A comprehensive evaluation of tyrosol and hydroxytyrosol derivatives in extra virgin olive oil by microwave-assisted hydrolysis and HPLC-MS/MS

Abstract

A rapid and reliable method to assay the total amount of tyrosol and hydroxytyrosol derivatives in extra virgin olive oil has been developed. The methodology intends to establish the nutritional quality of this edible oil addressing recent international health claim legislations (the European Commission Regulation No. 432/2012) and changing the classification of extra virgin olive oil to the status of nutraceutical. The method is based on the use of high-performance liquid chromatography coupled with tandem mass spectrometry and labeled internal standards preceded by a fast hydrolysis reaction step performed through the aid of microwaves under acid conditions. The overall process is particularly time saving, much shorter than any methodology previously reported. The developed approach represents a mix of rapidity and accuracy whose values have been found near 100% on different fortified vegetable oils, while the RSD% values, calculated from repeatability and reproducibility experiments, are in all cases under 7%. Graphical abstract Schematic of the methodology applied to the determination of tyrosol and hydroxytyrosol ester conjugates.

Impact of the malaxation temperature on the phenolic profile of cv. Cobrançosa olive oils and assessment of the related health claim

“…This latter strategy is based on the hydrolysis of the phenolic bound forms and, although not providing a deep information regarding the specific oils' phenolic profile, allows a fast estimation of the hydroxytyrosol and tyrosol derivatives contents. It has been widely applied (Bartella, Mazzotti, Napoli, Sindona, & Di Donna, 2018;Bellumori et al, 2019;Mastralexi et al, 2014;Olmo-García et al, 2019;Purcaro et al, 2014;Reboredo-Rodríguez et al, 2016;Romero & Brenes, 2012) and allowed assessing the oils' health claim fulfillment (European Commission Regulation EU No 432/2012, 2012, providing that conversion factors are applied to estimate the amounts of the original molecules before hydrolysis.…”

Why Tyrosol Derivatives Have to Be Quantified in the Calculation of “Olive Oil Polyphenols” Content to Support the Health Claim Provisioned in the EC Reg. 432/2012

“…As a result, there is a need of clarification about which compounds should be summed up to give the amount of at least 5 mg phenols per 20 g oil and the benefits of using such a claim for commercial reasons are still not explored enough by stakeholders. Nevertheless, almost at the same period different analytical approaches appear in literature to address this issue …”

Paper spray tandem mass spectrometry: A rapid approach for the assay of parabens in cosmetics and drugs

“…Conventionally, they are analyzed by gas chromatography (GC) or high‐performance liquid chromatography (HPLC) coupled with mass spectrometry (MS), ultraviolet, and electrochemical detection 17–23 . MS is certainly the most appropriate tool for a specific and sensitive analysis 24,25 ; moreover, this technique allows the use of labeled internal standards, which assure a high grade of accuracy in the analysis 26,27 . In this work, we developed a new approach based on the use of paper spray (PS) ionization coupled with tandem MS. PS is an ambient ion source, which allows to create ions directly in their native state, performing fast analysis of a wide variety of compounds present in complex mixtures, with a minimal sample pretreatment and without any chromatographic separation.…”