Selenium In Grain Research Articles

The nutritional quality of cereals varies geospatially in Ethiopia and Malawi

Micronutrient deficiencies (MNDs) remain widespread among people in sub-Saharan Africa1–5, where access to sufficient food from plant and animal sources that is rich in micronutrients (vitamins and minerals) is limited due to socioeconomic and geographical reasons4–6. Here we report the micronutrient composition (calcium, iron, selenium and zinc) of staple cereal grains for most of the cereal production areas in Ethiopia and Malawi. We show that there is geospatial variation in the composition of micronutrients that is nutritionally important at subnational scales. Soil and environmental covariates of grain micronutrient concentrations included soil pH, soil organic matter, temperature, rainfall and topography, which were specific to micronutrient and crop type. For rural households consuming locally sourced food—including many smallholder farming communities—the location of residence can be the largest influencing factor in determining the dietary intake of micronutrients from cereals. Positive relationships between the concentration of selenium in grain and biomarkers of selenium dietary status occur in both countries. Surveillance of MNDs on the basis of biomarkers of status and dietary intakes from national- and regional-scale food-composition data1–7 could be improved using subnational data on the composition of grain micronutrients. Beyond dietary diversification, interventions to alleviate MNDs, such as food fortification8,9 and biofortification to increase the micronutrient concentrations in crops10,11, should account for geographical effects that can be larger in magnitude than intervention outcomes.

Effects of different water management on absorption and accumulation of selenium in rice

Rice is the staple food for more than half of the world's population, but selenium (Se) is low in many rice growing countries. Water management model affects rice soil pH and Eh, and then affects the bioavailability of Se in soil. A pot experiment was conducted to investigate the effects of water management on soil Se species, dynamics and selenium uptake by rice plants. Sodium selenite was added to the soil so that the soil selenium content reached 0.5 mg kg−1 to study the effects of 3 different water management modes on soil selenium uptake by rice plants. These three modes are flood irrigation (F), aerobic irrigation (A) and alternate flood and aerobic irrigation (AFA). The results showed that flooded irrigation treatment increased the soil soluble selenium concentration, and the selenium in soil solution mainly existed in the form of selenite and selenomethionine selenium oxide. The content of selenium in grain was 2.44 and 1.84 times that of flooded irrigation treatment under A and AFA respectively. The content of selenium in straw was 1.32 and 1.58 times that of flooded treatment under A and AFA respectively. After rice grain enzyme hydrolysis, HPLC-ICP-MS analysis showed that Selenomethionine was the main selenium speciation in rice grains. This study showed that aerobic flooded treatment is one of the most effective ways to increase selenium content in rice field.

The Effects of Soil Chemical Characteristics on Accumulation of Native Selenium by Zea mays Grains in Maize Belt in Kenya

Background: Selenium which is an-antioxidant is important for human health enters food chain through crops. Both total amount of selenium in soil and its speciation determines the concentration in food crops. In Kenya Zea mays is consumed by 96% of population hence is a cheap and convenient method to provide selenium to large number of population. Soil chemical factors are known to have antagonistic effects on selenium speciation hence the uptake by Zea mays. The objective of this study was to determine the effects of the four soil chemical characteristics (pH, Tcarbon, CEC, Eh) on accumulation of selenium in Zea mays grains in Maize the Belt in Kenya. Research Methods: About 100 Zea mays grain samples together with 100 soil samples were collected from the study site, put in separate labeled Ziplocs and were transported to laboratories at room temperature for analysis. Maize grains were analyzed for selenium while soil samples were analyzed for pH, Cat Ion Exchange Capacity, Total carbon, and Electrical conductivity. Results: The mean selenium in Zea mays grains varied from 1.82 ± 0.76 mg/Kg to2 .11±0.86 mg/Kg.There was no significant difference between selenium levels between different grain batches {χ (Df =76) = 26.04 P= 1.00}. The pH levels varied from 5.43± 0.58 to 5.85± 0.32. No significant correlations between selenium in grains and soil pH (Pearson’s correlations = - 0.143) was observed. There was no signicant correlations between selenium levels in grains and the four (pH, Tcarbon, CEC,Eh) soil chemical characteristics {F (4,91) = 0.721 p = 0.579} was observed. Conclusion: Using the native selenium accumulation in Zea mays grains as proxy-indicator of selenium speciation in the soil, it can be concluded that the soil chemical characteristics in the study site did not significantly affect the speciation of available selenium species and hence accumulation of native selenium.

