Browsing by Author "Mendes Ribeiro, Mariana"
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- Differences in nutritional composition of Shiitake mushrooms (Lentinula Edodes) produced in PortugalPublication . Mendes Ribeiro, Mariana; Torres, Duarte; Santos, Mariana; Castanheira, IsabelThe aim of this study was to evaluate and compare the nutriWonal composiWon of shiitake mushrooms (LenWnula edodes) obtained by different culWvaWon processes from different areas (fruiWng induced by sprinkler from Amarante or dipping method from Sintra). Macronutrient, vitamin B1 and B2, minerals and contaminant trace metals were quanWfied in three samples. Variability among the different samples regarding macronutrients, minerals content was found. Regarding contaminants content, only one sample showed an atypical high value for arsenic. The results obtained indicate that the shiitake mushroom is an important dietary source of several nutrients, and the sample frucWfied by dipping seems to be nutriWonally richer and chemically safer.
- Évaluation du devenir du mercure et du sélénium dans le poisson lors de la cuissonPublication . Mendes Ribeiro, Mariana; Douis, L.; Silva, José Armando; Castanheira, Isabel; Leufroy, A.; Jitaru, P.Les produits de la pêche sont une source importante de nutriments, cependant, ils peuvent accumuler des niveaux substantiels de métaux toxiques, tels que le mercure (Hg). En effet, le poisson représente la principale voie d'exposition des humains au Hg, remettant en cause la consommation régulière d'un tel régime. La majorité des études concernant l'impact toxique du Hg lorsqu'il est ingéré à partir de poisson, a été liée aux niveaux de Hg dans les produits de poisson cru. Cependant, dans la plupart des cas, le poisson est consommé cuit. Plusieurs variables dans les traitements culinaires (température, mode de cuisson, temps, assaisonnement) peuvent influencer la présence de Hg, dans le poisson. De plus, différentes compositions dans la teneur en Se du poisson peuvent également affecter le devenir du Hg pendant les traitements culinaires. Des études antérieures concernant l'influence de différentes procédures de cuisson sur le devenir du Hg, tirent des conclusions contradictoires. Alors que certains d'entre eux observent une concentration réduite de Hg dans le poisson cuit, d'autres signalent son renforcement. Cette étude vise à évaluer l'effet des divers modes de cuisson traditionnels (bouilli, cuisson à la vapeur et grillé) chez différentes espèces de poissons sur la teneur en Hg. De plus, l'influence du Se sur le devenir du Hg pendant la cuisson a également été abordée.
- MERSEL FISH: Development and validation of a new analytical approach for the simultaneous speciation analysis of mercury and selenium by HPLC ICP MSPublication . Mendes Ribeiro, Mariana; Leufroy, Axelle; Danion, Morgane; Castanheira, Isabel; Silva, José Armando; Jitaru, PetruMercury (Hg) is one of the most hazardous chemicals to the environment and the most worrisome contaminant for public health. This is due to its extreme toxicity, particularly in the methylated form which is biomagnified in the food chain, the main pathway of contamination of the humans. The great ability of CH3Hg+ to be bioaccumulated in the aquatic food chain leads to considerably elevated levels of Hg in aquatic organisms, despite nearly immeasurable quantities in the water column. No maximum level for CH3Hg+ is yet regulated by the European commission (EC) in fishery products, despite its extreme toxicity. This is most likely arising from the difficulty in performing accurate speciation analysis of CH3Hg+ in complex matrices such as fishery products. It is also interesting to note that mercury bio-availability seems to be linked to the selenium levels. Although it was shown for a few decades that selenium (Se) shows protective effects against Hg bioaccumulation and toxicity, the mechanism is very poorly understood nowadays. This work report the development and optimization of a new analytical approach for the simultaneous speciation analysis of mercury (Hg2+ and CH3Hg+) and selenium (SeIV, Se VI, SeMet and SeCys) in fish by HPLC-ICP-MS. This method will be employed further for the assessment of dietary exposure to Hg & Se species bio-accumulation by fish, for the analysis of cooked samples as well as for the in vitro simulated digestion studies, to achieve the main aim of this study which is a deep assessment of the Hg-Se interaction in fish and the human dietary exposure.
