Hydrophilic antioxidants of virgin olive oil. Part 1: Hydrophilic phenols: A key factor for virgin olive oil quality

Abstract

Virgin olive oil (VOO) consumption is increasing all over the world due to its excellent organoleptic and nutraceutical properties. These beneficial traits stand from a prominent and well-balanced chemical composition, which is a blend of major (98% of total oil weight) and minor compounds including antioxidants. The main antioxidants are phenolic compounds, which can be divided into lipophilic and hydrophilic phenols. While lipophilic phenols such as tocopherols can be found in other vegetable oils, most hydrophilic phenols in olive oil are exclusive of the Olea europaea species endowing it with a chemotaxonomic interest. This review is focused on VOO antioxidant profile and, particularly, on hydrophilic phenols that are divided into different sub-families such as phenolic acids and alcohols, hydroxy-isochromans, flavonoids, secoiridoids, lignans and pigments. Analytical methods for qualitative and/or quantitative determination of these compounds are assessed. The implementation of efficient sample preparation protocols, separation techniques such as liquid chromatography, GC and capillary electrophoresis, as well as detection techniques such as ultraviolet absorption, fluorescence or MS are critical to succeed in the quality of the results. The effects of hydrophilic phenols on increasing VOO stability, its nutraceutical interest and organoleptic properties are also considered.

High-Performance Liquid Chromatography–Mass Spectrometry Profiling of Phenolic Compounds for Evaluation of Olive Oil Bitterness and Pungency

“…These compounds are also responsible for the relative high resistance of virgin olive oil against oxidative spoilage and play an important role in the health benefits, which are commonly associated with virgin olive oil in the "Mediterranean diet" concept. 2 In this paper, the influence of hydrophilic phenols on organoleptic properties of virgin olive oil is studied. The bitterness and pungency intensities are parameters for the sensory evaluation of olive oil quality, the so-called "Panel Test" developed by the International Olive Council.…”

High‐resolution mass spectrometry to evaluate the influence of cross‐breeding segregating populations on the phenolic profile of virgin olive oils

“…Thus the levels found for these three secoiridoids were clearly higher in Picual × Koroneiki VOOs, while no distinction was observed between Sikitita × Arbosana and Arbequina × Arbosana. This is a key aspect taking into account the relevance of secoiridoids from the organoleptical and nutraceutical perspectives . Levels of p ‐HPEA‐EA and 3,4‐DHPEA‐EA in the crosses were similar to those in their genitors, as can be seen in supplementary Fig.…”

“…This is a key aspect taking into account the relevance of secoiridoids from the organoleptical and nutraceutical perspectives. 25 Levels of p-HPEA-EA and 3,4-DHPEA-EA in the crosses were similar to those in their genitors, as can be seen in supplementary Fig. 3, which shows the range of concentration found for significant phenols in varieties and genitors.…”

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“…Furthermore, the phenolic compounds are radical (FI-OH•) which can react again with free radicals (ROO•) forming a non-radical compound. [32] One of the natural antioxidants is gallic acid (3, 4, 5-trihydroxybenzoic acid). Gallic acid is included in the phenolic compounds and has strong antioxidant activity.…”