Menthol‐Derived Acetal Flavour Precursors: Synthesis, Characterization, Thermal Release Properties

Dual‐aroma flavour precursors provide a molecular strategy for stabilizing volatile aroma compounds and regulating their thermal release. In this study, four acetal‐based precursors integrating menthol and aldehyde‐derived aroma units were synthesized through epichlorohydrin‐mediated diol formation followed by acetalization with benzaldehyde, anisaldehyde, furfural, or cinnamaldehyde. The structures of compounds 1a – 1d were confirmed by NMR spectroscopy and mass spectrometry. Thermogravimetric analysis showed that these precursors exhibited improved thermal stability compared with the corresponding free aroma compounds. Fixed‐bed reactor single photoionization mass spectrometry under slow‐heating conditions showed delayed and stepwise release of both menthol and aldehyde fragments, whereas Py‐GC–MS under rapid‐heating conditions confirmed efficient menthol generation and selective release of benzaldehyde‐ and anisaldehyde‐derived fragments. These results demonstrate that acetal construction is an effective strategy for improving aroma stability and enabling controlled thermal release. This work provides molecular‐level guidance for the design of flavour delivery systems with tunable thermal‐release behaviour.