Composition and Release Patterns of Volatile Compounds from the Atmosphere of Tobacco Curing Barns during Different Curing Stages

To clarify the composition and release dynamics of volatile compounds from the atmosphere of bulk curing barns during various stages of intensive tobacco curing, volatile substances were collected using ultrapure water at five distinct curing phases and analyzed by gas chromatography–mass spectrometry (GC/MS). The results indicated that the number of volatile components first increased and then decreased throughout the curing process, peaking at the late color-fixing stage (50 ℃) with 56 compounds detected, followed by the stem-drying stage (68 ℃) with 48 compounds, and the early yellowing stage (38 ℃) with the fewest, totaling 37 compounds. The volatile compounds identified during intensive tobacco curing were categorized into seven classes: alcohols, esters, aldehydes, organic acids, ethers, ketones, and others. Esters constituted the most abundant category, while ethers were the least represented. The contents of aldehydes, alcohols, esters, ketones, and other volatiles exhibited an initial increase followed by a decrease across curing stages, all reaching their highest levels at the late color-fixing stage (50 ℃). Each curing stage produced a certain number of unique volatile compounds, with the late color-fixing stage (50 ℃) generating the highest diversity and quantity—19 compounds spanning six categories. A total of sixteen common volatile compounds were identified across different curing stages. Esters constituted the largest proportion, followed by alcohols, while no ether compounds were detected among these shared volatiles. Moreover, the clustering results revealed distinct differences in the composition of common volatile compounds during various curing stages. Further studies combining the volatile substance content in tobacco leaves are expected to offer additional references for the curing process and quality management of tobacco leaves.