Varietal Authentication of Extra Virgin Olive Oils by Triacylglycerols and Volatiles Analysis

Abstract

In recent years, there is an increasing interest in high-quality extra virgin olive oils (EVOOs) produced from local cultivars. They have particular chemical/organoleptic characteristics and are frequently subjected to fraud, whereby the control of quality requires a powerful varietal check. In the present research, triacylglycerols (TAGs) and volatiles have been studied as chemical markers for the authentication of EVOO samples from four Italian varieties of Olea europea (Dolce Agogia, Frantoio, Leccino, and Moraiolo). The monocultivar EVOO samples have been subjected to a chemical–enzymatic chromatographic method in order to perform a stereospecific analysis, an important procedure for the characterization of TAG of food products. The results, combined with chemometric analysis (linear discriminant analysis, LDA), were elaborated in order to classify Italian EVOO monocultivar samples. In accordance with the total and intrapositional fatty acid (FA) composition of TAG fraction, the results were allowed to carry out a varietal discrimination. In addition, volatile compounds were also determined by solid-phase micro-extraction gas chromatography–mass spectrometry analysis. All EVOO samples were correctly classified when TAG stereospecific data and volatile results were elaborated by the LDA procedure, even if volatile compounds showed a higher discriminant power.

The employment of Fourier Transform Infrared Spectroscopy (FTIR) and chemometrics for analysis of candlenut oil in binary mixture with grape seed oil

“…Numerous analytical methods have been employed for authentication purposes based on molecular biology and physico-chemical properties such as chromatographic based techniques through analysis of major components of fatty acids and triacylglycerol compositions (Blasi et al, 2019) and minor components like tocopherol contents (Cserhati et al, 2005;Bosque-Sendra et al, 2012), visible spectroscopy (Ferreiro-González et al, 2011), synchronous fluorescence by analyzing the specific components capable of exhibiting photo-luminescence (Poulli et al, 2007;Ge et al, 2014), Ultrafast 2D nuclear magnetic spectroscopy (NMR) in combination with principal component analysis (Gouilleux et al, 2018), ambient mass spectrometry using direct analysis in real-time (Vaclavik et al, 2009) and vibrational-based spectroscopy such as infrared and Raman spectroscopy by applying specific wavenumbers corresponding wavenumbers specific to analyte(s) of interest (El-Abassy et al, 2009;Rohman and Che Man, 2012). Among these techniques, Fourier transformed infrared spectroscopy (FTIR) spectroscopy is the most commonly used techniques for authentication of edible oils.…”

A Social Analysis of the Olive Oil Sector: The Role of Family Business

“…Consequently, the quality assumes a key-role and it is associated with a product classified as EVOO (No. 13) [66]. The olive oil is used daily during both lunch and dinner (No.…”

Lipid Profiling and Stable Isotopic Data Analysis for Differentiation of Extra Virgin Olive Oils Based on Their Origin

“…Monocultivar PDO Commercially-Blended The differences between the two EVOO classes with respect to average TAG composition were not large ( Table 2). TAG composition is not evaluated among the parameters related to EVOO sensory quality, while a part of EVOO nutritional value linked to TAGs, related mainly to the FA unsaturation level, depends mostly on cultivar, geographical origin and fruit ripening degree [9][10][11]34]. The differences between the two classes of EVOO, observed for a relatively small number of TAG species, could be primarily ascribed to the abovementioned factors.…”

“…The percentage of TAGs with equivalent carbon number 42 (ECN 42) in total TAGs, where ECN is the sum of the number of carbon atoms in three constituent FAs in TAG molecule subtracted by 2 × total of double bonds, can be used as a marker for the detection of the presence of seed oils in olive oil [2]. In combination with other olive oil constituents, TAGs have been successfully utilized as markers of varietal [9][10][11] and geographical origin of EVOO [11]. In virgin olive oils, diglycerides (DAGs) are present in a range of 1% to 3% in the form of 1,2-and 1,3-isomers, whose ratio has been used as a marker of olive oil "freshness" [12].…”