Analysis of thermal degradation of Brazilian palm oil by quantitative 1H NMR and chemometrics

Abstract

Palm oil (Elaeis guineensis Jacq.) is an edible vegetable oil widely used in the processing industries and Afro-Brazilian culture. Due to its chemical composition rich in lipids, it is susceptible to hydrolytic and oxidative degradation. In this context, the present study describes an analytical method based on the high resolution nuclear magnetic resonance spectroscopy and the statistical analysis for the qualitative and quantitative monitoring of the thermostability of palm oil, subjected to heat treatment at temperatures 80, 100, 120, 140, 160, 180, and 200 °C. The palm oil profiles were characterized by 1H NMR spectra, which were used as data matrices for the statistical analysis. The NMR-based PCA allowed the identification of lipid descriptors related to the degradation mechanisms that were preponderant during the heating of palm oil. The NMR-based PCA allowed identifying the chemical shifts of lipid descriptors related to the mechanisms of degradation and secondary oxidation products observed in samples heated from 140 °C. The results showed the restrictions on the use of palm oil, commonly classified as a stable edible oil, given that the secondary oxidation products identified may present health risks.