Percorrer por autor "Nunes, Maria Leonor"
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- Bioaccessibility in risk-benefit analysis of raw and cooked seabream consumptionPublication . Afonso, Cláudia; Costa, Sara; Cardoso, Carlos; Coelho, Inês; Castanheira, Isabel; Lourenço, Helena; Gonçalves, Susana; Oliveira, Rui; Carvalho, Maria Luísa; Martins, Maria Fernanda; Bandarra, Narcisa; Nunes, Maria LeonorThe composition of raw and cooked gilthead seabream (Sparus aurata) was analysed. The bioaccessibility of arsenic (As), selenium (Se), mercury (Hg), and methylmercury (MeHg) in raw and cooked fish was studied by an in vitro model. A risk-benefit assessment was performed taking into account bioaccessibility. The content of contaminants Hg and As displayed a significant increase for every culinary treatment, only As content in boiled fish did not increase. Regarding bioaccessibility, while bioaccessible As was high (over 96%), the share of Hg (and MeHg) available for intestinal absorption was reduced by cooking, especially by grilling, 39% (60%) and roasting, 38% (55%). The risk-benefit probabilistic assessment leads to an advice of not exceeding one weekly meal of gilthead seabream. This recommendation concerns mainly pregnant and nursing women. However, Se bioaccessibility was high —minimum of 85% in boiled seabream—, thus helping to balance the deleterious effects of MeHg.
- Bioaccessibility of Hg, Cd and As in cooked black scabbard fish and edible crabPublication . Maulvault, Ana Luísa; Machado, Raquel; Afonso, Cláudia; Lourenço, Helena Maria; Nunes, Maria Leonor; Coelho, Inês; Langerholc, Tomaz; Marques, AntónioRegular consumption of seafood has been widely recommended by authorities. Yet, some species accumulate high levels of contaminants like Hg, Cd and As. In addition, the risks associated to the consumption of such seafood may increase if consumers use cooking practices that enhance the concentration of contaminants and their bioaccessibility. In this study, the bioaccessibility of Hg, Cd and As was assessed with in vitro human digestion of raw and cooked black scabbard fish (Hg; steamed, fried and grilled) and edible crab (Cd and As; steamed and boiled) tissues. Additionally, the toxicological hazards associated with the consumption of these products were also discussed. Generally, Hg, Cd and As bioacessibility increased throughout the digestion process. Cadmium and As revealed high bioaccessibility rates in raw and cooked samples (up to 100%), whereas lower bioaccessible fractions of Hg was observed (up to 40%). Furthermore, this study pointed out the importance of food matrix, elemental chemical properties and cooking practices in the bioaccessibility of Hg, Cd and As. The toxicological hazards revealed that edible crab brown meat (Cd) and grilled black scabbard fish (MeHg) consumption in children should be moderated. In contrast, edible crab muscle (Cd) and fried or steamed black scabbard fish (MeHg) should be consumed to minimize exposure. The use of bioaccessible contaminant data strongly reduced the toxicological risks of MeHg, whereas less risk reduction occurred with Cd and inorganic As.
- Chemical Composition, Nutritional Value, and Safety of Cooked Female Chaceon Maritae from Namibe (Angola)Publication . Mandume, Celso Manuel Cristovão; Bandarra, Narcisa M.; Raimundo, Joana; Lourenço, Helena Maria; Gonçalves, Susana; Ventura, Marta; Delgado, Inês; Rego, Andreia; Motta, Carla; Castanheira, Isabel; Nunes, Maria Leonor; Duarte, Maria PaulaDespite being highly appreciated and consumed, the nutritional value of Chaceon maritae from Namibe (Angola) had never been studied. In the present work, edible tissues (muscle, ovaries, and hepatopancreas) of boiled female C. maritae caught o Namibe coast in two distinct seasons were analyzed in terms of proximate chemical composition (fat, ash, protein, and moisture), fatty acid and amino acid profiles, cholesterol, essential minerals (macro and trace) and toxic elements. Results showed that, in both seasons, C. maritae muscle was a valuable source of protein, essential amino acids, polyunsaturated fatty acids, and essential elements, especially zinc, selenium, iodine, and copper. Ovaries and hepatopancreas are also good sources of protein, but were richer in fat, particularly when caught in October. Ovarian fat is rich in polyunsaturated fatty acids and that of hepatopancreas has higher values of monounsaturated and saturated fatty acids. Hepatopancreas and ovaries are also good sources of copper and, especially ovaries, of zinc. Moreover, in both seasons, all the edible tissues of C. maritae analyzed presented very low contents of heavy metals (mercury, cadmium, lead, and arsenic).
