Objective:This article is aimed to explore the influence of closed/open conditions on the flavor compounds of Maillard reaction.Methods:The species and amounts of flavor compounds produced from Tyrosine-based Maillard reactions under closed/open conditions in different solvents and reaction temperatures were determined by GC-MS.Results:The results showed that the species and contents of flavor products are quite different under closed and open conditions. The amounts of alcohol flavor compounds were higher in closed system, while the amount of esters and ketones were higher inopensystem.Conclusion:The amounts of active oxygen and intermediates produced during the reactions likely result in the difference between closed and opensystems from the proposed mechanisms.