Pheophorbide a Content and Chlorophyllase Activity in Green Tea

Area of Science:

• Food Chemistry
• Plant Biochemistry
• Agricultural Science

Background:

• Chlorophyll degradation impacts green tea quality and color.
• Pheophorbide a (PB a) is a key chlorophyll degradation product.
• Understanding enzyme activity in processed tea is crucial for quality control.

Purpose of the Study:

• To quantify the total pheophorbide a (PB a) content in processed green tea.
• To determine the extent of chlorophyllase activity remaining in Sencha and Matcha.
• To compare chlorophyllase activity in processed tea versus fresh green leaves.

Main Methods:

• Incubation of green tea samples (Sencha, Matcha) to measure PB a formation.
• Quantification of initially present and newly produced PB a.
• Comparison of PB a production from chlorophyll a (Chl a) incubation with tea samples and fresh leaf extracts.

Main Results:

• Total PB a content significantly increased in both Sencha and Matcha compared to initial levels.
• Chlorophyllase activity was detected in processed green tea, indicating enzyme retention.
• Chlorophyllase activity in Sencha was approximately 1/20th of that in fresh green leaves.

Conclusions:

• Chlorophyllase remains active in green tea even after processing.
• This residual activity contributes to PB a formation, affecting tea quality.
• Quantifying this activity provides insights into tea processing and storage stability.