Mineral and Trace Elements in Nutritious Flours: Total Contents, In Vitro Bioaccessibility and Contribution to Dietary Intake.

The consumption of fruits, vegetables, and cereals in the form of flour has been an alternative for the intake of nutrients, currently seen in a society that seeks a healthier diet. Thus, the assessment of total contents and bioaccessibility is important to better understand the actual intake of nutrients or contaminants present in foods. The objective of this study was to determine the total content and estimate the bioaccessible fraction of Cu, Fe, and Zn in nutritious flours by inductively coupled plasma optical emission spectrometry (ICP OES) after microwave acid digestion. Bioaccessibility was assessed using the in vitro method, taking into account the entire gastrointestinal tract (Unified Bioaccessibility Method (UBM)). The following concentration ranges, in µg g-1, were found: Ca (341-6275), K (2984-13,953), P (476-6110), Na (< 0.39-2995), Fe (1.4-167), Cu (< 0.01-59.6), and Zn (< 0.07-30.3). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed a tendency towards the formation of three groups. The bioaccessible fractions for Cu, Fe, and Zn were considered low, ranging from 0.96 to 40% in the gastrointestinal phase and from 4.1 to 100% in the gastric phase.

Multi-element determination in chocolate bars by microwave-induced plasma optical emission spectrometry.

Macro- and microelement determination in chocolate bars by microwave-induced plasma optical emission spectrometry (MIP OES) was evaluated after microwave-assisted sample digestion. Optimization of the sample digestion was carried out, and the recommended conditions were obtained at a temperature of 190 °C, with a digestion time of 40 min and in a mixture constituted by 2.3 mL of nitric acid, 1.0 mL of hydrogen peroxide and 4.7 mL of water. The method was applied in the analysis of chocolate bars, and the concentration ranges of the elements determined were (in mg kg-1): Ca (653-3096); Cr (<0.6-2.8); Cu (<0.16-19.5); Fe (<1.6-227); Mg (147-2775); K (3554-8573); Mn (<0.03-25.2); Na (45.6-1095); Ni (3.2-10.2); P (1111-22594) and Zn (4.8-33.3). The association of the proposed microwave-assisted acid digestion with the MIP OES technique was adequate for multi-element determination in chocolate bars for routine analysis.

Multi-element composition, physicochemical and pollen attributes of honeys from the Paraguaçu River (Bahia, Brazil) by inductively coupled plasma-optical emission spectrometry (ICP OES).

Honey is a food of nutritional, medicinal and commercial importance. The physicochemical characteristics, pollen spectrum and mineral composition of eighteen honey samples obtained from regions (Cachoeira, Coqueiros, Maragojipe and Santiago do Iguape) near the Paraguaçu River, Bahia, Brazil were evaluated. Botanical families Asteraceae, Leguminosae, Malvaceae, Myrtaceae and Palmae were most frequently found. Five samples had water contents above the maximum limit established by the Brazilian legislation (> 20%). The mineral composition was determined by ICP OES, after microwave digestion. Ca, K, Mg and Na were measured (mg Kg-1) in the range from: 18.85 to 79.61; 366.74 to 1214.98; 12.46 to 44.59 and 11.56 to 85.39, respectively. Cu, Fe, Mn and Zn had variable concentration ranges, between 0.05 and 6.13 mg Kg-1. Al, Ba, Cd, Co, Cr, Ni, Pb, Se and V showed values below the LOD. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) demonstrated that there are no similarities of mineral composition among honey samples.

Speciation analysis of inorganic As and Sb in urban dust using slurry sampling and detection by fast sequential hydride generation atomic absorption spectrometry.

