Fermented Milk Starter Composition for Low Post-Acidification
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Solution Overview
Problem
Current methods for producing fermented milk products, such as yoghurt, suffer from post-acidification during storage, leading to reduced shelf life, quality changes, and loss of health benefits due to heat treatment, while existing solutions either inhibit natural sweetness or require complex process adjustments.
Innovation Solution
A composition comprising a starter culture with a glucose-fermenting Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus strains, combined with a glucose-deficient Streptococcus thermophilus strain carrying a mutation in the glcK gene, which reduces post-acidification and enhances natural sweetness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rapid cooling is used to terminate fermentation, then post-acidification is prevented, but texture quality is lost
Solution Approach 1:
The invention changes the metabolic parameters of the bacterial culture by introducing a glucose-deficient strain, which alters the fermentation dynamics to prevent post-acidification without requiring rapid cooling, thus preserving texture quality
Solution Approach 2:
The invention extracts the harmful post-acidification effect by removing the ability of certain bacteria to utilize glucose, thereby eliminating the cause of further acidification after the desired pH is reached
2Duration of action of stationary object
If heat treatment is applied to extend shelf life, then post-acidification is reduced, but health benefits and product quality are diminished
Solution Approach 1:
The invention performs preliminary action by selecting and using glucose-deficient bacterial strains from the outset, which prevents post-acidification during storage without requiring subsequent heat treatment, thereby maintaining both shelf life and product quality
Solution Approach 2:
The invention converts the potential harm of continued bacterial activity into a benefit by using glucose-deficient strains that naturally stop producing acid after the desired pH is reached, eliminating the need for heat treatment and preserving health benefits
3Reliability
If acidic pH is used to control post-acidification, then lactic acid production is inhibited, but natural sweetness is reduced
Solution Approach 1:
The invention extracts the glucose utilization capability from certain bacterial strains, which prevents further acidification without requiring high acidic pH, thereby preserving the natural sweetness of the fermented milk product
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
Significantly reduces post-acidification, maintains product quality, extends shelf life, and enhances sweetness without heat treatment, benefiting consumers with lactose intolerance.
Implementation Method 1
a milk substrate is fermented by the addition of a starter culture comprising lactic acid bacteria (LAB) capable of metabolizing glucose obtained from lactose present in the milk; during fermentation the LAB metabolizes glucose and produces lactic acid (acidification)
Implementation Method 2
a glucose-deficient Streptococcus thermophilus (St) strain, wherein said St strain is galactose-fermenting and carries a mutation in the DNA sequence of the glcK gene encoding a glucokinase protein, which mutation inactivates the glucokinase protein or has a negative effect on expression of the gene
Data Source
AI summary
The invention relates to a composition for producing a fermented milk product comprising: (i) a starter culture comprising a glucose-fermenting Streptococcus thermophilus (St) strain and a glucose-fermenting Lactobacillus delbrueckii subsp. bulgaricus (Lb) strain; and (ii) a glucose-deficient Streptococcus thermophilus (St) strain, wherein said St strain is galactose-fermenting and carries a mutation in the DNA sequence of the glcK gene encoding a glucokinase protein, which mutation inactivates the glucokinase protein or has a negative effect on expression of the gene.