Kinetics of α‑dicarbonyl compounds formation in glucose-glutamic acid model of Maillard reaction.

As a potential health hazard, α-dicarbonyl compounds have been detected in the thermally processed foods. In order to investigate the formation kinetics of α-dicarbonyl compounds, liquid chromatography-electrospray tandem mass spectrometry was employed to determine the content of α-dicarbonyl compounds in glucose-only and glucose-glutamic acid (glucose-Glu) thermal reaction models. The 3-deoxyglucosone content was significantly higher than 6 α-dicarbonyl compounds at 90-110℃, 0-6 hr in the two tested systems. The glutamic acid promoted the content accumulation of 1-deoxyglucosone, diacetyl, methylglyoxal, and glyoxal, whereas inhibited the content of 3-deoxyglucosone and 3,4-dideoxyglucosone. Three-fifths of the tested compounds content increased linearly with time increasing, but in glucose-only system, the 1-deoxyglucosone content increased logarithmically at 95-110℃ over reaction time. The formation of glucose (100-110℃, glucose-only and glucose-Glu), 5-hydroxymethylfurfural (100-110℃, glucose-only), 1-deoxyglucose (105-110℃, glucose-Glu), 3,4-dideoxyglucosone (110℃, glucose-Glu), glyoxal (95-110℃, glucose-Glu) and diacetyl (90-95℃, glucose-Glu) could be well fitted by exponential equation. Shortening the heating time and reducing heating temperature (except glyoxal in glucose-only system) were the effective methods to decrease α-dicarbonyl compounds content in the two tested systems. Additionally, high temperature could also reduce α-dicarbonyl compounds content, such as 3-deoxyglucosone (≥110℃, glucose-only), 1-deoxyglucosone (≥110℃, glucose-only), glucosone (≥110℃, glucose-only; ≥100℃, glucose-Glu), methyloxyl (≥110℃, glucose-only; ≥100℃, glucose-Glu), diacetyl (≥110℃, glucose-only), and glyoxal (≥100℃, glucose-Glu).