High-performance liquid chromatography coupled to diode array and electrospray time-of-flight mass spectrometry detectors for a comprehensive characterization of phenolic and other polar compounds in three pepper (Capsicum annuum L.) samples

The healthy properties attributed to the intake of fruits and vegetables such as peppers are owed not only to the content of vitamins, minerals, and carotenoids but also to the high content of polyphenols. Since the major group of compounds investigated in Capsicum annuum L. samples relates to capsaicinoids, the aim of this study was to characterize three different non-pungent varieties, called Italian sweet, Lamuyo, and California wonder, a green, yellow, and red pepper variety, respectively. The methanol/water pepper extracts were qualitatively studied by using HPLC-DAD-ESI-TOF-MS. A total of 45 compounds were tentatively identified, mainly glycoside derivatives of flavonoids such as quercetin 3,7-di-O-alpha-L-rhamnopyranoside and narigenin-7-O-beta-D-(3 ''-p-coumaroyl)-glucopyranoside. Likewise, other polar metabolites were identified, such as organic acids, nucleosides, and amino acids. Regarding the number of identified compounds and their intensity, Italian sweet variety could be considered as the richest one. To our knowledge, 34 of the proposed compounds have been reported in pepper fruit for the first time. (C) 2013 Elsevier Ltd. All rights reserved.