title: Quantification, localization, and speciation of selenium in seeds of canola and two mustard species compared to seed-meals produced by hydraulic press.
abstract: Brassica plants accumulate selenium (Se) especially in seeds when grown in soils laden with Se. We report a chemical analysis of Se in Brassica seeds (canola, Indian mustard, and white mustard) and in their hydraulically pressed seed meals, which are used as a Se supplement in livestock animal feeds. Complementary techniques were used to measure total Se concentrations, to map the localization of Se, and to quantify different Se forms. Seeds and hydraulically pressed seed meals contained an average of 1.8 and 2.0 μg Se g(-1) DW, respectively. Selenium was primarily located in cotyledons and roots of seed embryos. Microfocused Se K-edge XANES and bulk XANES showed that seeds contained 90% of Se as C-Se-C forms. Hydraulically pressing seeds for oil caused changes in the forms of Se as follows: 40-55% C-Se-C forms, 33-42% selenocystine, 5-12% selenocysteine, and 11-14% trimethylselenonium ion. Aqueous extracts of seed and seed meals were also analyzed by SAX-HPLC/ICPMS and found to contain mainly the C-Se-C form SeMet, but also another C-Se-C form MeSeCys, which is of dietary pharmacological interest for cancer inhibition. In addition, SAX-HPLC/ICPMS also detected selenocystine and selenocysteine, further confirming the results obtained by XANES analyses.
authors: Agricultural Research Service, US Department of Agriculture, Parlier, California 93648, United States. Gary.Banuelos@ars.usda.gov
authors: Gary S
authors: GS
authors: Bañuelos
authors: Spencer S
authors: SS
authors: Walse
authors: Soo In
authors: SI
authors: Yang
authors: Ingrid J
authors: IJ
authors: Pickering
authors: Sirine C
authors: SC
authors: Fakra
authors: Matthew A
authors: MA
authors: Marcus
authors: John L
authors: JL
authors: Freeman
mesh_terms: D000821:Animal Feed; D002851:Chromatography, High Pressure Liquid; D007474:Ion Exchange; D013058:Mass Spectrometry; D055595:Mechanical Phenomena; D009149:Mustard Plant / Q000378:metabolism*; D012639:Seeds / Q000378:metabolism*; D012643:Selenium / Q000737:chemistry* / Q000378:metabolism*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D012643:Selenium