title: Separation and characterization of phenolic compounds from U.S. pecans by liquid chromatography-tandem mass spectrometry.
abstract: The phenolic acids and proanthocyanidins (PACs) of pecans possess bioactive properties, which might be useful in retarding the onset of and ameliorating the status of certain chronic disease states. There is a general lack of information in the literature regarding such compounds, especially the PACs. Crude phenolic extracts pooled from eight commercially significant cultivars were selected based on their relatively high antioxidant capacities. The pooled extracts were separated via Sephadex LH-20 column chromatography into five ethanolic low-molecular-weight (LMW) fractions and one acetonic high-molecular-weight (HMW) fraction. The preparations were then characterized using RP-HPLC-ESI-MS/MS and diol-phase HPLC-ESI-MS/MS in order to determine the key constituents present in the LMW and HMW fractions, respectively. As previously observed in pecan nutmeat, ellagic acid and (+)-catechin were found to be the major phenolics in the LMW fractions. The last eluting LMW fraction did not contain phenolic acids; rather it possessed PAC monomers and dimers. The HMW fraction comprised a majority of its PACs as dimers; yet, monomers, trimers, tetramers, pentamers, and hexamers were also separated and characterized.
authors.affiliation: Department of Food Science & Technology, College of Agricultural and Environmental Sciences, The University of Georgia , 100 Cedar Street, Athens, Georgia 30602-2610, United States.
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Robbins
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Ma
authors.forename: M Lenny
authors.initials: ML
authors.lastname: Wells
authors.forename: Phillip
authors.initials: P
authors.lastname: Greenspan
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Pegg
mesh_terms: D031325:Carya / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014481:United States
chemical_list: D010636:Phenols; D010936:Plant Extracts