Epicatechin carbonyl-trapping reactions in aqueous Maillard systems: Identification and structural elucidation

Vandana M. Totlani, Devin G. Peterson

Research output: Contribution to journalArticlepeer-review

107 Scopus citations

Abstract

Recently, our group reported via labeling experiments that epicatechin in Maillard reaction aqueous glucose-glycine model systems formed adduct reaction products with C2, C3, and C4 sugar fragments. In the current study, we investigated the identity of the sugar fragment precursors responsible for adduct generation by directly comparing the liquid chromatography-mass spectrometry properties of these reported epicatechin (EC) - sugar fragments adducts with those generated from reactions consisting of only EC and well-known Maillard-generated glucose fragments (i.e., glyoxal, glycolaldehyde, methylglyoxal, glyceraldehyde, etc.). The structural properties of an EC-methylglyoxal adduct reaction product were also analyzed by NMR. The most likely precursors for the C2, C3, and C4 sugar moiety of the EC-sugar fragment adducts were identified as glyoxal, hydroxyacetone, and erythrose, respectively. 1H NMR analysis of the EC-methylglyoxal indicated that the analyte underwent rapid conformational/ constitutional exchange. Using cold temperature (-25°C) two-dimensional NMR analyses (heteronuclear multiple bond coherence, heteronuclear multiple quantum coherence, and 1H-1H correlation spectroscopy), the structure of one of the isomers was reported to consist of a covalent linkage between the C1 position of the methylglyoxal and either the C6 or the C8 position of the EC A ring, presumably generated by hydroxyalkylation and aromatic substitution reactions.

Original languageEnglish (US)
Pages (from-to)7311-7318
Number of pages8
JournalJournal of agricultural and food chemistry
Volume54
Issue number19
DOIs
StatePublished - Sep 20 2006

Keywords

  • Carbonyl trapping
  • Epicatechin
  • Flavanol
  • Glycation
  • Maillard reaction
  • Methylglyoxal-epicatechin

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