Objective This study aims to investigate the effects of different drying methods on the volatile components and quality markers of cinnamon (Cinnamomum cassia), thereby providing a basis for optimizing and standardizing the primary processing and drying procedures in cinnamon-producing regions.

Method Four drying treatments (air-drying, hot-air drying at 30℃, hot-air drying at 60℃ and vacuum freeze-drying) were set up.Volatile components were analyzed qualitatively and semi quantitatively by simultaneous distillation extraction and gas chromatography-mass spectrometry (GC-MS). Orthogonal partial least-squares discriminant analysis (OPLS-DA) and cluster heatmap visualization were applied to screen for differential volatile components among the four drying treatments. Liquid chromatography-mass spectrometry (LC-MS) combined with external standard calibration method was used to determine the effects of four drying treatments on the contents of three quality markers—cinnamaldehyde, cinnamyl alcohol, and coumarin.

Result A total of 76 volatile components were identified from four dried cinnamon samples, which belonged to 14 chemical classes, including alkenes, enols, and aldehydes. There were 57 components in the four drying treatments, mainly alkenes and enols, and only 7 volatile components were significantly different between the groups. Based on an OPLS-DA model (R²X = 0.761, R²Y = 0.826, Q² = 0.452), 12 differential volatile components were screened out using the criteria of VIP > 1 and P < 0.05. Cluster heatmap analysis indicated that air-drying provided the best retention of aromatic constituents such as eucalyptol and decanal; hot-air drying at 60℃ yielded a chemical profile most similar to that of air-dryingwhile also elevating the levels of compounds like 1-phenyl-1, 2-propanedione; and hot-air drying at 30℃ enriched thermally inducedmetabolites such as ligustrazine. Quantitative LC-MS analysis revealed that, compared with airdrying, all other three drying treatments resulted in a highly significant decrease in cinnamyl alcohol content (P < 0.001); cinnamaldehyde decreased significantly only in the vacuum freeze-drying group (P < 0.05); while coumarin content was not significantly affected by any drying method.

Conclusion Hot-air drying at 60℃ can be prioritized for optimization in largescale production, while hot-air drying at 30℃ favors the accumulation of specific components. Air-drying preserves cinnamyl alcohol best, but it is limited by long drying cycles and a high risk of mold. In practical applications, the appropriate drying method can be selected according to the target components of interest.