Onion selenium

Plants of the genus Allium, e.g. garlic Allium sativum), leek Allium amp-eloprasum), and onion Allium cepa), produce a bewildering variety of sulfur compounds. Selenium analogs for some of these have also been found (Section 11.1.3.6). Much work has focused on garlic (contains more than 100 such materials) and onion.56,66,67 Key compounds for formation of the Allium sulfur-containing secondary metabolites are sulfoxides of cysteine derivatives,... 

Lead, Cadmium, Mercury, Selenium Onions Flame AAS [86]... 

Se Speciation in Plants The presence of a number of volatile Se species was reported in edible allium plants such as garlic by GC-AES [79]. Selenomethionine, Se-methylselenocysteine, and y-glutamyl-Se-methyl-L-seleno cysteine were identibed in garlic and onion by HPLC-ICP-MS and ES-MS/MS [80]. Selenomethionine is the primary species found in all types of nuts (19D25 percent of the total Se) [30], sunBower [81], and mushrooms [36, 37], The distribution of Se among different fractions (lipid extract, low molecular weight, and protein fractions) of nuts and speciation analysis was studied [30]. Selenium was not detected in any of the lipid extracts obtained from the different types of nuts [30], Results obtained for Brazil nuts by SEC with on-line ICP-MS detection showed that approximately 12 percent of total Se was weakly bound to proteins [30],... 

Katarzyna Wrobel, Kazimierz Wrobel, S. S. Kannamkumarath, J. A. Caruso, I. A. Wysocka, E. Bulska, J. Swiqtek, M. Wierzbicka, HPLC-ICP-MS speciation of selenium in enriched onion leaves - a potential dietary source of Se-methylseleno-cysteine, Food Chem., 86 (2004), 617-623. 

M. Shah, S. S. Kannamkumarath, J. C. A. Wuilloud, R. G. Wuilloud, J. A. Caruso, Identi Ovation and characterization of selenium species in enriched green onion Allium fistulosum) by HPLC-ICP-MS and ESI-ITMS, J. Anal. Atom. Spectrom., 19 (2004), 381D386. 

Se-enriched plants may be divided into two broad groups [199], i.e. selenium accumulators and/or selenium non-accumulators. Selenium-accumulating plants can be divided into three subgroups selenite-accumulators (broccoli and cucumber), selenomethionine accumulators (grains such as wheat, and mushrooms) and iS e-methyl selenomethionine accumulators (garlic and onion) [200]. 

Maidenhair fern (Adiantum capillus-veneris) extract Onion (Allium cepa) extract Pine (Pinus palustris) tar Piroctone olamine Potassium undecylenoyl hydrolyzed collagen Quaternium-51 Sage (Salvia officinalis) extract Selenium disulfide Sulfur TEA-undecenoyl hydrolyzed collagen Undecylenamide DEA Undecyleneth-6 Yarrow (Achillea millefolium) oil antidandruff agent, hair treatments Quaternium-51... 

The presence of asymmetric carbons in selenomethionine, other a-selenoamino acids, and related compounds produces different chiral enantiomers with different physiological activities. HPLC separation of enantiomers is possible with a range of chiral stationary phases, d- and 1-Selenomethionine enantiomers have been resolved with an a-cyclodextrin stationary phase and other species with a teicoplanin-based chiral phase. Hybrid chiral methodologies based on GC, HPLC, and capillary electrophoresis, coupled with ICP-MS are feasible. Enantiomers of d,l-selenocystine, d,l-selenomethio-nine, and d,l-selenoethionine were examined in a range of commercial dietary supplements using a chiral crown ether stationary phase and ICP-MS detection. Selenium-em-iched onion, garlic, and yeast were analyzed and some of the selenoamino acid enantiomers were identified. l-Fluoro-2, 4-dinitro-phenyl-5-l-alanine amide was used to derivatize enantiomers of selenoamides for enhanced resolution. 

Not only do people consider Allium vegetables important because of their characteristic flavor that contributes to the savoriness of various dishes in world cuisine, they are also aware of the nutritional potential of these vegetables since they are rich in nutrients such as high levels of phosphor, potassium, zinc, vitamins A, C and D, foUc acid, calcium and selenium etc. is also considered by people (Peter 2000 Rahman 2003). They are also rich sources of phenolic compounds (Vinson et al. 1998). Table 4.1 shows the approximate composition of fresh garlic and onion bnlbs. 

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