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1.
Biofortification of staple crops via breeding is an attractive strategy for reducing human micronutrient deficiencies. The objective of this research was to examine the concentration of carotenoids in diverse pea and chickpea accessions grown in Saskatchewan (Canada) using high performance liquid chromatography. In pea accessions mean concentration of lutein was highest (11.2 μg g−1) followed by β-carotene (0.5 μg g−1), zeaxanthin (0.3 μg g−1), and violaxanthin (0.3 μg g−1). Green cotyledon pea accessions were richer in β-carotene and total carotenoids compared to yellow cotyledon accessions. In chickpea accessions mean concentration of lutein (8.2 μg g−1) was highest followed by zeaxanthin (6.2 μg g−1), β-carotene (0.5 μg g−1), β-cryptoxanthin (0.1 μg g−1), and violaxanthin (0.1 μg g−1). Desi chickpea accessions had higher carotenoid concentration than kabuli accessions. This research identified pea and chickpea accessions that can be utilized in breeding for the improvement of carotenoid concentration through biofortification.  相似文献   

2.
In this paper, microwave-accelerated dispersive liquid–liquid microextraction has been developed for the extraction/preconcentration of some organophosphorus pesticides from aqueous samples prior to their analysis by gas chromatography–flame ionization detection. In this method, temperature of a high volume of aqueous sample is elevated by a microwave oven and then a mixture of extraction and disperser solvents is rapidly injected into the aqueous phase. After cooling to room temperature, the phase separation is accelerated by centrifuging. The main experimental factors affecting performance of the method including type and volume of the extraction and disperser solvents, temperature, pH, and salt addition were investigated and optimized. Under the optimum extraction conditions, the method resulted in low limits of detection and quantification within the ranges of 0.65–1.3 and 2.2–4.5 μg L−1, respectively. Relative standard deviations were in the range of 2–7% (C = 40 or 100 μg L−1) for intra-day (n = 6) and inter-day (n = 4) precisions. Finally, the proposed method was successfully applied to analysis of the target analytes in surface water and well water and fruit juice samples; diazinon was determined at μg L−1 level in apple juice.  相似文献   

3.
A single-run high performance liquid chromatography (HPLC) with diode array detector (DAD) based method was developed for the separation, identification and comprehensive quantification of degradation products of ergosterol formed in oyster mushroom (Pleurotus ostreatus) after UV-B exposure. After 60 min, 10 substances involved in the photoprocess were separated, identified by their characteristic DAD spectrum and distinguished by their molecular weight, in cases where spectra were identical: vitamin D2, previtamin D2, tachysterol2, lumisterol2 and ergosterol, and, in minor quantity, their structural analogues of the 22,23-dihydroergocalciferol (vitamin D4) series. Sample preparation protocol affected the total yields and the ratios of previtamin and vitamin D2/D4. Hot alkaline hydrolysis resulted in the best digestion of the mushroom matrix and accordingly gave the highest vitamin D yield (D2: 141.32 μg g−1 dry matter, DM; D4: 22.72 μg g−1 DM). Limit of detection for vitamin D2/4 was 0.02 μg g−1 dry matter (DM) and was estimated for previtamin D2/4 (0.06 μg g−1 DM), tachysterol2/4 (0.02 μg g−1 DM) and lumisterol2/4 (0.06 μg g−1 DM). Recovery of spiked vitamin D2 was 97 ± 0.7%. The study provides an analytical tool to assess the process of vitamin D generation after UV-B treatment for the production of oyster mushrooms with a balanced nutritional profile of vitamin D compounds.  相似文献   

4.
This study evaluates the nutritional potential of Sarcocornia ambigua as new a source of minerals. The mineral concentrations of two different growing populations (natural occurrence and irrigated) of S. ambigua were evaluated using inductively coupled plasma mass spectrometry. In all samples, the mineral present in highest amounts was potassium (K) (19–24 μg g−1), followed by magnesium (Mg) (8.6–14 μg g−1) and then calcium (Ca) (2.6–4.0 μg g−1). In addition, in vitro bioacessibility assay demonstrated that very high fraction (65–80%) of these K and Mg (80 and 65%) of total concentration of these elements is bioacessible from S. ambigua analyzed. The trace elements vanadium (V), chromium (Cr), cobalt (Co), copper (Cu) and lithium (Li) have more than above 50% of total concentration was found bioaccessible. In all cases, mass balance was verified by carrying out the total digestion of the remaining residue and the relationship between total concentration and bioaccessibility. The data related to the concentrations and the bioaccessible fractions of the minerals provide a starting point for more complex and in-depth evaluations from the nutritional point of view, including the establishment of a recommended daily dietary intake for this plant.  相似文献   

