Bioactive compounds detected for the first time in corn oil: Cyclic dipeptides and other nitrogenated compounds

摘要

Eleven edible oils, namely extra virgin olive, virgin olive, olive, sunflower, virgin soybean, refined soybean, virgin linseed and four corn oils were studied in order to analyze the occurrence in them of minor nitrogenated components. The study was carried out by using Solid Phase Microextraction (SPME) followed by Gas Chromatography/Mass Spectrometry (GC/MS). Apart from fatty amides no other nitrogenated compound was found in the first seven oils cited. However, it has been discovered that the four corn oils studied contain cyclic dipeptides or 2,5-diketopiperazines (DKPs), and other nitrogenated compounds such as oxazolines, pyrrolidines and other pyrrol derivatives, as well as indol, pyrazol, pyridine and beta-phenylethylamine derivatives. DKPs were the most numerous and some of them were the most abundant of all nitrogenated compounds detected. All these compounds are bioactive and for this reason they can give corn oil interesting properties from a technological, nutritional and health points of view. Cyclic dipeptides could be considered as corn oil markers in authentication and fraud studies and their concentration can be used for differentiation and classification of corn oils. This is the first time that the presence of these bioactive compounds has been reported in corn oils.