Table 7 Content of Phytosterol Oxidation Products (POPs) in Three Samples of Pure Phytosterol Mixtures and in Three Tablet Supplements Manufactured in Finland.

Very recently, POPs were quantified in several crude vegetable oils. Among the vegetable oils analyzed, sunflower oil and maize oil contained the highest amounts of POPs, ranging from 4 to 68ppm (36). The main POPs were 7α-,7β-hydroxy derivatives of sitosterol, campesterol, and stigmasterol, and 7-ketositosterol in all the samples. The authors suggested that the large differences in POP contents in various vegetable oils

might be influenced by fatty acid composition, i.e., oils containing more unsaturated fatty acids were more prone to oxidation. In addition, different conditions and times of storage of the raw materials and the crude oils before the refining process were also influenced the formation of POPs in the oils. The POPs content in some of the crude oils analyzed in this study is shown in Table 8.