Effects of reaction parameters on generation of volatile compounds from the Maillard reaction between L‐ascorbic acid and glycine

The formation of volatiles from the reaction between L‐ascorbic acid (ASA) and glycine (Gly) at different reaction parameters, such as temperature, time and pH, were reported and 20 different volatile compounds were identified using solid‐phase microextraction–gas chromatography–mass spectrometry (SPME‐GC‐MS). The results showed that the reaction parameters had the different effects on formation of volatiles, while the effect of pH was the most remarkable. When the initial solution pH was 4.5, the major volatiles were found to be furfural or derivatives of furan; while when pH ranged from 6.8 to 9.5, the major volatiles were found to be derivatives of pyrazines, including 2,5‐dimethyl‐pyrazine, 2‐ethyl‐5‐methyl‐pyrazine, trimethyl‐pyrazine, 3‐ethyl‐2,5‐dimethyl‐pyrazine and 2,3‐diethyl‐5‐methyl‐pyrazine. The quantity of 2,5‐dimethyl‐pyrazine and 2‐ethyl‐5‐methyl‐pyrazine reached the maximum when pH was 8.0. Finally, a possible reaction mechanism of ASA and Gly and the pathway for the formation of the various kinds of volatile products were proposed.