Selenium In Wheat Research Articles

Selenium-Containing Organic Fertilizer Application Affects Yield, Quality, and Distribution of Selenium in Wheat.

This study was designed to investigate the effect on wheat yield of applying organic fertilizers (OF) with five different selenium (Se) concentrations. The mineral nutrients, cadmium (Cd) content, and the distribution of Se in wheat plants were also measured. The results showed that wheat yields reached a maximum of 9979.78 kg ha-1 in Mengcheng (MC) County and 8868.97 kg ha-1 in Dingyuan (DY) County, Anhui Province, China when the application amount of selenium-containing organic fertilizer (SOF) was up to 600 kg ha-1. Among the six mineral nutrients measured, only the calcium (Ca) content of the grains significantly increased with an increase in the application amount of SOF in the two regions under study. Cd content showed antagonistic effects with the Se content of wheat grains, and when the SOF was applied at 1200 kg ha-1, the Cd content of the grains was significantly reduced by 30.1% in MC and 67.3% in DY, compared with under the Se0 treatment. After application of SOF, the Se content of different parts of the wheat plant ranked root > grain > spike-stalk > glume > leaf > stem. In summary, SOF application at a suitable concentration could increase wheat yields and significantly promote the Ca content of the grains. Meanwhile, the addition of Se effectively inhibited the level of toxic Cd in the wheat grains.

Soil and foliar selenium application: Impact on accumulation, speciation, and bioaccessibility of selenium in wheat (Triticum aestivum L.).

A comprehensive study in selenium (Se) biofortification of staple food is vital for the prevention of Se-deficiency-related diseases in human beings. Thus, the roles of exogenous Se species, application methods and rates, and wheat growth stages were investigated on Se accumulation in different parts of wheat plant, and on Se speciation and bioaccessibility in whole wheat and white all-purpose flours. Soil Se application at 2 mg kg–1 increased grains yield by 6% compared to control (no Se), while no significant effects on yield were observed with foliar Se treatments. Foliar and soil Se application of either selenate or selenite significantly increased the Se content in different parts of wheat, while selenate had higher bioavailability than selenite in the soil. Regardless of Se application methods, the Se content of the first node was always higher than the first internode. Selenomethionine (SeMet; 87–96%) and selenocystine (SeCys2; 4–13%) were the main Se species identified in grains of wheat. The percentage of SeMet increased by 6% in soil with applied selenite and selenate treatments at 0.5 mg kg–1 and decreased by 12% compared with soil applied selenite and selenate at 2 mg kg–1, respectively. In addition, flour processing resulted in losses of Se; the losses were 12–68% in white all-purpose flour compared with whole wheat flour. The Se bioaccessibility in whole wheat and white all-purpose flours for all Se treatments ranged from 6 to 38%. In summary, foliar application of 5 mg L–1 Se(IV) produced wheat grains that when grounds into whole wheat flour, was the most efficient strategy in producing Se-biofortified wheat. This study provides an important reference for the future development of high-quality and efficient Se-enriched wheat and wheat flour processing.

Effects of different forms and application methods of selenium fertilizers on wheat selenium uptake and utilization and its residual availability

<p id="C3">A two-year positioning field experiment was conducted to determine the reasonable regulation measures of selenium (Se) fertilizer for improving wheat grain Se nutrition, and to explore the feasibilities of different Se application approaches in Se agronomic biofortification of wheat grown in the typical Se-deficient soils of Yongshou County, Shaanxi Province. To study the effects of different forms and application methods of Se fertilizers on wheat yield, Se concentration and its accumulation and utilization, with the goal of producing wheat grain with Se concentration of 100 μg kg ^-1, five Se application rates of 0, 15, 18, 700, and 45 g hm^-2 were calculated for the treatments of no Se application (control), soil- and foliar-sodium selenate, and soil- and foliar-sodium selenite in the first year, respectively. In the following wheat season, for further investigating the residual Se availability, no Se fertilizer was applied and each plot was divided into straw removal and straw return. These results showed that the wheat grain yield and straw biomass were not influenced by Se forms and application methods. For the first wheat season, grain Se concentration reached the expected target value with a range of 109-397 μg kg ^-1, and the flour Se concentration varied from 101 μg kg ^-1 to 356 μg kg ^-1 for all the Se application treatments. In the next year, both grain and white flour Se concentrations were 100 μg kg ^-1 higher than under the treatment of soil-sodium selenite, and there was no significant difference of straw removal and straw return. Grain Se biofortification index was 4.7, 16, 0.3, 8.0 (μg kg^-1) (g hm^-2)^-1 for soil- and foliar-sodium selenate, and soil- and foliar-sodium selenite, respectively. The Se use efficiency was the highest for foliar-sodium selenate (7.3%), whereas its cumulative use efficiency was only 0.3% in soil-sodium selenite treatment with the long-term residue effects. At wheat harvest, the highest soil available Se was observed for soil-sodium selenite, with 91 μg kg ^-1 and 107 μg kg ^-1 for the straw removal and straw return, respectively. In conclusion, both soil- and foliar-sodium selenate /selenite were beneficial for producing wheat grain with target Se concentration of 100 μg kg ^-1, and the sodium selenite requirement was the highest, and its residual availability should be taken into consideration for Se biofortification in wheat production in the Se-deficient area of Chinese Loess Plateau.

