Browsing by Author "Castilho, M.C."
Now showing 1 - 10 of 38
Results Per Page
Sort Options
- Active Food Packaging with Antioxidant Properties: Incorporation of Plant Extracts in Polymeric Matrices to Extend Food Shelf-lifePublication . Sanches-Silva, A.; Carvalho-Costa, D.; Reis, A.R.; Albuquerque, T.G.; Castilho, M.C.; Ramos, F.; Machado, A.V.; Costa, H.S.Antioxidants (AOs) play an important role in biological processes because they prevent the effect of reactive oxygen species, protecting against cancer, inflammatory processes, cardiovascular diseases and aging, and consequently the degenerative diseases associated with it. In foods, AOs prevent oxidation which causes their deterioration and limits their shelf lives. Synthetic antioxidants are very effective against lipid oxidation, however some of them have been associated to toxic effects, which have increased the interest of food industry for natural substances also effective against this phenomenon. One of the main roles of food packaging is to retard the natural processes that lead to food deterioration. AOs can be incorporated into food packaging and be released by a controlled mechanism of diffusion. The use of AOs in food packaging may delay both lipid oxidation and protein denaturation. Packaging designed to foster desirable interactions with its content has been called active packaging. This innovative food packaging concept can extend the shelf life of food through the release of AOs by a controlled mechanism of diffusion from the packaging to the food surface and dissolution in it or in the inner atmosphere of the product or by the scavenging of free radicals. The release mechanism provides a continuous replenishment of AOs to foods and therefore, can reduce the direct addition of chemicals to the food. Rosemary (Rosmarinus officinalis L.) is a widely consumed aromatic herb that belongs to the Lamiaceae family. It is a xeromorphic species that grows spontaneously on sand, cliffs and stony places near the sea in many parts of the world. The fresh and dried leaves are frequently used as a food preservative and in traditional Mediterranean cuisine as a flavouring agent, being used with meat, fish, baked potatoes and sauces. Due to the influence of different factors such as growing conditions on the content of natural antioxidants, different rosemary commercial brands were compared. Antioxidant activity (radical 2,2-diphenyl-1-picrylhidrazyl (DPPH) scavenging activity), total phenolics and total flavonoids were evaluated. Moreover, their content on natural antioxidants, carnosic acid, carnosol and rosmarinic acid was quantified by an Ultra High Performance Liquid Chromatographic method coupled with a diode array detector (UHPLC-DAD) which has been validated in our laboratory. Finally, carotenoids and vitamin E were also evaluated following another UHPLC-DAD optimized in our laboratory. Rosemary extract has been approved as food additive (Directives 2010/67/EU and 2010/69/EU). In line with this, rosemary was also used to obtain a rosemary extract with high antioxidant activity. In fact, different solvents were tested in order to evaluate which originated higher antioxidant activity. Those with higher antioxidant activity and individual antioxidants content were used to produce active food packaging. Due to environmental motivation there is an increasing interest in the use of biodegradable/compostable packaging and/or edible materials. This tendency increases when materials come from industrial waste or renewable resources. Although rosemary extract has already been used in non-biodegradable matrices, to our knowledge, it is the first time that it has been used to produce biodegradable active packaging. Therefore, different polymeric matrices were evaluated, biodegradable and non-biodegradable. Migration tests were carried with food simulants at standard conditions. Promising results were found until now, and the new packaging material will also be tested in contact with foods in order to check their capacity to inhibit lipid oxidation, allowing to preserve the quality of foodstuffs and to increase their shelf-life. Our research group of the Department of Food and Nutrition from the National Institute of Health Dr. Ricardo Jorge (INSA) has great experience in the development of analytical methods for the determination of bioactive compounds (namely antioxidants) in foodstuffs and food byproducts as well as in food-packaging interactions and mathematical modelling of migration. Moreover it has a large number of peer-review publications in this field as well as national and international collaborations with other researcher groups that work in the same or complementary fields. Some of the groups that work in close collaboration with ours include the research group of Prof. Jaime López Cervantes from the Technological Institute of Sonora (México) and the research groups of Prof. Perfecto Paseiro and Prof. José Manuel Cruz from the Universities of Santiago de Compostela and Vigo, respectively. In the future, this research group intends to extend the research to other aromatic herbs and food by-products in order to search for new and interesting extracts that can be used to produce antioxidant active food packaging, with special interest in biodegradable matrices. The final aim is to be able to extend food shelf life reducing the direct additives of antioxidants to foods with positive health implications, at long term, for the consumers.
