Percorrer por autor "Nunes, Catarina"
A mostrar 1 - 10 de 14
Resultados por página
Opções de ordenação
- Antibacterial and antioxidant potential of aqueous extracts of bio-residues from agrocybe cylindracea and pleurotus ostreatus myceliumPublication . Sousa, Ana Sofia; Nunes, Catarina; Barros, Joana; Ferreira, Inês; Freitas, Ana C.; Morais, Alcina M. M. B.; Nunes, João; Pintado, ManuelaThe 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.
- A escola aliada ao território – o caso da Esproarte, uma educação que tocaPublication . Nunes, Catarina; Dias, José Francisco; Orvalho, LuísaNão obstante o importantíssimo trabalho social desempenhado pela escola ao longo dos anos, é hoje necessário (re)pensar o espaço público da educação e encará-lo enquanto um projeto de ação estrategicamente partilhado entre a escola, as famílias e outros atores sociais, culturais e políticos que operam num determinado território que, sem descurar os domínios e as missões específicas de cada um, são capazes de se aventurar num compromisso que é de todos. É com base nesta premissa que se pretende enfatizar o caso da ESPROARTE – Escola Profissional de Arte de Mirandela, um projeto visionário e vanguardista, cuja missão tem sido, ao longo de vinte e cinco anos de existência, estendido e partilhado com o meio envolvente e assumido de forma empreendedora e participada pelas organizações locais e sobretudo pelo município que potenciou a abertura de um novo ciclo cultural, não só na cidade de Mirandela, como em toda a região transmontana.
- Impact of extraction process in non-compliant ‘Bravo de Esmolfe’ apples towards the development of natural antioxidant extractsPublication . Vilas-Boas, Ana A.; Oliveira, Ana; Ribeiro, Tânia B.; Ribeiro, Sónia; Nunes, Catarina; Gómez-García, Ricardo; Nunes, João; Pintado, ManuelaThe ‘Bravo de Esmolfe’ apple (BE) is rich in antioxidants and represents one of the most important traditional cultivars in Portugal. A large amount of non-compliant BE, with no market value, it is generated every year. Thus, an effort to find value-added solutions is of utmost importance. For the first time, green extraction (microwave-assisted-extraction (MAE) and ultrasound-assisted-extraction (UAE)) were compared against conventional extraction (with (CET) and without temperature (CE)) to select the most efficient process to produce a natural antioxidant extract from non-compliant BE. The results showed that MAE and CET are good methodologies for developing a BE antioxidant extract. However, MAE is more sustainable than CET, requiring less time to reach high temperatures. The MAE-extract showed great antioxidant activity (14.80 ± 0.70 mg TE/g DE by ORAC, 3.92 ± 0.25 mg AAE/g DE by ABTS, and 5.11 ± 0.13 mg TE/g DE by DPPH). This extract revealed high amount of chlorogenic acid (0.48 ± 0.07 mg/g DE), (-)-epicatechin (0.30 ± 0.02 mg/g DE) and phloridzin (0.13 ± 0.01 mg/g DE). This study shows that non-compliant BE is a useful source of antioxidants, being a sustainable way for the recovery of value-added compounds from the rejected fruit in line with sustainable and circular bioeconomy principles.
