Unraveling the microbiological and chemical basis of aroma differences in Great Wall cigars: insights from amplicon sequencing and volatile metabolomics

Abstract

To clarify the microbiological and chemical bases underlying aroma differences among six Great Wall cigar types, 16S rRNA/ITS amplicon sequencing and headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) were integrated to characterize microbial community composition, volatile organic compound (VOC) profiles, and potential microbe–VOC associations. Microbial diversity and community composition differed among the six cigar types, and linear discriminant analysis effect size (LEfSe) identified 16 potential microbial biomarkers. Volatile metabolomics analysis identified 1,620 VOCs, which were classified into nine chemical classes. The combined results of relative odor activity value (rOAV) analysis and partial least squares discriminant analysis (PLS-DA) revealed 17 VOCs as key aroma compounds associated with aroma differences among the six cigar types. Notably, representative compounds, including β-damascenone (floral, fruity, sweet), dihydro-2-methyl-3(2H)-furanone (roasted, nutty, sweet), δ-cadinene (herbal, woody), and δ-dodecalactone (creamy, fruity), exhibited distinct rOAV distribution patterns across the six cigar types, which may contribute to the characteristic aroma profiles of these cigars. Correlation analysis further revealed that several microbial genera were significantly associated with key aroma compounds. In particular, the bacterial genus Atopostipes and the fungal genus Sampaiozyma displayed significant positive correlations with dihydro-2-methyl-3(2H)-furanone, β-damascenone, and other key aroma compounds. These findings provide useful insights for screening aroma-producing microorganisms and improving cigar quality control.