Sucrose-Negative S. Thermophilus Strains for Low-Sugar Fermentation
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Solution Overview
Problem
Existing fermented milk products face challenges in reducing sugar content while maintaining good organoleptic properties and avoiding post-acidification, as high sugar-producing strains of Streptococcus thermophilus and Lactobacillus bulgaricus strains are used to increase sweetness, leading to delayed fermentation and acidity issues.
Innovation Solution
Development of sucrose-negative (Suc−) and galactose-positive (Gal+) Streptococcus thermophilus strains that metabolize lactose and produce exopolysaccharides, allowing for reduced sugar use and faster fermentation without compromising texture and acidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high sugar producing strains of S. thermophilus are used to increase sweetness, then the sweetness of fermented milk products is improved, but the fermentation process is delayed and acidity increases
Solution Approach 1:
The patent applies parameter changes by selecting and characterizing S. thermophilus strains with specific metabolic parameters - namely sucrose negative (Suc-) and galactose positive (Gal+) phenotypes. This genetic parameter selection allows the bacteria to metabolize galactose instead of sucrose, achieving faster fermentation while maintaining sweetness through alternative sugar metabolism pathways.
2Quantity of substance
If high sugar producing strains are used to increase sweetness, then the sweetness of fermented milk products is improved, but post-acidification occurs due to consumption of other sugars
Solution Approach 1:
The patent extracts the problematic sucrose metabolism capability from the bacterial strain by selecting for sucrose negative (Suc-) variants. This extraction eliminates the harmful post-acidification effect while preserving the desired sweetness through alternative sugar utilization, specifically galactose metabolism as indicated by the galactose positive (Gal+) phenotype.
3Quantity of substance
If sucrose negative strains are selected to reduce sugar content, then the amount of sugar required is reduced, but the ability to metabolize lactose and produce exopolysaccharides must be maintained
Solution Approach 1:
The patent demonstrates multi-functionality by identifying S. thermophilus strains that simultaneously possess multiple metabolic capabilities: sucrose negative (Suc-) to reduce sugar content, galactose positive (Gal+) to provide alternative sugar metabolism, lactose positive (Lac+) to maintain fermentation function, and exopolysaccharide producing (EPS+) to preserve texturizing properties. This universal strain characterization allows a single strain to fulfill multiple functional requirements.
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 Suc− Gal+ strains enable the production of fermented products with lower sugar content, improved texture, and controlled acidity, maintaining desirable organoleptic qualities and reducing the need for additional sugar addition.
Implementation Method 1
Streptococcus thermophilus is a gram-positive lactic acid bacterium that is widely used in the preparation of fermented milk products
Implementation Method 2
the capacity to produce exopolysaccharides (EPS) in order to texturize the fermented product
Data Source
AI summary
The present invention relates to novel sucrose negative (Suc−) Streptococcus thermophilus strains, compositions comprising said strains, uses thereof, methods for obtaining such strains and methods for the preparation of fermented food products using such compositions.