1H NMR spectral analysis as a new aspect to evaluate the stability of some edible oils

Abstract

Oxidative stability is one of the most important indicators for maintaining the quality of edible oils. 1H NMR fingerprinting is used to evaluate the stability of edible oils at room temperature. The assignments of the 1H NMR signals of the major and minor components of unoxidized edible oils and the oil stability prediction were given. Minor components of the oils are playing an essential role in defining oil authenticity and quality. Extra virgin olive oil (EVOO) showed β-sitosterol, whereas, moringa oil (MO) showed β-sitosterol and stigmasterol. MO showed nonglyceride fraction, aliphatic chains and olefins. Sunflower oil (SO) could be easily distinguished due to its high linoleic acid content followed by apricot kernel oil (AKO). The order of stability of edible oils under study was: MO>EVOO>AKO>SO. 1H NMR spectral data agreed with the results obtained from Rancimat method for the determination of oxidative stability of edible oils under study. The main advantages of this method are the short time of analysis, the possibility to analyze samples without any preliminary treatment, and the small quantity of sample required.