Characterization of key aroma compounds and enantiomer distribution in Longjing tea

By comparing the enantiomers of authentic Longjing tea, the authenticity of Longjing tea can be effectively distinguished. In this study, 18 enantiomers were identified using a chiral column. At the same time, the unique enantiomer ratio (ER) of Longjing tea (LG1, LG2, LG3, LG4, LG5) of different grades and origins was determined. The ER can provide a theoretical basis for distinguishing Longjing tea of different grades and origins, and for identifying the authenticity of Longjing tea. The ER ratio of (R)-(-)-1-octen-3-ol and (S)-(+)-1-octen-3-ol can be used to identify LG1 (71:29). The ER ratio of (S)-(+)-α-ionone and (R)-(-)-α-ionone can be used to identify LG2 (65:35). The ER ratio of (R)-(-)-dihydroactinidiolide to (S)-(+)-dihydroactinidiolide (71:29) can also be used to detect LG3. The ER ratio of (R)-(+)-Limonene and (S)-(-)-limonene can be used to identify LG4 (20:80). The ER ratio of (R)-(-)-linalool to (S)-(+)-linalool (12:83) was available to identify LG5.