- Advances in phenolic compounds analysis of aromatic herbs and their potential applications.Publication . Carvalho-Costa, D.; Costa, H.S.; Reis, A.R.; Albuquerque, T.G.; Castilho, M.C.; Ramos, F.; Machado, A.V.; Sanches-Silva, A.; PhenolicIntroduction: Herbs can be considered important sources of antioxidants and have a long history of medicinal and culinary applications. The use of plants as sources of antioxidants for nutritional and preservation purposes in the food industry is currently growing. Materials and Methods: An extensive bibliographic review on the methods for analysis of phenolic compounds present in herbs was carried out. Results, Discussion and Conclusion: Plant derived phenolic compounds can be divided in four groups: phenolic acids, phenolic diterpenes, flavonoids and volatile compounds. Considering the first three groups, the identification and quantification of the compounds in the literature is accomplished using High Performance Liquid Chromatography while for volatile compounds, the identification and quantification is accomplished with Gas Chromatography. Several herbs, such as sage (Salvia officinalis), thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis), oregano (Origanum majorana), dandelion (Taraxacum officinale), peppermint (Mentha piperita) and basil (Ocimum basilicum) were analyzed in different studies regarding their phenolic compounds. The major phenolic acids found in herbs were ferulic, caffeic, neochlorogenic and rosmarinic. In terms of phenolic diterpenes, carnosol, rosmanol and carnosic acid were the most reported. Regarding flavonoids, luteolin, quercetin and apigenin were predominant. Concerning volatile compounds, thymol, carvacrol and eugenol were the most common. The herbs with more antioxidant potential regarding their composition on phenolic compounds were compared and the potential of utilisation of these food matrices for newer applications such as active packaging was discussed.
- Are mushrooms a good source of antioxidants for active food packaging?Publication . Silva, N.; Sanches-Silva, A.; Castilho, M.C.; Ramos, F.Active packaging is gaining considerable attention by consumers and food industry due to its unequivocal advantages such as improvement of food quality and extension of food shelf-life. In this frame, active packaging with antioxidant properties is one of the new packaging concepts that comprise greatest developments. Recently, in order to look for sources of natural antioxidants, a vast range of foods and food by-products have been evaluated. The aim of this work was to evaluate the content on phenolics and flavonoids of edible mushrooms of different species and cultivated according to different methods in order to check their potential use in active packaging. The total phenolics content (TPC) and total flavonoids content (TFC) was evaluated.
- Aromatic herbs: determination of phenolic compounds by ultra-high performance liquid chromatography with diode array detectionPublication . Reis, A.R.; Costa, H.S.; Carvalho-Costa, D.; Albuquerque, T.G.; Castilho, M.C.; Ramos, F.; Machado, A.V.; Sanches-Silva, A.Aromatic herbs contain phenolic compounds which have attracted scientific interest and consumers because of their health-promoting effects as antioxidants. Seven plants, Origanum majorana L. (marjoram), Ocimum basilicum L. (basil), Thymus vulgaris (thyme), Artemisia dracunculus L. (tarragon), Origanum vulgare L. (oregano), Mentha piperita L. (peppermint) and Rosmarinus officinalis L. (rosemary), have been examined in order to determine their phenolic composition. Ultra-high performance liquid chromatography with diode array detection (UHPLC-DAD) method was developed for the identification and quantification of phenolic compounds in the aforementioned plants. All samples were extracted with methanol. Chromatographic separation was performed with an Acquity UPLC® BEH Shield guard-column (5 mm, 2.1 mm I.D., 1.7 µm particle size) and an Acquity UPLC® BEH Shield RP18 (100 mm, 2.1 mm I.D., 1.7 µm particle size). Mobile phases were (A) water: acetic acid 0.1 % (v/v); (B) acetonitrile: acetic acid 0.1 % (v/v). Total phenolic content of the plants was also determined spectrophotometrically applying the Folin-Ciocalteu method. The major phenolic acids found in herbs were ferulic, caffeic and rosmarinic. In terms of volatile compounds thymol, carvacrol and eugenol were determined. The selected aromatic herbs are good sources of phenolic compounds which extend their potential of application to the cosmetics, pharmaceutical and food packaging industries besides the food industry.
