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

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Computational Chemistry

Background:

• Extra virgin olive oil (EVOO) adulteration is a significant concern, often involving imitation with common vegetable oils.
• Beta-carotene and oleic acids are crucial for distinguishing EVOO from other oils.
• Non-invasive and lossless methods are needed for effective adulteration detection.

Purpose of the Study:

• To present a laser confocal Raman spectroscopy technique for analyzing and comparing molecular differences between EVOO and simulated olive oil (SSO).
• To utilize theoretical Raman spectra calculated via density functional theory (DFT) for accurate analysis.
• To develop a quantitative method for beta-carotene detection in synthetic olive oils.

Main Methods:

• Laser confocal Raman spectroscopy was employed to analyze molecular compositions.
• Density functional theory (DFT) was used to calculate theoretical Raman spectra of key molecules (beta-carotene, oleic acids, linoleic acids).
• Chemometrics, specifically support vector regression (SVR), was applied for quantitative analysis of beta-carotene.

Main Results:

• The study successfully analyzed and compared molecular differences between EVOO and SSO using Raman spectroscopy.
• Support vector regression (SVR) achieved high accuracy in quantitative analysis of beta-carotene in synthetic samples (RMSE 0.0653, R² 0.9868).
• The combined approach accurately identified low-cost imitation olive oils.

Conclusions:

• Laser confocal Raman spectroscopy, supported by DFT calculations, provides an accurate method for analyzing vegetable oil composition.
• This technique effectively identifies adulterated olive oils, offering a reliable solution against low-cost imitations.