Accumulation of zinc, iron and selenium in wheat as affected by phosphorus supply in salinised condition

Biofortification of zinc (Zn), iron (Fe) and selenium (Se) in crops could be affected by environmental factors such as soil salinity and phosphorus supply levels, as well as by the genotypic effect. Two pot experiments were conducted with one examined the effects of P supply and salinity on plant growth and Zn, Fe and Se uptake in wheat, and the other examined genotypic differences in Zn, Fe and Se accumulation among 20 wheat genotypes. The results of the first pot study showed significant interactive effects between P supply and salinity on Zn, Fe and Se accumulation. Increasing salinity at the same P supply level increased shoot Zn concentrations, but significantly decreased total shoot Zn amount owing to decreased aboveground biomass. An increased accumulation of total shoot Fe and Se in P-added treatments, relative to the no-P treatments, was mainly due to increased aboveground biomass. The results of the second pot study showed substantial genotypic variations in Zn, Fe and Se accumulation; principal component analysis (PCA) suggested that agronomic traits and nutrient accumulation were controlled by independent genetic mechanisms. These results indicated that the amount of P supply is a key factor regulating biomass and accumulation of Zn, Fe and Se in certain saline soils; the sizable genotypic difference in Zn, Fe and Se accumulation observed in salinised conditions has provided potential scope for genetic improvement by breeding strategies.

Selenium in Wheat from Farming to Food.

Selenium (Se) plays an important role in human health. Approximately 80% of the world's population does not consume enough Se recommended by the World Health Organization. Wheat is an important staple food and Se source for most people in the world. This review summarizes literature about Se from 1936 to 2020 to investigate Se in wheat farming soil, wheat, and its derived foods. Se fortification and the recommended Se level in wheat were also discussed. Results showed that Se contents in wheat farming soil, grain, and its derived foods around the world were 3.8-552 μg kg-1 (mean of 220.99 μg kg-1), 0-8270 μg kg-1 (mean of 347.30 μg kg-1), and 15-2372 μg kg-1 (mean of 211.86 μg kg-1), respectively. Adopting suitable agronomic measures could effectively realize Se fortification in wheat. The contents in grain, flour, and its derived foods could be improved from 93.94 to 1181.92 μg kg-1, from 73.06 to 1007.75 μg kg-1, and from 86.90 to 587.61 μg kg-1 on average after leaf Se fertilizer application in the field. There was a significant positive correlation between the Se content in farming soil and grain, and it was extremely the same between the foliar Se fertilizer concentration rate and the grain Se increased rate. The recommended Se fortification level in cultivation of wheat in China, India, and Spain was 18.53-23.96, 2.65-3.37, and 3.93-9.88 g hm-2, respectively. Milling processing and food type could greatly affect the Se content of wheat-derived food and should be considered seriously to meet people's Se requirement by wheat.

Methods to Enhance Selenium in Wheat through Biofortification: A Review

Methods to Enhance Selenium in Wheat through Biofortification: A Review

Optimization of a Chemical Modifier in the Determination of Selenium by Graphite Furnace Atomic Absorption Spectrometry and Its Application to Wheat and Wheat Flour Analysis

A method for the determination of total selenium in wheat and wheat flour using graphite furnace atomic absorption spectrometry (GFAAS) with palladium/ascorbic acid as a chemical modifier was studied. The effects of nickel nitrate, palladium/ascorbic acid, and palladium/magnesium nitrate as chemical modifiers on the sensitivity in the determination of selenite, selenate and selenomethionine by GFAAS were compared. The palladium/ascorbic acid modifier was used for the determination of total selenium in wheat and wheat flour, because the oxidation states of the selenium ion are not important in the determination. The detection limit was estimated to be 1 microg L(-1) (calculated as 3sigma of the blank); the calibration curve was linear for the concentration range 5 - 50 microg L(-1) and the recovery range was 96.66 - 101.80%. The optimal ashing and atomizing temperatures were 1300 degrees C and 2250 degrees C, respectively. The proposed method was successfully applied to the determination of total selenium in wheat and wheat flour.