- Aromatic plants: a source of phenolic compounds?Publication . Oliveira, A.S.; Castilho, M.C.; Ribeiro-Santos, R.; Ramos, F.; Sanches-Silva, A.Nowadays there is a renaissance of the interest in aromatic plants due to their properties, specially their antioxidant properties. The antioxidant activity of the aromatic plants is mainly due to the high content of phenolic acids (gallic acid, protocatechuic acid, caffeic acid and rosmarinic acid), flavonoids (quercetin), phenolic diterpenes (carnosol and carnosic acid) and volatile oils (eugenol, carvacrol and thymol). The food industry has demonstrated an increasing interest in phenolic compounds to prevent the oxidative degradation of lipids and to improve the quality and nutritional value of the food and thus increasing the shelf life of food products. The aim of this study is to compare aromatic plants commonly used for culinary purposes in what regards to their composition in phenolic compounds.
- 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.
- Atividade antioxidante do alecrim (Rosmarinus officinalis L.): efeito do solvente de extraçãoPublication . Costa, D.; Costa, H.S.; Albuquerque, T.G.; Ramos, F.; Castilho, M.C.; Machado, A.V.; Sanches-Silva, A.O alecrim (Rosmarinus officinalis L.) é um subarbusto densamente ramoso e foliado e pertence à família Lamiaceae. É utilizado como erva aromática e foi recentemente aprovado como aditivo alimentar (Directivas 2010/67/UE e 2010/69/UE). As propriedades antioxidantes do alecrim tornam-no muito importante como conservante dos alimentos, e estas propriedades devem-se principalmente aos seus compostos fenólicos: ácidos fenólicos, diterpenos fenólicos, flavonóides e óleos voláteis. Neste estudo, o alecrim foi extraído com diferentes solventes e a sua actividade antioxidante foi testada através de três métodos: ensaio do DPPH● (2,2-difenil-1-picril-hidrazilo), determinação dos compostos fenólicos totais e determinação dos flavonóides totais. O alecrim foi extraído com acetona, metanol, etanol e hexano/etanol. No ensaio do DPPH● adicionou-se uma alíquota de extrato (50 μL) a 2 mL de solução metanólica de DPPH● (3,6 × 10-5 M) e agitou-se. Após 30 min, mediu-se a absorvência a 515 nm. Para a determinação dos compostos fenólicos totais adicionou-se uma alíquota de 1 mL da solução teste, a 7,5 mL de reagente Folin–Ciocalteu. Deixou-se à temperatura ambiente durante 5 min e adicionou-se 7,5 mL de solução aquosa de Na2CO3 (60 mg/mL). Mediu-se a absorvência a 725 nm, após 2 h. Para a determinação dos flavonóides totais a uma alíquota de 1 mL da solução, adicionou-se água até perfazer 5 mL. De seguida adicionou-se 0,3 mL de NaNO3 (5%, p/v) e homogeneizou-se. Após 5 minutos, juntou-se 0,6 mL de AlCl3 (10%, p/v) e homogeneizou-se novamente. Ao fim de 6 min, adicionou-se 2 mL de NaOH 1 M e 2,1 mL de água. A absorvência foi medida a 510 nm. No ensaio do DPPH●, para os extratos em metanol, etanol, hexano/etanol e acetona, os valores de EC50 (concentração de extrato que produz uma inibição de 50% do DPPH•) obtidos foram 1,66 ± 0,04; 2,90 ± 0,05; 2,97 ± 0,03; e 3,04 ± 0,02 mg/mL, respectivamente. No segundo ensaio, os resultados obtidos, em mg GAE (equivalentes de ácido gálico)/g de extrato, foram 82,4 ± 2,43; 24,7 ± 0,74; 26,4 ± 1,46; e 24,8 ± 1,58, respectivamente. Relativamente ao terceiro ensaio, os resultados obtidos, em mg ECE (equivalentes de epicatequina)/g de extrato, foram 74,5 ± 5,24; 18,72 ± 1,40; 36,5 ± 17,71; e 13,9 ± 5,55, respectivamente. Verificou-se que o melhor solvente, entre os testados, foi o metanol, sendo as diferenças obtidas estatisticamente significativas (P <0,05).