5.
Rice and its derivatives are important source of essential and non-essential elements. Essential elements as cobalt (Co) and selenium (Se) are vital for human homeostasis. However, non-essential elements such as arsenic (As), cadmium (Cd) and lead (Pb) may be present in rice-based food and consequently, people can be exposed—especially children and the celiac population. This study aimed to determine essentials and non-essentials elements in rice-based products and baby food and also to evaluate nutritional risk by estimating the daily intake of non-essential elements. Regarding essential elements, Co and Se presented the highest concentrations in rice flour (56 μg kg−1) and porridge (254 μg kg−1), respectively. For non-essential elements, the highest concentrations of As, Cd and Pb were 104 μg kg−1 (porridge), 16 μg kg−1 (flour), and 188 μg kg−1 (bread), respectively. Total As concentration in Brazilian rice-based baby food was <29 μg kg−1. However, As-speciation revealed inorganic-As (i-As) as the main specie. The highest estimated daily intake of Cd, Pb and i-As were 1.37 (rice-based baby food); 10.39 (pasta); and 3.34 (pasta) μg d−1, respectively. Therefore, continuous food monitoring for nutritional and toxicological purpose is necessary, especially concerning these particular populations and discussions for maximum levels of non-essential elements.  相似文献   

6.
A sensitive method for the determination of picogram level dibutyl phthalate (DBP) in wine by flow-injection chemiluminescence (FI–CL) analysis is presented for the first time, which was based on the quenching effect of DBP on the luminol–myoglobin (Mb) CL system. The decrement of CL intensity was linearly proportional to the logarithm of DBP concentration in the range of 0.1–100 pg mL−1 with the detection limit of 0.03 pg mL−1 (3σ). At a flow rate of 2.0 mL min−1, a complete determination of DBP including sampling and washing could be accomplished in 0.5 min, giving the maximum sample throughput of 120 h−1. The proposed method was successfully applied to the determination of DBP in wine, human serum and urine samples with the relative standard deviations (RSDs) of less than 3.0% (n = 5). The molecule docking results showed that DBP interacted with the amino acid residues near the heme moiety of Mb. The possible CL mechanism of luminol–Mb–DBP reaction should be that the binding of Mb with DBP forming a 1:1 complex (binding constant K = 1.55 × 104 L mol−1) led to the conformational change of Mb and resulted in the quenching of CL intensity.  相似文献   

7.
A slurry sampling flame atomic absorption spectrometric method is proposed for the determination of copper, manganese and iron in oysters (Crassostrea rhizophora), clams (Anomalocardia brasiliana) and mussels (Mytella guiyanensis; Perna perna). Optimization was carried out using univariate methodology involving the following variables: nature and concentration of the acid solution for slurry preparation, sonication time and sample mass. The optimized conditions were 80 mg of sample ground in a cryogenic mil, dilution using 1.0 mol L−1 nitric /hydrochloric acid solution, sonication time of 30 min and a slurry volume of 10 mL. The calibration curves had been prepared using standards of copper, manganese and iron also in 1.0 mol L−1 nitric/hydrochloric acid solution. This method allowed the determination of copper, manganese and iron by FAAS, with detection limits of 0.17, 0.09 and 0.46 μg g−1, respectively. The precision, expressed as relative standard deviation (RSD), are 3.0%, 2.9% and 3.8% (n=10), for concentrations of copper, manganese and iron of 17, 22 and 719 μg g−1, respectively. The accuracy of the method was confirmed by analysis of the certified oyster tissue (NIST 1566b). The proposed method was applied for the determination of copper, manganese and iron in samples of oyster, clams and mussels, collected in Ubatuba and Todos os Santos Bay, Brazil. The obtained concentrations varied between 17.1 and 143.9 μg g−1, 17.9 and 29.7 μg g−1 and 364 and 1388 μg g−1, respectively, for copper, manganese and iron. These values agree well with other data reported in the literature. The results showed no significant differences (P>0.005) using the proposed method with those obtained after complete digestion and determination by inductively coupled plasma-optical emission spectroscopy (ICP-OES).  相似文献   

