Authenticity in Olive Oils from an Empeltre Clonal Selection in Aragon (Spain): How Environmental, Agronomic, and Genetic Factors Affect Sterol Composition

Abstract

Sterol composition is used as a “fingerprint” to demonstrate the authenticity of olive oils. Our study’s objective was to exhaustively characterize the sterol composition of Empeltre olive oils from clonal selection during the ripening period in 2017, 2018, and 2019. We likewise assessed the influence of crop year, fruit ripening, and clonal selection on the oils’ regulatory compliance in terms of sterol composition. Empeltre olive oils were shown to have medium-range β-sitosterol and Δ5-avenasterol content, along with elevated amounts of campesterol and Δ7-stigmastenol. A total of 26% and 12% of the samples were non-compliant in terms of apparent β-sitosterol and Δ7-stigmastenol, respectively. Crop year was the most influential factor in the case of most sterols. Clone type was the least influential factor, except in the case of campesterol. Olive maturity was only significant for Δ7-sterols. We likewise applied a discriminant analysis, with “crop year” as the grouping variable: 94.9% of the oils were thereby classified correctly.

The Ancient Olive Trees (Olea europaea L.) of the Maltese Islands: A Rich and Unexplored Patrimony to Enhance Oliviculture

“…The total sterol content in the fruit pulp of the various genotypes under study was highly variable. This was in agreement with what was found in the literature on oils as well [ 72 , 73 ]. Sterols are minor components contained in the unsaponifiable fraction of the oil and, for this reason, the low contents of these compounds could be due to the low oil contents of the fruits.…”

Effect of cultivar and environment on chemical composition and geographical traceability of Spanish olive oils

“…The variability of the two latter sterols even remained minimal in the minority cultivar oils, whose results were not segregated by year as there were not enough samples. These variabilities coincide with those described in previous studies on Empeltre (Rey-Giménez & S anchez-Gimeno, 2022b), Arbequina, and other cultivars (Navas-L opez et al, 2020).…”

“…Thirty‐three percent of the oils had a Δ7‐stigmastenol content higher than 0.5% (EEC, 1991; IOC, 2022a, 2022b), of which 29% were Empeltre single‐varietal oils ( n = 60) and the rest were coupage oils ( n = 28) in which the Empeltre variety was predominant (individual sample data not shown; average Δ7‐stigmastenol values higher than 0.5% in bold, Table 2). High Δ7‐stigmastenol values that compromise the authenticity of single‐varietal olive oils have been described in Empeltre (Gracia et al, 2009; Rey‐Giménez & Sánchez‐Gimeno, 2022b; Romero et al, 2011) as well as in other varieties (Manai−Djebali et al, 2012; Sevim et al, 2022). These findings could support the hypothesis that a high Δ7‐stigmastenol content is characteristic of certain cultivars.…”

Pulsed electric field increases the extraction yield of extra virgin olive oil without loss of its biological properties

“…The variation of the peroxide index from 6.9 to 8.2 (mEq O 2 /kg), could be caused by the endogenous oxidases of the olive paste which remain more time in contact with the oil in the PEF EVOO, due to a greater breakdown of cellular structures. However, the values of free fatty acids of 0.11 and 0.14 for standard and PEF-EVOO were notoriously lower than those reported for this variety (0.61 ± 0.04) obtained by the Abencor method ( 41 ). The minimal differences in free fatty acids and peroxide index further reinforce the quality of the PEF EVOO from a chemical point of view.…”