Streptococcus thermophilus Strains With Biphasic Acidification Kinetics
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Solution Overview
Problem
There is a need for Streptococcus thermophilus strains that can provide both satisfactory rheological and organoleptic properties, as well as a prolonged shelf life for food and feed products, while also being bacteriophage-resistant.
Innovation Solution
The development of Streptococcus thermophilus strains with specific milk acidification kinetics, characterized by an average speed of acidification between pH 6.00 and pH 5.30 of at least 70×10−4 UpH/min and less than 22×10−4 UpH/min between pH 5.30 and pH 5.00, and a unique ratio of these acidification speeds, along with the presence of CRISPR loci for bacteriophage resistance, such as CRISPR4, CRISPR1, and CRISPR3 loci.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Streptococcus thermophilus strains are used to improve rheological and organoleptic properties through rapid acidification, then texture and flavor are enhanced, but the risk of bacteriophage infection increases
Solution Approach 1:
The patent applies preliminary anti-action by selecting S. thermophilus strains that possess inherent bacteriophage resistance mechanisms (such as CRISPR-Cas systems or phage resistance genes) before the actual fermentation process. This pre-selection ensures that the bacteria are already protected against phage infection, allowing them to maintain high acidification speeds without being vulnerable to phage attacks during the productive phase.
Solution Approach 2:
The patent changes the biological parameters of the S. thermophilus strain by selecting variants with specific genetic characteristics that confer both rapid acidification capability and bacteriophage resistance. This involves identifying and using strains with optimized metabolic pathways for lactate production while simultaneously possessing resistance mechanisms, thus changing the strain's inherent properties to satisfy both contradictory requirements.
2Loss of time
If Streptococcus thermophilus strains acidify milk rapidly to improve production efficiency, then fermentation time is reduced, but product shelf life may be compromised
Solution Approach 1:
The patent applies parameter changes by selecting S. thermophilus strains with specific acidification kinetics profiles. These strains are characterized by very rapid initial acidification (high speed between pH 6.5-5.5) to reduce fermentation time, followed by a deliberate slowdown in acidification rate (lower speed between pH 5.5-5.0) to prevent excessive acid production that would compromise shelf life and product quality.
Solution Approach 2:
The patent applies dynamics by utilizing strains whose acidification rate is not constant but dynamically changes during the fermentation process. The selected strains exhibit a biphasic acidification pattern: a fast initial phase that quickly reduces fermentation time, followed by a slower secondary phase that maintains product stability and extends shelf life, thus dynamically adapting the acidification speed to different stages of the process.
3Ease of manufacture
If conventional Streptococcus thermophilus strains are used for fermentation, then standard production processes can be maintained, but rheological and organoleptic properties remain suboptimal
Solution Approach 1:
The patent applies parameter changes by selecting S. thermophilus strains with optimized physiological and kinetic parameters that improve product quality. The selected strains exhibit specific characteristics including controlled acidification rates, enhanced exopolysaccharide production, and improved proteolytic activity, which collectively enhance rheological properties and organoleptic characteristics while maintaining compatibility with existing production processes.
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 produce products with improved texture and flavor, maintaining stability and resistance to bacteriophage infections, ensuring high-quality and long-lasting food and feed products.
Implementation Method 1
putting into contact a substrate, in particular milk substrate, with or in the presence of the S. thermophilus strain or a composition of the invention, optionally fermenting said substrate
Data Source
AI summary
The present invention relates to Streptococcus thermophilus strains, usable as starter cultures, able to provide both satisfactory rheological and organoleptic properties, and satisfactory shelf life to the media into which they are incorporated. In particular, these strains are also bacteriophage-resistant, thereby minimizing bacteriophage infection. The invention also provides a composition comprising one of these Streptococcus thermophilus strains, and feed or food products obtained with these strains.