrobial activity that encompasses action against fungi, yeast and bacteria. While recent studies have revealed a significant antibiofilm activity upon several microorganisms, including C. albicans, little is known regarding the impact of chitosan upon the adhesive process or mature biofilms. With that in mind, the purpose of this work was to evaluate, in vitro, the capability of chitosan to inhibit C. albicans growth and biofilm formation. The results obtained showed that chitosan is capable of inhibiting C. albicans planktonic growth (HMW, 1 mg/mL; LMW, 3 mg/mL). Regarding biofilm growth, chitosan inhibited C. albicans adhesion (ca. 95%), biofilm formation (percentages above 90%) and reduced mature biofilms by ca. 65% and dual species biofilms (C. albicans and S. mutans) by ca. 70%. These results display the potential of this molecule to be used as an effective anti-Candida agent capable of acting upon C. albicans infections.
- Antioxidant-loaded nanocarriers for drinksPublication . Veiga, Mariana; Costa, Célia; Carvalho, Maria João; Costa, Eduardo; Silva, Sara; Pintado, Manuela
- Bioavailability of phenolic compounds from blueberry leaf infusions (Vaccinium Corymbosum L.) In caco-2 cellsPublication . Silva, Sara; Norberto, Sónia; Costa, Eduardo; Pereira, Miguel; Costa, Maria do Rosário; Coelho, Marta; Faria, Ana; Pintado, M. E.; Calhau, ConceiçãoPhenolic compounds are widespread in plant-derived foodstuffs and therefore abundant in our diet. There are evidences regarding the positive association of their intake with several diseases prevention. Blueberry leaves are of particular interest as they have been described as being rich in phenolic compounds such as chlorogenic acid and quercetin glicosides. Bioavailability is a major issue regarding the biological impact of these compounds in vivo and remains unclear, with few data available on this matter. Studies in CaCo-2 cells (entrocyte cell line) tested the transport of blueberry leaf infusion (optimized to yield the highest amount total phenolics) across this cell line for different incubation times. From the different compounds originally identified only rutin (9%), quercetin-3- glucoside (Q3glu), chlorogenic (7%) and neochlorogenic acids (23%) were transported across the epithelia cells, after 60, 90 and 120 min. From these compounds, neochlorogenic acid and Q3glu exhibit the highest transport rates (23 and 22%, respectively of the original concentration) while for rutin and chlorogenic acid the transport was lower than 10% of the original amount of compound. It was interesting to note that two metabolites, that were not originally present, caffeic and p-coumaric acids were detected after 30 and 60 min, respectively. From this work it was possible to conclude that neocholorogenic acid and Q3glu are more efficiently transported through the CaCo-2 membrane and that this process resulted in the detection of some metabolites that were not originally present.
- 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
- Cellulose from sugarcane bagasse as a potential prebiotic agentPublication . Freixo, Ricardo; Bastos, Francisca; Costa, Eduardo; Ribeiro, Alessandra B.; Pereira, Carla F.; Pintado, Manuela E.; Ramos, Oscar L.
- Cellulose from sugarcane bagasse as a potential prebiotic agentPublication . Freixo, Ricardo; Casanova, Francisca; Costa, Eduardo; Ribeiro, Alessandra B.; Pereira, Carla F.; Pintado, Manuela E.; Ramos, Óscar L.Organic farming practices have been slowly replacing intensive agriculture with the use of plant growth promoting bacteria as key factor, as these bacteria interact effectively with plants and increase crop yields. However, despite the potential of bioinoculants, its usage in agriculture is still limited as their efficacy also depends upon other abiotic factors such as the soil type and its nutrients. A novel approach to bypass this limitation is the introduction of prebiotic agents to increase the richness of the soil and thus promote bacterial growth (Arif et., al 2020). Among the possible alternatives for soil supplementation, cellulose constitutes one of the best choices, as it is a renewable carbon source, widely abundant in nature and for which a great number of microorganisms produce enzymes. The aim of this work is to evaluate the prebiotic potential of cellulose, extracted from sugarcane bagasse, as prebiotic agent. To that end, cellulose was firstly extracted from sugarcane bagasse through an optimized procedure comprising an alkaline extraction with sodium hydroxide followed by a bleaching process with hydrogen peroxide. The capacity to promote the growth (prebiotic effect) of three soil representative microorganisms and nitrogen fixators i.e., Rhodococcus sp. EC35, Pseudomonas azotoformans and Chryseobacterium humi was evaluated for two cellulose extracts (i.e., raw cellulose and cellulose pulp) obtained from sugarcane bagasse. The results showed that the extraction process yielded ca. 63% and 42% for raw cellulose and cellulose pulp, respectively, being both extracts effective as prebiotic agents for the target microorganisms. Growth rates of 38 and 68% for Rhodococcus sp., and of 67 and 84% for C. humi was found for cellulose pulp and raw cellulose, respectively. On the other hand, for P. azotoformans, raw cellulose had no impact upon the growth rate, while cellulose pulp lead to a small decrease (ca. 7%). When comparing this data with the obtained for a standard cellulose from Sigma, it was possible to observe that the commercial cellulose was, in general, less effective as an environmental prebiotic as it only exhibited significant effects in the growth of C. humi. These results showed the potential of sugarcane bagasse as source of a natural bioinocula with prebiotic effect, thus potentiating the valorization of an industrial byproduct with low commercial value into a product with biological effect on soils supplementation.
- Characterization of edible films based on alginate or whey protein incorporated with Bifidobacterium animalis subsp. lactis BB-12 and prebioticsPublication . Pereira, Joana Odila; Soares, José; Costa, Eduardo; Silva, Sara; Gomes, Ana; Pintado, ManuelaRecently, edible films were shown to be an effective strategy for the delivery of functional ingredients, such as probiotics and prebiotics. With that in mind, two soluble fibres (inulin and fructooligosaccharides) were selected as prebiotic elements, in whey protein isolate (WPI) and alginate (ALG) matrices plasticized with glycerol and used for the incorporation of Bifidobacterium animalis subsp. lactis BB-12. The results obtained showed that the viability of the B. animalis subsp. lactis BB-12 probiotic strain was maintained within the minimum threshold (10(6) CFU/g) necessary to act as a probiotic throughout 60 days of storage at 23 degrees C. The incorporation of prebiotic compounds improved B. animalis subsp. lactis BB-12 viability, with inulin showing the best performance, as it maintained the viability at 7.34 log CFU/g. The compositional characteristics (biopolymer type and prebiotics addition) of the film forming solutions had no significant impact upon the viability of the probiotic strain. The incorporation of probiotics and prebiotics did not modify the infrared spectra, revealing that the molecular structure of the films was not modified. The moisture content and water solubility decreased positively in WPI- and ALG-based films with the addition of prebiotics compounds. Overall, the results obtained in this work support the use of WPI films containing inulin as a good strategy to immobilize B. animalis subsp. lactis BB-12, with potential applications in the development of functional foods.