In this work, a methodology for chemical speciation analysis of inorganic As and Sb in urban dust using slurry sampling and detection by fast sequential hydride generation atomic absorption spectrometry is proposed. Doehlert design and desirability function were used to find the optimum conditions for hydride generation (1.0 mol L-1 HCl and 0.9% m v-1 NaBH4). The accuracy of the analytical method was evaluated by analysis of reference material fly ash (BCR 176R), addition and recovery tests for inorganic As species, and comparison of independent methods for Sb determination in urban dust samples. The determination of the total concentrations of As and Sb and their inorganic species presented good accuracy, between 80 ± 1 and 101 ± 6%. Precision was expressed as the relative standard deviation and was better than 4.7% (n = 3). The limit-of-quantification values were 0.23 and 1.03 mg kg-1 for As and Sb, respectively. The methodology was applied to eight samples of dust collected in an urban area of Salvador and Jaguaquara cities, Bahia, Northeast, Brazil, with an aerodynamic size lower than 38 µm. Concentrations of pentavalent inorganic species (iAs5+ and iSb5+) in relation to trivalent species (iAs3+ and iSb3+) were found in urban dust collected in the city of Salvador, which are regarded as more toxic for both elements. The enrichment factor and geoaccumulation index (Igeo) values showed that for some samples, the concentrations of iAs and iSb presented strong enrichment and, and regarding environment, strong to moderately polluted by iAs and iSb, with an indication of anthropogenic contributions. The occurrence of these inorganic constituents in the urban area of Salvador can be related with intense industrial activities and vehicular traffic.

Assessment of cadmium and lead in commercial coconut water and industrialized coconut milk employing HR-CS GF AAS.

In this work, an analytical method for the determination of Cd and Pb in natural coconut water samples, industrialized coconut water samples and coconut milk using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS), after minimum treatment of the sample was developed. The analytical method was applied to 46 samples collected in Salvador, Bahia (Brazil). The ranges of concentrations obtained were: 0.42-18.72 µg L-1 Cd and <0.70-36.32 µg L-1 Pb for natural coconut water samples (n = 14); <0.06-1.49 µg L-1 Cd and 6.57-29.02 µg L-1 Pb for industrialized water coconut samples (n = 16); and <0.10-5.93 ng g-1 Cd and <0.85-22.41 ng g-1 Pb for coconut milk samples (n = 16). For all samples, Cd and Pb concentrations were below the maximum tolerated values recommended by Brazilian Health Surveillance Agency (Agência Nacional de Vigilância Sanitária, ANVISA).

Multivariate data analysis of trace elements in bivalve molluscs: Characterization and food safety evaluation.

Four species of bivalve molluscs (Anomalocardia brasiliana, Iphigenia brasiliana, Lucina pectinata and Trachycardium muricatum) were collected in the Todos os Santos Bay (TSB), Bahia, Brazil, in order to evaluate As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se, V and Zn levels and, consequently, the risk of bivalve mollusc consumption in humans. The samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) after closed-vessel microwave digestion. The accuracy was confirmed using the certified reference materials of oyster tissue (NIST 1566b) and mussel tissue (NIST 2977), and the results were statistically equivalent to the certified values. Application of principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed a tendency to form two groups between samples of Lucina pectinata and Trachycardium muricatum. All species showed As and Cr concentrations higher than the maximum tolerable limit specified in Brazilian legislation.

Analysis of children modelling clay (toy) using inductively coupled plasma-based methods.

