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

Abstract

Bitterness and pungency are important parameters for olive oil quality. Therefore, two instrumental methods for evaluation of these taste attributes were developed. The first one is based on the photometric measurement of total phenolic compounds content, whereas the second one is based on the semiquantitative evaluation of hydrophilic compounds by highperformance liquid chromatography−mass spectrometry (HPLC-MS). Evaluation of total phenolic compounds content was performed by a modified method for the determination of the K 225 value using a more specific detection based on the pH value dependency of absorbance coefficients of phenols at λ = 274 nm. The latter method was not suitable for correct prediction, because no significant correlation between bitterness/pungency and total phenolic compounds content could be found. For the second method, areas of 25 peaks detected in 54 olive oil samples by a HPLC-MS profiling method were correlated with the bitterness and pungency by partial least-squares regression. Six compounds (oleuropein aglycon, ligstroside aglycon, decarboxymethyl oleuropein aglycon, decarboxymethyl ligstroside aglycon, elenolic acid, and elenolic acid methyl ester) show high correlations to bitterness and pungency. The computed model using these six compounds was able to predict bitterness and pungency of olive oil in the error margin of the sensory evaluation (±0.5) for most of the samples.

Evaluation of matrix effect in one‐dimensional and comprehensive two‐dimensional liquid chromatography for the determination of the phenolic fraction in extra virgin olive oils

“…During mechanical pressing, hydrolysis reactions of the secoiridoids lead to the formation of the respective aglycons [4]. Oleuropein aglycon and ligstroside aglycone are present in EVOOs in the form of various isomers [2,14,15]; flavonoids are represented by apigenin (AP) and luteolin (LU), and, finally, lignans include pinoresinol and acetoxypinoresinol [4].…”

Reducing Phenolics Related to Bitterness in Table Olives

“…Flavonoids (C 6 C 3 C 6 ) frequently found in olives include luteolin-7-glucoside, cyanidin-3glucoside, cyanidin-3-rutinoside, rutin, apigenin-7-glucoside, quercetin-3-rhamnoside, and luteolin. Secoiridoids are phenolic compounds found in very few edible plants apart from olives and are among the more important compounds in regard to sensory perception of bitterness [2,26]. Secoiridoids are characterized by an exocyclic 8,9-ole nic functionality, comprised of an elenolic acid and a glucosidic residue, also known as an oleosidic skeleton.…”

“…Sensory studies that examine bitterness in olive products have been conducted using either taste dilution analysis (TDA) or correlating bitterness of olive oil with semiquantitative concentration of measured phenolics [26,32,34]. TDA of oleuropein and oleuropein aglycone indicated that these compounds are bitter at a concentration of 50 µg per 1 cm paper square [32].…”

A novel bioanalytical method based on UHPLC‐HRMS/MS for the quantification of oleuropein in human serum. Application to a pharmacokinetic study

“…Many analytical methods have been developed for the determination of OE in various matrices such as olive oil (Dierkes et al , ), table olives (Zoidou et al , ), byproducts of the olive oil industry (Lozano‐Sánchez et al , ) and biological fluids (Bazoti et al , ). Thus, OE has been analysed by employing high‐performance liquid chromatography coupled with ultraviolet detection (HPLC‐UV) (Ortega‐García & Peragón, ), HPLC‐fluorescence (Tan et al , ) and HPLC coupled with tandem mass spectrometry (HPLC‐MS/MS) (Zhou et al , ).…”