Browsing by Author "Matos, Ana Sofia"
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- Amino acid profile of foods from the Portuguese Total Diet Pilot StudyPublication . Motta, Carla; Matos, Ana Sofia; Soares, Ana; Gonzales, Gerard Bryan; Castanheira, Isabel; Cabral, Izunildo; Tavares, Nelson; Nicolai, MarisaThe amino acid content of foods commonly consumed by specific populations is rarely measured systematically, especially if we take into account the different ways that foods are usually processed or cooked. The objective of this study is to evaluate the amino acid profile of the representative foods on the Portuguese diet, with a particular focus on indispensable amino acids. We also aim to assess the amino acid intake of the population and the most common sources of amino acids within the Portuguese diet. To achieve these goals, the amino acid intake of Portuguese adults was assessed combining data of food consumption with the food analysis data from samples collected according to the Total Diet Study methodologies. Results of the amino acid profiles of food groups typically consumed in Portugal are reported in this paper. We found that red meat consumption is the most common source of amino acids of the Portuguese population, followed by white meat and fish. The main contribution of individual portions to the recommended intakes of essential amino acids were: cheese, 88%; red meat, 83%; fatty fish, 81% and seitan with 74%. This data could be used to show alternative amino acid sources within commonly consumed foods.
- Arsenic content in fish and associated measurement uncertainty as a metrological parameter for Total Diet StudiesPublication . Coelho, Inês; Gueifão, Sandra; Matos, Ana Sofia; Santos, Rui; Castanheira, IsabelTotal Diet Studies (TDS) are the most important tools to assure that chemical contaminants presence in foodstuffs remains within safety levels. Reliability of data provided by laboratories to assess the effectiveness of measurements aiming at reducing the risk of exposure to chemical hazards is of paramount importance. Evaluation of measurement uncertainty associated with a result is an important parameter in assessing the sources of analytical data variability. Two methods to estimate uncertainty in analytical measurement of arsenic in fish are discussed. Measurement uncertainty was estimated for the determination of arsenic content in fish samples by Inductively Coupled Mass Spectrometry (ICP-MS). The work addressed both approaches accepted by Eurolab and NIST: modeling (bottom up) and empirical (top down). The Ishikawa diagram was used to identify the most significant sources of uncertainty. The mathematical modeling techniques to assess uncertainty components based on a classical model that accounts for all recognized significant sources of errors was similar to the top down based on validation data from interlaboratory comparison studies. Both methods showed that analytical variability in arsenic content was less than 10%.
- Blank samples assessed through multivariate control chart as an internal quality control tool of ICP-MSPublication . Gomez, Filipe; Gueifão, Sandra; Cabral, Izunildo; Castanheira, Isabel; Matos, Ana SofiaInductively coupled plasma mass spectrometry (ICP-MS) is one of the most suitable analytical techniques used to quantify inorganic components at trace concentrations. Being considered one of the key activities in a Quality Assurance system, the Internal Quality Control (IQC) reveals is of utmost importance when ICP-MS is used. Involving a continuous and critical assessment of the analytical methods and work routines of an analytical chemistry laboratory, the main propose of IQC is to continuously monitor the developed methodologies, as well as, to assess the reliability of the results. Within the IQC, the blank sample is an excellent tool, allowing to evaluate and monitor the quality of reagents, identify possible contaminations from the analytical processes resulting from the method and analytical processes, as well as to estimate the detection limits and the quantification limits for the trace elements analysed by ICP-MS. This study presents a methodology based on multivariate control (T2) charts for monitoring and assessing the stability of blank samples for Copper, molybdenum and lead. The proposed methodology grounds on the Statistical Process Control, where the T2 chart was designed to detect possible contaminations that may occur during the analytical method. To validate this approach, three univariate control charts, based on the Z scores, were built for each element and compared with the multivariate control chart output. The data analysis was performed using a set of blank samples collected between the years 2016 and 2018. Based on the data analysis results, the T2 chart was built and then validated through the correspondent three univariate Z charts. By comparing this set of charts it is possible to conclude that the T2 chart is in accordance with the results obtained by the three univariate charts. Although the mathematical complexity is high, this T2 chart revealed to be an appropriate IQC tool, when multi-elemental analyses are performed by ICP-MS.
