Effect of Ionizing Radiation on Cholesterol in Aqueous Dispersion

Aqueous sodium stearate dispersions of cholesterol were irradiated at 0‐2°C with absorbed doses ranging from 2.5 to 50 kGy. The resulting mixture of cholesterol derivatives was isolated and examined for 7‐ketocholesterol and cholesterol 5α,6α‐epoxide and 5β,6β‐epoxide content. Concentrations of all three compounds increased with dose, while the ratio of 7‐ketocholesterol to total epoxides decreased with increasing dose. The ratio of 7‐ketocholesterol to the epoxides was approximately 1 or below at all dose levels while the same ratio in autoxidations of cholesterol in dispersions was normally 6 or greater. The change in the keto/epoxide ratio may be a means for determining whether meat or other foods containing cholesterol have been subjected to ionizing radiation.