Controlled Formation of Pyrazines: Inhibition by Ellagic Acid Interaction with N-(1-Deoxy-d-xylulos-1-yl)-glycine and Promotion through Ellagic Acid Oxidation

The effect of ellagic acid on the formation of pyrazine, methylpyrazine, 2,3-methylpyrazine, 2,6-methylpyrazine, 2,5-methylpyrazine, and trimethylpyrazine in the xylose–glycine Maillard reaction model was researched. Ellagic acid could either inhibit or promote pyrazine formation, depending on its addition time point and the pH of the system. The addition of ellagic acid during the accumulation period of an Amadori compound inhibited pyrazine formation by capturing the Amadori compound in the xylose–glycine Maillard system and decreasing the pyrazine precursors. The inhibitory effect of ellagic acid on pyrazine formation got more obvious with an increase in the pH of the system. However, when ellagic acid was added at the beginning of the xylose and glycine Maillard system and when the oxidizing substances such as glyoxal and methylglyoxal were significantly formed in the Maillard system, its oxidation could promote the formation of pyrazines.