- Bromine occurrence in Portuguese cabbage from center region of Portugal before and after forest firesPublication . Ventura, Marta; Delgado, Inês; Coelho, Inês; Gueifão, Sandra; Matos, Ana Sofia; Martins, Marta; Costa, Maria Helena; Castanheira, IsabelBromine (Br) is one of the main halogens of the periodic table and has been classified as emerging contaminant due to its persistence in the environment, bio-magnification properties and risk to human health [1]. The main goal of this work was to evaluate Bromine contents in Portuguese cabbage (Brassica Oleracea var. Costata DC), in the center region of Portugal before and after forest fires. This vegetable is one of the most consumed by the Portuguese population and is recognized as an accumulator of contaminants from the air and from soils. All cabbage samples were collected in the center region of Portugal. Before forest fire 3 Portuguese cabbage were collected in 9 different zones in a total of 27 samples (Control Group-CG) and used as a control. After forest fire (AFF), 3 Portuguese cabbage were collected in 8 zones over four periods of time (first campaign in August of 2017, second campaign in December of 2017, third campaign in April of 2018 and fourth campaign in August of 2018), in a total of 96 samples. Bromine contents was determined by inductively coupled plasma mass spectrometry (ICP-MS), preceded by an alkaline extraction with 25% ammonium tetramethylhydroxide (TMAH). The results were obtained through analytical procedures that reflected the quality assurance requirements described in ISO / IEC 17025: 2005. The concentration was expressed in mg Br/kg cabbage. The amount of Br in CG (mean of 27 samples) was 2 mg/kg. Most of the cabbage samples collected after forest fire presented concentrations above CG, with the following values; the first campaign (4.8 mg/kg), the second campaign (4.0 mg/kg) and the fourth campaign (4.5 mg/kg). The only campaign AFF that presented values below CG was the third one (1.7 mg/kg). Results before forest fires (CG) and after forest fire (4 campaigns) using One Way ANOVA pointed successfully on the existing statistical differences between bromine concentrations in CG and AFFs collection (p-value < 0.05). Through the Least significant differences (LSD) test the 1st and 4th campaigns (AFF) were the only ones that evidenced significant differences with the CG. After the forest fires, the 3rd campaign showed significantly lowest values when compared with the 1st and the 4th campaigns. However, these results do not pose risk to the Portuguese population, according to the commission regulation (EC) No 839/2008, wherein the value of bromide in brassicas is 30mg/kg [2].
- Characterization of a Population Concerning Vitamins and Anemia BiomarkersPublication . Mota, Carla; Tavares, Nuno; Torres, Duarte; Santos, Mariana; Castanheira, Isabel; Matos, Ana SofiaFolate, vitamin B12, iron and hemoglobin are essential for metabolic functions. Deficiency of these can cause several known pathologies and, untreated, severe morbidity and death. The objective of this study is to characterize a population, concerning serum levels of folate, B12, iron and hemoglobin, as well as finding evidence of correlations between these parameters and illnesses, mainly cardiovascular, gastrointestinal, neurological and anemia. The laboratorial data collected consists of blood analysis in patients, required by the patients’ doctors, and were retrieved in 2012. The total population consisted of 728 individuals, residing in Lisbon metropolitan area in Portugal. When coming in for examination, the patients were asked routine questions about their age, gender, county of residence, reason for examination and what medication or supplementation they were taking. The population consisted of 140 male patients and 588 female patients, aged from 2 to 95 years of age. There are 329 persons over 60 years old, these are considered elderly patients. Clinical data was submitted to multivariate analysis. The data was screened with Spearman correlation and Kruskal-Wallis analysis of variance to study correlations and variability between groups. To characterize the population, we used cluster analysis with Ward’s linkage method. A positive correlation between iron with, ferritin and transferrin, and with hemoglobin was observed with the Spearman correlation. Kruskal-Wallis analysis of variance showed significant differences between these biomarkers in persons aged 0-29, 30-59 and over 60 years old. Cluster analysis, evidence low folate levels for population in general, and hemoglobin levels below the reference values for 42.8% of study population. Iron and vitamin B12 were within the reference range for most of the population. Low levels of the parameters were registered mainly in cardiovascular, gastrointestinal, neurological diseases and anemia patients.