- Lavandula pedunculata polyphenol-rich extracts obtained by conventional, MAE and UAE methods: exploring the bioactive potential and safety for use a medicine plant as food and nutraceutical ingredientPublication . Vilas-Boas, Ana A.; Goméz-García, Ricardo; Machado, Manuela; Nunes, Catarina; Ribeiro, Sónia; Nunes, João; Oliveira, Ana L. S.; Pintado, ManuelaNowadays, plant-based bioactive compounds (BCs) are a key focus of research, supporting sustainable food production and favored by consumers for their perceived safety and health advantages over synthetic options. Lavandula pedunculata (LP) is a Portuguese, native species relevant to the bioeconomy that can be useful as a source of natural BCs, mainly phenolic compounds. This study compared LP polyphenol-rich extracts from conventional maceration extraction (CE), microwave and ultrasound-assisted extraction (MAE and UAE). As a result, rosmarinic acid (58.68–48.27 mg/g DE) and salvianolic acid B (43.19–40.09 mg/g DE) were the most representative phenolic compounds in the LP extracts. The three methods exhibited high antioxidant activity, highlighting the ORAC (1306.0 to 1765.5 mg Trolox equivalents (TE)/g DE) results. In addition, the extracts obtained with MAE and CE showed outstanding growth inhibition for B. cereus, S. aureus, E. coli, S. enterica and P. aeruginosa (>50%, at 10 mg/mL). The MAE extract showed the lowest IC50 (0.98 mg DE/mL) for angiotensin-converting enzyme inhibition and the best results for α-glucosidase and tyrosinase inhibition (at 5 mg/mL, the inhibition was 87 and 73%, respectively). The LP polyphenol-rich extracts were also safe on caco-2 intestinal cells, and no mutagenicity was detected. The UAE had lower efficiency in obtaining LP polyphenol-rich extracts. MAE equaled CE’s efficiency, saving time and energy. LP shows potential as a sustainable raw material, allowing diverse extraction methods to safely develop health-promoting food and nutraceutical ingredients.
- Modelos e práticas de avaliação na formação avançada em ciências da educação: Face - ensino profissionalPublication . Orvalho, Luísa; Nunes, Catarina
- Modelos e práticas de avaliação na formação avançada em ciências da educação: face-ensino profissionalPublication . Orvalho, Luísa; Nunes, CatarinaEsta investigação foi realizada no âmbito do projeto de Pós- Doutoramento em Ciências da Educação, na Faculdade de Educação e Psicologia (FEP), da Universidade Católica Portuguesa, intitulado “Colaborar para Inovar no Ensino Profissional”, num conjunto de escolas com ensino profissional, e pretende responder à questão-problema: Que estratégias formativas podem potenciar a mudança de práticas do professor na sala de aula e garantir a qualidade da educação e formação profissional? Seguiu-se a estratégia metodológica - Appreciative Inquiry (AI), assente no Ciclo AI-5 D, constituido por cinco fases de desenvolvimento: Define, Discovery, Dream, Design, Deliver/ Destiny.
- Phenolics content and antioxidant activity of aqueous extracts from bio-residues of agrocybe cylindraceaPublication . Sousa, Ana Sofia; Marçal, Sara; Nunes, Catarina; Barros, Joana; Ferreira, Inês; Freitas, Ana C.; Morais, Alcina M. M. B.; Nunes, João; Pintado, ManuelaMushrooms are known as a rich source of functional and bioactive compounds. Among these, phenolic compounds as important antioxidants are included. In the present work, the antioxidant potential and total phenolic compounds from bio residues obtained from edible mushroom production were evaluated in order to develop a circular bioeconomy approach. The studied species was Agrocybe cylindraceae. The extraction was performed using water as the only solvent, in order to obtain a process as green as possible and with minimal costs and it can be easily scaled up at industrial level. The aqueous extracts were obtained according to two different methods (1 and 2). In method 1, a hot extraction was performed (90°C; 1h; 500 rpms; extract 1A). In method 2, a temperature room extraction was done (extract 2A) and the resulting residue was subsequently extracted with hot water (90 °C; 1 h; 500 rpms; extract 2B). Extracts were freeze-dried and the extraction yields were determined. The content of total phenolic compounds was determined using Folin-Ciocalteu method. The antioxidant activity was also evaluated by ABTS, DPPH and ORAC assays. The extraction yields relative to aqueous extracts 1A, 2A and 2B from A. cylindraceae were 39.5 ± 1.5 %, 34.4 ± 1.2 % and 11.4± 0.8 %. The total phenolic contents obtained was 13.4 ± 0.3, 12,28 ± 0.01 and 12.3 ± 0.3 mg gallic acid equivalents per g dry extract for extracts 1A, 2A and 2B, respectively, which values are again lower than values reported in literature for ethanolic extracts, as expected. Regarding the antioxidant activity the results showed that the extracts of A. cylindraceae are a possible source of natural antioxidants. According to ABTS assay, the results were: 10 ± 1 (1A); 8.4 ± 0.1 (2A); 8.3 ± 0.9 (2B) mg ascorbic acid equivalent per g dry extract. According to the results, these extracts could still be considered as a natural source of antioxidants. Thus, the valorisation of these bio-residues through the development of value-added “green” products is an opportunity to increase the sustainability of the mushroom production chain.
