Browsing by Author "Vilarinho, Fernanda"
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- Active Edible PackagingPublication . Barbosa, Cássia; Andrade, Mariana; Vilarinho, Fernanda; Fernando, Ana; Sanches-Silva, AnaDefinition: Active edible packaging is a food packaging made of comestible bioproducts and active compounds that interacts with the food. The bioproducts, usually biopolymers, must be recognized as safe and with characteristics to be consumed by humans—comestible—and not toxic and capable of carrying an active compound, like anti-browning agents, colorants, flavors, nutrients, antimicrobial and/or antioxidant compounds, in order to extend the product shelf-life, reduce contamination and maintain or even enhance the nutritional value.
- Active polylactic acid film incorporated with green tea extractPublication . Vilarinho, FernandaThe goal of this work was to produce a biodegradable active film based on polylactic acid (PLA) in which green tea extract (GTE) has been immobilized by extrusion, Two GTE concentrations were tested, 1% (w/w) and 2% (w/w). Four different GTEs were characterized regarding its antioxidant capacity, total phenolics content (TPC) and total flavonoids content (TFC). The commercial GTE chosen presented with highest antioxidant capacity by the DPPH radical assay (EC50= 0.12 ± 0.00 mg/mL) and highest TPC (416 ± 9.95 mg gallic acid equivalents (GAE)/g extract) being selected to be incorporated in the active film. The new film was to evaluated regarding its mechanical properties (e.g. tensile strength decreased 12% with the incorporation of GTE in the PLA matrix and strain at break increased 9.6% and 36% with the addition of 1% and 2% of GTE, respectively), water vapour transmission rate (water-vapour barrier properties improved with the addition of higher amounts of GTE) and effectiveness to inhibit lipid oxidation of model food. Smoked salmon was selected due to be a much appreciated high-fat content food with considerable high value in the market. The methods applied were: peroxide value, p-anisidine value, thiobarbituric acid reactive substances (TBARS) assay and hexanal monitoring, after packaging smoked salmon slices during different storage times (0, 7, 15, 30, 45 and 60 days). According to the results, the incorporation of GTE in the PLA films protects the smoked salmon from lipid oxidation in the different storage times tested. However, further studies should be performed to better understand the GTE mechanism of action as the results indicate a pro-oxidant effect of PLA/GTE 2% after 60 days of storage and to evaluate the potential antimicrobial activity of active films. To our information, this is the first time that an active PLA film containing GTE is evaluated regarding mechanical and barrier properties as well as its effectiveness in inhibiting lipid oxidation of smoked salmon.
- Active polylactic acid film incorporated with green tea extract: Development, characterization and effectivenessPublication . Martins, Carla; Vilarinho, Fernanda; Sanches-Silva, A.; Andrade, Mariana; Machado, A.; Vaz, M.F.; Ramos, F.A new antioxidant active packaging film has been developed based on polylactic acid (PLA) in which green tea extract (GTE) has been immobilized by extrusion. Two GTE concentrations were tested, 1% (w/w) and 2% (w/ w). Four GT samples were compared regarding their antioxidant capacity (by DPPH radical scavenging method and β-carotene bleaching method), total phenolics content (TPC) and total flavonoids content (TFC). The commercial GTE presented with highest antioxidant capacity by the DPPH radical assay (EC50=0.12 ± 0.00 mg/mL) and the highest TPC (416 ± 9.95 mg gallic acid equivalents (GAE)/g extract) and it was selected to be incorporated in the active film. Films were evaluated regarding their mechanical properties (e.g. tensile strength decreased 12% with the incorporation of GTE in the PLA matrix and strain at break increased 9.6 and 36% with the addition of 1 and 2% of GTE) and water vapour transmission rates (watervapour barrier properties improved with the addition of higher amounts of GTE). The study of the effectiveness of PLA/GTE films against lipid oxidation was performed by the following methods: peroxide value, p-anisidine value, thiobarbituric acid reactive substances (TBARS) assay and hexanal monitoring, after packaging smoked salmon slices during different storage times (0, 7, 15, 30, 45 and 60 days). The results showed that the incorporation of GTE in the PLA films protects the smoked salmon from lipid oxidation in the different storage times tested. However, additional studies should be performed to better understand the GTE mechanism of action as the results suggest a pro-oxidant effect of PLA/GTE 2% after 60 days of storage and to evaluate the potential antimicrobial activity of active films.
