Browsing by Author "Morais, R. M. S. C."
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- Alga Fucus sp. extracts to produce edible filmsPublication . Martins, V.; Machado, M.; Costa, E.; Gomes, A. M.; Poças, F.; Pintado, M.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: Macroalgae are a good source of nutrients, such as carbohydrates (dietary fiber and polysaccharides), proteins, lipids and minerals [1,2]. Fucus sp. is composed of valuable bioactive compounds, such as fucoxanthin, vitamins, water-soluble (vitamin C and of complex B) and fat-soluble (vitamins A, D, E and K), phenolic compounds, lipids (MUFA and PUFA), and polysaccharides (fucoidans and alginic acid) [1]. This brown alga has been associated with health benefits, such as antioxidant, antimicrobial, anti-tumoral and anti-cancer properties [2]. Its application in the production of edible films presents high potential in food packaging, extending the shelf life of food products. Objectives: To evaluate the antioxidant activity and cytotoxicity bioactive extracts from Fucus sp. To produce an edible film based on PS enriched with the bioactive extracts. To test the antioxidant activity of the edible film. To test physico-chemical properties of the edible film, such as the color, thickness, solubility and water vapor permeability. Conclusions: Extraction at 300 W during 20 minutes is recommended for highest TPC and AA of the liquid extract. This extract showed no cytotoxicity for cells line HaCat. The edible film based on the PS extracted from Fucus sp. enriched with bioactives extracted also from this alga shows antioxidant activity, presents a high water vapor permeability, and 100 % solubility in water, which simulates hydrophilic foods, and lower solubility in hydroalcoholic solutions, which simulate hydrophobic foods. It has a brown color, characterized by relatively low luminosity and saturation values. This edible film has potential to be used in food packaging, whereas presenting high biodegradability.
- Alterações de cor e actividade da polifenol oxidase de cubos de maçã "starking" revestidos com alginato e desidratados por convecçãoPublication . Fernandes, S. D. S.; Ribeiro, C. A. S.; Morais, R. M. S. C.; Morais, A. M. M. B.
- Alterações de cor e actividade da polifenol oxidase de cubos de maçã ‘starking’ revestidos com alginato e desidratados por convecçãoPublication . Fernandes, S. D. S.; Ribeiro, C. A. S.; Morais, R. M. S. C.; Morais, A. M. M. B.O presente trabalho consistiu na aplicação de um revestimento comestível de alginato em cubos de maçã ‘Starking’ e subsequente desidratação por convecção. Pretendeu-se estudar o efeito que este revestimento poderia ter sobre a cor e a actividade da polifenol oxidase (PPO) dos cubos de maçã com teores em água variáveis. Os cubos de maçã foram desidratados a 20, 35 ou a 40°C, com fluxo paralelo de ar. Foram realizadas análises de cor (L*, a*, b*), actividade da PPO e matéria seca ao longo da secagem. A capacidade de absorção de água das amostras obtidas por secagem a 40°C também foi avaliada. Os melhores resultados, relativamente ao aspecto e à actividade da PPO dos cubos de maçã revestidos com alginato, foram obtidos no processo de secagem com fluxo perpendicular de ar a 40ºC, tendo sido previamente efectuado um branqueamento da maçã inteira com casca a 60ºC, durante 10 minutos. Ao fim de duas semanas de exposição ao ar, os cubos de maçã secos a 40°C sem revestimento apresentaram uma maior absorção de água do que os cubos de maçã seca com revestimento, concluindo-se que o revestimento protege, em alguma medida, a amostra contra a absorção de água presente no ar.