- Phenolics content and antioxidant activity of aqueous extracts from bio-residues of agrocybe cylindraceaPublication . Sousa, Ana Sofia; Marçal, Sara; Nunes, Catarina; Barros, Joana; Ferreira, Inês; Freitas, Ana C.; Morais, Alcina M. M. B.; Nunes, João; Pintado, ManuelaMushrooms are known as a rich source of functional and bioactive compounds. Among these, phenolic compounds as important antioxidants are included. In the present work, the antioxidant potential and total phenolic compounds from bio-residues obtained from edible mushroom production were evaluated in order to develop a circular bioeconomy approach. The studied species was Agrocybe cylindraceae. The extraction was performed using water as the only solvent, in order to obtain a process as green as possible and with minimal costs and it can be easily scaled up at industrial level. The aqueous extracts were obtained according to two different methods (1 and 2). In method 1, a hot extraction was performed (90°C; 1h; 500 rpms; extract 1A). In method 2, a temperature room extraction was done (extract 2A) and the resulting residue was subsequently extracted with hot water (90 °C; 1 h; 500 rpms; extract 2B). Extracts were freeze-dried and the extraction yields were determined. The content of total phenolic compounds was determined using Folin-Ciocalteu method. The antioxidant activity was also evaluated by ABTS, DPPH and ORAC assays. The extraction yields relative to aqueous extracts 1A, 2A and 2B from A. cylindraceae were 39.5 ± 1.5 %, 34.4 ± 1.2 % and 11.4± 0.8 %. The total phenolic contents obtained was 13.4 ± 0.3, 12,28 ± 0.01 and 12.3 ± 0.3 mg gallic acid equivalents per g dry extract for extracts 1A, 2A and 2B, respectively, which values are again lower than values reported in literature for ethanolic extracts, as expected. Regarding the antioxidant activity the results showed that the extracts of A. cylindraceae are a possible source of natural antioxidants. According to ABTS assay, the results were: 10 ± 1 (1A); 8.4 ± 0.1 (2A); 8.3 ± 0.9 (2B) mg ascorbic acid equivalent per g dry extract. According to the results, these extracts could still be considered as a natural source of antioxidants. Thus, the valorisation of these bio-residues through the development of value- added“green” products is an opportunity to increase the sustainability of the mushroom production chain.
- Pleurotus ostreatus and Pleurotus eryngii as a source of phenolic compoundsPublication . Marçal, Sara; Vale, Pedro; Sousa, Ana Sofia; Nunes, Catarina; Barros, Joana; Ferreira, Inês; Nunes, João; Pintado, ManuelaThe intake of phenolic compounds from food products and supplements has been associated to prevention of degenerative diseases, mainly due to their antioxidant activity. The phenolic compounds can be found in plant foods and mushrooms. The main goal of this study was to quantify the total phenolic compounds of aqueous extracts from two mushrooms species, Pleurotus ostreatus and Pleurotus eryngii, and evaluate their antioxidant activity. The aqueous extracts from P. ostreatus and P. eryngii were obtained through two extraction methods (M1 and M2). In M1, a hot extraction was performed (extract M1) (90 ºC, 500 rpm, 1 h). In M2, a room temperature extraction (extract M2A), followed by a hot extraction (extract M2B) (90 ºC, 500 rpm, 1 h) of extract M2A residue, was done. Extracts M1, M2A, and M2B obtained from each mushroom species were lyophilized, and the extraction yields were determined. Total phenolics content was quantified through Folin Ciocalteu method. The results were expressed as gallic acid equivalents (GAEs). In its turn, the antioxidant activity was determined through ABTS and ORAC methods. The results of the two methods were expressed as ascorbic acid equivalents (AAEs) and trolox equivalents (TEs), respectively. The cytotoxicity (PrestoBlue) and mutagenicity (Ames) of all extracts also were evaluated.The extraction yield of extracts M1, M2A and M2B from P. ostreatus were 41.33% ± 4.29, 33.60% ± 0.39 and 15.18% ± 0.70, respectively. In its turn, the extraction yield of extracts M1, M2A, and M2B from P. eryngii were 46.03 ± 2.18, 44.46 ± 3.96, 12.58 ± 0.94. All extracts from both mushroom species were good sources of phenolic compounds. The extracts M1, M2A and M2B from P. ostreatus had 15.80 ± 1.54, 16.57 ± 0.26 and 16.65 ± 1.01 mg GAEs / g dry extract, while extracts M1, M2A and M2B from P. eryngii had 9.06 ± 0.63, 7.90 ± 0.46, 9.25 ± 0.28 mg GAEs / g dry extract. Antioxidant activity was observed in all extracts. The antioxidant activity of extracts from P. ostreatus (M1: 5.78 ± 0.31; M2A: 6.33 ± 0.83; M2B: 4.39 ± 1.12 mg AAEs / g dry extract) was higher than antioxidant activity of extracts from P. eryngii (M1: 5.48 ± 0.03; M2A: 2.23 ± 0.15; M2B: 3.87 ± 0.39 mg AAEs / g dry extract). No extract showed any genotoxic or cytotoxic effect. The results of this study indicate that aqueous extracts from P. ostreatus and P. eryngii are a source of phenolic compounds. Possibly, these extracts have the potential to be used in the development of food products and nutraceuticals enriched in phenolic compounds associated to other relevant properties ascribed to these mushrooms.
