title: Detailed investigation of the production of the bread flavor component 6-acetyl-1,2,3,4-tetrahydropyridine in proline/1,3-dihydroxyacetone model systems.
abstract: The production of 6-acetyl-1,2,3,4-tetrahydropyridine (ATHP), an important Maillard flavor component, in the reaction of L-(-)-proline and 1,3-dihydroxyacetone was investigated as a function of different reaction conditions. The two major side products from the reaction were identified as 5-acetyl-6-methyl-2,3-dihydro-1H-pyrrolizine and 5-acetyl-6-hydroxymethyl-2,3-dihydro-1H-pyrrolizine, the last one being a new compound described here for the first time. A maximum yield of ATHP of 2.7 mol % from L-(-)-proline and 1,3-dihydroxyacetone was noted at 130 degrees C in the presence of 2 equiv of sodium bisulfite. The role of sodium bisulfite as a reducing species, and as a stabilizing agent for 6-acetyl-1,2,3,4-tetrahydropyridine, was clarified. In view of the new data obtained, the hypothesized mechanism of formation of 6-acetyl-1,2,3,4-tetrahydropyridine was confirmed, and the reaction mechanisms leading to 2,3-dihydro-1H-pyrrolizines were reconsidered.
authors.affiliation: Department of Organic Chemistry, Faculty of Agricultural and Applied Biological Sciences, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: An
authors.initials: A
authors.lastname: Adams
authors.forename: Kourosch Abbaspour
authors.initials: KA
authors.lastname: Tehrani
authors.forename: Milda
authors.initials: M
authors.lastname: Kersiene
authors.forename: Norbert
authors.initials: N
authors.lastname: De Kimpe
mesh_terms: D001939:Bread / Q000032:analysis*; D004098:Dihydroxyacetone / Q000737:chemistry*; D015416:Maillard Reaction; D008956:Models, Chemical; D011392:Proline / Q000737:chemistry*; D011725:Pyridines / Q000138:chemical synthesis*; D013447:Sulfites / Q000737:chemistry; D013649:Taste
chemical_list: C492489:6-acetyl-1,2,3,4-tetrahydropyridine; D011725:Pyridines; D013447:Sulfites; D011392:Proline; D004098:Dihydroxyacetone; C009279:sodium bisulfite