Quantification, Localization, and Speciation of Selenium in Seeds of Canola and Two Mustard Species Compared to Seed-Meals Produced by Hydraulic Press

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• 作者：Gary S. Ba帽uelos ; Spencer S. Walse ; Soo In Yang ; Ingrid J. Pickering ; Sirine C. Fakra ; Matthew A. Marcus ; John L. Freeman
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：July 17, 2012
• 年：2012
• 卷：84
• 期：14
• 页码：6024-6030
• 全文大小：302K
• 年卷期：v.84,no.14(July 17, 2012)
• ISSN：1520-6882

文摘

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 渭g Se g^鈥? 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鈥揝e鈥揅 forms. Hydraulically pressing seeds for oil caused changes in the forms of Se as follows: 40鈥?5% C鈥揝e鈥揅 forms, 33鈥?2% selenocystine, 5鈥?2% selenocysteine, and 11鈥?4% trimethylselenonium ion. Aqueous extracts of seed and seed meals were also analyzed by SAX-HPLC/ICPMS and found to contain mainly the C鈥揝e鈥揅 form SeMet, but also another C鈥揝e鈥揅 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.