Elucidating the linkage between non-volatile precursors and particulate-phase flavor compounds in mainstream smoke...

Understanding the chemical linkage from non-volatile precursors in leaf to flavor compounds in mainstream smoke is critical for evaluating the contrasting sensory perceptions of different tobacco phenotypes.

To elucidate this mechanism, we systematically compared high-quality Zimbabwe tobacco leaf and China Hehua tobacco dust using a multi-platform analytical strategy, including cascade membrane ultrafiltration, UV-vis, ¹H NMR, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high resolution mass spectrometry (LC-HRMS).

The results indicated that the bulk macromolecules were predominantly carbohydrates and highly conserved across both tobacco leaves, while trace chemical divergences drive their distinct sensory profiles. Zimbabwe tobacco smoke particulates were enriched in aromatic pyrazoles and other N-heterocycles, fueled by a nitrogen-rich precursor matrix in the uncombusted extract of Zimbabwe tobacco leaf. Conversely, Hehua smoke featured sweet-toned furans and heavy alkanes, originating from an altered chemical balance alongside a carbon-hydrogen-oxygen (CHO) fraction that is relatively more aliphatic and lipid-rich. Furthermore, by tracking nontargeted markers in the smoke particulates generated from filtrates and retentates attained through the cascade filtration stages, potential macromolecular interactions were found influencing the combustion transformation. Specific macromolecular fractions of the 50 to 300 kDa range in the Hehua matrix exhibit pronounced co-enrichment with free small-molecule precursors.

The observed co-enrichment suggests that these specific macromolecular fractions may act as carriers during their transfer into mainstream smoke. This novel comparative framework successfully bridges the analytical gap between uncombusted tobacco precursors and flavors in smoke particulates, establishing a chemical foundation for the digital quality evaluation and targeted formulation of substitute tobacco materials.