Browsing by Issue Date, starting with "2021-05"
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- Chitosan-olive oil microparticles for phenylethyl isothiocyanate delivery: optimal formulationPublication . Coscueta, Ezequiel R.; Sousa, Ana Sofia; Reis, Celso A.; Pintado, ManuelaPhenylethyl isothiocyanate (PEITC), a chemopreventive compound, is highly reactive due to its considerably electrophilic nature. Furthermore, it is hydrophobic and has low stability, bioavailability and bioaccessibility. This restricts its use in biomedical and nutraceutical or food applications. Thus, the encapsulation of this agent has the function of overcoming these limitations, promoting its solubility in water, and stabilizing it, preserving its bioactivity. So, polymeric microparticles were developed using chitosan-olive oil-PEITC systems. For this, an optimisation process (factors: olive oil: chitosan ratio and PEITC: chitosan ratio) was implemented through a 3-level factorial experimental design. The responses were: the particle size, zeta-potential, polydisperse index, and entrapment efficiency. The optimal formulation was further characterised by FTIR and biocompatibility in Caco-2 cells. Optimal conditions were olive oil: chitosan and PEITC: chitosan ratios of 1.46 and 0.25, respectively. These microparticles had a size of 629 nm, a zeta-potential of 32.3 mV, a polydispersity index of 0.329, and entrapment efficiency of 98.49%. We found that the inclusion process affected the optical behaviour of the PEITC, as well as the microparticles themselves and their interaction with the medium. Furthermore, the microparticles did not show cytotoxicity within the therapeutic values of PEITC. Thus, PEITC was microencapsulated with characteristics suitable for potential biomedical, nutraceutical and food applications.
- Mapeamento do abandono escolar precoce em Portugal: versão curtaPublication . Azevedo, Joaquim; Oliveira, António; Azevedo, Margarida; Melo, Rodrigo Queiroz e
- Orósio e o curso da históriaPublication . Bolinhas, Maria Inês
- Apresentação da obraPublication . Albuquerque, Paulo Pinto de; Cardoso, Rui; Moura, Sónia
- Future trends on electrical vehicles servitization driven by the digital revolutionPublication . Serrano, Luís Manuel Ventura; Gaspar, Marcelo Rudolfo Calvete; Julião, Jorge
- Bioactive peptides produced from the mussel mytilus galloprovincialis by enzymatic hydrolysis with corolasePublication . Cunha, S. A.; Castro, R. de; Coscueta, E. R.; Pintado, M. E.Bioactive peptides have been produced from several marine sources since they can exhibit positive effects for humans and animals. Mytilus galloprovincialis is highly consumed in several countries and has a meat rich in proteins, which has been described as a source of bioactive peptides with relevant properties such as antioxidant, anti-hypertensive and antimicrobial activities. Mussel commercialization generates waste, since the small or broken mussels are discarded. Thus, in this work discarded mussels were used with the goal of producing water soluble extracts rich in proteins and bioactive peptides. The mussel meat was firstly minced, and then submitted to different conditions of enzymatic hydrolysis, using the protease corolase to generate peptides. The variable factors evaluated were temperature, incubation time and enzyme concentration. To achieve the optimal extraction conditions, a Box-Behnken experimental design was performed using statgraphic centurion software. Factorial design allowed the evaluation of the effects of the three factors on protein release, antioxidant and anti-hypertensive properties of the extracts. The protein content of each extract was determined by Kjeldahl, the antioxidant activity was determined by oxygen-radical absorbance-capacity (ORAC) assay and anti-hypertensive property was determined by the inhibition method of Angiotensin-I converting enzyme (ACE). The incubation of the minced mussel meat with 3% of enzyme, at 40 ºC for 3 hours, appears to be the best conditions to obtain the best results of protein extraction, and antioxidant and anti-hypertensive properties. With these conditions, the obtained extracts showed 48% of protein content, an antioxidant activity of 821 μmol TE / g of extract, and an ability of inhibiting the activity of ACE in 61% (using a concentration of 10 mg / mL). Thus, the factorial design allowed to confirm the combination of experimental factors that leads to the most efficient extraction of antioxidant and anti-hypertensive peptides of the mussel Mytilus galloprovincialis. In conclusion, the use of discarded mussels to produce functional ingredients for food, cosmetic and pharmaceutic industries contribute to valorise world waste in a circular economy context.
