Effects of manufacturing procedures and preparation conditions on European Union priority polycyclic aromatic hydrocarbons in Oolong tea samples.

The study evaluated the changes in polycyclic aromatic hydrocarbons (PAHs) of Oolong tea samples at each heat treatment stage of the manufacturing process, different post-treatment methods and different brewing conditions. The content of PAHs in the tea leaves was significantly increased during stir fixation (280 °C for 8 min) stage of the manufacturing process. In the subsequent heat treatment process, the PAHs content did not change much until the Oolong tea product (primary) was further roasted.