Percorrer por autor "Morales, Patricia"
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- Adding molecules to food, pros and cons – A review on synthetic and natural food additivesPublication . Carocho, Márcio; Barreiro, M.F.; Morales, Patricia; Ferreira, Isabel C.F.R.The pressing issue to feed the increasing world population has created a demand to enhance food production, which has to be cheaper, but at the same time must meet high quality standards. Taste, appearance, texture, and microbiological safety are required to be preserved within a foodstuff for the longest period of time. Although considerable improvements have been achieved in terms of food additives, some are still enveloped in controversy. The lack of uniformity in worldwide laws regarding additives, along with conflicting results of many studies help foster this controversy. In this report the most important preservatives, nutritional additives, coloring, flavoring, texturizing, and miscellaneous agents are analyzed in terms of safety and toxicity. Natural additives and extracts, which are gaining interest due to changes in consumer habits are also evaluated in terms of their benefits to health and combined effects. Technologies, like edible coatings and films which have helped overcome some drawbacks of additives, but still pose some disadvantages, are briefly addressed. Future trends like nanoencapsulation and the development of “smart” additives and packages, specific vaccines for intolerance to additives, use of fungi to produce additives, and DNA recombinant technologies are summarized.
- Aditivos antioxidantesPublication . Carocho, Márcio; Morales, Patricia; Ferreira, Isabel C.F.R.La química entre los radicales libres y antioxidantes se fundamenta en un equilibrio entre ambos. Los radicales libres son compuestos muy reactivos que tienden a captar un electrón de moléculas biológicas estables con el fin de alcanzar su estabilidad electroquímica. Una vez que el radical libre ha conseguido sustraer el electrón que necesita, la molécula estable que se lo cede se convierte, a su vez, en un radical libre al quedarse con un electrón desapareado, iniciándose así una verdadera reacción en cadena. La vida media biológica dei radical libre es de microsegundos, pêro tiene la capacidad de reaccionar con todo lo que este a su alrededor provocando dano molecular en membranas celulares y tejidos. Los radicales libres se pueden definir como "cualquier espécie química con un número impar de electrones, con uno o más electrones desapareados, que se encuentra de forma libre en el médio".
- Aditivos edulcorantesPublication . Carocho, Márcio; Morales, Patricia; Ferreira, Isabel C.F.R.El poder edulcorante es una de las propiedades más conocidas de los azúcares. Se determina en relación con la sacarosa, el azúcar de referencia (a una solución de 30 g/L a 20°C se lê asigna un poder edulcorante igual a l), y no depende unicamente de su concentración, sino también de la intensidad dei sabor dulce. Se calcula mediante la determinación dei umbral de percepción dei sabor o por comparación con la sustancia de referencia (sacarosa). El umbral de reconocimiento de la sensación dulce es la concentración mínima dei azúcar a la cual es posible percibir el sabor dulce [1-4 mM). La intensidad dei sabor dulce está condicionada a la solubilidad de la sustancia, de manera que, una vez solubilizada en la saliva, esta entra en contacto con el receptor. También depende de otros parâmetros, como son la estructura dei edulcorante, la temperatura, el pH, y de la presencia de otras sustancias que puedan interferir con los receptores dei sabor. Con respecto a la estructura, la intensidad dei sabor dulce suele disminuir a medida que aumenta el número de unidades de monosacáridos que conforme el edulcorante, siendo, por tanto, mucho menor en el caso de los oligosacáridos.
