Olive oil authentication based on quantitative β-carotene Raman spectra detection

Abstract

β-carotene and oleic acids are important molecules to distinguish between extra olive oil (EVOO) and other oils. To identify adulteration which use common vegetable oils blended with β-carotene to imitate EVOO, a non-invasive, lossless method is proved to be effective. The present work presents a laser confocal Raman technique for analyzing and comparing the differences of molecule between EVOO and SSO, which based on theoretical Raman spectra of β-carotene, oleic acids and linoleic acids calculated by density functional theory (DFT). Chemometrics based on support vector regression (SVR) was used to realize quantitative analysis of β-carotene in synthetic olive oils. Nine different volume ratios were prepared independently, and test set evaluation index of linear kernel of SVR as follow: RMSE 0.0653, R² 0.9868. The results show that laser confocal Raman technique, combined with theoretical Raman spectra based on DFT, could analyze composition of vegetable oil accurately, and identify low-cost imitation of olive oil.

Keywords: Adulteration; DFT; Olive oil; Raman spectroscopy; SVR; β-carotene.