Effect of chlorophyll fluorescence quenching on quantitative analysis of adulteration in extra virgin olive oil

Extra virgin olive oil (EVOO) is both edible oil and health care product. Adulteration in high quality vegetable oil is a ubiquitous fraud, especially in the market of EVOO. Spectroscopy is an effective means to realize the rapid detection of adulteration in EVOO, but the accuracy of quantitative analysis is the short board of spectral detection. Traditional Raman spectroscopy is used to detect the adulteration of EVOO by analyzing the content of monounsaturated fatty acids. However, high oleic acid content is not unique to EVOO. Confocal Raman and Fluorescence Spectroscopy (CRFS) was employed to characterize EVOO along with potential adulterant oils based on their Oleic acid and photosensitive substances content. Statistical analysis of these Oleic acid and photosensitive substances using Multiple Linear Regression (MLR) allowed for a rapid approach to determine EVOO authenticity. The quantitative analysis model of adulteration in EVOO was established using this approach, and the RMSE was 0.0068, and the R-Squared of external Prediction was 0.9996. In addition, Fluorescence quenching which interfered with the quantitative analysis of chlorophyll was found in the adulteration experiment of EVOO. Compared to traditional Raman methods, CRFS with MLR involves minimal sample preparation combined with fast analysis.