Identification of 9,10-anthraquinone contamination during black and green tea processing in Indonesia

Black and green tea are popular owing to their unique flavors and health benefits. However, these teas can be contaminated with anthraquinones, which are associated with health risks in humans. Levels of 9,10-anthraquinone were determined at each step of the manufacturing process for green and black tea using gas chromatography-tandem mass spectrometry. For green tea, anthraquinone was present beginning at the withering process and increased in concentration until the first drying step. Additionally, for black tea, the first drying step resulted in a significant increase in anthraquinone content, whereas the concentration decreased during the final drying step. For black tea, anthraquinone was also detected during withering, although the concentration continued to increase throughout the entire procedure, particularly during drying. Therefore, it can be suggested that the presence of anthraquinone in these teas was influenced by the smoke emitted by the wood fires used to drive the processing machinery.