Insight into the volatile profiles of four types of dark teas obtained from the same dark raw tea material

Various dark teas are quite different in their volatile profiles, mainly due to the huge differences in the phytochemical profiles of dark raw tea and the diverse post-fermentation processing technologies. In this study, gas chromatography-mass spectrometry (GC-MS), qualitative GC-olfactometry (GC-O), and enantioselective GC-MS coupled with multivariate analysis were applied to characterise the volatile profiles of various dark teas obtained from the same dark raw tea material. A total of 159 volatile compounds were identified by stir bar sorptive extraction (SBSE) combined with GC-MS, and 49 odour-active compounds were identified. Moreover, microbial fermentation could greatly influence the distribution of volatile enantiomers in tea, and six pairs of enantiomers showed great diversity of enantiomeric ratios among various dark teas. These results suggest that post-fermentation processing technologies significantly affect the volatile profiles of various dark teas and provide a theoretical basis for the processing and quality control of dark tea products.

Automated summary

The volatile profiles of various dark teas derived from the same dark raw tea material were characterized in this study, revealing that post-fermentation processing technologies significantly impact the volatile properties of dark teas. Techniques such as enantioselective gas chromatography-mass spectrometry can provide essential help in analyzing volatile compounds in dark teas.