Comprehensive speciation of selenium in selenium-rich yeast

Yeast grown in selenium (Se)-rich media is the most popular supplement of organic Se for human and animal supplementation. Its insufficient characterization made the European Union exclude Se yeast from the permitted food supplements of Directive 2002/46/EC. However, during the past decade, the progress of analytical methodology allowed the accurate, reliable determination of the key parameters of Se-rich yeast (selenomethionine, selenocysteine, and inorganic Se) whereas new instrumental techniques, especially Fourier transform mass spectrometry, made possible advanced characterization of Se-rich yeast in terms of the Se metabolome and proteome. The manuscript discusses critically the state of the art of knowledge of Se speciation in Se-rich yeast and highlights trends in analytical methodology. (C) 2012 Elsevier Ltd. All rights reserved.