title: Separation and characterization of phenolic compounds from dry-blanched peanut skins by liquid chromatography-electrospray ionization mass spectrometry.
abstract: A large variety of phenolic compounds, including phenolic acids (hydroxybenzoic acids, hydroxycinnamic acids, and their esters), stilbenes (trans-resveratrol and trans-piceatannol), flavan-3-ols (e.g., (-)-epicatechin, (+)-catechin, and their polymers {the proanthocyanidins, PACs}), other flavonoids (e.g., isoflavones, flavanols, and flavones, etc.) and biflavonoids (e.g., morelloflavone), were identified in dry-blanched peanut skins (PS) by this study. High-performance liquid chromatography (HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS(n)) was applied to separate and identify the phenolic constituents. Reversed-phase HPLC was employed to separate free phenolic compounds as well as PAC monomers, dimers, and trimers. PACs with a degree of polymerization (DP) of >4 were chromatographed via hydrophilic interaction liquid chromatography (HILIC). Tentative identification of the separated phenolics was based solely on molecular ions and MS(n) fragmentation patterns acquired by ESI-MS in the negative-ion mode. The connection sequence of PAC oligomers (DP <5) could be deduced mainly through characteristic quinone methide (QM) cleavage ions. When the DP reached 6, only a proportion of the flavan-3-ols could be ascertained in the PACs because of the extremely complicated fragmentation patterns involved. The identification of free phenolic acids, stilbenes, and flavonoids was achieved by authentic commercial standards and also by published literature data. Quantification was performed based on peak areas of the UV (free phenolic compounds) or fluorescence (PACs) signals from the HPLC chromatograms and calibration curves of commercial standards. Overall, PS contain significantly more PACs compared to free phenolic compounds.
authors.affiliation: Department of Food Science & Technology, College of Agricultural and Environmental Sciences, The University of Georgia, 100 Cedar Street, Athens, GA 30602, USA.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Division of Food Science, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, ul. Tuwima 10, 10-748 Olsztyn, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kosińska-Cagnazzo
authors.affiliation: Department of Food Science & Technology, College of Agricultural and Environmental Sciences, The University of Georgia, 100 Cedar Street, Athens, GA 30602, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Kerr
authors.affiliation: Division of Food Science, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, ul. Tuwima 10, 10-748 Olsztyn, Poland.
authors.forename: Ryszard
authors.initials: R
authors.lastname: Amarowicz
authors.affiliation: Department of Foods and Nutrition, College of Family and Consumer Sciences, The University of Georgia, 305 Sanford Drive, Athens, GA 30602, USA.
authors.forename: Ruthann B
authors.initials: RB
authors.lastname: Swanson
authors.affiliation: Department of Food Science & Technology, College of Agricultural and Environmental Sciences, The University of Georgia, 100 Cedar Street, Athens, GA 30602, USA. Electronic address: rpegg@uga.edu.
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Pegg
mesh_terms: D010367:Arachis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002853:Chromatography, Liquid; D056148:Chromatography, Reverse-Phase; D004952:Esters; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification*; D013058:Mass Spectrometry; D009754:Nuts / Q000737:chemistry; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D004952:Esters; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts
keywords: Biflavonoids; Dry-blanched peanut skins; ESI–MS(n); HILIC; Proanthocyanidins (PACs); RP-HPLC