Analysis of sitosteryl oleate esters in phytosterols esters enriched foods by HPLC–ESI-MS2

• HPLC–MS2 method was developed to analyze sitosteryl oleate and its oxides in spread.
• Addition of lithium in mobile phase was allowed to obtain precursor ions.
• The content of sitosteryl oleate in spread highly decreased with the temperature.
• A wide variety of oxidation products was formed in spreads after heating treatment.
• Sunlight radiation did not result in the degradation of sitosteryl oleate.

Phytosteryl esters (PE)-enriched spreads are marketed for eating and cooking purposes. Temperature and also light exposure are the major factors leading to the formation of PE oxides in food matrix. In this study a high-speed HPLC–MS2 method was developed to analyze the major PE present in PE-enriched spreads: sitosteryl oleate (SO) and its oxidation products, by using synthesized compounds as standards. This analytical method was used to quantify seven SO oxides formed in PE-enriched spreads after heating at different temperatures for varying time periods and after prolonged exposure to sunlight. Quantification of remaining native SO was also performed after these different treatments. It was found that under specific heating conditions the decrease of the SO amount was much more important compared to the formation of SO oxides showing that many other products are formed. In contrast to heating, sunlight radiation did not result in the degradation of SO and very few oxides were formed.

Figure optionsDownload as PowerPoint slide