Characterization of polyphenols in apricot and peach purees by UHPLC coupled to HRMS Q-Exactive(™) mass spectrometer: an approach in the identification of adulterations.

Abstract

The genuineness of fruit juices and purees is regulated by guidelines of European Fruit Juice Association. Nevertheless, the addition of peach puree to apricot puree is considered the most common adulteration, very difficult to discover. In this study, the composition in free and conjugated polyphenols of apricot and peach purees was performed by target and untarget approaches with Q-Exactive(™) quadrupole-Orbitrap mass spectrometer. Apricot purees showed a higher polyphenol content than those of peaches. Between target coumpounds, chlorogenic acid, rutin, catechin and smaller quantities of hyperoside and kaempferol-3-rutinoside were found in both purees. Apricot puree was also found to contain epicatechin and procianidin B2, absent in peach puree. Peach puree was found to contain small amounts of kaempferol-3-glucoside, absent in apricot. In order to identify untarget polyphenols, data obtained by ultra-high pressure liquid chromatography tandem mass spectrometry analysis were processed with Thermo Scientific automated label-free differential expression software (sieve(™) 2.1 software). Three hydroxycinnamic acid conjugates and a procyanidin were identified and confirmed by tandem mass spectrometry spectra. Some compounds of interest found from differential analysis had a putative identification, while others remained unidentified. The high-resolution mass spectrometry approach using Q-Exactive(™) quadrupole-Orbitrap mass spectrometer could be an important and powerful tool for determination of new biomarkers in fruits and vegetables. Copyright © 2016 John Wiley & Sons, Ltd.