Identification and determination of selenohomolanthionine – The major selenium compound in Torula yeast.

Torula yeast ( Candida utilis ) was found to metabolize selenium in a totally different way to Brewer’s yeast ( S. cerevisiae ) leading to the biosynthesis of selenohomolanthionine (SeHLan), a major selenium compound accounting for 60–80% of the total selenium. The identity of SeHLan was confirmed by retention time matching in hydrophilic ion interaction chromatography (HILIC) with inductively coupled plasma mass spectrometric detection (ICP MS) using a custom synthesized standard molecule and by HILIC – Orbitrap MS and MS-MS fragmentation. Selenohomolanthionine escapes the current assays for the organic character of Se-rich yeast based on the protein-bound selenomethionine determination. A HILIC – ICP MS method was developed for the quantitative determination of selenohomolanthionine in yeast supplements with a detection limit of 146 ng/g. [ABSTRACT FROM AUTHOR]