Lactobacillus bulgaricus Mutants for Balanced Dairy Fermentation

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Solution Overview

Problem

Current Lactobacillus delbrueckii subsp. bulgaricus strains either exhibit high post-acidification or high texturing properties, but not both, making it difficult to produce fermented dairy products with a moderate acidity and high texture without adding thickening agents.

Innovation Solution

Development of Lactobacillus delbrueckii subsp. bulgaricus strains, such as CHCC10019, CHCC8535, and CHCC7159, and their mutants, which are treated with a weak mutagen to achieve a balance between low post-acidification and high texturing properties, using a method that differs from previous attempts by employing high texturing strains as mother strains and applying mild mutagenesis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If high post-acidification strains are used, then acidification speed is improved, but texturing power remains low

Engineering Contradiction:
Improveacidification speedVSAvoidtexturing power
Core Design Contradiction:
SpeedVSStrength

Solution Approach 1:

The patent applies parameter changes by selectively modifying the physiological parameters of Lactobacillus delbrueckii subsp. bulgaricus strains through controlled mutagenesis. Specifically, the invention changes the post-acidification rate parameter while preserving texturing power, creating strains that achieve moderate acidification without sacrificing texture development. This resolves the contradiction by independently optimizing the acidification speed parameter rather than relying on naturally occurring high-acidification strains.

Inventive Principle:
Principle #35Parameter changes

2Strength

If low post-acidification strains are used, then texture development is improved, but acidification speed decreases

Engineering Contradiction:
Improvetexturing powerVSAvoidacidification speed
Core Design Contradiction:
StrengthVSSpeed

Solution Approach 1:

The invention modifies the acidification kinetics parameters of Lactobacillus delbrueckii subsp. bulgaricus through directed mutagenesis. By changing specific genetic parameters related to lactic acid production rates, the strain achieves low post-acidification (maintaining texture) while preserving adequate acidification speed for product safety and quality. This parameter optimization resolves the trade-off between texture development and acidification velocity.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If known strains are used to achieve low post-acidification, then acidity development is controlled, but texturing power remains insufficient

Engineering Contradiction:
Improveacidity controlVSAvoidtexturing power
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent changes the functional parameters of existing Lactobacillus delbrueckii subsp. bulgaricus strains through mutagenesis, transforming them from low-texturing strains to high-texturing strains while maintaining low post-acidification characteristics. This parameter transformation allows the same species to simultaneously achieve acidity control and enhanced texturing power, resolving the contradiction between these two product qualities.

Inventive Principle:
Principle #35Parameter changes

4Strength

If thickening agents are added to increase texture, then texturing power is improved, but product complexity increases

Engineering Contradiction:
Improvetexturing powerVSAvoidproduct complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention enables the bacterial strain to self-produce the texturing function that would otherwise require external thickening agents. By modifying the strain's physiological parameters through mutagenesis, the bacteria themselves generate the necessary texture development during fermentation, eliminating the need for additional thickening agents and simplifying the overall product formulation. This self-service approach resolves the contradiction between texturing power and product complexity.

Inventive Principle:
Principle #25Self-service

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

These strains result in dairy products with a pleasant, mild taste and increased texture without significant post-acidification, eliminating the need for thickening agents and improving the texture of fermented products.

Implementation Method 1

Such strains usually produce lactic acid during the shelf life of the dairy products fermented with the bacterial cultures of which the strains are a component

Methodology Applied
Scientific EffectLactic acid production: Fermentation

Implementation Method 2

chemical mutagenesis (with the mutagen MNNG (N-methyl-N-nitroso-N-nitroguanidin)) of a strain of Lactobacillus delbrueckii subsp. bulgaricus

Methodology Applied
Scientific EffectChemical mutagenesis:

Data Source

PatentEP2034847B1Low post-acidifying lactic acid bacteria
Publication Date: 2017.08.09 CHR HANSEN AS
  • EP2034847B1 patent drawingFigure 1~2
  • EP2034847B1 patent drawingFigure 3
  • EP2034847B1 patent drawingFigure 4~5

AI summary

The present invention relates to lactic acid bacteria that have low or reduced post-acidification properties, and to a method for providing such bacteria. Also, the invention relates to the use of such bacteria for manufacturing of fermented dairy products, and to dairy products contain- ing the bacteria.