Chen Yulong,Jiang Yueming,Shi John,Xu Xinlan,Yang Shaoyu,Duan Jun
The contents of starch and catechins in the fresh leaf of ‘Huang Zhi Xiang’ Oolong tea trees girdled at the bottom, middle (on the big branches) and top (on the small branches) were determined. The study demonstrated that the starch contents from girdled trees were significantly higher ( p < 0.05) than that from non-girdled ones. Furthermore, the contents of (−)−epicatechin (EC), (−)−epigallocatechin (EGC), total catechins (TC) and simple catechins (SC) from girdled trees were significantly higher ( p < 0.05) than those from non-girdled ones. Especially, the contents of (−)−epigallocatechin gallate (EGCG), (−)−epicatechin gallate (ECG) and catechin gallate (CG) from girdled at the middle were also significantly higher ( p < 0.05) than those from the non-girdled. The starch contents were negatively correlated with the contents of (−)−gallocatechin (GC), EC, SC, TC and EGC, while positively correlated with the contents of EGCG and CG in fresh shoots.
Oolong tea is one of the most popular beverages due to the presence of significant amount of catechins. Experiments were conducted to investigate the effect of girdling treatment on levels of catechins in fresh tea leaf related to quality of the ‘Huang Zhi Xiang’ Oolong tea ( Camellia sinensis ). The variations in the levels of catechins in fresh tea leaf and the quality score (QS) of the ‘Huang Zhi Xiang’ Oolong tea were examined. The study demonstrated that girdling treatment increased significantly the levels of (−)-epicatechin, (−)-epigallocatechin, (−)-epigallocatechin gallate, (−)-epicatechin gallate, total catechins, simple catechin, and catechin gallate present in fresh leaf of tea trees. Furthermore, the girdling treatment improved significantly the quality of the ‘Huang Zhi Xiang’ Oolong tea. Thus, it was suggested that application of girdling treatment could be an effective agronomic practice to increase the quality of ‘Huang Zhi Xiang’ Oolong tea.