Untargeted metabolomics revealing changes in aroma substances in flue-cured tobacco

Abstract

Abstract The composition and content of aroma substances in flue-cured tobacco (Nicotiana tabacum L.) will affect the quality of tobacco. To investigate the correlation between various aroma substances of K326 before and after flue-curing, and their impact on tobacco quality and diversity, this study employed the middle leaves of K326 and KRK26 as test materials. Samples were collected both before and after flue-curing for untargeted metabolomics analysis. The results of K326 showed that 584 metabolites were significantly different and there were 44 aroma-related metabolites, including alcohols, aldehydes, phenols, organic acids, etc. The analyzed aroma compounds consist of 37 known tobacco aroma substances, while 7 metabolites, previously not associated with tobacco aroma, have been identified as aroma substances in other food products. These findings suggest that these seven metabolites might may be potential tobacco aroma compounds. Further analysis showed that the content of phenols, alcohols, and aldehydes increased significantly after flue-curing, but the content of organic acids decreased. Furthermore, the analysis of KRK26 revealed a correlation between the quantity of aroma substances and the type of tobacco. These findings serve as a reference for enhancing the flue-curing process of K326 and optimizing the industrial production of cigarettes that use cured K326 tobacco leaves.