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

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.