LC-ESI-MS/MS characterization of organic selenium compounds in red wine

Selenium, in the form of selenoamino acids and selenoproteins, is an essential component of the immune system reducing free radicals, which may lead to chronic diseases, such as cancer and heart disease. Selenomethionine (SeMet) and Se-methylselenocysteine (MeSeCys) are the major selenium-containing amino acids in dietary sources. SeMet is a bioactive form of selenium with antioxidant properties, playing a significant role in cardiovascular health, autoimmune conditions, and the prevention of certain cancers. Additionally, selenomethionine oxide (SeMetO), which possesses a protective mechanism against oxidative stress, is the oxidized form of amino acid selenomethionine. In this study, a rapid and sensitive HPLC-ESI-MS/MS technique was applied for the first time to identify and quantify organic selenium compounds, including: selenomethionine, selenomethionine oxide and selenium methylselenocysteine in Kratošija wines (a synonym of Zinfandel, Primitivo and Crljenak Kaštelanski). The wines were produced by inoculating two commercial yeasts: ZymafloreTM Xpure (Laffort) and Lalvin ICVD80 (Lallemand) in order to study the effect of yeasts on selenium compounds content in the final wines. The effect of the yeasts on the selenium compounds in both wines was observed. Thus, wine fermented with Lalvin ICVD80 contained higher amounts of SeMet and MeSeCys, probably due to a better ability to transform the inorganic selenium into organic selenium compounds (especially selenomethionine). Both wines contained high levels of SeMetO, produced as a result of the oxidation of SeMet during fermentation and/or storage. The obtained results suggest that the red wine Kratošija can be considered as an adequate source of SeMet and SeMetO, possessing healthy properties.

Keywords: Organic selenium compounds, SeMet, SeMetO, MeSeCys, HPLC-ESI-MS/MS, Kratošija wine.