Guidelines for extraction and quantitative analysis of phytosterols and oxidation products

Phytosterols (PS) are widely distributed in the plant source foods, and research on their health benefits has become increasingly active. This article briefly outlines the main extraction processes of PS and instrumental analysis methods of PS in detail. The PS isolation technique depends on the nature of the matrix and the form of the PS (free, esterified, and glycosylated). Conventional extraction technologies for PS commonly used in practice were Soxhlet extraction and maceration method. Due to their inherent molecular structure, PS exhibits poor stability to heat, light, oxygen, pH, and metal ions. It is of great significance to find a reliable analytical technique to extract PS and oxidation products from food substances and an accurate detection method of PS in different foods due to the instability of plant sterol and the interference of complex plant-based matrices. Generally, it is common to use GC–MS to determine the composition of total PS and their oxidation products, which requires standard monomer PS. It is desirable to use LC–MS to determine free PS in liquid samples. These methodologies could be meaningful in the quality assessment, health function evaluation, and applications and limitations of plant-sourced foods.