Spatial distribution differences in volatile aroma compounds and the sensory evaluation of white tea

The prolonged withering period collectively shapes the distinctive olfactory profile of tea. However, the contribution of different tissues in tea shoots of different tea cultivars to aroma development during the withering process of tea remains unexplored. This present research investigates the influence of various tissues in tea shoots on the aroma development of tea during the withering processing. The Camellia sinensis cultivars 'Fuding Dabaicha' (FD) and 'Zhonglong 22' (ZL22) were chosen as the material for aroma scores and compound analysis in the present research. The second and third leaves primarily exhibit a grassy fragrance, whereas the tender stems and first leaves display floral aromas. FD tea had higher flowery and fresh fragrance ratings in contrast to the more herbaceous ZL22. Different tissues also showed distinct volatile profiles: Tender stems mainly accumulated terpenoids, the leaves released fatty acid derivatives, and the terminal buds had balanced phenylpropanoid compounds. Key contributors to the grassy odor in ZL22 include 1-heptanol and (E,Z)-3,6-nonadien-1-ol, whereas the floral aroma of FD stems from nonanal, cis-linalool 3,7-oxide, and linalool oxide. In FD, volatile compounds primarily collect in tender stems and the third leaves; in ZL22, the aroma compounds mainly accumulate in tender stems and the second leaves. Our results demonstrate the tissue-specific differences in aroma accumulation among different tea plant cultivars and further indicate the physiological basis for the variability of withering duration across cultivars.