8.
A new spectrophotometric method has been developed for the determination of protein in Tween 20 microemulsion medium. The method is based on the interaction between protein and o-nitrophenylfluorone–Mo(VI) complex as a spectral probe. Under the optimal conditions, Beer's Law is obeyed over the range of 0–16 μg mL−1 bovine serum albumin (BSA) with the detection limit being 15 ng mL−1. Both the influence of reaction variables and the interference of coexisting substance are studied. The proposed method has been applied to the whole milk powder samples with satisfactory results. The recoveries are between 97.6% and 105.8%, and the standard relative deviations are less than 4.3%. Molar ratio and slope ratio methods are used to determine the binding number of BSA with the complex and the value 96.  相似文献   

9.
Twenty nine organic air pollutants including carbonyl compounds, alkanes, aromatic hydrocarbons and terpenes were measured in the indoor environment of different houses together with the corresponding outdoor measurements in Puertollano, the most industrialized city in central Iberian Peninsula. VOCs were sampled during 8 weeks using Radiello® passive samplers, and a questionnaire on potential VOCs sources was filled out by the occupants. The results show that formaldehyde and hexanal was the most abundant VOCs measured in indoor air, with a median concentration of 55.5 and 46.4 μg m−3, respectively followed by butanal (29.1 μg m−3), acetone (28.4 μg m−3) and acetaldehyde (21.4 μg m−3). After carbonyls, n-dodecane (13.1 μg m−3) and terpenes (α-pinene, 13.4 μg m−3 and limonene, 13.4 μg m−3) were the compounds with higher median concentrations. The indoor/outdoor (I/O) ratios demonstrated that sources in the indoor environment are prevailing for most of the investigated VOCs especially for limonene, α-pinene, hexanal, formaldehyde, pentanal, acetaldehyde, o-xylene, n-dodecane and acetone with I/O ratio >6. Multiple linear regressions were applied to investigate the indoor VOC determinants and Spearman correlation coefficients were used to establish common sources between VOCs. Finally, the lifetime cancer risk associated to formaldehyde, acetaldehyde and benzene exposure was estimated and they varied from 7.8 × 10−5 to 4.1 × 10−4 for formaldehyde, from 8.6 × 10−6 to 3.5 × 10−5 for acetaldehyde and from 2.0 × 10−6 to 1.5 × 10−5 for benzene. For formaldehyde, the attributed risk in most sampled homes was two orders of magnitude higher than the one (10−6) proposed as acceptable by risk management bodies.  相似文献   

10.
The elemental composition of 37 bottled waters from the UK and continental Europe has been determined. Ca, K, Mg, Na, Al, As, Ba, Cd, Cr, Co, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Sr, U, V and Zn were determined by ICP-OES and ICP-MS, in addition to inorganic and total organic carbon. The composition of all the waters analysed fell within the guideline values recommended by the World Health Organization. Na, Ca, Sr and Ba showed the widest variation in concentrations, ranging over two orders of magnitude. Levels of Fe were below the limit of detection (30 μg L−1) in all samples analysed. Waters produced in the UK generally showed lower levels of most major elements and trace metals, with the exception of Ba (up to 455 μg L−1). Italian waters showed the highest concentrations of Sr (3000–8000 μg L−1) and U (8–13 μg L−1), whereas waters produced in Slovakia and the Czech Republic showed the highest levels of Pb (0.7–4 μg L−1). The use of multivariate analysis reveals an association between high alkaline metal content and high concentrations of As and Cr. There also appears to be a correlation between high Ca and Sr content and high levels of U. Analysis of variance (ANOVA) indicates that the composition of bottled water can be distinguished primarily by the country of origin, over other factors including the geological environment of the source. This would suggest that composition reflects, and is biased towards, consumer preferences.  相似文献   

