Aroma Characterization of Gardenia Black Tea Based on Sensory Evaluation and Headspace Solid-Phase Microextraction–Gas Chromatography–Mass Spectrometry

Gardenia black tea (GBT) is a prized Chinese scented tea, renowned for its pleasant aroma. However, the influence of repeated scenting rounds on its volatile profile remains poorly characterized. This study investigated the aroma profiles of GBT produced with zero, two, and three scenting rounds (T0, T1, T2) using sensory evaluation and Headspace Solid-Phase Microextraction–Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS). Sensory analysis revealed that GBTs (T1, T2) scored significantly higher in aroma and taste than the black tea base (T0). GC-MS analysis identified numerous volatile compounds, with esters, terpenoids, and ketones being predominant. Multivariate analysis identified 52 key volatiles (VIP > 2.0) that differentiated the tea samples. Among these, 28 compounds had odor activity values (OAVs) > 1, indicating significant sensory contributions. Ultimately, 11 volatiles, including (Z)-hex-3-enyl acetate, linalool, and (E)-hex-2-enal, were identified as the crucial basis for the characteristic fresh and floral scent of GBTs. The specific abundance levels of these compounds are hypothesized to underlie the superior, fresh, and elegant aroma of T1, compared to the slightly ripe and stuffy floral notes of T2. Therefore, it is advisable to prioritize two rounds of scenting during the production of gardenia black tea. These findings provide a theoretical foundation for optimizing the scenting process and enhancing the quality of GBT.