Selenium Distribution in Wheat Grain, and the Effect of Postharvest Processing on Wheat Selenium Content

Selenium (Se) is an essential micronutrient for animals and humans, and wheat is a major dietary source of this element. It is important that postharvest processing losses of grain Se are minimized. This study, using grain dissection, milling with a Quadrumat mill, and baking and toasting studies, investigated the distribution of Se and other mineral nutrients in wheat grain and the effect of postharvest processing on their retention. The dissection study, although showing Se concentration to be highest in the embryo, confirmed (along with the milling study) previous findings that Se (which occurs mostly as selenomethionine in wheat grain) and S are more evenly distributed throughout the grain when compared to other mineral nutrients, and, hence, lower proportions are removed in the milling residue. Postmilling processing did not affect Se concentration or content of wheat products in this study. No genotypic variability was observed for grain distribution of Se in the dissection and milling studies, in contrast to Cu, Fe, Mn, and Zn. This variability could be exploited in breeding for higher proportions of these nutrients in the endosperm to make white flour more nutritious. Further research could include grain dissection and milling studies using larger numbers of cultivars that have been grown together and a flour extraction rate of around 70%.

Evidence of low selenium concentrations in UK bread‐making wheat grain

AbstractThe selenium concentration of representative bread‐making wheat (Triticum aestivum L) samples was measured in national grain surveys collected in 1982 (n (number of samples) = 180), 1992 (n = 187) and 1998 (n = 85) from major wheat‐growing regions around the UK. The means and distributions of selenium concentrations over the three years were similar, with mean grain concentrations of 0.025, 0.033 and 0.025 mg kg−1 dry weight respectively and inter‐quartile ranges varying from 0.015 mg kg−1 in 1982 to 0.019 mg kg−1 in 1992 samples. No long‐term changes in the distribution of wheat selenium concentrations were found over the 17 year period. Geographical mapping of the concentrations identified an area of eastern England as having high grain concentrations compared with other UK regions. There were no significant correlations between grain selenium and grain sulphur concentrations for the national survey samples. However, at an individual field experimental site, increasing the rate of sulphur addition was found to decrease grain selenium concentration significantly. The daily UK dietary contribution of selenium from wheat‐based products was estimated and the daily intake was calculated to be 6.4 µg selenium, around one‐tenth of the UK recommended intake values for men and women.© 2002 Society of Chemical Industry

Selenium-enriched sprouts. A raw material for fortified cereal-based diets.

The selenium supply in almost all European countries, including Austria and Germany, is below the recommended daily intake. In these countries, selenium fortification of foods and the use of selenium supplements are quite popular to compensate for low Se intake from diets. In general, wheat (Triticum aestivum) is known to be a good source for bioavailable selenium, and many studies have been performed to enrich selenium in wheat by selenium fertilization of the soil. In the present work, the process of sprouting was investigated as an alternative to enrich selenium in wheat. Sprouting was chosen because it additionally improves the nutritional value of seeds, for example, by a higher vitamin content, a better quality of protein, and some other parameters. Wheat, alfalfa (Medicago sativa), and sunflower (Helianthus annuus) seeds were germinated for 5 and 7 days in solutions containing selenate. The selenium sensitivity of the sprouts was tested by measuring visible germination levels and seedling development. Uptake rates were studied by determination of total selenium using inductively coupled plasma mass spectrometry (ICP-MS). Metabolism of the absorbed selenium was analyzed by determination of selenium species in extracts of the sprouts using anion exchange HPLC coupled to ICP-MS. It was shown that sunflower sprouts were the most resistant and had the highest uptake rates (up to 900 mg/kg), but almost 100% of the selenium was extracted with water and found to be nonmetabolized selenate. Wheat and alfalfa were less resistant and enriched selenium up to concentrations of 100 and 150 mg of Se/kg of dry mass, respectively. The metabolism of the selenate was inversely related to the total uptake rates. At low Se enrichment (approximately 1-2 mg of Se/kg), <20% of the total selenium content within the sprouts remained as inorganic selenium, indicating a high metabolism rate. With increasing uptake the amount of selenate increased to approximately 40-50%. However, with the method used it is possible to produce sprouts containing certain amounts of selenium, which might provide substantial proportions of bioavailable selenium. In combination with the generally high nutritional value of sprouts, they might serve for production of improved cereal-based diets.

