Discrimination of botanical origin of olive oil from selected Greek cultivars by SPME‐GC‐MS and ATR‐FTIR spectroscopy combined with chemometrics

BACKGROUND In recent years, consumers are asking to know the botanical origin of the olive oil they consume. The objects of the present study were the development of robust chemometric models based on gas chromatography-mass spectrometry (GC-MS) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) for the purpose of botanical differentiation of three Greek commercial olive oil cultivars. RESULTS Using the solid phase microextraction technique (SPME), volatile compounds (VC) were received and analyzed by GC-MS. Five hydrocarbons and one ester were selected by the forward stepwise algorithm that best discriminated the olive oil samples. From the ATR-FTIR analysis, the spectral regions chosen from the forward stepwise algorithm were associated with the C=O stretching vibration of the esters of triglycerides and the C-H bending vibrations of the CH2 aliphatic group and the double bonds. Application of the supervised methods of linear and quadratic discriminant cross-validation analysis, based on VC data, provided a correct classification score of 97.4 and 100.0%, respectively. The corresponding statistical analyses were used in the mid-infrared spectra where the 96.1% of samples were discriminated correctly. CONCLUSION The ATR-FTIR and SPME-GC-MS techniques in conjunction with the appropriate feature selection algorithm and classification methods, proved to be powerful tools for the authentication of Greek olive oil. The proposed methodology can be used in industrial setting for the determination of the Greek olive oil botanical origin. This article is protected by copyright. All rights reserved.