Chemistry of 2-acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine, 2-acetyl-2-thiazoline, and 5-acetyl-2,3-dihydro-4H-thiazine:: Extraordinary Maillard flavor compounds

To date, a number of Maillard flavor compounds have been discovered. Two such compounds are 2-acetyl-1-pyrroline(1) and 6-acetyul-1,2,3,4-tetrahydropyridine (2). The extraordinary flavor properties of these compounds are related with the α-iminoketone or α-acylenamine structural element as part of a ring system. This review covers the chemistry of these important flavor compounds, their occurrence and significance, their mechanisms of formation, their biological origin, the developed synthetic routes, and their applications in the food industry.