- Alecrim vs Chá Verde: Comparação do Poder Antioxidante Entre Dois Extratos NaturaisPublication . Castro, Frederico; Andrade, Mariana; Sanches Silva, A.; Vaz, M.F.; Vilarinho, FernandaO objetivo deste estudo foi a comparação da atividade antioxidante de extratos de alecrim e chá verde, para uma possível incorporação numa embalagem ativa.
- Alimentos PT.ON.DATA - Contaminantes químicos na cadeia alimentar em Portugal em amostras do controlo oficialPublication . Mascarenhas, Fernanda; Ravasco, Francisco; Brazão, Roberto; Pereira, João; Tomé, Sidney; Lopes, Ana; Vilarinho, Fernanda; Oliveira, LuisaA recolha de dados analíticos de géneros alimentícios e alimentos para animais é uma importante tarefa da Autoridade Europeia para a Segurança dos Alimentos (EFSA) e uma componente essencial na avaliação do risco associado à alimentação. Os Estados Membros (EM) têm o dever de transmitir para a EFSA os resultados do Controlo Oficial sendo os contaminantes químicos (CQ) uma das áreas a reportar. Os CQ podem estar presentes nos alimentos devido à contaminação ambiental, processo de fabrico, manipulação e transporte e, mesmo quando presentes em quantidades abaixo dos limites legais, o seu efeito cumulativo poderá trazer consequências graves para a saúde humana e animal. Para melhorar a comparabilidade técnica dos dados que recebe e analisa, a EFSA desenvolveu um modelo de dados Standard Sample Description (SSD), de utilização obrigatória para a transmissão de dados pelos EM. O INSA, em colaboração com várias entidades nacionais competentes para o Controlo Oficial, desenvolveu o sistema alimentos PT.ON.DATA para recolha, validação, transformação em modelo SSD e criação de ficheiros em formato XML para transmissão para a EFSA dos dados de CQ. O sistema criado permitiu ainda concentrar e harmonizar os dados produzidos pelas diversas entidades competentes, possibilitando uma melhor utilização dos mesmos. O sistema possui dados de contaminantes químicos do controlo oficial desde 2009 existindo atualmente 17149 resultados de géneros alimentícios (47,9 %) e 18644 resultados de alimentos para animais (52,1 %), distribuídos por quatro grupos de CQ, dos quais: 4618 (12,9%) para o grupo de contaminantes do processo, maioritariamente dioxinas e PCBs; 613 (1,7 %) para o grupo de contaminantes ambientais, sobretudo histamina (incluída no grupo das toxinas desde 2012) e hidroximetilfurfural; 18531 (51.8 %) para o grupo das toxinas, maioritariamente aflatoxinas (B1, B2, G1, G2); e 12031 (33,6 %) para o grupo dos metais e substâncias inorgânicas, maioritariamente cádmio, chumbo e mercúrio.
- Antioxidant and antimicrobial properties of PLA based active packaging with pomegranate peels and extractPublication . Andrade, Mariana; Rodrigues, Pedro; Barros, Carolina; Cruz, Vasco; Machado, Ana; Barbosa, Cássia; Coelho, Anabela; Furtado, Rosália; Correia, Cristina; Saraiva, Margarida; Vilarinho, Fernanda; Ramos, Fernando; Sanches Silva, AnaActive food packaging’ primary goal is to extend foodstuffs’ shelf life, through a dynamic and continuous interaction between the package and the packaged food. In an emission active packaging, the objective is the gradual release of antioxidant and/or antimicrobial compounds into the food surface, to delay the natural foods’ degradation. The active compounds can be extracted from several sources, such as aromatic plants, seaweeds, fruits by-products, among others. Since 50% of pomegranate is composed by peels, and since it is mainly consumed in juice and jam form, pomegranate peels may represent a considerable asset for the extraction of such compounds. The principal objective of this work was to evaluate the antioxidant and antimicrobial properties of polylactic-based active packaging incorporated with 3% (w/w) of pomegranate peels (PLA/3PP) and 3% (w/w) of pomegranate peels extract (PLA/3PPE). For the in vitro antioxidant activity evaluation, 9.08 cm2 of films were immersed in the food simulator, ethanol 95% (v/v), at 40 °C for 10 days. Then, the DPPH radical scavenging assay was performed, as well as the total content of phenolic compounds, total content in flavonoids, content in punicalagin (A+B) and ellagic acid were determined. Also, to fully determine the total content in punicalagin (A+B) and ellagic acid, the films were kept in methanol at 25 and 40 °C for 24 h. The antimicrobial activity of the films was evaluated with Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli, in accordance with ISO 22196:2011. Results showed that PLA/3PPE presented a higher antioxidant potential and higher content in phenolic compounds and flavonoids. Only ellagic acid was detected in the active PLA-based films. Regarding the antimicrobial activity, both films presented antimicrobial activity against S. aureus.
