Action of phytosterols on thermally induced trans fatty acids in peanut oil.

The effects of six phytosterols on thermally induced trans fatty acids (TFAs) in peanut oil were investigated. Peanut oil, triolein, trilinolein and trilinolenin heated at 180 °C for 12 and 24 h with or without phytosterols were analyzed by GC-FID. The atomic net charge distribution, frontier molecular orbital energy (FMOE), and bond dissociation energy (BDE) of six phytosterols were calculated by density functional theory. Results showed that six phytosterols inhibited the formation of trans oleic acid, trans linoleic acids, trans linolenic acids, and total TFAs. The anti-isomerization effects of phytosterols were mainly associated with hydroxyl site activities, which were affected by the double bond position in the main skeleton of cyclopentane tetrahydrophenanthrene and the number of double bonds on the C17 branch chain. The FMOE difference and BDE of phytosterol molecules were closely related to their anti-isomerization rates. The anti-isomerization mechanisms of phytosterols on TFAs in peanut oil were proposed.