- Integrating public health policies in the epidemiological modeling of hepatitis C with LEHC tool: application in AustriaPublication . Lopes, Henrique; Baptista-Leite, Ricardo; Franco, Diogo; Pirke, Roxana; Gschwantler, MichaelBackground: Eliminating hepatitis C requires addressing issues other than medicines or therapies. Public health policies focused on the hepatitis C virus (HCV) must be emphasized and worked to know the impacts on its epidemiologic dynamics. This research aims to provide a tool to evaluate and simulate alternatives by redefining policies meeting specific needs in each country towards the HCV elimination target by 2030. Methods: The development of a gamified model with 24 public health policies focused on HCV was conducted to evaluate the impact of measures in the disease epidemiologic dynamics. The Let’s End HepC (LEHC) project encompassed key populations (people who inject drugs [PWID], prisoners, blood products and remnant population) in Austria and other countries, presenting prospects for every year from 2019 to 2030. The LEHC epidemiological model comprised an integrated solution for HCV, with adaptive conjoint analysis (ACA) and Markov chains constituting its main processes. Results: Despite Austria’s efforts towards achieving the HCV elimination goal by 2030, the LEHC model forecast quantitative analysis predicts that it is still not enough to meet the target; however, prospects are very optimistic if public health policies are adapted to the country’s needs, being possible to achieve the goal as early as 2026. Conclusion: In Austria, the LEHC tool allowed to forecast the HCV elimination year anticipation to 2026, instead of being achieved after 2030. This target will only be valid if adequate management of the 24 public health policies focused on this pathology is further implemented.
- Europe’s vaccine paradox: from supply to demand issuesPublication . Bongardt, Annette; Torres, Francisco
- Multi-step subcritical water extracts of fucus vesiculosus l. And codium tomentosum stackhouse: Composition, health-benefits and safetyPublication . Soares, Cristina; Paíga, Paula; Marques, Marta; Neto, Tânia; Carvalho, Ana Paula; Paiva, Alexandre; Simões, Pedro; Costa, Leonor; Bernardo, Ana; Fernández, Naiara; Pinto, Edgar; Almeida, Agostinho; Bronze, Maria Rosário; Delerue-Matos, Cristina; Grosso, ClaraMental health and active aging are two of the main concerns in the 21st century. To search for new neuroprotective compounds, extracts of Codium tomentosum Stackhouse and Fucus vesiculosus L. were obtained through multi-step (four step) subcritical water extraction using a temperature gradient. The safety assessment of the extracts was performed by screening pharmaceutical compounds and pesticides by UHPLC-MS/MS, and iodine and arsenic levels by ICP-MS. Although the extracts were free of pharmaceutical compounds and pesticides, the presence of arsenic and high iodine contents were found in the first two extraction steps. Thus, the health-benefits were only evaluated for the fractions obtained in steps 3 and 4 from the extraction process. These fractions were tested against five brain enzymes implicated in Alzheimer’s, Parkinson’s, and major depression etiology as well as against reactive oxygen and nitrogen species, having been observed a strong enzyme inhibition and radical scavenging activities for the step 4 fractions from both seaweed species. Regarding the variation of the chemical composition during the extraction, step 1 fractions were the richest in phenolic compounds. With the increase in temperature, Maillard reaction, caramelization and thermo-oxidation occurred, and the resulting products positively affected the antioxidant capacity and the neuroprotective effects.
- The inhibitory concentration of natural food preservatives may be biased by the determination methodsPublication . Gomes, Joana; Barbosa, Joana; Teixeira, PaulaThe demand for natural antimicrobials as food preservatives has increased due to the growing interest of the population for a healthy lifestyle. The application of screening methods to identify the antimicrobial activity of natural compounds is of great importance. The in vitro determination of antimicrobial activity requires determining their minimum inhibitory concentrations to assess microbial susceptibility. This study aimed to evaluate the minimum inhibitory concentrations of three natural antimicrobial compounds-chitosan, ethanolic propolis extract, and nisin-against 37 microorganisms (different pathogens and spoilage microorganisms) by the methods of agar dilution and drop diffusion on agar. Culture media at different pH values were used for both methods to simulate different food products. Most of the microorganisms were inhibited by chitosan (0.5% w/v) and propolis (10 mg/mL), and most of the Gram-positive bacteria by nisin (25 mu g/mL). Different pH values and the in vitro method used influenced the inhibition of each compound. Generally, lower minimum inhibitory concentrations were observed at lower pH values and for the agar dilution method. Furthermore, some microorganisms inhibited by the compounds on the agar dilution method were not inhibited by the same compounds and at the same concentrations on the drop diffusion technique. This study reinforces the need for using defined standard methods for the in vitro determination of minimum inhibitory concentrations. Natural compounds with potential antimicrobial action are a bet on food preservation. The use of standard techniques such as those used for antimicrobials of clinical applications are crucial to compare results obtained in different studies and different matrices.