Characterization of the key aroma compounds in Laoshan green teas by application of odour activity value (OAV), gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and comprehensive two-dimensional gas chromatography mass spectrometry (GC x GC-qMS)

To investigate the key aroma compounds in Laoshan green teas (Huangshan (S1), Changling (S2), and Fangling (S3)), gas chromatography-mass spectrometry-olfactometry (GC-MS-O), a flame photometric detector (FPD), odor activity value (OAV), and comprehensive two-dimensional gas chromatography mass spectrometry (GC x GC-qMS) were employed. A total of 50 aroma compounds were perceived and 24 compounds were identified as important compounds related to OAV, such as dimethyl sulfide (OAV: 126-146), skatole (OAV: 27-50), furaneol (OAV: 8-27), (Z)-jasmone (OAV: 16-23), 2-methylbutanal (OAV: 15-22), and 3-methylbutanal (OAV: 68-87). Furthermore, the S-curve method was used to research the effect of aroma compounds on the threshold of aroma recombination (AR). The AR thresholds decreased from 3.8 mL to 0.45, 0.66, 0.93, 0.95, 0.75, 1.09, 3.01, and 2.57 mL after addition of eight compounds (skatole, furaneol, (Z)-jasmone, alpha-damascenone, sclareololide, dihydroactinidiolide, vanillin, and delta-valerolactone), indicating that those compounds (OAV > 1) were contributors to the overall aroma of Laoshan teas.

Automated summary

Through the use of GC-MS-O, FPD, OAV, and GC × GC-qMS techniques, the key aroma compounds in Laoshan green teas were investigated. A total of 24 important compounds related to OAV were identified, with certain compounds found to contribute significantly to the overall aroma of the teas. The impact of aroma compounds on the threshold of aroma recombination was also studied using the S-curve method, revealing that eight specific compounds played a crucial role in enhancing the aroma profile of Laoshan teas.