Soybean oil, rape oil and olive oil were heated to 100°C, 190°C and 230°C and the changes in the unsaponifiable matter were examined.
From experimental results, it was concluded that the decrease in the unsaponifiable matter was more at higher temperature and for the longer heating time. The decrease in the unsaponifiable matter was about 20 percent at 200°C for 26 hours. In case of autoxidation there was no change.
The steroid fraction in the unsaponifiable matter was fled in all directions during the heating process, which was examined by the thin-layer chromatography.