Aluminum Content in Camellia sinensis (L.) O. Kuntze Cultivars with Delayed Leaf-plucking

Two or three young shoots and a bud from the branches on tea plants of 13 Camellia sinensis (L.) O. Kuntze cultivars were plucked in either the normal manner for oolong tea or during different time periods to study the variation on aluminum (Al) content in the resulting teas for safety evaluation. The results showed that the Al concentrations ranged from 445.17 mg·kg^-1 to 814.51 mg·kg^-1 in the tea leaves picked by the standard method, and they were higher on Rougui, Huangmeigui, and Zimeigui varieties, while lower on Meizhan, Jinmudan, and Foshou. In general, Al in the young shoots increased exponentially with delayed plucking. Therefore, it appeared that by postponing the leaf-plucking time the Al content in the teas could be altered in a certain degree. In other words, the steeped tea would contain less Al with a timely plucking of the leaves. On the other hand, the general daily consumption of oolong tea does not exceed the safety intake limits, and should not post any harm to human health.