- Combining multielement analysis and chemometrics to trace the geographical origin of Rocha pearPublication . Coelho, Inês; Matos, Ana Sofia; Teixeira, Rita; Nascimento, Ana; Bordado, João; Donard, Olivier; Castanheira, IsabelThis work aims at characterizing the mineral profile of a Portuguese variety of pear, Rocha pear, and study the relationship between the nutritional profile and geographical origin. Multielement analysis of twenty-four elements (Al, As, B, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Se, Sn, Sr, Tl, Zn) was performed using an ICP-MS and ICP-OES, on 50 samples originating from two regions, one with Protected Designation of Origin (PDO), known as “Pera Rocha do Oeste”, and the other without (nPDO). Correlation analysis was performed to check for potential relationships between elements. Results from PDO and nPDO regions were compared using chemometric tools, namely Principal Component Analysis, Hierarquical Cluster Analysis and Linear Discriminant Analysis (LDA). The predictive model, built and validated, classified samples according to their regional origin with 100% accuracy. The present study shows that multielement analysis combined with the appropriate statistical tools can be a valuable contribution from the identification of the geographical provenance of Rocha Pears. It provides important nutritional information regarding the mineral composition of Rocha pears, not available until know, promoting the linkage between the nutritional profile and geographical origin, filling the gap of absent values in FCDBs.
- Correlação entre perfil em aminoácidos e acumulação de arsénio em grãos de arroz (Oryza sativa L.) consumidos em PortugalPublication . Mota, Carla; Lopes, J.; Coelho, Inês; Santos, Mariana; Castanheira, Isabel; Matos, Ana SofiaO arroz é um dos alimentos base mais importantes para a população mundial, sendo um dos cereais mais consumidos em todo o mundo. Portugal é o maior consumidor de arroz da Europa, com um consumo de 17 kg per capita por ano. Possui um elevado teor em hidratos de carbono, constituídos essencialmente por amido, e tem como segundo constituinte a proteína. Pelo papel determinante deste cereal na alimentação mundial e por constituir, devido ao tipo de cultivo, uma das maiores fontes de ingestão de arsénio, importante agente carcinogénico e contaminante da cadeia alimentar. Assim será objetivo deste trabalho correlacionar o perfil em aminoácidos com os níveis de acumulação de arsénio. Foram determinados em 39 amostras de diferentes tipos de arroz, cultivados em diferentes zonas de Portugal, os níveis de arsénio total e o correspondente perfil em aminoácidos. A determinação dos aminoácidos foi realizada por cromatografia líquida de ultra resolução (UPLC), enquanto o Arsénio foi determinado espectrometria de massa com plasma acoplado (ICP-MS/MS). Foram efetuadas caracterizações e comparações entre tipos, variedades e regiões de cultivo das diferentes amostras de arroz. Os aminoácidos essenciais mais abundantes foram aromáticos com 11,8% da proteína total, no entanto possui um único aminoácido considerado limitante, a lisina .Os aminoácidos não-essenciais, representam 65,5% da proteína total, sendo o ácido glutâmico, o mais abundante (12,9 mg/g na Indica e 12,4 mg/g na japónica). Utilizando o teste ANOVA e Kruskal-Wallis encontramos diferenças entre as variedades Arroz integral e Arroz branco. No que diz respeito aos níveis de arsénio não são encontradas diferenças entre as várias características estudadas do arroz, no entanto através da correlação Spearman este correlaciona-se positivamente com o arroz integral e negativamente com o arroz branco. Para a análise de clusters formaram-se 3 conjuntos com base na variável aminoácidos: baixa, média e alta concentração. Estes resultados corroboram com os resultados obtidos com a análise de variância, revelando ser uma boa ferramenta para monitorar as mudanças no perfil proteico de arroz. Para classificar o arroz no futuro, com base no seu perfil em aminoácidos, foi possível através do uso desta base de dados a criação de um modelo k-NN cujo erro de classificação fosse nulo.
