Effect of physicochemical parameters on enzymatic biodecaffeination during tea fermentation

Area of Science:

• Biotechnology
• Food Science
• Enzymology

Background:

• Traditional tea processing involves fermentation, a stage where caffeine content is a key consideration.
• Existing decaffeination methods can impact tea's sensory qualities and chemical composition.
• Enzymatic approaches offer potential for targeted and efficient bioprocesses.

Purpose of the Study:

• To develop and optimize a biodecaffeination process for tea synchronized with the fermentation stage.
• To utilize enzymes from *Pseudomonas alcaligenes* for efficient caffeine degradation during tea processing.
• To assess the impact of this enzymatic process on tea's flavor, aroma, and polyphenol content.

Main Methods:

• Isolation of enzymes from *Pseudomonas alcaligenes* for cell-free extract preparation.
• Application of the cell-free extract during the tea fermentation (dhool) stage.
• Optimization of reaction conditions including moisture, aeration, enzyme addition, and mixing.
• Inclusion of glycine (5% w/w) to prevent inhibitory interactions.

Main Results:

• Achieved 80% caffeine degradation within 90 minutes of incubation during tea fermentation.
• Optimized process parameters for effective biodecaffeination.
• Prevented inhibitory protein-polyphenol and caffeine-polyphenol interactions using glycine.
• Preserved the original flavor and aroma of the decaffeinated tea.
• Observed an increase in the total polyphenol content of the tea.

Conclusions:

• The developed enzymatic biodecaffeination process is effective and can be synchronized with tea fermentation.
• This method successfully reduces caffeine content without compromising sensory attributes.
• The process enhances the overall quality of tea by increasing polyphenol content.