- Carotenoids and α-tocopherol content of some aromatic herbs by ultra-high performance liquid chromatography with diode array detectionPublication . Carvalho-Costa, D.; Albuquerque, T.G.; Costa, H.S.; Reis, A.R.; Castilho, M.C.; Ramos, F.; Machado, A.V.; Sanches-Silva, A.Carotenoids are colorful plant pigments with antioxidant properties that can prevent some forms of cancer and heart disease as well as enhance immune response to infections. Several aromatic herbs, such as Origanum majorana L. (marjoram), Ocimum basilicum L. (basil), Thymus vulgaris (thyme), Artemisia dracunculus L. (tarragon), Origanum vulgare L. (oregano), Mentha piperita L. (peppermint) and Rosmarinus officinalis L. (rosemary) have been examined in order to determine their carotenoids and vitamin E composition. Carotenoids were extracted from aromatic herbs with a mixture of hexane/ethanol, 4:3 (v/v). All samples were subjected to a procedure with and without saponification step. Separation and quantification was performed by Ultra-High Performance Liquid Chromatography with diode array detection (UHPLC-DAD). Chromatographic separation was performed with Acquity UPLC® BEH C18 analytical column (50 mm, 2.1 mm I.D., 1.7 µm particle size) and an Acquity UPLC® BEH C18 guard column (5.0 mm, 2.1 mm I.D., 1.7 µm particle size). Mobile phases were (A) ultrapure water; (B) acetonitrile/methanol (containing 0.05 M ammonium acetate)/dichloromethane (75:20:5, v/v/v). The flow-rate was 0.5 mL/min. In the case of rosemary, lutein, zeaxanthin, α-carotene and α-tocopherol were quantified and saponification decreased the amount of these carotenoids. The analysed aromatic herbs can be considered good sources of carotenoids, although a great variability was found among their content. Due to the putative health benefits of these compounds, their consumption shall be encouraged and promoted.
- Carotenoids and α-tocopherol determination in common aromatic herbsPublication . Sanches-Silva, A.; Carvalho-Costa, D.; Albuquerque, T.G.; Reis, A.R.; Castilho, M.C.; Ramos, F.; Machado, A.V.; Costa, H.S.Aromatic herbs have long been recognised for their pleasant flavour and therapeutic properties. Nowadays there is an increasing interest on their study, especially in what concerns to their bioactive compounds with potential health benefits. The objective of this study was to analyse seven aromatic herbs regarding their content on carotenoids (zeaxanthin, lutein, β-cryptoxanthin, lycopene, α-carotene and β-carotene) and α-tocopherol. Samples were acquired in supermarkets of Lisbon in the dried form. The following aromatic herbs were selected for the study: basil (Ocimum basilicum L.), marjoram (Origanum majorana L.), oregano (Origanum vulgare L.), peppermint (Mentha piperita L.), rosemary (Rosmarinus officinalis L.), tarragon (Artemisia dracunculus L.) and thyme (Thymus vulgaris). Carotenoids were extracted from samples with hexane/ethanol, 4:3 (v/v). In the case of peppermint, thyme, basil and tarragon, two sample preparation procedures were compared, with and without saponification with methanolic KOH (10%, w/v) during 4 h. Ultra-High Performance Liquid Chromatography with diode array detection (UHPLC-DAD) was used for quantification. An Acquity UPLC® BEH C18 guard column (5.0 mm x 2.1 mm I.D., 1.7 µm particle size) and an Acquity UPLC® BEH C18 analytical column (50 mm x 2.1 mm I.D., 1.7 µm particle size) were selected for the separation. The mobile phase was a gradient of solvent (A) ultrapure water and solvent B [acetonitrile/methanol (containing 0.05 M ammonium acetate)/dichloromethane (75:20:5, v/v/v)]. The run time was 22 min and the flow-rate was 0.5 mL/min. Saponification is a common step for the determination of carotenoids in foods from plant origin because it allows the hydrolysis of carotenoid esters