- Composição mineral de peixes pelágicos da costa portuguesaPublication . Lourenço, Helena Maria; Afonso, Cláudia; Coelho, Inês; Gueifão, Sandra; Martins, Maria Fernanda; Nunes, Maria LeonorOs peixes pelágicos, como a sardinha, o carapau e, nalgumas regiões, também a cavala, fazem parte da gastronomia nacional, estando associados aos hábitos alimentares de muitos consumidores. Todavia, apesar de ser bem conhecido o teor proteico e o perfil lipídico, a sua composição mineral ainda não está suficientemente estudada. Assim, o objectivo principal deste trabalho foi o de caracterizar o perfil elementar destas espécies a fim de contribuir para a avaliação dos benefícios e perigos associados ao seu consumo. Foram utilizadas várias técnicas para realizar as análises elementares - espectrometria de absorção atómica (chama e por combustão directa), espectrometria de massa acoplada a plasma indutivo (ICP-MS) e espectrometria de absorção molecular (UV-Vis). Em regra, a distribuição dos elementos essenciais nas espécies estudadas foi semelhante. Os elementos predominantes foram potássio, fósforo, sódio, magnésio e cálcio seguidos do ferro, zinco, cobre, crómio, selénio, manganês e níquel. Os resultados obtidos indicam que as três espécies podem contribuir para satisfazer as doses diárias recomendadas de vários elementos essenciais, nomeadamente no que se refere ao fósforo, magnésio e ferro. Os níveis dos elementos não essenciais para as três espécies - arsénio, cádmio, chumbo e mercúrio (total e metilmercúrio) - foram sempre muito baixos e no caso dos três últimos, muito inferiores aos limites estabelecidos pela União Europeia. Os resultados obtidos indicam que o consumo destas espécies deve ser aconselhado pois as concentrações dos elementos essenciais são uma boa contribuição para satisfazer as doses diárias recomendadas (cerca de 60 % da dose do fósforo, 40 % da do ferro e 20 % da do magnésio). Por outro lado, com base nos teores dos contaminantes, pode afirmar-se que a ingestão de 7 refeições por semana é ainda muito inferior aos TMI/PTWI propostos pela Organização Mundial de Saúde (cádmio - 25 µg/kg de massa corporal, por mês; metilmercúrio - 1,6 µg/kg de massa corporal, por semana).
- Effects of industrial boiling on the nutritional profile of common octopus (Octopus vulgaris)Publication . Oliveira, Helena; Muniz, José António; Bandarra, Narcisa Maria; Castanheira, Isabel; Coelho, Inês Ribeiro; Delgado, Inês; Gonçalves, Susana; Lourenço, Helena Maria; Motta, Carla; Duarte, Maria Paula; Nunes, Maria Leonor; Gonçalves, AmparoIndustrial cooking of common octopus (Octopus vulgaris) under well-established procedures is advantageous for current consumers, which demand healthy and convenient food. This work aimed to evaluate the e ect of industrial water boiling, without the addition of salt, on the nutritional profile of common octopus. True retentions (TRs) were calculated for essential nutrients and toxic elements. After boiling, the moisture content decreased, resulting in a concentration of other constituents (protein, fat, fatty acids, majority of amino acids, phosphorus, zinc, and iodine). High TRs were obtained for some essential nutrients: 90.2% (eicosapentaenoic acid, EPA), 89.1% (docosahexaenoic acid, DHA), 74.6% (indispensable amino acids, IAA), and 86.8% (iodine). In both raw and boiled octopus, polyunsaturated fatty acids (252.2 and 425.1 mg/100 g), leucine (940.1 and 1613.4 mg/100 g), glutamate (1971.5 and 3257.1 mg/100 g), sodium (393.3 and 332.5 mg/100 g), and zinc (12.6 and 16.6 mg/kg) were, respectively, the most abundant fatty acids, IAA, dispensable amino acids, macro, and micro elements. Cadmium, lead, and mercury levels found in boiled octopus were 0.02, 0.10, and 0.08 mg/kg, respectively. The consumption of 150 g (usual portion) of boiled octopus is advisable because it contributes to significant daily intakes of EPA+DHA (>100%), selenium (75.6%), and iodine (12.4%), and 25% of the daily adequate intake of sodium for adults.