- Anti-biofilm potential of phenolic acids: the influence of environmental pH and intrinsic physico-chemical propertiesPublication . Silva, Sara; Costa, Eduardo M.; Horta, Bruno; Calhau, Conceição; Morais, R. M. S. C.; Pintado, M. E.Phenolic acids are a particular group of small phenolic compounds which have exhibited some anti-biofilm activity, although the link between their activity and their intrinsic pH is not clear. Therefore, the present work examined the anti-biofilm activity (inhibition of biomass and metabolic activity) of phenolic acids in relation to the environmental pH, as well as other physico-chemical properties. The results indicate that, while Escherichia coli was not inhibited by the phenolic acids, both methicillin resistant Staphylococcus aureus and methicillin resistant Staphylococcus epidermidis were susceptible to the action of all phenolic acids, with the pH playing a relevant role in the activity: a neutral pH favored MRSE inhibition, while acidic conditions favored MRSA inhibition. Some links between molecular polarity and size were associated only with their potential as metabolic inhibitors, with the overall interactions hinting at a membrane-based mechanism for MRSA and a cytoplasmic effect for MRSE.
- Antimicrobial, antiadhesive and antibiofilm activity of an ethanolic, anthocyanin-rich blueberry extract purified by solid phase extractionPublication . Silva, Sara; Costa, Eduardo M.; Mendes, M.; Morais, R. M. S. C.; Calhau, Conceição; Pintado, M. E.Aims: The present work aimed to characterize the impact of an anthocyaninrich blueberry extract upon the growth, adhesion and biofilm formation of several pathogens including some multiresistant bacteria. Methods and Results: A group comprised of reference strains and clinical multiresistant isolates of Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Acinetobacter baumannii and Staphylococcus aureus, were used to screen for antimicrobial activity. Microbial growth was determined through the measurement of the optical density while adhesion and biofilm formation was determined using the standard crystal violet staining procedure. The results showed that, while blueberry extract was only effective in hindering the growth of Staph. aureus and E. coli, it was capable of significantly inhibiting biofilm formation and bacterial adhesion for all micro-organisms tested. Conclusions: The extract demonstrated a considerable potential as a natural, alternative antimicrobial capable of either interfering with microbial growth or hamper the adhesion to surfaces, with Staph. aureus proving to be the most susceptible micro-organism. Significance and Impact of the Study: The overall study demonstrates the potential of anthocyanin extracts as natural effective alternative antimicrobial agents. Additionally, the extract’s capacity to reduce adhesion without reducing bacterial growth reduces the likeliness of resistance development while reducing the probability of infection.
- Antioxidant activity and total phenolic content of different extracts from depilified olive oil pomacePublication . Martins, V. F. R.; Ribeiro, T. B.; Pintado, M. E.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: The use of by-products as a source of bioactive compounds with economic added value is one of the objectives of the circular economy. Olive oil industry is a source of olive pomace, as a by-product. The olive pomace used in the present study was the exhausted (delipidified) olive pomace, which is the by-product generated after drying and subsequent hexane extraction of residual oil from the olive pomace. This exhausted olive oil pomace may contain remaining bioactive compounds, such as phenolic compounds, which can be of interest not only for the food industry, but also for the pharmaceutical and cosmetic industries. Objectives: Various types of green methodologies, such as solvent extraction (water and hydroalcoholic), ultrasound-assisted extraction, ultra-turrax-assisted extraction and enzyme-assisted extraction (cellulase; viscoenzyme) were used to obtain extracts rich in bioactive compounds from the exhausted olive oil pomace. The bioactivity of these extracts was evaluated through the antioxidant activity. Conclusions: Among all methodologies used the extractions with enzymes produced the best yields of extraction and the conventional extraction with water at 50 °C produced the best results for the total phenolic content and antioxidant activity: ABTS, DPPH and ORAC.