- Amaranthus caudatus L. as a source of betacyanins with coloring and antimicrobial properties.Publication . Roriz, Custódio Lobo; Alves, Maria José; Morales, Patricia; Barros, Lillian; Ferreira, Isabel C.F.R.Amaranthus caudatus L. is a plant belonging to the Amaranthaceae family, and is a very interesting crop, since it resists drought, heat, and pests, and adapts readily to new environments. The visual appearance of this plant is a bright red-violet, being betacyanins the compounds responsible for the color, and several bioactivities. Therefore, and despite being considered a good source of nutrients with high quality proteins, vitamins, minerals and bioactive molecules, such as phenolic compounds, A. caudatus can also be commercially exploited as a source of natural colorants. In the last decade, and due to the growing demand of consumers, natural matrices have been used to search natural colorant alternatives, in order to replace the artificial counterparts, which have been revealed some toxic effects. Betacyanins are natural colorants and have been used in the food industry, not only because of the high colouring power, but also due to recognized bioactive properties, such as antioxidant and antimicrobial, among others. Thus, the objective of this work was to obtain an extract rich in betacyanins to be used as food coloring agents, offering an alternative source of these coloring compounds, but at the same time conferring bioactive properties. A dynamic maceration extraction was carried out, being the extracts characterized by HPLC-DAD-ESI/MS regarding betacyanins’ composition. The antibacterial activity was evaluated against a panel of four Gram-positive and five Gram-negative bacteria, and the absence of cytotoxicity was confirmed in a porcine liver primary culture. By the chromatographic analysis it was possible to identify four compounds, being amaranthine (171 ± 1 mg/g extract) and isomaranthine (38 ± 1 mg/g) the two major compounds, and betanin (1.6 ± 0.1 mg/g) and isobetanin (1.3 ± 0.1 mg/g) the minor compounds. The extract presented minimum growth inhibitory concentrations (MICs) ranging from 20-10 mg/mL, with no cytotoxicity. After such promising results, this plant can be a viable alternative to obtain natural colorant ingredients.
- Análise de vitamina 69 e minerais em plantas silvestres: estudos de Biodisponibilidade com milefólio, louro e dente-de-leãoPublication . Dias, Maria Inês; Morales, Patricia; Barreira, João C.M.; Oliveira, Beatriz; Sánchez-Mata, María Cortes; Ferreira, Isabel C.F.R.As plantas silvestres usadas tradicionalmente têm suscitado um interesse cada vez maior, por serem consideradas uma fonte valiosa de compostos naturais com reconhecidos efeitos benéficos para a saúde do consumidor. Entre estes compostos estão as vitaminas e os elementos minerais, com um reconhecido papel na manutenção da saúde humana. A vitamina B9 (ácido fólico) é um importante cofactor de muitas reações que ocorrem nas células, enquanto que os macro e microelementos desempenham um papel fundamental na produção de energia e na manutenção da integridade estrutural da membrana celular. Os macroelementos funcionam também como modeladores do metabolismo e do equilíbrio ácido-base. Apesar destes componentes terem sido já estudados em diferentes espécies de plantas, a sua análise em espécies silvestres e, sobretudo, em aspetos relacionados com biodisponibitidade, é ainda escassa. No presente trabalho, foi realizado um processo de diálise por membrana com o objetivo de simular condições gastrointestinais para a avaliação da biodisponibilidade dos elementos minerais presentes em diferentes formulações (planta seca e infusão) de Achillea millefollium L. (milefólio), Laurus nobilis L. (louro) e Taraxacum sec. Ruderalia (dente-de-leão). A dinâmica de retenção/passagem foi avaliada utilizando uma membrana de celulose com 34 mm de porosidade. Os teores em vitamina B9 foram também analisados, por cromatografia líquida de alta eficiência acoplada a detecção por fluorescência, nas diferentes preparações de cada amostra. O dente de leão apresentou os níveis mais elevados de elementos minerais (exceto zinco) independentemente da formulação utilizada (planta seca ou infusão). Por outro lado, o milefólio mostrou um conteúdo mais elevado de vitamina B9. As plantas secas, como era expectável, mostraram maiores quantidades de todos os elementos estudados, em relação às respetivas infusões; no entanto, os rendimentos de extração dos elementos minerais variaram muito, sendo mais elevados para os macroelementos. Os níveis de vitamina 89 foram muito mais baixos nas infusões, possivelmente devicto à degradação induzida pela água fervente aquando da sua preparação. Relativamente à biodisponibilidade, o cálcio e o potássio demonstraram maior capacidade para atravessar a membrana de diálise. As espécies de plantas estudadas, especialmente se usadas diretamente na forma seca, podem ser consideradas para o desenvolvimento de formulações que atuem como fontes de vitamina B9 e minerais.
