Metabolomics reveals the effects producing region and fermentation stage on substance conversion in cigar tobacco leaf

Background The quality of cigar tobacco leaves was closely related to fermentation. To investigate the substance changes in cigar tobacco leaves during their fermentation, metabolomics was determined at different fermentation stages. In this study, the metabolic profile among different regions and fermentation periods of cigar tobacco leaf were evaluated. Results A total of 1103 metabolites were identified in cigar tobacco leaf samples. A total of 293, 105 and 199 metabolites showed differential accumulation in the cigar tobacco leaf among different regions (PEF0 vs. LCF0, PEF0 vs. DHF0, PEF0 vs. YXF0) and 216, 242, 220, 227 and 198 metabolites showed differential accumulation in the different fermentation (LCF0 vs. LCF1, LCF0 vs. LCF2, LCF0 vs. LCF3, LCF0 vs. LCF4, LCF0 vs. LCF5). The main upregulated compounds were flavonoids, phenolic acids and lignans and coumarins, and the main downregulated compounds were organic acids, phenolic acids and amino acids and derivatives in the fermentation comparison group. Conclusions These results provide valuable information for accurately grasping the end time of fermentation and improve efficiency of cigar tobacco leaf fermentation. Graphical Abstract