11.
Polycyclic aromatic hydrocarbons (PAH) in traditional/industrial smoked and unsmoked Circassian cheeses available in Turkish markets were analysed using solid-phase extraction, followed by high-performance liquid chromatography (HPLC) with fluorescence detection. Mean levels of a total of 9 PAHs in smoked traditional and industrial Circassian cheeses were 19.6 and 6.73 μg kg−1, while levels in unsmoked traditional and industrial cheeses were 0.77 and 0.49 μg kg−1, respectively. The dominant individual PAHs found were naphthalene and acenaphthene. Benzo[a]pyrene, a marker compound representing carcinogenic PAHs, was found in 90% and 30% of traditional smoked and unsmoked Circassian cheeses, 52% and 24% of industrial smoked and unsmoked cheeses, respectively. Correlation statistical analysis showed that benzo[a]pyrene was a good marker for total 9 PAHs in Circassian cheese samples (rB[a]P/sum of 9 PAHs = 0.816, p < 0.01) as well as the best marker for 5 carcinogenic PAHs (rB[a]P/carcinogenic PAHs = 0.904, p < 0.01). Risk assessment conducted using daily intakes of sum of 9 PAH levels found in both traditional and industrial smoked Circassian cheese samples showed high risk compared with unsmoked cheeses.  相似文献   

12.
A fast and sensitive method has been developed for the determination of five fluoroquinolones and a quinolone in commercial bovine milk by capillary-LC–DAD–MS after simple extraction method based on milk deproteinization with 15% trichloroacetic acid. Separation was carried out in a Zorbax SB-C18 column (150 mm × 0.5 mm, 5 μm) using a mixture of acetonitrile–5 mM ammonium formate (pH 3.7) as mobile phase in gradient elution mode. The sample was prepared in a 5 mM aqueous ammonium formate buffer for focusing purposes and 20 μL were injected. Flow rate and temperature were set at 20 μL min−1 and 25 °C, respectively. Method validation was performed according to the European Commission Decision 657/2002/EC. Sample detection limits were between 2.8 and 25 μg kg−1, and good linearity was observed up to 250 μg kg−1 for all analytes. Acceptable and constant recoveries of 96% for enrofloxacin, 77% for its metabolite ciprofloxacin, and 64% for flumequine, with RSDs (n = 4) lower than 8%, were obtained at the 100 μg kg−1 maximum level permitted in milk. Recoveries between 70% and 83% were obtained when difloxacin, sarafloxacin and ofloxacin (not allowed in animals that produce milk for human consumption) were added to milk samples at levels in the range 75–150 μg kg−1. Decision limit (CCα), detection capability (CCβ), repeatability, within-laboratory reproducibility and robustness were compliant with European Union regulations.  相似文献   

13.
The aim of this work is to present a simple and sensitive reverse-phase liquid chromatography method for the determination and investigation of amino acids in wolfberry fruit (Lycium barbarum) after solid-phase extraction-derivatization. The method linearity, calculated for each amino acid, had a correlation coefficient higher than 0.9950, in concentrations ranged from 9.60 to 3.33 × 103 μmol L−1. The detection limits of amino acids were between 2.42 and 6.51 μmol L−1. The calculated recoveries for amino acids in wolfberry fruit were from 87.3% to 97.1% and relative standard deviations were from 2.62% to 5.22%. The investigation illustrated that each tested wolfberry fruit contained at least 16 amino acids and the main amino acids were glutamic acid, aspartic acid, proline, alanine, serine, glycine, lysine, and tyrosine. The levels of amino acid in wolfberry fruit were varying from different areas.  相似文献   