- Analysis of tocopherols and phenolic compounds in extruded lentil flour formulations for development of snack-type functional foodsPublication . Ciudad-Mulero, María; Fernandes, Ângela; Barros, Lillian; Ferreira, Isabel C.F.R.; Berrios, José de J.; Montaña, Cámara; Morales, Patricia; Fernández-Ruiz, VirginiaPulses are currently considered as functional gluten-free foods, which could be included in extrusion formulations in order to develop functional products with high nutritional value [1]. In the present study individual phenolic compounds and tocopherols were evaluated in different lentil flours (raw and extruded at 140 and 160ºC) formulated with nutritional yeasts.Phenolic compounds were analysed by using a HPLC equipped with a diode-array detector and coupled to a mass detector [2].For the analysis of tocopherols, it was used HPLC coupled to a fluorescence detector [1]. Extrusion cooking may affect bioavailability of phenolic compounds due to high temperature that causes decomposition of heat-labile phenolic compounds and may also lead to polymerization of some phenolic compounds under high pressure [3]. Catechin hexoside was the most abundant phenolic compound, with values around 30.7 to 66.1 mg/100g dw in raw samples. After the extrusion process, it was observed the highest decrease in the lentil flours formulated with the highest amount of nutritional yeast (16%). The other phenolic compounds, also experiment a decrease but in a less extend, probably due to partial hydrolysis of conjugated phenolics[4].Particularly in the case of kaempferol-O-desoxyhexide-O-hexoside- O-rutinoside, quercetin-3-O-glucoside, quercetin-O-hexoside and quercetin-O-pentoside. Regarding tocopherols content, there was a significant decrease in all tocopherol vitamer safter the extrusion process.In the studied raw samples, total tocopherols content ranged from 2.05 to 3.02 mg/ 100g (dw). The results showed a reduction of 81.5-92% in total tocopherols, which is in accordance with other authors [3].
- Antimicrobial and antifungal activities of a coloring extract rich in betacyanins obtained from the flowers of Gomphrena globosa LPublication . Roriz, Custódio Lobo; Barros, Lillian; Prieto Lage, Miguel A.; Morales, Patricia; Soković, Marina; Barreiro, M.F.; Ferreira, Isabel C.F.R.There is a huge diversity of pigments from natural origin that can be exploited as colorants in the food industry. Nonetheless, they can additionally provide several bioactive properties, which represent an added-value for food products. Carotenoids, chlorophylls, anthocyanins and betalains are some of the most studied plant-based pigments. Betalains, can be subdivided according to their chemical structure into betacyanins and betaxanthins [1]. Although less exploited than Beta vulgaris L., Gomphrena globosa L. is an important source of betacyanins [2], with antimicrobial and antifungal activity [3]. Thus, the aim of this study was to obtain a pigmented extract from G. globosa with a high antimicrobial and antifungal activity. This objective was implemented by the application of the response surface methodology (RSM), a robust optimization technique that allows to study jointly the effects of several variables and responses, namely in extraction procedures (in this case ultrasound assisted extraction (UAE)). To evaluate the antimicrobial and antifungal properties, the responses were the minimum inhibitory (MIC), minimum bactericidal (MBC) and minimum fungicidal (MFC) concentrations. The optimized UAE conditions were: 10.8 min, 410.5 W, 57.8% ethanol content (ethanol-water mixtures were used) and 5 g/L as solid-liquid ratio, providing the following responses: 1) antibacterial activity: MIC of ~0.15-0.35 g/L) and MBC of ~0.30-0.65 g/L; and 2) antifungal activity: MIC of ~0.20-0.30 g/L and MFC of ~0.40-0.65 g/L. In conclusion, the obtained results evidenced the potential application of the extracts from G. globosa as sources of betacyanins (natural colorants), but also as important antimicrobial and antifungal agents.