The Human Selenium Status in 27 Regions of Russia

Russia is the largest nation in the world and it has vastly different climatic and geochemical conditions. The human selenium status is determined mainly by the selenium intake from foods, whose concentration is subject to geochemical, geological and temporal factors. The data on the selenium status of populations in Russia are scarce and sporadic. This review presents the most recent selenium data acquired using adequate quality assurance measures. Serum samples were obtained from 2462 healthy blood donors between 1990-1996 from 125 locations representing 27 different regions of Russia. Samples of wheat flour and dried milk were also analyzed from most regions. The mean serum selenium concentration per region varied from 0.80 mumol/l in the western regions (Pskov) to 1.84 mumol/l in the easternmost regions (Sakhalin). A low (0.76-1.00 mumol/l) serum selenium concentration was found in only 6% of the locations. In 88% of the locations the mean serum selenium concentrations were moderate (1.01-1.40 mumol/l) and the highest values, > 1.45 mumol/l were found in eight towns. Wheat flour selenium concentrations varied widely from 44 to 557 micrograms/kg depending on the origin. The low values were either domestic or European and the high values of American or Australian origin. A high correlation between serum selenium and wheat flour (r = 0.79) suggests that the selenium status in most instances is determined by high selenium in wheat. Overtly very low or high serum selenium levels were not found in the 27 regions studied in Russia.

Comparison of Closed-Vessel and Focused Open-Vessel Microwave Dissolution for Determination of Cadmium, Copper, Lead, and Selenium in Wheat, Wheat Products, Corn Bran, and Rice Flour by Transverse-Heated Graphite Furnace Atomic Absorption Spectrometry

A method is described for the determination of Pb, Cd, Cu, and Se in cereal samples. An atomic absorption spectrometer equipped with a transverse-heated graphite furnace with Zeeman background correction was used for all determinations. Sample preparation was performed by closed-vessel microwave digestion using nitric acid and focused openvessel microwave digestion using nitric acid-hydrogen peroxide. Both techniques were evaluated by using 15 cereal reference materials and comparing results with certified or reference values for each element. Cereal reference standards obtained from the Community Bureau of Reference (Europe), the National Institute of Standards and Technology (USA), the National Institute for Environmental Studies (Japan), the National Research Centre for Certified Reference Materials (People's Republic of China), and the Canadian Grain Commission were used. Application of a series of t-tests, conducted according to Sidak's modified Bonerroni t-procedure, showed that both techniques yielded accurate results for cereal reference materials. Some differences from certified and reference values, however, were found for each element.

Supplementation with wheat selenium induces a dose-dependent response in serum and urine of a Se-replete population

In spite of a rather modest dietary intake of selenium (80 micrograms/10 MJ), Norwegian serum Se levels are among the highest in Europe. As part of an ongoing study of Se bioavailability, effects of different doses of wheat Se were investigated in eighteen healthy, Norwegian women. The participants were given Se-rich bread providing 100, 200 and 300 micrograms Se daily for 6 weeks. About 50% of the Se intake was excreted in the urine by week 6, compared with 67% before the intervention started. Serum Se increased by 20, 37 and 53 micrograms/l respectively, in the three group (P less than 0.001). The blood response and renal clearance results compare well with data obtained from less Se-replete populations, and support the hypothesis that selenomethionine from the diet is incorporated into a non-specific amino acid pool. Our study indicates that the intake of wheat Se is the main determinant of blood Se levels in Norway.

Effect of various levels of selenium in wheat and meat on blood Se status indices and on Se balance in Dutch men

After a 5-week period of low selenium intake, twenty-four Dutch men received 55, 135 or 215 micrograms Se/d as Se-rich meat or bread for a 9-week period. Four unsupplemented subjects served as controls. Plasma Se increased more rapidly than erythrocyte Se levels; the increases were significantly dependent (P less than 0.001) on Se intake level. Glutathione peroxidase (EC 1.11.1.9; GSH-Px) activity in platelets increased rapidly after supplementation and plateaued after 4-9 weeks. At 10 weeks after supplementation ended, plasma Se levels and platelet GSH-Px were still higher than the baseline values whereas erythrocyte Se levels continued to increase. Except for the higher erythrocyte Se levels after supplementation with high-Se meat, there were no differences in bioavailability of Se between meat and wheat products. Daily urinary and faecal Se excretions as well as Se retention increased with an increased Se intake irrespective of the form of the supplement. Regression of Se excretion v. intake indicated that 33 micrograms Se/d is necessary to compensate for urinary and faecal losses.

