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).