Natural Tobacco Flavor Profiling Under Heat-Not-Burn Conditions Using Reference Tobacco Leaves and Tobacco from 1R6F Reference Cigarettes

Studying the organoleptic properties of heated tobaccos in relation to natural flavors is essential for understanding how lower-temperature processing influences the release of intrinsic tobacco flavor compounds. Unlike combustion processes (> 600 °C), which generate numerous undesirable substances, the heat-not-burn approach (< 350 °C) helps preserve the integrity of natural terpenoids, alkaloids, phenols, and other bioactive molecules while reducing harmful byproducts. This research studied which natural flavor compounds are released from different tobacco types when heated at temperatures typical of heated tobacco products (HTPs) and how these compounds likely contribute to the flavor and aroma profiles. No preliminary modifications were made to the tobacco samples. Four tobacco types were selected: flue-cured, Oriental, Burley, and dark air-cured. The ground lamina of these tobaccos, along with filler from reference 1R6F cigarettes (all provided by the Center for Tobacco Reference Products), were analyzed. Gas Chromatography–Mass Spectrometry (GC-MS) analysis was performed using a Thermal Separation Probe (TSP), which thermally desorbed volatile and semi-volatile constituents from the ground leaf materials at controlled inlet temperatures (200–325 °C). The released compounds were directly introduced into the GC inlet for chromatographic separation and subsequent mass spectrometric identification. Among the numerous peaks detected, flavor-like compounds previously identified in the literature were selected for further evaluation. Flue-cured tobacco yielded 16 identified flavor compounds, oriental tobacco 21, burley 15, and dark air-cured 15. Sixteen compounds were detected in the reference 1R6F cigarette sample. In total, 32 natural flavor compounds were identified across the five tobacco samples. Flavor properties of each compound were assigned based on various literature sources. Compounds were also categorized by chemical class and compared across the five tobacco types. Based on this class-wise distribution, the natural organoleptic profile of each tobacco type was estimated. Several natural compounds were detected that have not previously been reported in aerosols generated from heated tobacco products at low temperatures (200–325°C). These compounds may potentially expand the flavor profile of heated tobacco products.