The effects of organic and inorganic fertilization on the content of trace elements in cereal grains

To compare the effects of organic manuring and inorganic fertilization, the contents of zinc, copper, iron, managanese and selenium in wheat and oats harvested from a field experiment were analysed using atomic absorption spectrophotometry. Inorganic fertilization compared to organic manuring increased the content of copper in oats and of manganese in wheat and of zinc and iron in wheat and oats. Organic manuring was more effective for the uptake of copper by wheat, manganese by oats and selenium by both wheat and oats. Inorganic fertilization compared to organic manuring increased the yield of oats, but organic manuring was equally effective in the case of wheat to obtain higher yield. There was no correlation between yield and trace element contents either in wheat or oats.

Bioavailability to chicks of selenium in wheat and fish meal.

SummaryThe bioavailability of selenium (Se) in wheat and fish meal, measured by the restoration of plasma GSH‐Px activity and the retention of Se in tissues, was determined in chicks obtained from Se depleted hens. Following a Se‐depletion period of 14 days, a low Se basal diet was fed to the chicks either alone or supplemented with 0.03, 0.06, 0.09 or 0.12 mg Se/kg diet. Se was supplied in the diets either as sodium selenite to provide a standard dose response (100%), or via wheat, fish meal and their extracted counterparts. The plasma GSH‐Px activity was measured at 5, 10, 20 and 30‐days of Se treatment, while the Se content in plasma and liver was determined at 30‐days Se supplementation. The slope ratio assay was used to analyse the results. The biological availability of Se in wheat, extracted wheat, fish and extracted fish meals, as indicated by the restoration of plasma GSH‐Px activity was 83, 90, 61 and 73%, respectively. The retention of Se in plasma showed a biological availability of: wheat, 109%; extracted wheat, 107%; fish meal, 85% and extracted fish meal, 89% while that for the retention of Se in liver gave a biological availability of 140, 151, 113 and 119%, for wheat, extracted wheat, fish and extracted fish meals, respectively. It was established that the Se in wheat is less effective than that in sodium selenite, but more effective than the Se in fish meal for the induction of plasma GSH‐Px in Se depleted chicks. Although the retention of Se in plasma and liver of chicks fed wheat or fish meal was comparable or even higher than that of chicks fed sodium selenite, a higher proportion of the retained Se was not biologically available for GSH‐Px synthesis in comparison to the Se in sodium selenite.ZusammenfassungBioverfügbarkeit von Selen in Weizen und Fischmehl bei KükenDie Bioverfügbarkeit von Selen (Se) in Weizen und Fischmehl wurde anhand der Plasma‐GSH‐Px‐Aktivität und der Se‐Retention im Gewebe bei von Se‐depletierten Hennen abstammenden Küken bestimmt. Nach einer 14tägigen Se‐Depletions‐Periode erhielten die Küken entweder eine Se‐arme Basaldiät oder die mit 0,03, 0,06, 0,09 bzw. 0,12 mg Se/kg supplementierte Basaldiät. Se wurde den Diäten entweder in Form von Natriumselenit oder über Weizen und Fischmehl zugesetzt. Die Reaktion der Küken auf die mit Selenit ergänzten Diäten diente dabei als Standard (= 100%). Die Plasma‐GSH‐Px‐Aktivität wurde nach 5‐, 10‐, 20‐ und 30tägiger Se‐Supplementierung, der Se‐Gehalt des Plasmas und der Leber nach 30tägiger Supplementierung bestimmt. Die Ergebnisse wurden mit Hilfe der “slope ratio”‐Methode ausgewertet. Die anhand der Plasma‐GSH‐Px‐Aktivität ermittelte Bioverfügbarkeit von Se in Weizen, extrahiertem Weizen, Fischmehl und extrahiertem Fischmehl betrug 83, 90, 61 bzw. 73%. Die Retention von Se im Plasma ergab für die biologische Se‐Verfügbarkeit folgende Werte: Weizen 109%; extrahierter Weizen 107%; Fischmehl 85% und extrahiertes Fischmehl 89%. Anhand der Se‐Retention in der Leber ergab sich für Weizen, extrahierten Weizen, Fischmehl und extrahiertes Fischmehl eine Bioverfügbarkeit von 140, 151, 113 bzw. 119%. Es wurde somit festgestellt, daß bei Heranziehung der GSH‐Px‐Aktivität des Plasmas als Maßstab für die Se‐Bioverfügbarkeit Se im Weizen weniger verfügbar als Se in Natriumselenit, aber besser verfügbar als Se in Fischmehl ist. Obgleich die Retention von Se im Plasma und in der Leber bei den Küken nach Verfütterung von Weizen oder Fischmehl ähnlich wie oder sogar höher als bei den Küken war, die Natriumselenit erhielten, war für die GSH‐Px‐Synthese im Vergleich zum Se des Natriumselenit weniger Se verfügbar.