- Nutritional and Inorganic contaminants profiles of Shitake mushrooms (Lentinula edodes) growing under different conditionsPublication . Mendes Ribeiro, Mariana; Torres, Duarte; Santos, Mariana; Castanheira, IsabelBackground and objective(s): Different factors affect nutritional composition and contaminant profile of shiitake mushroom such as: cultivation process, strain used, method and fruiting conditions, species of wood used for the underlying base structure, and geographic origin. This study evaluated nutritional composition and heavy metals profile of Shiitake mushrooms (Lentinula edodes) obtained by different cultivation processes and areas. Materials and methods: Three samples of organically cultivated Shiitake donko mushrooms were collected (A1, A2, A3).A1 e A2 were produced in Amarante by a similar process, using the sprinkler method to induce the fruiting coming from spawns produced by a Portuguese and a Belgian company, respectively. A3 from a production located in Sintra. Fruiting was induced by dipping. Macronutrients, Vitamins, Mineral and Trace elements were determined by standardized methods. Heavy metals by ICP-MS and Arsenic Species by HPLC-ICP-MS. The statistical design was completely randomized with three replicates per treatment and analysis of variance with an F-test using the Statistical Analysis Software System (SAS). Results: Macronutrient and mineral profile changes according to cultivation process and geographic area. Carbohydrate content ranged from 1.0 g/100 g (A1) to 6.7 g/100 g (A3). Total sugars ranged between 1.0/100g (A1) to 4.1 g 100 (A3)/g. A significant content of vitamin B2 in all samples was observed. A3 revealed superior mineral content. A2 presented highest arsenic content, whitout risk to consumer. Discussion and conclusion(s): In conclusion, results obtained indicate shiitake mushroom as a dietary source of several nutrients, and the sample fructified by dipping (A3) seems nutritionally richer and chemically safer.
- The effect of the time on the antioxidant activity of three main vegetablesPublication . Mendes Ribeiro, Mariana; Rego, Andreia; Castanheira, IsabelIntroduction: Antioxidants are gathering increased attention. They are believed to play a key role in maintaining health with several studies demonstrating proportionality between the daily intake of foods rich in antioxidants and the decrease in the incidence of certain pathologies. Objective: It is known that vegetables are important sources of various antioxidant compounds. For the purpose of this study have been chosen three vegetables commonly used in Portugal - broccoli, spinach and watercress - to test the loss of antioxidant activity by the freezing process, with the aim of better understanding the actual amount of antioxidants that reaches the consumer when opts to frozen vegetables. Methodology: The samples were analysed according to two different methods - TPC and DPPH∙. The analyses were carried out in three different times: as fresh samples at day one, and after being freeze at third and sixth day. Main findings: IC50 value ranged from 11.91 mg/ml (broccoli) to 6.71 (watercress) mg/ml and TPC content ranged from 1.18 mg eq. gallic acid/ g sample (broccoli) to 2.07 mg eq. gallic acid/ g sample in the first day. The higher antioxidant activity was observed at the sixth day of frozen for spinach and watercress, and the highest phenol content was detected on the 3rd day for all the vegetables studied. Conclusions: Our studies are in line with literature, reporting that phenolic contents in vegetables remains unchanged or increase during freezing processes. More studies are needed to understand the mechanism involve in this processes. However, these properties can open doors to innovation in the food industry. Ongoing studies are being performed in this sense.
- Towards a better assessment of the mercury-selenium antagonism in fishPublication . Mendes Ribeiro, Mariana; Zephyr, N.; Silva, José Armando; Damion, M.; Guérin, T.; Castanheira, Isabel; Leufroy, A.; Jitaru, P.The fish were killed by cutting the spinal cord in t 0 t 1 t 2 and t 3 All the data related to the fish growth were recorded similar growth was observed for all exposure conditions. The levels of Hg T and Se T in the fish diet were also measured by ICP MS. Hg T in control and MeHg spiked diets were 0.05 ±0.002 and 0.24 ±0.01 mg/kg, respectively, whereas Se T were 0.95 ±0.02 mg/kg and 5.41 ±0.36 mg/kg in the control and the spiked diets. Se saturation ( p = 0.30) occurs after two months of fish be exposed throught diet to SeMet solely. Quasilinear (R 2 0.99) bioaccumulation of Hg in the fish exposed individualy to MeHg during 3 months. Threshold (p = 0.30) in total Hg level is reached in fish exposed simultaneously to MeHg and SeMet. ↓ of Hg burden 18%) after two months of fish exposure to SeMet and no MeHg. Possible Hg detoxification due to Se supplementation.