Abstract:

To screen the characteristic metabolites of cigar tobacco leaves and analyze the aroma differences of cigar tobacco leaves under baking and drying conditions, two cigar varieties, ‘QX103’ and ‘QX108’, were used as experimental materials. After treating the materials with drying and baking preparation methods, metabolomics detection was conducted to explore the differences in the transformation results of volatile and semi-volatile metabolites in tobacco leaves caused by different preparation methods. 172 semi-volatile metabolites were obtained through pre-column derivatization GC-MS technology. The OPLS-DA model was constructed, and 56 differential metabolites were screened out. Most of the differential metabolites were upregulated in baked cigars. By using the headspace solid-phase microextraction GC-MS technology, 65 volatile metabolites were detected in the cigars after drying, and 104 volatile metabolites were detected in the cigars after baking, among which 46 were shared by both. Differential metabolite pathways were mainly enriched in various types such as organic acids, sugars, amino acids, and esters. The effects of the two modulation methods on the metabolite transformation of cigar tobacco leaves were different. The quantity and abundance levels of volatile aroma and semi-volatile metabolites in the tobacco leaves after roasting were higher than those in the tobacco leaves after drying. It provides a theoretical basis for the design and construction of cigar drying rooms and the temperature and humidity control of the drying process in the future.

Key words: cigar, metabolomics, baking, air-drying, differential metabolites, path analysis