Application of low-resolution Raman spectroscopy for the analysis of oxidized olive oil

The aim of this study was to evaluate the potential of low-resolution Raman spectroscopy for monitoring the oxidation status of olive oil. Primary and secondary oxidation parameters such as peroxide value, K232 and K270 were studied. Low-resolution Raman spectra ranging from 200 to 2700 cm−1 in a set of 126 oxidized and virgin olive oil samples were collected directly using a probe. Partial Least Squares was used to calibrate the Raman instrument for the different targeted parameters. The performance of the models was determined by using validation sets, and the best results obtained were: R2 = 0.91, RMSEP = 2.57 for the peroxide value content; R2 = 0.88, RMSEP = 0.37 for K232; and R2 = 0.90, RMSEP = 0.08 for K270. These results demonstrated that low-resolution Raman spectroscopy could be a relevant technique for evaluating the oxidation status of olive oils because the key oxidation parameters can be determined quickly and in a non-destructive and direct way.

► In this study, the aim was to evaluate the potential of low-resolution Raman spectroscopy for monitoring the oxidation status of olive oil. ► Primary and secondary oxidation parameters such as peroxide value, K232 and K270 were studied. ► The results obtained with the constructed PLS models correlated well with those obtained in the laboratory. ► The models had an RPD value lower than 5, which can be considered acceptable for screening and for generate ranking data. ► The use of portable Raman spectroscopy, combined with some chemometric tools for analyzing the oxidative state of olive oil.