Comprehensive Characterization of Aroma Compounds in Four Different Varieties of Cigar Tobacco Leaves from China Using HS-SPME-GC × GC-TOF-MS Combined with Flavor Profiling

In order to conduct in-depth research on the stylistic
characteristics
of different varieties of cigar tobacco leaves (CTLs), we have carried
out the following research work: first, the Soxhlet extraction method
was utilized for the pretreatment of 4 different varieties of CTLs
currently available in China. Then, the two-dimensional (2D) gas chromatography–time-of-flight
mass spectrometry (GC × GC-TOF-MS) technology was applied for
the nontargeted flavoromics analysis of CTLs. A total of 2117 volatile
compounds were identified in the extracts of the 4 CTLs varieties,
encompassing alcohols, aldehydes, ketones, carboxylic acids, and their
derivatives, esters, hydrocarbons, alkenes, heterocyclic compounds,
and aromatics. Results from multivariate statistical analyses (principal
component analysis (PCA) and orthogonal partial least-squares discriminant
analysis (OPLS-DA)) revealed significant differences in the volatile
compound profiles among different CTL varieties. Based on the relative
odor activity value (ROAV) analysis, key flavor compounds were determined
for each variety, contributing to the unique aroma profiles of the
cigars. Overall, the 4 CTLs shared similar flavor profiles, characterized
by sweetness, fruitiness, greenness, nuttiness, and floral notes,
with BX1 and DX2 particularly standing out in sweetness and BX1 additionally
prominent in fruitiness. HY101, however, was relatively lacking in
these flavor attributes compared to the other 3 varieties. Nine key
differential compounds1-butanol, 3-methyl; 1-hexanol; benzeneacetaldehyde;
naphthalene; benzaldehyde; isophorone; 2-heptanone, furan, 2-pentyl;
and pyrazine, trimethyl, and trimethylpyrazinewere identified
as the characteristic markers among different CTL varieties. We believe
that this study will not only provide important value for the analysis
of flavor characteristics and variety identification of cigar tobacco
leaves but also offer scientific basis for improving the quality and
market advantages of cigar tobacco leaves.