수소화물발생-유도결합플라즈마 질량분석법(HG-ICP/MS)을 이용한 곡류 중 셀레늄의 정량분석

본 연구에서는 유도결합 플라즈마 질량분석법에서 수소화물 발생법을 이용하여 곡류시료 중에 포함되어 있는 미량의 셀레늄을 분석하였다. 시료 전처리법으로 비커 산분해법과 마이크로파 분해법을 비교한 결과 비커 산분해법이 더 좋은 회수율을 보여 주었다. 수소화물 발생법에서 시료의 흐름속도가 0.60 mL/min일 때에 4.0 M HCl과 3% <TEX>$NaBH_4$</TEX> 조건에서 최적신호를 보여 주었고, 검출한계는 0.02 <TEX>${\mu}g/kg$</TEX>(<TEX>$3{\sigma}$</TEX>)로 수소화물 발생법을 사용하기 전보다 10 배가 개선되었다. 팔중극자 충돌셀을 이용한 동중 간섭의 제거에서 충돌기체로 <TEX>$H_2$</TEX> (흐름속도; 3.8 mL/min)를 사용하였을 때 헬륨보다 더 우수함을 보여 주었지만 시료 중에 Br이 포함된 경우에는 충돌기체와 반응하여 <TEX>$^{80}[BrH]^+$</TEX>, <TEX>$^{82}[BrH]^+$</TEX>가 생성되어 m/z 80과 82에서 간섭을 보여주었다. 여러 표준시료들을 사용하여 Se 정량을 분석한 결과 인증값과 일치되는 결과를 얻을 수 있었다. 국내의 여러 곡류시료를 정량한 결과, 농도는 12.7 <TEX>${\mu}g/kg$</TEX>에서 29.6 <TEX>${\mu}g/kg$</TEX>정도를 보여주었다. The purpose of this study is to determine the quantity of selenium in grains by hydride generation-inductively coupled plasma mass spectrometry. Two sample preparation methods, beaker and microwave digestions, are compared and the former shows better result. The optimum condition for hydride generation is 4.0 M for HCl, 3% for <TEX>$NaBH_4$</TEX> with the sample flow of 0.6 mL/min. The detection limit is 0.02 <TEX>${\mu}g/kg$</TEX>(<TEX>$3{\sigma}$</TEX>) and improved by 10 times. Isobaric interferences on Se is removed by Octopole Reactoin Cell and <TEX>$H_2$</TEX> (3.8 mL/min) shows better performance over He. However, in case Br exists in a matrix, <TEX>$H_2$</TEX> could induce interferences on m/z 80 and 82 (<TEX>$^{80}[BrH]^+$</TEX> and <TEX>$^{82}[BrH]^+$</TEX>). The accuracy of this experiment is examined successfully by analyzing several reference materials. The results for several domestic grain analysis show that the concentrations are between 12.7 <TEX>${\mu}g/kg$</TEX> and 29.6 <TEX>${\mu}g/kg$</TEX>.

Content of phenolic antioxidants and selenium in grain of einkorn (Triticum monococcum), emmer (Triticum dicoccum) and spring wheat (Triticum aestivum) varieties

Wheat is worldwide consumed and contributes significantly to the intake of antioxidants with beneficial healthy effects. In the precise two-year field experiments in 2008 and 2009 two varieties of wheat einkorn, two varieties of emmer wheat and three varieties of spring wheat and in 2009 in addition two other spring wheat varieties, three einkorn varieties and three emmer wheat varieties were evaluated for selenium content and antioxidants &amp;ndash; total polyphenols (TP). Selenium content was determined by atomic absorption spectrometry with hydride generation technique (HGAAS) and total polyphenols with Folin-Ciocalteau assay. Higher selenium content in grain is related to emmer (58.9&amp;ndash;68.4 mg/kg DM) and einkorn (50.0&amp;ndash;54.8 mg/kg DM) varieties; in spring varieties selenium content ranged from 29.8 to 39.9 mg/kg DM. Among the varieties with high TP (expressed in gallic acid equivalents) emmer varieties prevail (584&amp;ndash;692 mg/kg DM), less represented are einkorn (507&amp;ndash;612 mg/kg DM) and spring wheat (502&amp;ndash;601 mg/kg DM) varieties. Among varieties significant differences were determined. TP were significantly higher in emmer wheat varieties and one einkorn and one spring wheat variety. Between TP and Se significant linear correlation was determined (r = 0.709). &amp;nbsp;

Rapid determination of selenium in grain

The development of selenium (Se)-enriched foods to reduce cancer risk would require servings to provide amounts of Se that, when added to daily Se intakes from other foods, would raise consumers' plasma Se levels to those associated with reduced cancer risk, e.g., >120 ng/ml (Duffield et al, JNCI 95:1477, 2003). For Americans consuming 85–175 ug Se/d, 50–100 ug added Se/d would meet that target safely. To provide such amounts, foods consumed in servings of 50 g/d (e.g., 2 slices bread) would need to contain 1.8 ug/g. Grains produced on high-Se soils of the Northern Plains offer opportunities, as they can contain 2–10 ug Se/g; however, this advantage is lost by the mixing, in elevators/mills, with grain of lower Se content, as it is currently not practical to sort grains by Se content. We addressed this problem by developing a rapid method to identify Se-rich grains. It involves 4 steps: 1) pulverization in a Teflon ball mill; 2) aqueous slurrification; 3) drying on a polyacrylic disc; 4) measurement of fluorescence in response to low-angle X-irradiation (Bruker Picofox X-ray spectrometer, Madison, WI). With wheat grain, this method can detect Se concentrations ≥0.4 ug/g with 95% confidence and takes <30 min, compared to 1–2 days by other methods. This XRF-based method offers a means of identifying high-Se grains that is sufficiently accurate, robust and efficient for use in handling grains in food processing. Supported by USDA.