- Physicochemical properties of iodine and selenium biofortified Sparus aurata and Cyprinus carpio during frozen storagePublication . Barbosa, Vera; Camacho, Carolina; Oliveira, Helena; Anacleto, Patrícia; Maulvault, Ana Luisa; Delgado, Inês; Ventura, Marta; Dias, Jorge; Ribeiro, Laura; Pousão-Ferreira, Pedro; Eljasik, Piotr; Panicz, Remigiusz; Sobczak, Małgorzata; Tsampa, Kalliopi; Karydas, Andreas; Nunes, Maria Leonor; Carvalho, Maria Luísa; Martins, Marta; Marques, AntónioFish biofortification with natural ingredients like iodine-rich macroalgae and selenized-yeast is an excellent strategy to enhance the nutritional quality of farmed fish. This study aimed to assess the effect of frozen storage during 12-months on physicochemical quality of biofortified seabream (Sparus aurata) and carp (Cyprinus carpio). Frozen storage reduced iodine content in biofortified seabream fillets (17%), as well as selenium content in biofortified carp fillets (24%). Yet, biofortified fillets still presented enhanced iodine and selenium contents at the end of the storage period. Increased lipid oxidation (3.45 mg MDA kg-1 for seabream and 2.41 mg MDA kg-1 for carp) and decreased water holding capacity (23-29% for seabream and 14-23% for carp) was observed during storage, whereas major changes in colour and texture occurred after 45 days (seabream) and 225 days (carp) of storage. In general, biofortified fish fillets maintained their nutritional value and quality after 360 days of frozen storage.
- Production and characterization of protein-rich extracts from the red macroalga Gelidium corneum and its industrial agar extraction residuesPublication . Mateus, Marília; Mão de Ferro, Rita; Pinheiro, Helena M.; Machado, Remígio; R. da Fonseca, M. Manuela; Sapatinha, Maria; Pires, Carla; Marmelo, Isa; Marques, António; Nunes, Maria Leonor; Motta, Carla; Cesário, M. TeresaThe red macroalga Gelidium corneum is a species commercially exploited for agar extraction, though with enormous potential for other industrial applications. This work aimed to produce protein-rich extracts from the crude alga and from residues of the industrial agar extraction process by applying different extraction and recovery procedures, and to characterize the obtained protein extracts. The sequential implementation of two water extractions followed by two alkaline extractions resulted in the recovery of 12.0 ± 1.2 % and 15.4 ± 0.9 % of the total protein contents of the crude alga and industrial residues, respectively. Two sequential water extractions assisted by Celluclast® and Alcalase® enzymes followed by two alkaline extractions recovered 52.1 ± 1.7 % and 36.5 ± 1.3 % of the protein contents of the crude alga and industrial residues, respectively. Extracts produced by these processes were characterized focusing on proximal composition, protein accessibility, nutrition and antioxidant potential, showing value as aquaculture feed ingredients. As all protein products revealed high carbohydrate contents and, aiming at enriching protein content, different protein precipitation methods were assessed, namely through ammonium sulfate precipitation and pH-shift protocols. The pH-shift method in sequential mode proved to be simple and fast with low reagent consumption. The purification of extracts by this precipitation mode allowed precipitating up to 72 % of the extracted protein. The results obtained suggest that protein concentrates extracted from Gelidium corneum appear to be promising sustainable sources for fish feed production, owing to their essential amino acid content, protein bioaccessibility and antioxidant properties.
- The emerging farmed fish species meagre (Argyrosomus regius): How culinary treatment affects nutrients and contaminants concentration and associated benefit-risk balancePublication . Costa, Sara; Afonso, Cláudia; Bandarra, Narcisa; Gueifão, Sandra; Castanheira, Isabel; Carvalho, Maria Luísa; Cardoso, Carlos; Nunes, Maria LeonorThe effect of cooking methods (boiling, grilling, and roasting) on the proximate and mineral composition, contaminants concentration and fatty acids profile was evaluated aiming to understand the benefits and risks associated to the consumption of the emerging farmed fish meagre (Argyrosomus regius). All the treatments led to lower moisture content. After grilling and roasting, the SFA, MUFA and PUFA contents increased. There was no degradation of EPA and DHA during the culinary processes. Significant retention of minerals in grilled and roasted meagre samples was registered. For Pb and Cd there were no concentration differences between culinary treatments and regarding raw fish. Whereas As level was higher in grilled meagre, total Hg and Me-Hg values were augmented in grilled and roasted meagre. The consumption of meagre is advisable due to the low and healthy fat, high selenium and protein content. Grilling would be the best culinary treatment due to the retention of protein, EPA, DHA and minerals. But as the risk of ingestion of Me-Hg content also increases, based on the risk assessment, intake should not exceed two weekly meals, provided that no other important Me-Hg food source is present in the diet. Otherwise, even this maximum threshold should be lower.