Comparative Study of Leaf Morphology, Phenolics and Methylxanthines in Camellia sinensis Teas from the Italian Market

In this study, we compared leaf morphology and the phenolic and methylxanthine contents of different teas (Camellia sinensis (L.) Kuntze). Different tea types in loose leaf form available in the Italian market were investigated. The presence of numerous fine silvery-white hairs on the young leaves and buds, and the small-clavate glands on the leaf margins, light-colored and gelatinous in young leaves while dark and leathery in the old ones easily detached, showed to be diagnostic characters useful to distinguish the young leaf from the old one. White tea types were the richest of caffeine (mean value 4.42 g/100 g dry weight); in the other teas the mean caffeine levels were in the range from 2.56 to 3.38 g/100 g dry weight, and the differences were not statistically significant. Phenolics were comparable in white and green types (around 15 g/100 g dry weight) and significantly higher than oolong and black types (around 2.9 g/100 g dry weight). The principal component analysis allowed description of results with 84.02 % of variance establishing a clear grouping for each tea type. The results show that leaf morphology coupled with chemical data could be useful for tea type characterization.