- Antioxidant activity and total phenolic content of different extracts of delipidified olive oil pomacePublication . Martins, V. F. R.; Ribeiro, T. B.; Pintado, M. E.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: The use of by-products as a source of bioactive compounds with economic added value is one of the objectives of the circular economy. Olive oil industry is a source of olive pomace, as a by-product. The olive pomace used in the present study was the exhausted (delipidified) olive pomace, which is the by-product generated after drying and subsequent hexane extraction of residual oil from the olive pomace. This exhausted olive oil pomace may contain remaining bioactive compounds, such as phenolic compounds, which can be of interest not only for the food industry, but also for the pharmaceutical and cosmetic industries. Objectives: Various types of green methodologies, such as solvent extraction (water and hydroalcoholic), ultrasound-assisted extraction, ultra-turrax-assisted extraction and enzyme-assisted extraction (cellulase; viscoenzyme) were used to obtain extracts rich in bioactive compounds from the exhausted olive oil pomace. The bioactivity of these extracts was evaluated through the antioxidant activity. Conclusions: Among all methodologies used the extractions with enzymes produced the best yields of extraction and the conventional extraction with water at 50 °C produced the best results for the total phenolic content and antioxidant activity: ABTS, DPPH and ORAC.
- Bioactive compounds from marine microalgae — health applicationsPublication . Raposo, M. Filomena de J.; Morais, R. M. S. C.; Morais, Alcina M. M. B.
- Biodegradation of p-chlorophenol by a microalgae consortiumPublication . Lima, Sofia A. C.; Raposo, M. F.; Castro, Paula M.L.; Morais, R. M. S. C.An aquatic communitywas recovered from a waste discharge container fed with several aromatic pollutants. After 3 months of selective enrichment with p-chlorophenol and p-nitrophenol, two microalgae species, Chlorella vulgaris and Coenochloris pyrenoidosa, were recovered from the microbial consortium. As an axenic culture, this microalgae consortium was able to remove p-chlorophenol under different photo-regimes. Cultures grown under a 24 h light regime were capable of biodegrading 50mg l 1 of p-chlorophenol within 5 days. Addition of zeolite, an adsorbing material, did not improve the p-chlorophenol removal. However, when p-chlorophenol at 150mg l 1 was fed to the culture supplemented with zeolite, the growth rate of the consortium improved, but the lag phase was longer (16 against 14 days in the absence of zeolite).
- Characterization of alga Fucus sp. extracts and residues and their application in producing edible filmsPublication . Martins, V.; Coelho, M.; Machado, M.; Costa, E.; Gomes, A. M.; Poças, F.; Pintado, M.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: Macroalgae are a good source of nutrients, such as carbohydrates (dietary fiber and polysaccharides), proteins, lipids and minerals, and they are sustainable, because they do not compete with food crops for arable land and potable water [1,2]. Fucus sp. is composed of valuable bioactive compounds, such as fucoxanthin, vitamins, water-soluble vitamins (vitamin C and of complex B) and fat-soluble vitamins (vitamins A, D, E and K), phenolic compounds, lipids (MUFA and PUFA), and polysaccharides (fucoidans and alginic acid) [1]. This brown alga has been associated with health benefits, with antioxidant, antimicrobial, anti-tumoral and anti-cancer properties [2]. Its application in the production of edible films presents high potential in food packaging, extending the shelf life of food products. Objectives: The integral valorization of Fucus sp. macroalgae, by extracting bioactive compounds, such as phenolic compounds, and extracting polysaccharides (PS). To evaluate the cytotoxicity and antioxidant activity of the bioactive extracts. To produce an edible film based on PS enriched with the bioactive extracts from Fucus sp. To test the physico-chemical properties of the edible film, such as the solubility. The nutritional characterization of the residues from the extractions. Conclusions: Extraction at 300 W during 20 minutes is recommended for highest TPC and AA of the liquid extract. This extract showed no cytotoxicity for cells line HaCat. The edible film based on the PS extracted from Fucus sp. enriched with bioactives extracted also from this alga presents 100 % solubility in water, which simulates hydrophilic foods, and lower solubility in hydroalcoholic solutions, which simulate hydrophobic foods. This edible film has potential to be used in food packaging, whereas presenting high biodegradability.