Oxidative Stability of Lipids by Means of EPR Spectroscopy and Chemiluminescence

摘要

The aim of this study was to investigate the oxidation of selected vegetable oils (CLSO, CCSO, CBO) at accelerated oxidation rates. Several seldom used analytical methods were applied including electron paramagnetic resonance (EPR), spin trapping with alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), Fe2+-induced chemiluminescence, Rancimat tests, and the determination of conjugated diens at lambda = 233 nm. The antioxidative properties of POBN and DMPO were also investigated. The time required for each method was determined. EPR spectrometry of trapped radicals generated during oxidation turned out to be the fastest method to determine oxidative stability. Chemiluminometric determination of oxidation kinetics showed that POBN has a very strong anti-oxidative potential: it significantly (by 160-277%) lengthened the time to the chemiluminescence peak, as well as the induction time in the Rancimat test (by 110-140%). Photo-oxidation studies showed that superoxide anion radicals are the main factor responsible for the oxidation of lipids in the investigated oils.