- Antioxidant and Cytoprotective Properties of Cyanobacteria: Potential for Biotechnological ApplicationsPublication . Guerreiro, Adriana; Andrade, Mariana; Menezes, Carina; Vilarinho, Fernanda; Dias, ElsaAntioxidant compounds from cyanobacteria may constitute a natural alternative to current synthetic antioxidants, which contain preservatives and suspected toxicity. In this work, we evaluate the antioxidant potential of cyanobacterial strains of distinct species/genus isolated from freshwater (n = 6), soil (n = 1) and wastewater (n = 1) environments. Lyophilized biomass obtained from in-vitro cultures of those strains was extracted with ethanol and methanol. The antioxidant potential was evaluated by chemical (DPPH scavenging method, β-carotene bleaching assay, determination of total phenolic and total flavonoid compounds) and biological (H2O2-exposed HEK293T cell line model) approach. Some strains showed high yields of antioxidant activity by the DPPH assay (up to 10.7% IP/20.7 TE µg/mL) and by the β-carotene bleaching assay (up to 828.94 AAC), as well as significant content in phenolic (123.16 mg EAG/g DW) and flavonoid (900.60 mg EQR/g DW) compounds. Normalization of data in a “per cell” or “per cell volume” base might facilitate the comparison between strains. Additionally, most of the cyanobacterial extracts conferred some degree of protection to HEK293T cells against the H2O2-induced cytotoxicity. Freshwater Aphanizomenon gracile (LMECYA 009) and Aphanizomenon flos-aquae (LMECYA 088), terrestrial Nostoc (LMECYA 291) and wastewater Planktothrix mougeotii (LEGE 06224) seem to be promising strains for further investigation on cyanobacteria antioxidant potential.
- Applying Cynara cardunculus L. leaf extracts to increase poultry meat shelf lifePublication . Barbosa, Cássia; Andrade, Mariana; Vilarinho, Fernanda; Sanches Silva, Ana; Fernando, Ana LuisaCardoon, Cynara cardunculus L. (Asteraceae), is a multipurpose crop. Its flower is used as vegetal rennet in the production of some cheeses, and its leaves, the main by-product generated, have excellent antioxidant and antimicrobial activities. These properties may be an asset in the food industry, as cardoons’ leaves may be used to delay lipid oxidation and microbial growth, thus prolonging foods’ shelf life. This study aims to evaluate the effectiveness of cultivated cardoon and globe artichoke leaf ethanolic extracts on poultry meat preservation. Extracts were mixed with the poultry meat (1% w/w) and stored under refrigeration (5°C ± 2°C) for 15 days. The microbiological growth was evaluated as well as moisture, pH, acidity, colour, Total Volatile Basic Nitrogen (TVBN), and lipid oxidation by Thiobarbituric Acid Reactive Substances (TBARS). Both extracts were effective in retarding microbial growth by maintaining a constant pH and level of acidity. After 15 days, poultry meat with both extracts showed a difference of up to 11 log CFU/g compared to control samples (without extract). Also, both extracts were able to reduce the lipid oxidation of the poultry meat when compared to the control samples at the end of the assay. The colour of extracts can be a limitation due to the greenish-yellow colour that is seen in the meat, although it was more evident in the sample with the cardoon extract. Overall, cardoon extract was the most effective in extending the shelf life of poultry meat.
