title: Ultrafiltration as alternative purification procedure for the characterization of low and high molecular-mass phenolics from almond skins.
abstract: A combination of sample preparation (ultrafiltration) and analysis techniques is proposed for the characterization of complex phenolic mixtures such as extracts from almond (Prunus dulcis (Mill.) D.A. Webb) skins. LC/ESI-MS analysis of the permeates obtained after ultrafiltration on semipermeable membranes (low molecular-mass phenolic fractions) allowed the identification of several benzoic acids and aldehydes, flavan-3-ol monomers and oligomers, and flavonol and flavanone glycosides in almond skins. MALDI-TOF and ESI-MS/MS analysis of the diafiltered concentrates (high molecular-mass phenolic fractions) demonstrated the presence of proanthocyanidin oligomers up to decamers, composed of (epi)afzelechin, (epi)catechin and (epi)gallocatechin units linked by C-C bonds (type B) and by both C-C and C-O bonds (type A). This analytical protocol can be of utility in the study of low and high molecular-mass phenolic compounds in natural products.
authors.affiliation: Departamento de Agroalimentación, IMIDRA, Ctra. A-2, km 38.200, Finca El Encín, E-28800 Alcalá de Henares, Madrid, Spain.
authors.forename: Marin
authors.initials: M
authors.lastname: Prodanov
authors.forename: Ignacio
authors.initials: I
authors.lastname: Garrido
authors.forename: Visitación
authors.initials: V
authors.lastname: Vacas
authors.forename: Rosa
authors.initials: R
authors.lastname: Lebrón-Aguilar
authors.forename: Montserrat
authors.initials: M
authors.lastname: Dueñas
authors.forename: Carmen
authors.initials: C
authors.lastname: Gómez-Cordovés
authors.forename: Begoña
authors.initials: B
authors.lastname: Bartolomé
mesh_terms: D002853:Chromatography, Liquid; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D062385:Hydroxybenzoates / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification*; D008970:Molecular Weight; D027861:Prunus / Q000033:anatomy & histology* / Q000737:chemistry* / Q000254:growth & development; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry; D014462:Ultrafiltration / Q000379:methods*
chemical_list: D062385:Hydroxybenzoates; C017616:phenolic acid