Formation of (E,E)-2,4-decadienal in sugar-smoked chicken thighs via lipidomics, flavoromics, and free radical analysis

Sucrose smoke is widely used in smoked chicken production, and lipids, along with free radicals, play a crucial role in the formation of its characteristic flavor. However, the molecular mechanism by which pyrolytic radicals from sucrose convert endogenous lipids into key odorants (such as (<i>E,E</i>)-2,4-decadienal) remains unknown. This study used gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze sugar-smoked chicken thighs and revealed that sucrose pyrolysis increased (<i>E</i>,<i>E</i>)-2,4-decadienal (key flavor). The phospholipid molecules PE (18,2/20,2), PE (18,2/22,4), PC (18,2/17,1), and PC (18,2/22,2) were significantly negatively correlated with (<i>E</i>,<i>E</i>)-2,4-decadienal, and they may be key substrates for its formation. Linoleic acid increases for 0-4 min and then decreases after 5 min (maximizing the aldehyde). Electron paramagnetic resonance (EPR) spectroscopy reveals that radicals (especially alkoxy) grow with increasing smoking time and attack linoleic acid to form them. This study elucidates the sucrose pyrolysis mechanism, aiding flavor regulation.