Abstract:

In order to investigate selenium (Se) levels and speciation in Se-enriched wheat, organic and inorganic selenium
(Se) from wheat samples grown in Lanzhou were separated by ultrasonic pretreatment, centrifugation and dialysis and
determined by flame atomic absorption spectrometry. The results showed that Se existed mainly in organic form, accounting
for 84.36% of the total Se in Se-enriched wheat. The organic Se was mainly bound to protein (54.46%), followed by
polysaccharide, and a small amount of Se was bound to nucleic acid or other organic components. Albumin and glutelin
comprised 19.46% and 16.83% of total Se-containing proteins, respectively. The results of antioxidant activity showed
that the polysaccharides had longer induction time and higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging
activity and reducing activity than protein extracts and nucleic acid extracts. Pearson correlation analysis indicated that the
antioxidant capacity of Se-enriched wheat extracts had a significant positive correlation with Se contents.

Key words: selenium-enriched wheat, speciation, selenium content, flame atomic absorption spectrometry, antioxidant capacity