Monitoring olive oil oxidation under thermal and UV stress through synchronous fluorescence spectroscopy and classical assays

Abstract

Abstract Synchronous fluorescence (SyF) spectra combined with principal component analysis (PCA) is proven to be a useful tool for monitoring olive oil deterioration under UV irradiation at 80 °C. Spectra acquired in the range 300–500 nm during 12 h accelerated oxidation stress using a surface per volume ratio of 0.95 cm2 ml−1 reveal five different classes after PCA. Parallel monitoring of lipid oxidation parameters peroxide value (PV), anisidine value (AV) shows that after 12 h, TOTOX value increases 10-fold, 19-fold and almost 38-fold for extra virgin olive, olive and olive-pomace oil, respectively. Linear correlations between parameter values versus exposure time were observed during extra virgin olive oil deterioration under UV at different temperatures: ambient (∼20 °C), 40, 60 and 80 °C. The rate of increase was found to be 6.3, 18.7, 37 and 56 TOTOX h−1, 2.8, 8.3, 16.5 and 25.6 meq peroxides kg−1 h−1 and 0.84, 2.0, 3.6 and 4.9 AV h−1, respectively. The rates of parameter change increase linearly with temperature, the slopes being 0.84 ± 0.06 TOTOX h−1 °C−1, 0.38 ± 0.03 meq peroxides kg−1 h−1 °C−1 and 0.07 ± 0.003 AV h−1 °C−1.