This work proposes the application of a Doehlert design to optimize dilute HNO3 and H2O2 concentrations employed for the digestion of samples of modelling clay for children (used as toy). Inductively coupled plasma-based (ICP) methods were employed to determine 22 inorganic constituents (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Sb, Se, Sr, V and Zn) in children's modelling clay samples. The limits of quantification (LoQ) obtained were between 0.003 mg kg-1 (Cd, Co and Sb) and 0.54 g kg-1(Ca) employing ICP-based methods. The accuracy and precision of the methods were evaluated by analysing the certified reference materials (CRMs) oyster tissue (NIST 1566b), rice flour (NIST 1568b), peach leaves (NIST 1547) and tomato leaves (NIST 1573a), along with addition and recovery tests. The children's modelling clay samples presented concentrations of As, Ba, Cd, Cr, Pb, Sb and Se in agreement with the maximum values established by National Institute of Metrology, Quality and Technology (Instituto Nacional de Metrologia, Qualidade e Tecnologia - INMETRO). However, for other elements it were obtained concentrations within the following ranges: Al (0.83 ±â€¯0.12-2.91 ±â€¯0.04 g kg-1), Ca (16.09 ±â€¯0.20-24.56 ±â€¯1.00 g kg-1), Cu (< 0.30-30.01 ±â€¯2.11 mg kg-1), Fe (< 5.3 - 13.21 ±â€¯3.94 mg kg-1), K (1.31 ±â€¯0.33-33.47 ±â€¯0.75 g kg-1), Mg (0.90 ±â€¯0.04-1.36 ±â€¯0.05 g kg-1), Mn (3.32 ±â€¯0.10-121.05 ±â€¯1.88 mg kg-1), Na (12.07 ±â€¯0.88-36.77 ±â€¯0.50 g kg-1), Sr (4.23 ±â€¯0.47-22.43 ±â€¯6.95 mg kg-1), P (1.00 ±â€¯0.13-57.43 ±â€¯0.88 g kg-1), V (0.25 ±â€¯0.07-1.15 ±â€¯0.19 mg kg-1), S (3.57 ±â€¯0.77-48.49 ±â€¯1.02 g kg-1), Zn (< 4.4-11.82 ±â€¯0.49 mg kg-1), Co (0.020 ±â€¯0.002-0.060 ±â€¯0.020 mg kg-1) and Ni (< 0.03-1.33 ±â€¯0.46 mg kg-1). These elements have no minimum and maximum limits established by legislation for children's modelling clay so, a comparison was not possible. The ICP-based methods presented an efficient routine application in the analysis of modelling clay.

Flow-through dynamic microextraction system for automatic in vitro assessment of chyme bioaccessibility in food commodities.

An automatic flow-through dynamic extraction method is proposed for the first time for in vitro exploration, with high temporal resolution, of the transit of the chyme from the gastric to the duodenal compartment using the Versantvoort's fed-state physiologically relevant extraction test. The flow manifold was coupled on-line to an inductively coupled plasma optical emission spectrometer (ICP OES) for real-time elucidation of the bioaccessible elemental fraction of micronutrients (viz., Cu, Fe and Mn) in food commodities across the gastrointestinal tract. The simulated intestinal and bile biofluid (added to the gastric phase) was successively pumped at 1.0 mL min-1 through a large-bore column (maintained at 37.0 ±â€¯2.0 °C) initially loaded with a weighed amount of linseed (250 mg) using a PVDF filter membrane (5.0 µm pore size) for retaining of the solid sample and in-line filtration of the extracts. The lack of bias (trueness) of the on-line gastrointestinal extraction method coupled to ICP OES was confirmed using mass balance validation following microwave assisted digestion of the residual (non-bioaccessible) elemental fraction. Mass balance validation yielded absolute recoveries spanning from 79 to 121% for the overall analytes and samples. On-line dynamic extraction was critically appraised against batch counterparts for both gastric and gastrointestinal compartments. Due to the lack of consensus in the literature regarding the agitation method for batch oral bioaccessibility testing, several extraction approaches (viz., magnetic stirring, end-over-end rotation and orbital shaking) were evaluated. Improved gastric extractability of Fe along with bioaccessible data comparable to the dynamic counterpart based on the continuous displacement of the extraction equilibrium was obtained with batchwise magnetic stirring, which is deemed most appropriate for ascertaining worst-case/maximum bioaccessibility scenarios.

Baseline trace elements in the seagrass Halodule wrightii Aschers (Cymodoceaceae) from Todos os Santos Bay, Bahia, Brazil.

Trace elements concentrations (As, Ba, Cd, Cr, Cu, Ni, Pb, V and Zn) were found in samples of Halodule wrightii Aschers (Cymodoceaceae) seagrass from Todos os Santos Bay, Bahia, Brazil by inductively coupled plasma mass spectrometry (ICP-MS). This bay has been impacted by the presence of industrial activity that includes chemical and petrochemical plants as well as an oil refinery and harbor activities located in the north and northeastern area. Samples were collected at 4 stations to evaluate the distribution of element concentrations in this area and under different climatic conditions. The mean concentrations, in mgkg(-1), found in dry tissues for all the studied metals and stations were: As (1.08-5.42), Ba (3.72-32.0), Cd (0.135-1.68), Cr (1.15-10.4), Cu (2.23-13.4), Ni (1.95-9.87), Pb (0.873-5.18), V (3.39-22.4) and Zn (13.1-39.5). Statistical analysis (ANOVA) of the seagrass data showed significant inter-site differences for all elements examined except nickel and vanadium.

