OT is a type of a partially oxidized tea, produced by a unique
process called blue-making (“Zuoqing” in Chinese, Diagram 1).
Blue-making includes repeatedly tossing the leaves in baskets and
stacking them indoors. The degree of oxidation of OT can be
adjusted by increasing or reducing the cycles of blue-making (Lu &
Shen, 2012; Zhou et al., 2013). Compared to the other teas (Table 2),
OT has two special characteristics in chemical composition. Firstly,
OT possesses the highest content of EGC (26.89 mg/g) and lowest
content of CAF (19.67 mg/g) of all the teas. Secondly, the ratio of
total catechins/total alkaloids in OT is the highest (up to 3.75).
These results indicate that blue-making can reduce levels of alkaloids
and improve the content of EGC.