Author(s):
Moreira, Ana S. P. ; Coimbra, Manuel A. ; Nunes, Fernando M. ; Passos, Claudia P. ; Santos, Sonia A. O. ; Silvestre, Armando J. D. ; Silva, Andre M. N. ; Rangel, Maria ; Domingues, M. Rosario M.
Date: 2015
Persistent ID: http://hdl.handle.net/10773/19366
Origin: RIA - Repositório Institucional da Universidade de Aveiro
Subject(s): SUPERHEATED WATER EXTRACTION; MASS-SPECTROMETRY; BREW MELANOIDINS; CINNAMOYLSHIKIMATE ESTERS; PHENOLIC-COMPOUNDS; MOLECULAR-WEIGHT; LACTONES; POLYSACCHARIDES; MECHANISMS; BEANS
Description
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 (alpha 1 -> 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-MSn). 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-MSn. Pent(1-2)CQA 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. (C) 2015 Elsevier Ltd. All rights reserved.
