Promotion effect of sulfite on deoxyosones and 4-methylimidazole in caramel model system

• H/D exchange showed the promotion of aldo-enol transition by sulfite.
• Aldo-enol transition promoted the formation of MGO and 4-MeI.
• The antioxidants sulfite inhibited osones formation.

In this study, hydrogen-deuterium (H/D) exchange experiment was carried out to reveal the promotion effect of sulfite on the formation of deoxyosones and 4-methylimidazole (4-MeI) in the Maillard reaction. Glucose-ammonium (40 mmol/L, pH 7.4 in PBS) model systems with different levels of sulfite were incubated at 110 °C for 2 h. Alpha-dicarbonyls were detected after derivatization by a high-performance liquid chromatography with a diode array detector (HPLC-DAD). 4-MeI in the Maillard reaction was tested using a high-performance anion exchange chromatography with an electrochemical detector (HPAEC-ED). The H/D exchange ratios of hexose (fructose, glucose and mannose) were tested by HPAEC-MS. Results showed that the aldo-enol transition of enediol was promoted by sulfite, which promoted the formation of deoxyosones and 4-MeI. In addition, the oxidation reaction of enediols was inhibited by the antioxidant sulfite, which caused the inhibition of osones formation in the Maillard reaction.