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Bio-fortification and isotopic labelling of Se metabolites in onions and carrots following foliar application of Se and 77Se

Kapolna, Emese; Laursen, Kristian Holst; Husted, Søren and Larsen, Erik H. (2011) Bio-fortification and isotopic labelling of Se metabolites in onions and carrots following foliar application of Se and 77Se. Food Chemistry, 133 (3), pp. 650-657. [Submitted]

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Summary

The aims were to bio-fortify onions by foliar application of selenium (Se) and to intrinsically label bioactive Se-metabolites in onion and carrot by enriched, stable77Se for use in human physiological studies. Onion bulbs and leaves were enriched in Se by repeated foliar spraying of 10 or 100 μg Se mL-1 solutions of sodium selenite (Se(IV)) or sodium selenate (Se(VI)). ICP-MS analysis of onion leaves and bulbs showed that the Se concentration was enhanced by up to a factor of approximately 50 and 200 in bulbs and leaves, respectively. HPLC-ICP-MS analysis of proteolytic plant extracts showed that foliar application of Se(IV) gave rise to bio-synthesis of a higher fraction of the desired organic Se species and was better tolerated by the plants than Se(VI). Based on these findings onions and carrots were bio-fortified by foliar application of a solution of 77Se(IV) that was enriched to 99,7 % as 77Se. The 77Se- labeled metabolites in onions were predominantly -glutamyl-77Se-selenomethyl-selenocysteine (-glu-Me77SeCys), 77Se-methylselenocysteine (Me77SeCys) and 77Se-selenomethionine (77SeMet). Furthermore, we report here for the first time the finding in carrots of the bioactive Me77SeCys, the identity of which was verified by HPLC-ESI-MS/MS.


EPrint Type:Journal paper
Keywords:Foliar application; Onion; Carrot; Methylselenocysteine; Intrinsic 77Se labeling; HPLC-ESI-MS/MS.
Subjects: Food systems > Food security, food quality and human health
Crop husbandry > Crop health, quality, protection
Research affiliation: Denmark > DARCOF III (2005-2010) > ORGTRACE - Organic food and health
Deposited By: Larsen, Prof Erik H.
ID Code:19812
Deposited On:06 Dec 2011 15:34
Last Modified:13 Mar 2013 15:07
Document Language:English
Status:Submitted
Refereed:Submitted for peer-review but not yet accepted

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