title: Short communication: Study on the formation of 2-methylimidazole and 4-methylimidazole in the Maillard reaction.
abstract: 2-Methylimidazole (2-MI) and 4-methylimidazole (4-MI) can be formed via the Maillard reaction during dairy thermal treatment. In this study, different reactions between α-dicarbonyl compounds (methylglyoxal, glyoxal) and aldehydes (formaldehyde, acetaldehyde) in the presence of ammonium sulfate were performed to investigate the formation of 2-MI and 4-MI. Two formation pathways of 2-MI and 4-MI were proposed. One pathway is that α-dicarbonyl compound reacts with equivalent ammonia to form an intermediate, while aldehyde reacts with equivalent ammonia to form another intermediate, then the 2 intermediates react together to generate 2-MI or 4-MI. Alternatively, α-dicarbonyl compound can react with double ammonia to form an intermediate, and subsequently reacts with aldehyde to form 2-MI or 4-MI. Additionally, possible mechanisms were also proposed to explain the phenomenon that the 2-MI content was much lower than 4-MI in Maillard reaction.
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China.
authors.forename: Xinlan
authors.initials: X
authors.lastname: Wu
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Huang
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China.
authors.forename: Fansheng
authors.initials: F
authors.lastname: Kong
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; State Key Laboratory of Pulp and Paper Engineering, Guangzhou 510640, China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou 510640, China. Electronic address: shujuanyu8@gmail.com.
authors.forename: Shujuan
authors.initials: S
authors.lastname: Yu
mesh_terms: D000447:Aldehydes / Q000032:analysis; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005511:Food Handling; D007093:Imidazoles / Q000032:analysis*; D015416:Maillard Reaction; D008892:Milk / Q000737:chemistry; D011765:Pyruvaldehyde / Q000032:analysis; D053719:Tandem Mass Spectrometry
chemical_list: D000447:Aldehydes; D007093:Imidazoles; D011765:Pyruvaldehyde; C023439:4-methylimidazole; C032655:2-methylimidazole
keywords: 2-methylimidazole; 4-methylimidazole; glyoxal; methylglyoxal