- Pleurotus ostreatus bio-residues: a source of bioactives with antioxidant and antimicrobial activityPublication . Sousa, Ana Sofia; Nunes, Catarina; Barros, Joana; Ferreira, Inês; Freitas, Ana C.; Morais, Alcina M. M. B.; Nunes, João; Pintado, ManuelaMushrooms are known to be a rich source of functional and bioactive compounds. Among these, phenolic compounds and polysaccharides, mainly β-glucans, stand out due to their antioxidant and immunomodulatory effects, respectively. In the present work, the total phenolic compounds content, the content in β-glucans and bioactivity properties from the bio-residues obtained from mushroom production were evaluated in order to develop a circular bioeconomy approach. Pleurotus ostreatus, one of the most cultivated species worldwide, was studied. The extraction was performed using water as the only solvent to obtain the possible greener process and easy to scale up at the industrial level.The aqueous extracts were obtained according to two different methods (1 and 2). In method 1, a hot extraction was performed (90 °C; 1 h; 500 rpm; extract 1A). In method 2, a room temperature extraction was carried out (extract 2A), and the resulting residue was subsequently extracted with hot water (90 °C; 1 h; 500 rpm; extract 2B). Extracts were freeze-dried, and the content of total phenolic compounds (TPC) was determined using the Folin-Ciocalteu method. β-glucans content was determined according to the "β-Glucan Assay Kit (Yeast & Mushroom)" assay. Moreover, the extracts' bioactivity was evaluated by assessing the antioxidant (ABTS, DPPH and ORAC) and antimicrobial (minimum inhibitory concentration – MIC) activities. The mutagenicity and cytotoxicity were evaluated by Ames and PrestoBlue assays, respectively. The TPC obtained was 11.94 ± 1.50, 9.95 ± 0.50 and 12.39± 0.57 mg gallic acid equivalent per g of dry extract for extracts 1A, 2A and 2B, respectively. Regarding the β-glucan content the results were: 10.67 ± 0.19 (1A), 7.62 ± 0.09 (2A), 5.96 ± 0.03 (2B) g per 100 g of dry mushroom. The extracts M2B and M1 were the ones that presented the highest results for the phenolic compounds and β-glucans, respectively. Furthermore, all extracts showed antioxidant activity (lower activity in the DPPH assay) and antimicrobial activity against the tested bacteria (Salmonella enterica, Escherichia coli, Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas tolaasii, Pseudomonas agarici, Yersinia enterocolitica, Staphylococcus aureus, Bacillus cereus e Listeria monocytogenes), with the 2A extract standing out as an inhibitor of bacterial growth. The extracts did not show mutagenicity or cytotoxicity at the tested concentrations (40 mg/mL). Thus, the aqueous extracts from P. ostreatus bio-residues could be considered a promissory natural source of bioactives, namely phenolic compounds and β-glucans with relevant biological properties. Besides, the valorisation of these bio-residues presents an opportunity to promote the mushroom production chain sustainability.