Sterol Oxidation Products in French Fries and in Stored Potato Chips.

Potato chips and french fries were analyzed by high performance liquid chromatography and thin layer chromatography for cholesterol and (β-sitosterol oxidation products. Chips stored for 150 d at 23°C in unopened foil bags contained no detectable sitosterol oxidation products, but those held at 40°C contained 7α-hydroxysitosterol, 7β-hydroxysitosterol, and sitosterol (β-epoxide only after an extended storage of 95 d. French fries as purchased contained sterol α- and β-epoxides, and 7α- and 7β-hydroxysterols. These sterol oxidation products were present in repeat samples from five different fast food restaurants. Ingestion of sterol oxides from potato chips is unlikely, whereas ingestion of sterol oxides from french fries is possible.