Determination of total polar parts with new methods for the quality survey of frying fats and oils.

During the frying process the fat undergoes several chemical and physical changes caused by heat, water and atmospheric oxygen. With prolonged heating time the accumulation of deterioration products leads to organoleptic failures and a decrease of the nutritive value. For the quality control of frying fats or oils the determination of total polar parts by preparative column chromatography is an approved standard method. Many attempts were undertaken to replace this time and chemical consuming method. To substitute for the determination of polar components by column chromatography the measurement of dielectric properties with a food oil sensor, nuclear magnetic resonance spectroscopy (NMR) and near infrared spectroscopy (NIR) proved to be suitable.