title: Identification/quantification of free and bound phenolic acids in peel and pulp of apples (Malus domestica) using high resolution mass spectrometry (HRMS).
abstract: Free and bound phenolic acids were measured in the pulp and peel of four varieties of apples using high resolution mass spectrometry. Twenty-five phenolic acids were identified and included: 8 hydroxybenzoic acids, 11 hydroxycinnamic acids, 5 hydroxyphenylacetic acids, and 1 hydoxyphenylpropanoic acid. Several phenolics are tentatively identified for the first time in apples and include: methyl gallate, ethyl gallate, hydroxy phenyl acetic acid, three phenylacetic acid isomers, 3-(4-hydroxyphenyl)propionic acid, and homoveratric acid. With exception of chlorogenic and caffeic acid, most phenolic acids were quantified for the first time in apples. Significant varietal differences (p<0.05) were observed in both peel and pulp. The levels of total phenolic acids were higher in the pulp as compared to apple peel (dry weight) in all varieties. Coumaroylquinic, protocatechuic, 4-hydroxybenzoic, vanillic and t-ferulic acids were present in free forms. With exception of chlorogenic acid, all other phenolic acids were present only as bound forms.
authors.affiliation: Department of Food Science and Technology, Chung-Ang University, Anseong 17546, South Korea.
authors.forename: Jihyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Bronte Lee Shan
authors.initials: BL
authors.lastname: Chan
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA. Electronic address: aemitchell@ucdavis.edu.
authors.forename: Alyson E
authors.initials: AE
authors.lastname: Mitchell
mesh_terms: D002109:Caffeic Acids / Q000032:analysis; D002726:Chlorogenic Acid / Q000032:analysis; D003373:Coumaric Acids / Q000032:analysis; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000032:analysis; D062385:Hydroxybenzoates / Q000032:analysis*; D027845:Malus / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D010636:Phenols / Q000032:analysis; D010666:Phenylpropionates / Q000032:analysis
chemical_list: D002109:Caffeic Acids; D003373:Coumaric Acids; D062385:Hydroxybenzoates; D010636:Phenols; D010666:Phenylpropionates; C048734:ethyl gallate; D002726:Chlorogenic Acid; C052082:methyl gallate; D005707:Gallic Acid; C008869:phloretic acid; C004999:ferulic acid; C017616:phenolic acid; C040048:caffeic acid
keywords: Apple; High resolution mass spectroscopy; MS/MS; Peel; Phenolic acid; Pulp; QTOF; UHPLC-(ESI)QTOF MS/MS