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, K-232 and K-270 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: R-2 = 0.91, RMSEP = 2.57 for the peroxide value content; R-2 = 0.88, RMSEP = 0.37 for K-232; and R-2 = 0.90, RMSEP = 0.08 for K-270. 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. (C) 2011 Elsevier Ltd. All rights reserved.