14.
In this work a variety of beverage samples had been kept in a contaminated area to investigate their lead adsorption. To determine the adsorbed Pb(II), a novel magnetic lead ion-imprinted polymer, grafted onto Fe3O4 nanoparticles, was synthesized and used as a selective sorbent for the preconcentration of Pb(II) ions. The sorbent was characterized by different techniques. The synthesized sorbent was applied for highly accurate and selective determination of Pb(II) ions absorbed from polluted air in several beverages and results were compared. To validate the method, three certified reference materials were analyzed by the proposed method and the results showed that pre-concentrating by this sorbent and subsequent determination by flame atomic absorption spectroscopy is an accurate method for lead determination in beverage samples (recoveries higher than 95%). The limits of detection and the relative standard deviations were less than 1.7 μg kg−1 and 4.1%, respectively. The sorption capacity of this new sorbent was 51.8 mg g−1. Finally, this method was used for the determination of Pb(II) ions in polluted beverage samples, and the results revealed that under equal conditions, coffee exhibits more tendency to adsorb Pb(II) ions.  相似文献   

15.
Non-destructive applications for the detection of food quality, especially internal properties, are highly relevant for process control in the food industry. In this respect, colour measurement and near-infrared spectroscopy (NIRS) were evaluated and compared for their ability to predict β-carotene content in mango cv. ‘Nam Dokmai’. Colorimetric analysis of peel and flesh colour as well as NIR measurements in the short- (700–1100 nm) and long-wave regions (1000–2500 nm) were analysed for prediction ability. It was found that β-carotene content could be estimated by multiple linear regression (MLR) models developed from b* and hue angle (h°) values of the flesh with good results for coefficient of determination (R2) and standard errors of cross validation (SECV) of 0.941 and 10.2 retinol equivalents (RE) 100 g−1 edible part (EP), respectively, while peel colour showed poor results. However, flesh colour measurement is a destructive method. NIRS calibration showed good results with R2 > 0.800 and standard error of prediction (SEP) 11.642–20.2 RE 100 g−1 EP. Long-wave NIR provided better prediction ability than short-wave. From these results, NIRS can be recommended for non-destructive and reliable determination of β-carotene content in mango. The results have implications for quality control in the industrial handling and processing of fruits.  相似文献   

16.
A sensitive, precise and reliable flow-batch method for the determination of aluminium (Al) was developed using a sequential injection-monosegmented flow system incorporating a mixing chamber unit. Eriochrome cyanine R (ECR) was used as a chromogenic reagent in the presence of N,N-dodecyltrimethylammonium bromide (DTAB). The Al-ECR complex at pH 6 gave a maximum absorption at 584 nm. In-line single standard calibration and a standard addition procedure were developed employing the monosegmented flow technique. Under the optimum conditions, a linear calibration graph in the range of 0.0075–0.625 mg L−1 Al was obtained with limits of detection and quantitation of 0.0020 and 0.0070 mg L−1, respectively. Relative standard deviations were 0.8 and 1.3% for 0.010 and 0.025 mg L−1 Al (n = 11), respectively. A sample throughput of 24 h−1 using an in-line standard calibration approach and 6 h−1 using four standard addition levels was achieved. The developed system was successfully applied to water samples and beverage samples. The results agreed well with those obtained from the ICP-AES method. Good recoveries between 85 and 104% were obtained.  相似文献   

17.
The presence of diterpenes in coffee has received a great deal of attention in recent years, due to their physiological effects on human health. Some studies related to kahweol and cafestol contents in Coffea arabica are available in the literature; however, information on the impact of genetic variability on the profile of diterpenes in Coffea canephora is scarce. This work evaluates the contents of kahweol, cafestol and 16-O-methylcafestol in 15 genotypes of C. canephora. Coffees corresponded to three cultivars – Diamante ES8112, ES8122 ‘Jequitibá’ and Centenária ES8132 – with different fruit-ripening seasons (early, medium and late). Coffees were grown at two locations in the state of Espírito Santo, the largest C. canephora growing region in Brazil, resulting in 30 samples. Kahweol was absent in 70% of the samples and the highest content observed was 14.1 mg 100 g−1 in the Jequitibá cultivar. Cafestol was present in all samples and it was the main representative of the diterpene class, with contents varying from 152 mg 100 g−1 to 360 mg 100 g−1. Contents of 16-O-methylcafestol varied from 26.3 mg 100 g−1 to 132 mg 100 g−1. A significant difference among genotypes was observed, and there was an interaction between genotypes and growing site for the three diterpenes studied.  相似文献   