and carotenol esters, and eliminates chlorophylls and other interfering substances like unwanted lipids. However in the analysis of peppermint, thyme, basil and tarragon, saponification degraded carotenoids. Lutein was found in all the studied aromatic herbs (from 389 to 20739 µg/100 g of sample, for tarragon and thyme, respectively) and zeaxanthin in all except one. Remarkable amounts of lutein were found in thyme, indicating this particular herb as an excellent source of this carotenoid. The highest content of β-carotene was found for peppermint (1149 µg/100 g of sample) followed by marjoram (359 µg/100 g of sample). The quantification of β-carotene in rosemary, peppermint, marjoram and oregano indicates that these aromatic herbs present provitamin A activity. α- tocopherol was quantified in rosemary (9.3 mg/100 g of sample) and oregano (8.1 mg/100 g of sample). Comparing all the analysed herbs, rosemary presented the highest concentrations of α-tocopherol and zeaxanthin, and considerable concentrations of lutein. The intake of aromatic herbs may contribute for the total daily intake of antioxidants, which have positive health benefits, like prevention of cardiovascular disease and cancer, and may help to reduce the addition of sugar and salt to foods; therefore their consumption shall be encouraged and promoted.
- Cogumelo ostra (Pleurotus ostreatus) comercializado e cultivado em borras de café e palha de trigo: fonte de compostos antioxidantes.Publication . Ricardo, S.; Sanches-Silva, A.; Costa, H.S.; Ramos, F.; Albuquerque, T.G.; Castilho, M.C.Os cogumelos comestíveis são apreciados em todo o mundo não só pelas suas características organoléticas, mas também pelas suas propriedades nutricionais e funcionais. Estas propriedades devem-se ao facto dos cogumelos possuírem compostos bioativos, nomeadamente, ergosterol (precursor da vitamina D2), compostos fenólicos, tocoferóis, ácido ascórbico e carotenóides, responsáveis pela atividade antioxidante, pelo que podem ser associados à promoção da saúde. Um dos cogumelos comestíveis que tem suscitado maior interesse nos últimos anos é o cogumelo ostra (Pleurotus ostreatus) devido à facilidade de cultivo e ao seu grande potencial económico e qualidade nutricional. Este estudo determinou a atividade antioxidante pelo método do radical DPPH• (2,2-difenil-1-picril-hidrazilo) do cogumelo ostra cultivado em diferentes substratos, nomeadamente, borras de café, borras de café em papelão e palha de trigo, dada a sua possível influência no teor de compostos bioativos na matriz em estudo. Para tal, 2 mL de solução metanólica de DPPH• (1,5x10-3 mg/mL) foram adicionados a 0,05 mL de extrato num tubo de ensaio. Após a agitação da mistura realizou-se a leitura da absorvência no espectrofotómetro a 517 nm, no início da reação e após 30 minutos do início da mesma. Os resultados obtidos para a atividade antioxidante, expressos em EC50 (concentração de extrato que produz uma inibição de 50% do DPPH•), indicaram uma maior atividade antioxidante no caso das amostras de cogumelo ostra cultivado em borras de café (17 mg/mL) e em borras de café e papelão (14 mg/mL), comparativamente à amostra cultivada em palha de trigo (26 mg/mL) e às restantes amostras obtidas comercialmente. Estes resultados também sugerem a influência da composição do substrato utilizado no cultivo no teor de compostos antioxidantes no cogumelo ostra, sendo que tal pode ser justificado pelo facto das borras de café apresentarem teores consideráveis de compostos fenólicos totais na sua composição. O estudo da atividade antioxidante dos cogumelos ostra cultivados em diferentes substratos é o primeiro passo na avaliação dos mesmos como fonte promissora de compostos bioativos e é fundamental para o conhecimento dos substratos mais indicados para o seu cultivo.