Fermented Leaf Tea Catechin Oxidation Process
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Solution Overview
Problem
Existing methods of producing fermented leaf tea often result in unwanted bitter taste and pale appearance due to expressing juice before fermentation, which affects the quality and sensory experience of the final product.
Innovation Solution
A process involving maceration of fresh tea leaves to produce dhool, followed by fermentation to reduce catechin content, expressing juice, and then re-contacting the juice with the leaf residue before drying, ensuring a significant proportion of catechins are oxidized to enhance the dark appearance and reduce bitterness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If juice is expressed before fermentation, then the extraction process is simplified, but the final tea product develops unwanted bitter taste and pale appearance
Solution Approach 1:
The patent applies preliminary action by conducting fermentation before juice expression instead of the conventional sequence. The dhool (macerated leaves) is fermented for a specified time to allow enzymatic oxidation to occur, and only then is the juice expressed. This reversal of the conventional sequence ensures that catechins are oxidized before extraction, preventing the formation of bitter compounds and maintaining dark color in the final product.
2Object-generated harmful factors
If juice is expressed after fermentation, then bitter taste and pale appearance are reduced, but the process complexity increases
Solution Approach 1:
The patent uses preliminary action by implementing a controlled fermentation step with specific time parameters before juice expression. The dhool is fermented for a defined duration to achieve adequate catechin oxidation, then juice is expressed using conventional equipment. This approach adds a controlled time element but uses standard fermentation and expression equipment, maintaining reasonable process complexity while eliminating the harmful taste and appearance defects.
3Manufacturing precision
If fermentation time is extended to oxidize more catechins, then appearance quality improves, but production time increases
Solution Approach 1:
The patent applies partial action by fermenting the dhool for a specific intermediate time period that achieves sufficient catechin oxidation for dark color development, but does not allow complete fermentation. This controlled partial fermentation oxidizes enough catechins to prevent bitterness and ensure dark appearance, then the process moves to juice expression. This optimizes the balance between oxidation extent and time consumption, avoiding both under-fermentation (pale appearance) and over-fermentation (excessive time and potential quality degradation).
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process results in fermented leaf tea products with high appearance scores and balanced flavor, avoiding excessive bitterness and achieving a dark color, thus meeting consumer preferences for unique organoleptic properties.
Implementation Method 1
fermented (in which process enzymes in the tea use atmospheric oxygen to oxidise various substrates to produce brown-coloured products)
Implementation Method 2
fermenting the dhool for a fermentation time sufficient to reduce the content of catechins in the dhool
Data Source
AI summary
Disclosed is a process for manufacturing leaf tea. The process comprising the steps of: providing a supply of fresh tea leaves comprising catechins; macerating the fresh tea leaves to produce dhool; fermenting the dhool for a first fermentation time sufficient to reduce the content of catechins in the dhool to less than 50% of the content of catechins in the fresh tea leaves prior to maceration on a dry weight basis before expressing juice from the dhool thereby to produce leaf residue and tea juice; contacting at least part of the tea juice with at least part of the leaf residue to provide a tea mixture; and then drying the tea mixture to produce the leaf tea.