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.
The variations in the contents of catechins and phenolic compounds in relation to the quality scores (QS) and taste scores (TS) in the ‘ Huang Zhi Xiang ’ Oolong tea grown in different seasons and at different altitudes were determined. The study demonstrated that the contents of (−)-epigallocatechin gallate (EGCG), catechin gallate (CG), and total catechins (TC) in the Oolong teas grown at a high altitude were significantly higher than those grown at a low altitude. Furthermore, the contents of EGCG, CG, and TC in the autumn tea were significantly higher than those from the spring tea grown at a low altitude. However, no significant differences in the contents of EGCG, CG, and TC were observed between the spring and autumn teas grown at a high altitude. In addition, the contents of (−)-epigallocatechin (EGC), (+)-catechin (C), (−)-gallocatechin (GC), and simple catechins (SC) in the spring tea leaves were significantly higher than those in the autumn tea leaves grown at a low altitude, but they were not significantly different from those in the autumn tea leaves grown at a high altitude. The contents of EGCG, CG, and TC in the Oolong teas were positively and significantly correlated to the taste score (TS) and quality score (QS) of the Oolong tea. Thus, the contents of EGCG, CG, and TC could be the important quality parameters of the ‘ Huang Zhi Xiang ’ Oolong tea. This work suggested that the production of the ‘ Huang Zhi Xiang ’ Oolong tea grown at low altitudes should utilize the autumn tea leaves while the production of Oolong tea grown at high altitudes can use both the spring and autumn tea leaves.
危险品化学品经营许可证（带存储）