title: Structure-reactivity relationships of flavan-3-ols on product generation in aqueous glucose/glycine model systems.
abstract: Ring structure-reactivity relationships of three flavan-3-ols [epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG)] and three simple phenolic compounds (1,3,5-trihydroxybenzene, 1,2,3-trihydroxybenzene, and methylgallate as the analogous individual A, B, and C benzene rings of EGCG) on product generation in an aqueous glucose-glycine reaction model system (125 degrees C and 30 min) were investigated. The addition of EC, ECG, or EGCG to a glucose-glycine model was reported to similarly significantly reduce the formation of pyrazine, methyl-substituted pyrazines, and cyclotene. All three flavan-3-ols were also reported to generate phenolic-C2, C3, C4, and C6 sugar fragment adducts and to statistically reduce the concentration of glyoxal, glycolaldehyde, methylglyoxal, hydroxyacetone, diacetyl, acetoin, and 3-deoxyglucosone during the reaction time course, except for the EGCG reaction where 3-deoxyglucosone was not statistically different from the control after 20 min. For the simple phenolic compounds, methylgallate followed by 1,2,3-trihydroxybenzene was the least reactive, while 1,3,5-trihydroxybenzene was reported as the most reactive phenolic structure for quenching or reducing the concentration of the alpha-hydroxy- and alpha-dicarbonyl sugar fragments during the reaction time course. These results imply that the main mechanism flavan-3-ols reduced product generation was phenolic-sugar fragment carbonyl trapping reactions primarily on the A ring (the meta-polyhydroxylated benzene ring) or not due to the alteration of the reaction reduction potential.
authors: Department of Food Science, The Pennsylvania State University, 327 Food Science Building, University Park, Pennsylvania 16802-2504, USA.
authors: Yuko
authors: Y
authors: Noda
authors: Devin G
authors: DG
authors: Peterson
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D005419:Flavonoids / Q000737:chemistry* / Q000494:pharmacology*; D005947:Glucose / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D015416:Maillard Reaction / Q000187:drug effects*; D010636:Phenols / Q000494:pharmacology; D011719:Pyrazines / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D005419:Flavonoids; D010636:Phenols; D011719:Pyrazines; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; D005947:Glucose; D005998:Glycine