Comparative Effect of Selenium in Wheat, Barley, Fish Meal and Sodium Selenite for Prevention of Exudative Diathesis in Chicks

Groups af White Leghorn chicks obtained from dams deprived on selenium (Se), were fed from hatching a low-Se-vitamin E basal diet alone, or supplemented with 0.02, 0.04, 0.06 or 0.08 mg Se/kg diet, as sodium selenite (Na2SeO3 · 5H2O), wheat, barley or fish meal. Prevention of the Se-vitamin E deficiency responsive disease exudative diathesis (ED) as it was clinical observed, induction of the plasma Se dependent enzyme glutathione peroxidase (GSH-Px) activity, and Se concentration in the cardiac muscle were observed to be dietary Se level and source dependent. Slope ratio assay was applied to estimate the biological availability of Se in the natural sources relative to Se in sodium selenite. For the prevention of ED, the bioavailability of Se in wheat, barley and fish meal was 99, 85 and 80 %, respectively. The increase in the plasma GSH-Px activity revealed a bioavailability for Se in wheat, barley and fish meal of 79, 71 and 66 %, respectively. Using retention of Se in the cardiac muscle as the bioassay, a bioavailability of 108, 87 and 100 % was calculated for wheat, barley and fish meal Se, respectively.

Bioavailability to Rats of Selenium in Various Tuna and Wheat Products

Bioavailability of selenium (Se) in tuna and wheat at various stages of processing was studied in rats. The protein source of the rat diets was torula yeast with Se supplied by either raw, precooked or canned tuna, or whole wheat flour, whole wheat bread or bran. Sodium selenite was used as the standard. Each Se source was fed at three levels: 0.05, 0.10 and 0.15 ppm. By using increase in glutathione peroxidase (GSH-Px) activity in liver, kidney and whole blood as an indicator of bioavailability, no differences were found among the three tuna products or among the three wheat products tested. However, significantly lower GSH-Px activity was found in the combined tuna groups as compared to the combined wheat groups, suggesting that selenium in wheat was more available than that in tuna. There was a significant increase in the liver Se content of rats fed all levels of Se in canned tuna and in kidney, blood and muscle Se of rats fed 0.10 and 0.15 ppm Se in canned tuna in comparison to the tissue Se content in rats fed these same levels of Se in raw or precooked tuna. Since this did not correspond with an increase in GSH-Px activity it was concluded that it did not represent increased bioavailability of canned tuna. Thus, food processing does not appear to affect Se availability, but Se appears to be more available in wheat than tuna.

Investigations on selenium in wheat

Pronase hydrolysates of crude gluten preparations from naturally seleniferous wheat seeds were subjected to ion-exchange chromatography and the eluates were examined chemically for selenium. Almost half of the selenium in the hydrolysate was accounted for as selenomethionine, but selenocystine was not detected. More detailed studies were then made on wheat gluten, seeds and straw from plants grown on soil to which 75Se-selenate had been added. On pronase hydrolysis of the seeds or the gluten, about half of the selenium could again be accounted for as selenomethionine. On examining protein-free, hot-water extracts of the seeds or straw of these plants, no free selenomethionine could be detected, suggesting the rapid incorporation of this amino acid into protein. Neither selenocystine, the seleno-half-cystine moiety nor Se-methylselenocysteine was detected in the hydrolysates or in the water extracts. The results suggest, however, the presence of selenocysteic acid in significant amounts in the gluten, the seeds and the straw. Over half of the selenium in the straw could be accounted for as selenate, but selenite was not found. Selenium compounds eluted shortly after selenite, selenate and cysteic acid, suggesting the presence of oxides of selenomethionine.

Determination of Selenium in Wheat and Soils

Determination of Selenium in Wheat and Soils