Browsing by Author "Morais, A. M. M. B."
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- Actividade da pectinametilesterase da pêra "Rocha" após armazenamento em atmosfera controladaPublication . Sanchez, A. C. G.; Morais, A. M. M. B.
- Activity of 'Jonagored' apple polyphenoloxidase (PPO) stored in controlled atmospherePublication . Rocha, A. M. C. N.; Morais, A. M. M. B.
- 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.
- Antibacterial and antioxidant potential of aqueous extracts of bio-residues from agrocybe cylindracea and pleurotus ostreatus myceliumPublication . Sousa, A. S.; Marçal, S.; Costa, C.; Ferreira, I.; Barros, J.; Nunes, J.; Freitas, A. C.; Morais, A. M. M. B.; Pintado, M.The production of fresh mushrooms results in a large quantity of bio-residues, which may account for more than 20% of a crop volume and contributes to production costs and environmental impact, if not used. These products consist mainly of stalks, mushrooms of irregular dimensions and shape and basal material. Thus, the main objective of MicoBioExtract project is the valorisation of these bio-residues and the development of add-value by-products with bioactive compounds such as polysaccharides and phenolic compounds produced by mushrooms. In the present work, the aqueous extracts from Agrocybe cylindracea byproducts (ACB) and Pleurotus ostreatus mycelium (POM) were evaluated for potential antioxidant and antimicrobial activities. Water soluble substances were extracted from mushrooms according to two different methods. In method 1 it was performed a hot extraction (extract 1A; 90 °C; 1 h; 500 rpms). In method 2, the biomass was submitted to an extraction at room temperature (extract 2B) and the resulting residue was extracted with hot water (extract 2C; 90 °C; 1 h; 500 rpms). The aqueous extracts from POM were obtained only by method 1. Extracts were lyophilized and their bioactivity evaluated measuring the antioxidant (ABTS, DPPH and ORAC) and antimicrobial (determination of the minimum inhibitory concentration – MIC) activities. The mutagenicity was also tested (Ames assay with and without S9). Moreover, it was determined the total phenolics content of the extracts and α and β – glucans (Folin Ciocalteu and Beta-Glucan Assay methods, respectively). The results obtained from antioxidant methods showed that all extracts from both mushrooms are a potential source of natural antioxidant and phenolic compounds. According to ABTS, extract 2B from ACB showed the best value with 8.48±0.33 mg ascorbic acid equivalent (AAE)/g dry extract and 4.14±0.52 mg AAE/g dry extract for POM. Regarding the antimicrobial activity, MIC results showed that ACB and POM extracts inhibited the growth of Gram- (Salmonella enteritidis) and Gram+ (Bacillus cereus and Listeria monocytogenes). Concerning the mutagenicity, the results showed no toxic effect except for extract 1A from ACB. Regarding the β-glucan content, the extracts from ACB presented higher content of β-glucan than the C extracts from POM. Thus, aqueous extracts from mushroom bio-residues showed potential antioxidant and antimicrobial properties and to develop a circular bioeconomy approach.
- 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.
- Atmosfera modificada para preservação de espargoPublication . Morais, A. M. M. B.
- Avaliação do “shrinkage” ao longo da secagem por convecção de castanha (Castanea sativa)Publication . Ramalhosa, E.; Lamas, H.; Pereira, J. A.; Morais, A. M. M. B.Geralmente nos estudos que envolvem modelagem matemática da secagem por convecção de castanha (Castanea sativa), os frutos são aproximados a corpos esféricos e assume-se que a dimensão dos mesmos se mantém constante ao longo da secagem. Neste trabalho pretendeu-se encontrar um modelo que relacionasse, de forma simples e rápida, as dimensões axiais das castanhas com o diâmetro de esferas de volume equivalente e avaliar se o efeito de “shrinkage” era significativo ou não ao longo da secagem por convecção a diferentes temperaturas. Para tal, determinaram-se as dimensões axiais (a, b, c) e calcularam-se os diâmetros médios aritmético (Da) e geométrico (Dg), a esfericidade e os diâmetros das esferas equivalentes a castanhas da variedade “Longal”, utilizadas no presente trabalho. Procedeu-se posteriormente à sua secagem por convecção a diferentes temperaturas, designadamente a 40, 50, 65, 85 e 100ºC e avaliou-se o seu efeito nas dimensões dos frutos. Verificou-se que os Da e Dg permitiram estimar os diâmetros das esferas equivalentes, x, através de dois modelos lineares: y=0,771x+0,730, r = 0,922 e y=0,814x+0,545, r = 0,916, respectivamente. Além disso, verificou-se que um modelo do tipo: diâmetro estimado pelo modelo = k1a + k2b + k3c + k4ab + k5bc + k6ac + k7(abc)n, também permitiu relacionar de forma adequada estes diâmetros estimados com os das esferas correspondentes (r = 0,949) demonstrando que as castanhas podem ser consideradas corpos esféricos com diâmetros estimados a partir das dimensões axiais, as quais são fácil e rapidamente determinadas. Em relação à secagem por convecção a diferentes temperaturas, verificou-se um comportamento linear (r entre 0,834 e 0,997) entre as três dimensões axiais das castanhas com casca, avaliadas no início e no final de cada experiência, determinando-se na maior parte dos casos declives próximos de 1,0. Estes resultados indicam que as castanhas com a casca não sofrem um efeito de “shrinkage” significativo ao longo da secagem. Após calcular a proporção do fruto interno sem casca em relação ao fruto com casca ao longo das secagens a diferentes temperaturas, verificou-se que a mesma variou entre 78,3+4,3 e 89,2+4,6 % e que, para cada temperatura, se observou uma diminuição nessa percentagem ao longo do tempo, indicando que o fruto internamente sofreu efeito de “shrinkage” significativo à medida que foi secando. Em conclusão, este trabalho permitiu verificar que no futuro ao realizar a modelagem da secagem por convecção da castanha pode aproximar-se a mesma a esferas com diâmetros estimados a partir de Da,Dg ou de outro modelo que seja adequado. No entanto, deve-se ter em conta a forma como a castanha se encontra, designadamente com ou sem casca, uma vez que o efeito de "shrinkage” poderá ser significativo na castanha sem casca.