Influence of tobacco Flower bud extract on microbial community and aroma quality during cigar leaves fermentation

Results revealed that tobacco flower buds contain 23 characteristic aroma compounds, including β-ionone and phenylethanal. Notably, the extract induced a pronounced microbial shift, enriching <i>Aspergillus</i> in unfermented leaves and promoting <i>Staphylococcus</i> dominance (97%-98%) during fermentation. This shift facilitated carbohydrate and protein degradation, significantly reducing nicotine content (P < 0.001), increased total sugar (12.5%-18.75%) and reducing sugar levels (13.04%-27.27%), and optimized the potassium-to-chloride ratio. Aroma analysis demonstrated significant enrichment of carotenoid degradation products (farnesyl acetone, citronellal) and Maillard reaction products (5-methyl-2-furaldehyde) in the FE group, with total aroma content increasing by 11.9% compared to control (FW). Metagenomic functional analysis further indicated that the extract inhibited pathways related to harmful metabolite synthesis (47.0% reduction) and enhanced carbohydrate metabolism (30.6% increasing). This study confirms that tobacco flower bud extract reshapes microbial communities and metabolic networks by simultaneously suppressing harmful microbes and enhancing aroma, providing theoretical support for optimizing cigar fermentation and agricultural waste utilization.