Improving Ancha tea aroma quality via innovative processing: Characterization of key odorants by GC-MS, GC-O, Sensomics, and Chemometrics

The new "steaming and heaping" processing was proposed to enhance the aroma quality of Ancha tea (ACT) as an alternative to traditional dew wetting. By contrast, no dew wetting ACT (DDW) showed the strongest roasted aroma, while steaming-fermentation 8 ACT (SF8) exhibited the most pronounced woody and fruity aromas and the best aroma quality among all samples. Using gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), Chemometrics, and aroma validation experiments, this study identified five key odorants, namely, (E)-linalool oxide (furanoid), α-ionone, linalool, 2-ethyl-5-methylpyrazine, and 2,5-dimethylpyrazine. These compounds play a crucial role in contributing to the woody, fruity, and roasted aromas of ACT. The new processing facilitated the nonenzymatic conversion of geranyl pyrophosphate, β-primeveroside, and α-carotene by enhancing the moist heat effect, thereby improving the aroma profile of ACT. This study provides a theoretical and technical basis for further improvements in the aroma quality of ACT.