title: Chlorogenic acid-arabinose hybrid domains in coffee melanoidins: Evidences from a model system.
abstract: Arabinose from arabinogalactan side chains was hypothesized as a possible binding site for chlorogenic acids in coffee melanoidins. To investigate this hypothesis, a mixture of 5-O-caffeoylquinic acid (5-CQA), the most abundant chlorogenic acid in green coffee beans, and (α1 → 5)-L-arabinotriose, structurally related to arabinogalactan side chains, was submitted to dry thermal treatments. The compounds formed during thermal processing were identified by electrospray ionization mass spectrometry (ESI-MS) and characterized by tandem MS (ESI-MS(n)). Compounds composed by one or two CQAs covalently linked with pentose (Pent) residues (1-12) were identified, along with compounds bearing a sugar moiety but composed exclusively by the quinic or caffeic acid moiety of CQAs. The presence of isomers was demonstrated by liquid chromatography online coupled to ESI-MS and ESI-MS(n). Pent1-2CQA were identified in coffee samples. These results give evidence for a diversity of chlorogenic acid-arabinose hybrids formed during roasting, opening new perspectives for their identification in melanoidin structures.
authors.affiliation: QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Ana S P
authors.initials: AS
authors.lastname: Moreira
authors.affiliation: QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Coimbra
authors.affiliation: CQ-VR, Chemistry Research Centre, Department of Chemistry, University of Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal.
authors.forename: Fernando M
authors.initials: FM
authors.lastname: Nunes
authors.affiliation: QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Cláudia P
authors.initials: CP
authors.lastname: Passos
authors.affiliation: CICECO, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Sónia A O
authors.initials: SA
authors.lastname: Santos
authors.affiliation: CICECO, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Armando J D
authors.initials: AJ
authors.lastname: Silvestre
authors.affiliation: UCIBIO/REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal.
authors.forename: André M N
authors.initials: AM
authors.lastname: Silva
authors.affiliation: UCIBIO/REQUIMTE, Instituto de Ciências Biomédicas de Abel Salazar, University of Porto, 4050-313 Porto, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Rangel
authors.affiliation: QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: mrd@ua.pt.
authors.forename: M Rosário M
authors.initials: MR
authors.lastname: Domingues
mesh_terms: D001089:Arabinose / Q000032:analysis*; D002726:Chlorogenic Acid / Q000031:analogs & derivatives / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003069:Coffee / Q000737:chemistry*; D005511:Food Handling; D005685:Galactans / Q000737:chemistry; D006358:Hot Temperature; D010429:Pentoses / Q000032:analysis; D011108:Polymers / Q000737:chemistry*; D011801:Quinic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001089:Arabinose; D002726:Chlorogenic Acid; D003069:Coffee; D005685:Galactans; D010429:Pentoses; D011108:Polymers; D011801:Quinic Acid; C011908:melanoidin polymers; C473200:5-caffeoylquinic acid; C005653:arabinogalactan
keywords: Arabinogalactans; Caffeoylquinic acid; Mass spectrometry; Polysaccharides; Roasting; Transglycosylation