Abstract: Gas chromatography-ion mobility spectroscopy (GC-IMS) and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used to analyze the changes in volatile components in Fuzhuan tea during fermentation and drying. The results of GC-IMS showed that there were 44 small-molecular volatile components (C3–C10) that differed between the two processing stages. The contents of volatile components increased continuously during the fermentation process. The contents of volatile components did not change significantly during the first four days of fermentation, but changed significantly by the eighth day, and then tended to change slowly later. During the drying process, the contents of volatile components increased gradually. Further, by HS-SPME-GC-MS, a total of 57 of C8–C15 organic compounds were identified, belonging to seven chemical classes, mainly terpenes, alcohols, aldehydes, esters, ketones and ethers. The contents and kinds of volatile components increased with fermentation and drying time. The contents and kinds of terpenes with characteristic wood-like and grassy odor decreased gradually, and the contents and kinds of alcohols, esters ketones and aldehydes with fruity, herbal and mushroom-like aroma as the characteristic odor increased. Finally, the odor of tea samples was characterized as mushroom-like and floral aromas integrating herbal, wood-like, flowery and fruity aroma notes. The results of GC-IMS and HS-SPME-GC-MS showed some differences from each other. Most of the components detected by GC-IMS were small molecules at low levels, while most of the components detected by HS-SPME-GC-MS were large molecules at high levels. The general trend of changes in volatile components determined by HS-SPME-GC-MS was consistent with that determined by GC-IMS, and the change in odor-active volatile components was basically consistent with the sensory evaluation results. To sum up, combined use GC-IMS and HS-SPME-GC-MS can make up for each other’s limitations and more comprehensively reflect changes in volatile components of samples.

Key words: gas chromatography-ion mobility spectroscopy; headspace solid-phase microextraction-gas chromatography-mass spectrometry; aroma components; Fuzhuan tea