Characterization of aroma profile and microbial community of cigar tobacco leaves from different aging periods and varieties and their correlations analysis.

Abstract

In this study, the CTLs from Hainan, China, were used, the aroma profiles of CTLs from five years (2017-2021) and three varieties [Hainan2 (HN2), Jianheng3 (JH3), and Guyin4 (GY4)] were analyzed, and the microbial communities of these CTLs and the relation with aroma constituents were explored. Results revealed the contents of total aroma constituents (3.55-7.67 mg/kg), esters (47.4-824 μg/kg), alcohols (123-561 μg/kg), aldehydes (51.4-97.1 μg/kg), and nitrogen heterocycles (1.86-4.25 mg/kg), firstly increased and subsequently declined with the increase of years, whereas ketones (1.07-3.56 mg/kg) exhibited an inverse trend. Among the different varieties, the highest aldehyde (142 μg/kg) content was observed in JH3, while the highest total aroma constituents, acids, ketones, and nitrogen heterocycles were found in GY4, reaching 10.5, 0.604, 1.86, 6.43 mg/kg, respectively. Furthermore, the bacterial communities of CTLs from different years exhibited discernible succession with increasing years. The abundances of Staphylococcus (3.03-47.5%) and Sphingomonas (1.18-10.2%) first increased and then decreased, whereas Pseudomonas (1.63-11.5%), Ralstonia (0.669-20.2%), and Pantoea (6.07-10.5%) exhibited the opposite trend, and Aspergillus and Cladosporium with total abundances of 90.2-94.2% were predominant in all years. The dominant bacteria and fungi of CTLs from different varieties were identified as Staphylococcus (15.0-81.1%) and Aspergillus (45.6-85.0%), respectively. However, the dominant microbial abundances in JH3 were significantly lower than those in HN2 and GY4, while other microorganism abundances were increased. Partial least square-regression analysis demonstrated that Paracoccus, Staphylococcus, Aerococcus, Pantoea, Methylobacterium-Methylorubrum, and Bacillus of CTLs from different years were associated with aroma constituents.