Browsing by Author "Cabral, Izunildo"
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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.
- 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.
- Impact of malting process on the amino acid profile of buckwheat seedsPublication . Motta, Carla; Matos, Ana Sofia; Rosa, Filipa; Cabral, Izunildo; Castanheira, Isabel; Moreira, TiagoBuckwheat is a gluten-free pseudocereal recognised as an important source of protein. Malting is a form of processing that can improve the protein quality of food. The aim of this study is the optimization of malting conditions on protein content and its essential amino acids on buckwheat seeds. To achieve this goal, soaking time was optimised to a moisture content of 50% (2h) and the drying time to a moisture content below 10% (4h). Quantification of protein and amino acid (AA) profile was determined after different soaking and germination conditions. Design of experiments was applied to optimise the malting process, considering 2 factors and 3 levels: time (24, 48 and 72 h) and germination temperature (18, 23 and 28 ºC). The experiments were performed in 2 blocks considering the soaking temperature (20 ºC and 30 ºC). Moisture was determined by the AOAC method, 952.08. Total nitrogen content was assessed by the Kjeldahl method. AA profile was performed after acid hydrolysis by UPLC with a PDA detector. Concerning protein, soaking temperature increased significantly at 30 ºC, (13.7 ± 1.45 g/100g) when compared with soaking at 20 ºC (12.08 ± 1.43 g/100g). For all essential AA, at a soaking temperature of 20 ºC, germination time was the only significant factor with the best germination conditions at 48 h. The soaking temperature of 30 ºC, produces the best germination conditions at 72 h, with an exception on methionine where both factors, temperature and time, constitutes significant factors. For methionine, the best conditions were found at 23 ºC with 48 h of germination. In conclusion, results demonstrate that in the tested conditions, the levels that can be used to improve the quality protein of buckwheat seeds were: 30 ºC for soaking step and 18 ºC during 48 h for germination step. This work reveals a valuable tool that can be used in domestic or in controlled environments, as industries, for the improvement of protein quality of this gluten-free pseudocereal.