Blood and Tissue Selenium Concentrations in Calves Treated with Inorganic or Organic Selenium Compounds – a Comparison

Pavlata L., J. Illek, A. Pechova: Blood and Tissue Selenium Concentrations in Calves Treated with Inorganic or Organic Selenium Compounds – a Comparison. Acta Vet. Brno 2001, 70: 19–26. Selenium concentrations were investigated in 5 calves treated parenterally with inorganic selenium (Group II), 5 calves treated orally with organic selenium (Group III), and 5 untreated control calves (Group I). Blood samples for analyses were collected at the beginning and at the end of the treatment period and tissue samples (liver, kidney, striated muscle, myocardium) after slaughter. Selenium was determined in the samples after microwave mineralisation using the hydride technique of AAS. Both treated groups showed highly significant increases in whole blood selenium concentrations (Group II from 53.4 ± 10.5 to 75.9 ± 4.0 µg.l-1; Group III from 70.25 ± 12.07 to 127.5 ± 16.7 µg.l -1 ). The comparison of tissue concentrations showed highly significant differences (P < 0.01) in the liver (213.3 ± 56.8, 206.5 ± 36.2 and 424.7 ± 88.4 µg.kg-1 wet tissue for the Groups I, II, and III, respectively), striated muscles (92.4 ± 29.2, 81.4 ± 12.1, and 263.4 ± 47.4 µg.kg -1 wet tissue for the Groups I, II and III, respectively), and myocardium (121.5 ± 31.8, 108.3 ± 9.6, and 251.4 ± 51.0 µg.kg -1 wet tissue for the Groups I, II and III, respectively) not only between Groups I and II, but also between Groups II and III. The among-group differences in selenium concentrations in the kidney (991.9 ± 49.1, 960.6 ± 36.3, and 1050.5 ± 336.8 µg.kg -1 wet tissue in the Groups I, II and III, respectively) were nonsignificant. It is apparent that oral administration of organic selenium resulted in higher tissue concentrations than parenteral administration of inorganic selenium. Highly significant (P < 0.01) correlations were found between selenium concentrations in the liver and striated muscles, in the liver and the myocardium, and in striated muscles and the myocardium (r = 0.78, 0.85, and 0.94, respectively). No relations were found between selenium concentrations in the kidney and other tissues. Highly significant (P < 0.01) correlations were also between the concentrations of selenium in the blood and in the liver, striated muscles, and the myocardium (r = 0.85, 0.80, and 0.77, respectively). Cattle, liver, striated muscle, myocardium, kidney Recent knowledge of biological effects of trace elements has prompted studies of their effects on animal health and performance. The importance of such studies is enhanced by the use of trace elements as feed additives as a replacement for antibiotic and hormonal growth stimulants. Considerable attention in this respect is paid to selenium. The principal source of this element for animals are plants. Groce et al. (1995), who studied correlations between the contents of essential trace elements in soil, forages, and blood, found a highly significant correlation coefficient (r = 0.96) for selenium. Availability of soil selenium to plants depends on soil acidity, structure and degree of aeration. Availability of oxidised forms is higher than that of the reduced form which remains undissolved in the soil. Selenium is incorporated into plant tissues mostly in the form of selenomethionine present in the protein component of grain. Hence, the content of selenium in grain closely correlates with the content of protein (Mahan1999). Further factors influencing the content of selenium in plants include the vegetation phase,

Method for the Determination of Selenium in Low-Selenium Grain and the Effect of Liming on the Uptake of Selenium by Barley and Oats

Abstract Selenium was determined in grain of barley and oats grown at locations distributed all over Sweden with the objective of studying the influence of liming on the selenium uptake at natural levels in the soil. The samples were taken from on-going field experiments, limed to different levels. An analytical procedure, carried out in a single test tube, was developed to cope with the low selenium concentrations in the grain. It involves combined wet/dry ashing of the organic matter, reduction to selenite by hydrochloric acid, complexation to obtain a brominated piazselenol, extraction of the complex into toluene, and finally determination by capillary gas chromatography with electron capture detection. The concentrations of selenium in the grains investigated were low, ranging from 1.5 to 16 ng g−1 dry weight. The limit of detection for a 0.1 g sample is 0.4 ng g−1, as estimated by three times the standard deviation of the blank determination (n = 34) and the absolute limit of detection for pure solutions is below 20 fg (0.5 μl injection on the column). The procedure was validated by determinations on reference materials, testing an alternate digestion procedure, and by determination using hydride generation atomic absorption spectrometry. Liming of the soil was found to have a small, but significant negative effect on plant uptake of selenium.