- Antioxidant potential of wild food plantsPublication . Barros, Lillian; Morales, Patricia; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.A free radical is defined as any species containing one or more unpaired electrons (electrons singly occupying an atomic or molecular orbital), whereas reactive species is the collective term for radicals and some other non-radical derivatives of oxygen, nitrogen, or sulfur that can easily generate free radicals and/or cause oxidative damage (Halliwell 2012). As shown in Table 10.1, reactive oxygen species (ROS) include free radicals such as hydroperoxyl radical (HO2), superoxide anion radical (O2−), hydroxyl radical (HO) and peroxyl radical (ROO; e.g., lipid derived), and other species such as hydrogen peroxide (H2O2), singlet oxygen (1O2), hypochlorous acid (HOCl), and peroxide (ROOR; Lü et al. 2010; Carocho and Ferreira 2013).
- Antioxidants: Reviewing the chemistry, food applications, legislation and role as preservativesPublication . Carocho, Márcio; Morales, Patricia; Ferreira, Isabel C.F.R.Food antioxidants play a critical role in the food industry, and have become one of the most widespread methods of conserving food. Their cheapness and ease of use have made them a part of virtually all foodstuffs. Although different, all groups of food antioxidants have a same common objective, to conserve food for the longest possible time without altering it, conferring taste or color. Consumer trends have shifted the industry to find natural antioxidants for conservation, and although synthetic additives have been the mainstream, their natural counterparts have been gaining interest. Scope and approach This review focuses of the different antioxidant groups, describing their properties, function and applicability, as well as indexing the relevant legislation in order to be a guide for academia and industry. Key findings and conclusions The wide number of antioxidant additives allowed by the different countries if of synthetic origin, and consist of pure molecules. Although consumers are leaning toward natural additives, this offer is still quite limited despite the permission of rosemary extract within the European Union. There is still much work to be done in order to completely demystify the importance and safety of antioxidants as well as to harmonize legislation worldwide.
- Atividade antioxidante de decocções e infusões de flores de castanheiro, uma árvore de grande interesse apícolaPublication . Carocho, Márcio; Bento, Albino; Morales, Patricia; Ferreira, Isabel C.F.R.O mel tem sido usado pelo homem como alimento e medicamento desde tempos imemoriais. A importância deste recurso apícola intensificou-se quando o seu potencial medicinal foi provado pela comunidade científica [1] . Numa altura em que o interesse dos consumidores por alimentos funcionais é cada vez maior, torna-se essencial determinar o potencial bioativo, não só deste recurso natural, mas também das flores que lhe dão origem . O nosso grupo de investigação tem estudado o potencial antioxidante de extratos metanólicos de diferentes flores, nomeadamente as de castanheiro [2]. O objetivo do presente trabalho foi avaliar a atividade antioxidante de infusões e decocções de duas cultivares Portuguesas muito apreciadas, Longal e a Judia, visto constituírem as formas de consumo tradicional mais disseminado. De facto, estas infusões e decocções são empregues sobretudo contra tosse, diarreias e níveis altos de colesterol, entre outros. O potencial antioxidante foi obtido pelos ensaios da atividade captadora de radicais 2,2-difenil-1-picril-hidrazilo (DPPH), poder redutor, inibição da descoloração do B-caroteno e ini bição da peroxidação lipídica pela diminuição da formação de espécies reativas do ácido tiobarbitúrico (TBARS) em homogeneizados cerebrais. A decocção de flores de Judia apresentou a maior atividade antioxidante (menores valores de EC50 ; entre 38 e 99 [.Jg/ml), destacando-se bastante das outras amostras. No entanto, ficou bem evidente o grande poder antioxidante das decocções e infusões das flores de castanheiro, em comparação com outras flores já estudadas [3] . Estes resultados trazem evidências científicas de que o poder antioxidante do mel, divulgado em diferentes estudos incluindo do nosso grupo de investigação [4], pode estar relacionado com as flores que lhe dão origem.