- Atividade antimicrobiana: extrato de chá verde versus ácido poliláctico com o extrato incorporadoPublication . Martins, Cristiana; Maia, Carla; Furtado, Rosália; Correia, C.B.; Vilarinho, Fernanda; Sanches Silva, A.; Ramos, Fernando; Castilho, M.C.As folhas de cha verde (Camellia sinensis (L.) Kuntze) contem, na sua constituicao quimica, uma percentagem elevada de polifenois, que sao considerados otimos agentes antioxidantes e antimicrobianos. Este trabalho teve como objetivo avaliar a atividade antimicrobiana do extrato de cha verde e do filme de acido polilactico (PLA), destinado a aplicacoes alimentares, com extrato de cha verde incorporado em diferentes concentracoes, 1% e 2%. A atividade antimicrobiana foi avaliada utilizando estirpes padrao das bacterias Gram-positivas Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis e Bacillus cereus e das bactérias Gram-negativas Escherichia coli, Pseudomonas aeruginosa e Salmonella Thyphimurium. Placas de Agar Mueller Hinton foram inoculadas com os microrganismos em estudo. Para o extrato de cha verde, a atividade antimicrobiana foi testada pelo metodo de difusao em pocos preenchidos com o extrato. Para testar a atividade antimicrobiana dos filmes foram colocados, em contacto com a superfície de agar, os filmes PLA com extrato de cha verde (1% e 2%) (filmes ativos) e sem extrato (filme controlo). Procedeu-se de seguida a incubacao das placas em condicoes de tempo e temperatura de acordo com cada microrganismo. A atividade antimicrobiana foi estimada a partir dos halos de inibicao total de crescimento microbiano Os resultados revelaram que o extrato de cha verde apresentou atividade antibacteriana sobre as bactérias Gram positivas estudadas (Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis e Bacillus cereus). No entanto, quando e incorporado nos filmes ativos, nas concentracoes 1% e 2%, nao apresenta capacidade antimicrobiana sobre nenhum dos microrganismos testados. A quantidade de extrato de cha verde incorporado no acido polilactico e/ou metodo utilizado na incorporacao podem justificar os resultados obtidos.
- Avaliação da capacidade antioxidante de extratos de Fucus vesiculosus para aplicação a embalagens alimentares ativasPublication . Andrade, Mariana; Reboleira, J.; Bernardino, S.; Ganhão, R.; Mendes, S.; Vilarinho, Fernanda; Sanches Silva, A.; Ramos, FernandoA indústria alimentar usa antioxidantes sintéticos para prevenir a degradação natural dos alimentos com alto teor lipídico causada, em grande parte, por fenómenos de oxidação. Estes antioxidantes, incluindo o BHT e o BHA, têm sido nas últimas décadas associados a efeitos negativos sobre a saúde humana, como a promoção da carcinogénese e reações alérgicas [1,2]. Atualmente, a maioria dos alimentos é adquirida numa embalagem que, na sua grande maioria, são feitas de plástico, obtido através de fontes não renováveis. O grave problema ambiental que se coloca com estas embalagens, aliado à procura e exigência dos consumidores por produtos naturais e com mínimo impacto ambiental, tem impulsionado a indústria e a comunidade científica a procurar alternativas, quer para as embalagens, quer para os antioxidantes sintéticos. Nesta linha de pensamento, foram criadas as embalagens alimentares ativas antioxidantes que interagem intencionalmente com o alimento embalado, libertando para o mesmo compostos bioativos capazes de retardar ou inibir a oxidação dos mesmos, aumentando assim o seu tempo de vida útil. A Fucus vesiculosus, também conhecida como fava-do-mar, é uma macroalga castanha (Phaeophyceae) presente em zonas frias e temperadas do Oceano Atlântico Norte, com uma poderosa capacidade antioxidante [3,4]. Na sua constituição, esta macroalga tem vários compostos bioativos, como os polissacarídeos sulfatados, que possuem poderosas atividades biológicas como atividades anti-tumorais, antioxidantes e antimicrobianas. O objetivo deste trabalho foi avaliar a capacidade antioxidante de cinco extratos hidro-etanólicos de F. Vesiculosus para avaliar o seu potencial de aplicação a embalagens alimentares ativas. Os extratos foram obtidos da alga seca e da alga liofilizada. Os ensaios de avaliação da capacidade antioxidante utilizados foram o Sistema de Inibição do Radical DPPH (2,2-diphenyl-1-picrylhydrazyl) e o Ensaio do Branqueamento do β-caroteno. Os extratos obtidos a partir da alga liofilizada obtiveram uma melhor capacidade antioxidante do que os extratos obtidos a partir da alga seca. Esta diferença pode ser explicada pela diferença de temperatura, uma vez que no caso da alga liofilizada, esta é seca através de um processo com baixas temperaturas, o que acaba por conservar os compostos bioativos da alga. O mesmo não acontece com a alga seca através de um processo normal de secagem.