Rapid Assessment of Monovarietal Portuguese Extra Virgin Olive Oil's (EVOO's) Fatty Acids by Fourier‐Transform Near‐Infrared Spectroscopy (FT‐NIRS)

Abstract

A rapid method for the evaluation of fatty acids (FA) of monovarietal Portuguese extra virgin olive oils (EVOOs) (n = 82) from Alentejo, south‐central region of Portugal, is developed based on Fourier‐transform near‐infrared spectroscopy (FT‐NIRS). The contents of FA‐components (previously determined per conventional gas chromatography) are correlated with FT‐NIRS data (independent variable), by means of full cross‐validation partial least squares regression (CVPLSR). CVPLSR is run using standard normal variate (SNV) data pre‐processing and the nonlinear iterative partial least squares (NIPALS) algorithm. Obtained correlation models are characterized with good statistics: high correlation coefficients (R > 0.85) and low root mean square errors (RMSE < 2.04). Obtained values of the residual predictive deviation (RPD) of CVPLSR‐model, higher than 5.0 (C18:1, C18:2, MUFA, PUFA) confirm the FT‐NIRS as a potential method for rapid quality control of EVOO's FA.Practical Applications: In this work for the first time, fatty acid (FA) profile of monovarietal extra virgin olive oil (EVOO) samples of the greatest olive region in Portugal—Alentejo—is analyzed by Fourier‐transform near‐infrared spectroscopy (FT‐NIRS) and chemometrics. Obtained high‐quality results allow one to recommend this technique from monitoring to quality control analysis of FA (in particular, of representative unsaturated FA), in a great number of olive oil samples, in near‐real time.Quality of olive oil can be assessed by target or non‐target analysis and it is of mandatory importance. Fourier‐transform near‐infrared spectroscopy (FT‐NIRS), combined with chemometrics, for the analysis of the fatty acid profile of varietal olive oils from Alentejo (Portugal) can be a useful technique for quality control. Furthermore, FT‐NIRS is rapid, non‐destructive, and a more environmental friendly technique.