Black Koji Fermented Tea Leaves Reducing Citric Acid
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Solution Overview
Problem
Black koji mold-based malted rice produces excessive citric acid, resulting in a strong acid taste that affects food products when used as a seasoning, while maintaining enzyme activity is desirable for digestion and umami extraction.
Innovation Solution
Inoculating black koji mold into tea leaves to cultivate a koji fermented composition that reduces citric acid production by half, enhances acid protease and xylanase activity, and maintains enzyme functionality, especially in acidic environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If black koji mold is used to produce malted rice for seasoning, then enzyme activity (protease and xylanase) is enhanced for digestion and umami extraction, but excessive citric acid is produced resulting in a strong acid taste that affects food products
Solution Approach 1:
The patent changes the substrate parameter from rice to tea leaves, which fundamentally alters the metabolic pathway of black koji mold. Tea leaves contain different carbohydrate compositions and lower citrate synthase activity compared to rice, resulting in reduced citric acid production while maintaining enzyme synthesis. This parameter change in the substrate resolves the contradiction between maintaining enzyme activity and reducing acid taste.
2Quantity of substance
If black koji mold proliferates in rice to produce malted rice, then protease activity is enhanced for protein degradation and digestion promotion, but citric acid accumulation occurs causing strong acid taste in food applications
Solution Approach 1:
The patent extracts the black koji mold from its traditional rice substrate and relocates it to tea leaves. This separation removes the source of excessive citric acid production (rice-based metabolism) while preserving the mold's enzyme production capability. The tea leaf substrate does not support the same level of citric acid accumulation, thus extracting the harmful aspect while retaining the beneficial enzyme activity.
3Reliability
If black koji mold is used for fermentation, then xylanase activity increases for plant cell wall degradation and softening, but the resulting acid taste from citric acid limits its use as a seasoning
Solution Approach 1:
By changing the substrate parameter from rice to tea leaves, the patent alters the metabolic environment of black koji mold. Tea leaves provide alternative carbon sources that redirect metabolic flux away from citric acid production while still supporting xylanase synthesis. This parameter change enables the mold to maintain high xylanase activity for plant material softening without generating the excessive acid taste that would limit seasoning applications.
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
The resulting koji fermented composition provides a low-acid taste with enhanced enzyme activities, promoting digestion and adding umami flavor to food products while acting as a safe antioxidant.
Implementation Method 1
inoculating black koji mold into tea leaves, and culturing the tea leaves
Data Source
AI summary
Provided are: a koji fermented composition that, when using black koji fungus, has a reduced amount of generated citric acid without a loss in xylanase activity or acid protease activity of the black koji fungus; and a method for producing the koji fermented composition. The koji fermented composition is obtained by contacting tea leaves to black koji fungus, and culturing the result.