Preliminary results of mercury levels in raw and cooked seafood and their public health impact.

Mercury is toxic for human health and one of the main routes of exposure is through consumption of contaminated fish and shellfish. The objective of this work was to assess the possible mercury contamination of bivalves (Anomalocardia brasiliana, Lucina pectinata, Callinectes sapidus), crustacean (C. sapidus) and fish (Bagre marinus and Diapterus rhombeus) collected on Salinas da Margarida, BA (Brazil), a region which carciniculture, fishing and shellfish extraction are the most important economic activities. The effect of cooking on Hg concentration in the samples was also studied. The results showed that Hg concentration was generally higher in the cooked samples than in raw samples. This increase can be related to the effect of Hg pre-concentration, formation of complexes involving mercury species and sulfhydryl groups present in tissues and/or loss of water and fat. The highest concentrations were found in B. marinus samples ranging 837.0-1585.3 µg kg(-1), which exceeded those recommended by Brazilian Health Surveillance Agency (ANVISA). In addition, Hg values found in the other samples also suggest the monitoring of the Hg concentrations in seafood consumed from the region.

Trace elements distribution in hawksbill turtle (Eretmochelys imbricata) and green turtle (Chelonia mydas) tissues on the northern coast of Bahia, Brazil.

Concentrations of elements (As, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Sr, V, Zn) were determined in liver, kidneys and bones of Eretmochelys imbricata and Chelonia mydas specimens found stranded along the northern coast of Bahia, Brazil. Results showed that the concentrations of Cd, Cu, Ni and Zn in the liver and kidneys of juvenile C. mydas were the highest found in Brazil. We also observed a significant difference (p<0.05) on the bioaccumulation of trace elements between the two species: Al, Co, Mo, Na and Se in the liver; Al, Cr, Cu, K, Mo, Ni, Pb, Sr and V in the kidneys; and Al, Ba, Ca, Cd, Mn, Ni, Pb, Se, Sr and V in the bones. This study represents the first report on the distribution and concentration of trace elements in E. imbricata in the Brazilian coast.

Microwave-assisted diluted acid digestion for trace elements analysis of edible soybean products.

A new method for the decomposition of soybean based edible products (soy extract, textured soy protein, transgenic soybeans, and whole soy flour) was developed to essential (Co, Cr, Cu, Fe, Mn, Ni, Se, V, and Zn) and non-essential (As, Ba, Cd, Pb, and Sr) trace elements determination by ICP OES and ICP-MS respectively. Effects related to the concentration of HNO3 (2.1-14.5 mol L(-1)) and the use of hydrogen peroxide on the efficiency of decomposition was evaluated based on the residual carbon content (RCC). It was demonstrated that 2.1 mol L(-1) HNO3 plus 1.0 mL H2O2 was suitable for an efficient digestion, since RCC was lower than 18% and the agreement with certified values and spike recoveries were higher than 90% for all analytes. The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: As (<0.007-0.040), Ba (0.064-10.6), Cd (<0.006-0.028), Co (0.012-102), Cr (0.56-5.88), Cu (6.53-13.9), Fe (24.9-126), Mn (16.4-35.2), Ni (0.74-4.78), Se (<2.90-25), Sr (2.48-20.1), Pb (<0.029-0.11), V (<0.027-20), and Zn (30.1-47.3). Soy-based foods investigated in this study presented variable composition in terms of essential and potentially toxic elements, which can be attributed to different methods of processing.

Levels and spatial distribution of trace elements in macroalgae species from the Todos os Santos Bay, Bahia, Brazil.