18.
Total (Ast), inorganic arsenic (Asi = As(III) + As(V)) and dimethylarsonic acid (DMA) were determined in 37 commercial rice samples collected in France. Ast was measured by inductively coupled plasma-mass spectrometry (ICP-MS) whereas anion-exchange chromatography – ICP-MS was used for Asi and DMA determination. Ast in raw rice varied from 0.041 to 0.535 mg kg−1 whereas Asi varied from 0.025 mg kg−1 (polished Basmati rice) up to 0.471 mg kg−1 (organic rice duo). The daily intake and associated health risk for different population groups as a function of age and gender was also assessed. The intake varied between 0.002 and 0.184 μg kg−1 body weight for Ast and 0.002 and 0.153 μg kg−1 body weight for Asi, which do not pose a chronic toxicity risk. Organic wholegrain rice may entail a risk for children in the case of sole consumption at the expense of polished rice. The impact of rice cooking/boiling in terms of the overall toxicological risk related to As species was also investigated. Pre-rinsing and boiling the raw rice by using an excess of water is the most efficient mode to obtain a significant Asi removal and further reduction of the toxicological risk for children, particularly for white rice varieties.  相似文献   

19.
The article presents the results of optimization of operation parameters, investigation of analytical characteristics and the abilities of a graphite filter-furnace (FF) atomizer for the direct electrothermal atomic absorption spectroscopy (ET AAS) determination of trace amounts of Mn, As, Pb, Cu, Cd and Zn in some vegetable oils and fats. The effect of pyrolysis and atomization temperatures of the graphite FF atomizer on atomic absorbance values of the listed elements at their evaporation from some organic solutions in the presence of a Pd-Mg chemical modifier (CM) was investigated. For the ET AAS determination of As, Pb, Cd and Zn with Pd-Mg CM, the temperature of the graphite FF atomizer for the pyrolysis step can be raised by 250–350 °C. This mode allows to eliminate the background absorption, to increase the sensitivity of the elements to be analyzed and to enhance the total content of vegetable oils or fats in organic solutions up to 0.5 g mL−1. The obtained limits of quantification for Mn, As, Pb, Cu, Cd and Zn were 0.002, 0.004, 0.004, 0.002, 0.0008, 0.0004 mg kg−1, respectively. The relative standard deviation (RSD) varied between ∼3 and 8% and the time of one element determination did not exceed ∼3–5 min. The reliability of the proposed method was checked using the reference method. A paired Student's t-test showed no significant difference between the results obtained by both methods on a 95% confidence level.  相似文献   

20.
Different honey types were collected in Croatia during 2010 and 2011: 7 multifloral orchard honeys, 7 multifloral meadow honeys, 19 black locust, 9 chestnut, 11 lime and 6 sage honeys. Elements were measured using graphite (As, Cu, Cd, Pb, Se) and flame atomic absorption spectrometer (Ca, Fe, K, Mg, Na, Zn) and by mercury analyser (Hg). Significant differences in Ca, Fe, K, Mg, Zn, As and Hg levels were observed between honey types. In chestnut honey were determined (K, Ca, Mg: mg kg−1; Hg, Ad, Cd: μg kg−1): the highest concentrations of K 2824.4, Ca 486.7, Mg 59.1 and Hg 2.52; the lowest of As 24.1 and Cd 2.52. Lime honey has been shown the highest content of Cu (20.6 mg kg−1), Zn (6.78 mg kg−1), Cd (2.14 μg kg−1) and Pb (810.3 μg kg−1). The lowest levels of following elements were determined in black locust honey (Fe, K, Mg: mg kg−1; Hg: μg kg−1): Fe 2.77, K 304.7, Mg 8.02 and Hg 0.82. Sage honey had the lowest Ca and Na content (173.9 and 31.8 mg kg−1). Among the multifloral honeys, the following was determined (Fe, Na, Cu: mg kg−1; As, Pb: μg kg−1): orchard honey – highest of Fe 5.17 and As 276.1, lowest Pb 301; meadow honey – highest Na 36.1, lowest Cu 4.38. The average Ca, Cu and Pb levels found in multifloral honey types were much higher than those reported in other European countries. Calcium levels in lime, chestnut and black locust were higher than those from other countries.  相似文献   

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