Pu'er tea main pigment substances are theaflavin, thearubigin, and theabrownin. Currently, these three pigments are considered the main water-soluble oxidation products of tea polyphenols.

Theaflavin is the main component responsible for the "brightness" of the tea liquor; thearubigin is the main component responsible for the "redness" of the tea liquor; and theabrownin is the main component responsible for the "brownness" of the tea liquor.

 

       (1) The content of theaflavin in Pu'er tea fluctuates significantly during storage. The general trend is that the theaflavin content increases in dry storage and decreases in wet storage.

 

 

        (2) The changes in thearubigin content in Pu'er tea during storage show that raw Pu'er tea stored in dry conditions exhibits an increasing trend, rising from 7.47% (dry-stored raw Pu'er loose tea) and 7.22% (dry-stored raw Pu'er cake tea) in the early stage to 7.73% and 7.77% after two years. In wet storage, however, whether for raw or pile-fermented ripe Pu'er tea, the thearubigin content decreases significantly. After two years, the reductions reach 35.55% (wet-stored raw Pu'er loose tea), 47.40% (wet-stored raw Pu'er cake tea), 65.96% (wet-stored ripe Pu'er loose tea), and 38.71% (wet-stored ripe Pu'er cake tea).

 

 

       (3) The change in theabrownin content in Pu'er tea during storage shows a consistent pattern. Except for pile-fermented ripe Pu'er tea (including both ripe loose tea and ripe cake tea), which remains basically unchanged in dry storage, all other types increase. This is especially true for raw Pu'er tea stored in wet conditions, where the content rises from 4.86% (raw Pu'er loose tea) and 4.46% (raw Pu'er cake tea) in the early stage to 10.49% (wet-stored raw Pu'er loose tea) and 8.62% (wet-stored raw Pu'er cake tea) after two years—roughly doubling and approaching the general level of pile-fermented Pu'er tea. The combined changes in these pigments gradually darken the color of the tea liquor.