Concentrations of elements (As, Ba, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, V, and Zn) were determined in ten species of macroalgae collected from six sites in the Todos os Santos Bay, Brazil, between May and July of 2010. An optimized microwave-assisted digestion procedure was used to digest the samples. The elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). A wide range of metal concentrations were observed between the species analysed. Somewhat higher concentrations of Cd (5.99µg g(-1)), Co (372µg g(-1)), Mn (640µg g(-1)), Ni (17.2µg g(-1)) and Zn (51.4µg g(-1)) were found in the brown macroalgae species Padina spp., whereas elements, such as As (19.7µg g(-1)) and Pb (8.27µg g(-1)), were mainly concentrated in the species Sargassum spp. and Bostrychia montagnei, respectively. Statistical analyses (ANOVA) of the Padina data showed significant inter-site differences for all metals examined except nickel.

Multi-element determination of Cu, Fe, Ni and Zn content in vegetable oils samples by high-resolution continuum source atomic absorption spectrometry and microemulsion sample preparation.

The aim of this work was to evaluate the microemulsification as sample preparation procedure for determination of Cu, Fe, Ni and Zn in vegetable oils samples by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS). Microemulsions were prepared by mixing samples with propan-1-ol and aqueous acid solution, which allowed the use of inorganic aqueous standards for the calibration. To a sample mass of 0.5g, 100µL of hydrochloric acid and propan-1-ol were added and the resulting mixture diluted to a final volume of 10mL. The sample was manually shaken resulting in a visually homogeneous system. The main lines were selected for all studied metals and the detection limits (3σ, n=10) were 0.12, 0.62, 0.58 and 0.12mgkg(-1) for Cu, Fe, Ni and Zn, respectively. The relative standard deviation (RSD) ranged from 5% to 11 % in samples spiked with 0.25 and 1.5µgmL(-1) of each metal, respectively. Recoveries varied from 89% to 102%. The proposed method was applied to the determination of Cu, Fe, Ni and Zn in soybean, olive and sunflower oils.

Sequential injection fluorimetric determination of Sn in juices of canned fruits.

The present work describes the development of a fast and robust sequential injection fluorimetric procedure for the determination of Sn in juices of canned fruits. The developed automatic methodology is based on the complexation of Sn with 8-hydroxyquinoline-5-sulfonic acid (HQSA) to form a fluorimetric product (lambda(exc)=354 nm; lambda(em)=510 nm). The influence of dimethylsulfoxide (DMSO) and cetylpyridinium bromide (CPB) on the sensitivity of the fluorimetric determination was evaluated. Linear calibration plots were obtained for Sn concentrations between 1 and 10 mg L(-1), with a detection limit of 0.38 mg L(-1). In each analytical cycle 0.006 mg of HQSA and 0.47 mg of CPB were consumed and 1.5 mL of effluent was generated. The developed methodology was applied to the determination of Sn in juices of canned fruits and the results complied with those furnished by an electrothermal atomic absorption spectrometry comparison procedure, with relative deviations lower than 5.2%. The automatic procedure exhibited good precision (R.S.D.<1.4%) and the sampling rate was about 70 determinations per hour.

A critical evaluation of digestion procedures for coffee samples using diluted nitric acid in closed vessels for inductively coupled plasma optical emission spectrometry.

The efficiency of diluted nitric acid solutions for digesting regular coffee samples was evaluated employing two closed vessel procedures: one was based on microwave-assisted heating and the other was based on conductive heating using pressurized Parr bomb. The efficiency of digestion was evaluated by determining residual carbon content (RCC) and residual acidity. The digestion was effective using both procedures, i.e. there were no solid residues after the decomposition reactions when using up to 3.5 mol L(-1) nitric acid solutions. It was demonstrated that the digestion procedures are critically dependent on reactions occurring in liquid and gas phase and that the formation of NO and its conversion to NO2 by O2 exerts a major effect in the oxidation of organic matter. These processes are more effective in closed vessels heated by microwave radiation due to the greater volume of these flasks and the temperature gradient that exists during the first step of the digestion process. The proposed model for the digestion processes in diluted nitric acid solution is corroborated by data about consumption of acid during the digestion and by measuring the pressure during the whole process.