Correlation of Oleocanthal and Oleacein Concentration With Pungency and Bitterness in 'Koroneiki' Virgin Olive Oil

Abstract

It is known that the organoleptic attributes of pungency and bitterness in olive oil are attributed to phenolic compounds. Recent research has demonstrated that oleocanthal, a secoiridoic phenolic, is a naturally occurring anti-inflammatory and neuroprotective agent, and that it elicits a throat stinging sensation through a specific TRPA1 receptor. Oleacein, a hydroxytyrosol derivative is considered as the most powerful antioxidant in olive oil and although it differs from oleocanthal only by one additional phenolic hydroxyl, organoleptically it is associated more with bitterness and less with pungency. The present study examined the correlations between oleocanthal and oleacein concentrations and the intensity of pungent and bitter sensations in a group of 21 virgin olive oil samples of the Koroneiki variety, produced in a specific geographic region of Greece (Messini). The qualitative and quantitative determination of the chemical compounds was carried out by a new method based on quantitative 1 H-NMR in CDCl 3 at 600 MHz after extraction of olive oil with acetonitrile. The concentrations of the studied compounds ranged for oleocanthal between 34.6-154.6 mg/L (mean value 94.5±31.8 mg/L) and for oleacein between 11.5-191.9 mg/L (mean value 63.3±36.1 mg/L). The organoleptic assessment of the samples was performed by a trained sensory panel according to the IOC method. The values of the positive attributes were distributed between 0.40-2.65 (mean value 1.45±0.72) for bitterness, 1.50-3.70 (mean value 2.62±0.56) for pungency and 0.40-3.60 (mean value 2.14±0.82) for fruitiness. The results showed that there is a positive correlation (r=0.79, p≤0.05) between the concentration of oleocanthal and oleacein, and the intensity of pungency and bitterness, suggesting that virgin olive oils with intense organoleptic attributes may offer more health benefits. Moreover, a proposal for a new index for describing and quantifying the positive organoleptic attributes of virgin olive oils is discussed.

Probing Downstream Olive Biophenol Secoiridoids

“…Oleuropein causes most of bioactive functions and contributes to the food taste and the prevention of several lethal human diseases [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Moreover, oleacein and oleocanthal are downstream forms of decarbomethoxy-oleuropein and decarbomethoxy-ligstroside, respectively, via aglycones to dialdehydes formation, which are responsible for the intensity of the hedonic-sensorial response to pungency and bitterness in olive oil and table olives [ 27 , 28 , 29 ]. Similarly, hydroxytyrosol and tyrosol are downstream bioactive metabolites of oleuropein and ligstroside, respectively [ 16 ].…”

Effect of Processing on Phenolic Composition of Olive Oil Products and Olive Mill By-Products and Possibilities for Enhancement of Sustainable Processes

“…The phenolic constituents of olive oil typically include oleocanthal, oleacein, oleuropein, hydroxytyrosol, and tyrosol. Of all endogenous phenolic groups, oleocanthal (decarboxymethyl ligstroside aglycone), a representative secoiridoid, is considered distinctively beneficial, particularly with respect to its anti-inflammatory effects, which are comparable to those exerted by ibuprofens [15][16][17][18]. Oleocanthal potentially plays a part in curtailing the activities of inflammation-induced enzymes such as cyclooxygenase-2 (COX-2) [15,[18][19][20].…”

“…Another representative secoiridoid in olive oil is oleacein (3,4-dihydroxyphenylethanolelenolic acid dialdehyde), which possesses a molecular structure relatively similar to that in oleocanthal but slightly differs in terms of the hydroxyl group, where oleacein bears one further OH group [17]. This component significantly exhibits antioxidation [17] and anti-inflammation [22], and it reportedly contributes to the suppression of platelet aggregation, partly through hindering the action of 5-lipoxygenase (5-LOX) enzymes [8]. The antioxidative activity exerted by oleacein has been justified in the literature in a way that it may competitively be greater than that exhibited by hydroxytyrosol and oleuropein [16,23].…”

NMR spectroscopy: a powerful tool for the analysis of polyphenols in extra virgin olive oil

“…NMR spectroscopy is particularly suitable for the investigation of complex matrices such as EVOO, and allows the quantification of minor components . The qualitative and quantitative determination of the phenolic fraction by NMR have both been used to characterize EVOO varieties and geographical origin as well as for sensory analysis . The chromatographic analysis of a mixture of components requires calibration using standard compounds, many of which are unstable and/or not commercially available.…”

“…8 The qualitative and quantitative determination of the phenolic fraction by NMR have both been used to characterize EVOO varieties and geographical origin [9][10][11][12] as well as for sensory analysis. 13 The chromatographic analysis of a mixture of components requires calibration using standard compounds, many of which are unstable and/or not commercially available. In contrast, quantitative 1 H nuclear magnetic resonance (qHNMR) enables the quantification of molecules in multicomponent solutions without the need for identical pure reference standards, 14,15 and represents an alternative for accurate quantification of compounds in a complex food matrix.…”