Detection of low-quality extra virgin olive oils by fatty acid alkil esters evaluation : a preliminary and fast mid-infrared spectroscopy discrimination by a chemiometric approach

A set of eighty-one extra virgin olive oils (EVOOs) was analysed according to the new quality parameters relative to the total amount of methyl and ethyl esters of fatty acids [Σ (FAMEs + FAEEs)] and the ratio between ethyl and methyl esters [ratio of FAEEs/FAMEs (RFF)]. Acquisition of the mid-infrared spectra was also performed by Fourier Transform Infrared Spectroscopy (FT-IR). Chemical and spectroscopy data were chemometrically elaborated, and FT-IR coupled by Partial Least Square (PLS) methodology was developed. Results were statistically similar to official procedure in terms of analytical performance for Σ (FAMEs + FAEEs) and RFF in EVOOs: a good agreement between predicted and actual values on calibration data sets was found (0.98 and 0.83, respectively) and the limit of quantification was low enough (29.3 mg kg-1) considering the actual limits for Σ (FAMEs+ FAEEs). This new approach, time-saving and environmentally friendly, can be considered as a useful tool for screening procedures.