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Changes in selenium speciation associated with increasing tissue concentrations of selenium in wheat grain
Francesco Cubadda1, Federica Aureli, Silvia Ciardullo
1Food and Veterinary Toxicology Unit, Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanita, Viale Regina Elena 299, Rome 00161, Italy.
Journal of Agricultural and Food Chemistry
|January 28, 2010
Summary
Wheat from Punjab, India, exhibits record-high selenium levels, primarily as selenomethionine. This finding suggests potential health risks from excessive intake but also highlights the grain
Area of Science:
- Agricultural Science
- Analytical Chemistry
- Human Nutrition
Background:
- Wheat (Triticum aestivum) from the Nawanshahr-Hoshiarpur Region of Punjab, India, displayed exceptionally high selenium concentrations, unprecedented in cereal grains.
- A significant positive correlation was observed between selenium levels in wheat shoots and kernels, enabling prediction of grain selenium content from vegetative tissues.
Purpose of the Study:
- To identify and quantify selenium species in high-selenium wheat samples from Punjab, India.
- To investigate the relationship between selenium concentration and the speciation of selenium compounds in wheat.
- To assess the implications of high selenium wheat consumption on human and animal nutrition.
Main Methods:
- Ultrasound-assisted enzymatic extraction was employed to isolate selenium species from wheat samples.
- High-Performance Liquid Chromatography (HPLC) coupled with Inductively Coupled Plasma-Dynamic Reaction Cell-Mass Spectrometry (ICP-DRC-MS) was utilized for separation and quantification.
- Reversed-phase, cation exchange, and anion exchange HPLC methods were applied, alongside retention time matching with standards for compound identification.
Main Results:
- Selenomethionine constituted the predominant selenium species (72-85%), with selenate present at 2-6%.
- The proportion of organic selenium species varied with total selenium content; selenomethionine decreased relatively, while other organoselenium compounds increased.
- Se-methyl-selenocysteine was identified as a minor compound (0.2-0.5%) in high-selenium wheat.
Conclusions:
- Regular consumption of wheat from the study region may lead to excessive selenium intake for the local population.
- The high prevalence of selenomethionine in this wheat makes it a valuable source for naturally selenium-enriched products for human and animal dietary supplementation in selenium-deficient areas.
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