Analysis of Key Aroma Components and Formation Mechanism of Chuanhong Congou Black Tea Based on HS-SPME-GC-MS

The key aroma components of Chuanhong congou black tea made from the fresh leaves of tea tree 'Tianfu 5' and their formation mechanism during processing were analyaed by sensoromics, head space-solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and electronic nose (E-nose). Then principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and their replacement test were conducted. Finally, the key aroma components were screened by the odor activity value (OAV). As the results, the aroma components of Chuanhong congou black tea were different in different processing stages. Specifically, the aroma intensity of tea samples gradually increased with the process. The tea samples had a strong fruity and sweet aroma after drying. A total of 52 volatile compounds were identified. Alcohols, esters, and aldehydes were the main aromatic substances of Chuanhong congou black tea. In addition, the OAV analysis led to the identification of 16 aroma components (OAV≥1) as key differential volatile compounds. In particular, geranyl, linalool, and β-ionone were the key aroma components (OAV≥100). The contents of linalool and geranyl were increased during rolling. The β-ionone was detected in fermentation sample. The concentration of geranyl content increased and linalool content decreased in fermentation stage. In conclusion, this study revealed the aroma components of Chuanhong congou black tea and their formation mechanism during the processing, which could provide a scientific basis for quality control and improvement of Chuanhong congou black tea.