title: Identification of hydroxycinnamic acid-maillard reaction products in low-moisture baking model systems.
abstract: The chemistry and fate of hydroxycinnamic acids (ferulic, p-coumeric, caffeic, sinapic, and cinnamic acid) in a glucose/glycine simulated baking model (10% moisture at 200 degrees C for 15 min) were investigated. Liquid chromatography-mass spectrometry analysis of glucose/glycine and glucose/glycine/hydroxycinnamic acid model systems confirmed the phenolics reacted with Maillard intermediates; two main reaction product adducts were reported. On the basis of isotopomeric analysis, LC-MS, and NMR spectroscopy, structures of two ferulic acid-Maillard reaction products were identified as 6-(4-hydroxy-3-methoxyphenyl)-5-(hydroxymethyl)-8-oxabicyclo[3.2.1]oct-3-en-2-one (adduct I) and 2-(6-(furan-2-yl)-7-(4-hydroxy-3-methoxyphenyl)-1-methyl-3-oxo-2,5-diazabicyclo[2.2.2]oct-5-en-2-yl)acetic acid (adduct II). In addition, a pyrazinone-type Maillard product, 2-(5-(furan-2-yl)-6-methyl-2-oxopyrazin-1(2H)-yl) acetic acid (IIa), was identified as an intermediate for reaction product adduct II, whereas 3-deoxy-2-hexosulose was identified as an intermediate of adduct I. Both adducts I and II were suggested to be generated by pericyclic reaction mechanisms. Quantitative gas chromatography (GC) analysis and liquid chromatography (LC) also indicated that the addition of ferulic acid to a glucose/glycine model significantly reduced the generation of select Maillard-type aroma compounds, such as furfurals, methylpyrazines, 2-acetylfuran, 2-acetylpyridine, 2-acetylpyrrole, and cyclotene as well as inhibited color development in these Maillard models. In addition, adducts I and II suppressed the bacterial lipopolysaccharide (LPS)-mediated expression of two prototypical pro-inflammatory genes, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, in an in vitro murine macrophage model; ferulic acid reported negligible activity.
authors.affiliation: Department of Food Science and Nutrition, 147 FScN Building, The University of Minnesota, St. Paul, Minnesota 55108, USA.
authors.forename: Deshou
authors.initials: D
authors.lastname: Jiang
authors.forename: Christopher
authors.initials: C
authors.lastname: Chiaro
authors.forename: Pranav
authors.initials: P
authors.lastname: Maddali
authors.forename: K Sandeep
authors.initials: KS
authors.lastname: Prabhu
authors.forename: Devin G
authors.initials: DG
authors.lastname: Peterson
mesh_terms: D003373:Coumaric Acids / Q000737:chemistry*; D005511:Food Handling; D005947:Glucose / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D006358:Hot Temperature; D006813:Humidity; D015416:Maillard Reaction; D008956:Models, Chemical
chemical_list: D003373:Coumaric Acids; D005947:Glucose; D005998:Glycine