- Correlation of amino acids profile with arsenic accumulation in rice grain (Oryza sativa L.) consumed in PortugalPublication . Mota, Carla; Lopes, Joel; Coelho, Inês; Santos, Mariana; Castanheira, Isabel; Matos, Ana Sofia
- Design of experiments to optimized the determination of TDIs in agglomerated cork stoppersPublication . André, Catarina; Delgado, Inês; Matos, Ana Sofia; Castanheira, IsabelIsocyanates are included into a class with an extreme commercial importance because their use in the manufacture of polyurethanes. Polyurethanes are used in several applications such as adhesives, coatings, foams, thermoplastics resins, printing inks, foundry moulds and rubbers. Agglomerated cork stoppers are currently used for still wines, semi-sparkle and gaseous wines, beer and cider. Methylene diphenyl diisocyanate (MDI) is presently the isocyanate used in the production of polyurethane based adhesive in use due to its lowest toxicity comparing with toluene diisocyanate (TDI) previously employed. However, free monomeric TDI or MDI, depending on the based polyurethane, can migrate from agglomerated cork stoppers to beverages therefore it needs to be under control. The presence of these compounds are usually investigated by HPLC with Fluorescence or UV-Vis detector depending on the derivatising agent. Ultra Performance Liquid Chromatography with Diode Array Detector (UPLC-DAD) method is replacing HPLC. The objective of this study is to determine which method is better to analyze isocyanates from agglomerated cork stoppers, essentially TDI to quantify its monomer. A Design of Experiments (DOE) with three factors, column temperature, flow and solvent, at two levels was done. Eight experiments with three replications and two repetitions were developed. Through an ANOVA the significance of the factors was evaluated and the best level’s factors were selected. As the TDI has two isomers and in this method these two isomers were not always separated an ANOVA with results of resolution between peaks was performed. The Design of Experiments reveals to be a suitable statistical tool to determine the best conditions to quantified free isocyanates from agglomerated cork stoppers to real foodstuff. The best level’s factors to maximize area was column temperature at 30ºC, flow to 0,3 mL/min and solvent 0,1% Ammonium Acetate, to maximize resolution was the same except the solvent that was 0,01% Ammonium Acetate.
- Determinação da composição mineral de quinoa, amaranto, milho roxo e trigo sarraceno: comparação de três métodos de digestãoPublication . Nascimento, A.C.; Santos, Mariana; Coelho, Inês; Gueifão, Sandra; Mota, Carla; Matos, Ana SofiaA quinoa (Chenopodium quinoa), amaranto (Amaranthus caudatus), milho roxo (Zea mays L.) e trigo-sarraceno (Fagopyrum esculentum) têm ganho cada vez mais atenção da comunidade científica, especialmente devido ao seu alto valor nutricional e benefícios para a saúde. O seu perfil mineral pode variar com a origem geográfica, ou com as condições de cultivo, sendo por isso aconselhável o uso de metodologias validadas que assentem em pressupostos de controlo de qualidade rigorosos. A preparação prévia da amostra para a determinação de minerais é uma etapa crítica de ensaio devido às possíveis contaminações e perdas de analito que podem ocorrer. A destruição da matéria orgânica e disponibilização dos analitos, para posterior determinação dos minerais, pode ser efetuada por diferentes métodos (digestão por via seca, digestão ácida a baixa e a alta temperatura e digestão por microondas). O objetivo deste trabalho foi comparar os resultados de teor de minerais em pseudocereais (quinoa, amaranto e trigo mourisco) e milho roxo obtidos por Espectrometria de Emissão Atómica com Plasma acoplado indutivamente (ICP-OES) quando três métodos digestão diferentes – digestão por via seca, sistema de aquecimento por bloco de grafite (DigiPREP) e digestão por microondas - foram utilizados. Os teores de minerais obtidos com os três procedimentos foram comparados e o desempenho dos métodos foi avaliado usando materiais de referência certificados apropriados. Estatisticamente, não houve evidência de que os três métodos de digestão diferentes tenham influenciado os resultados finais, (P <0,05), na maioria das amostras e minerais analisados. A digestão por microondas, além disso, permitiu um controle mais efetivo das contaminações ou perdas do que a digestão por via seca, com um tempo mais curto de preparação das amostras.
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