Biphasic Sourdough Fermentation for Propionic Acid Enrichment
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Solution Overview
Problem
Existing methods for sourdough fermentation struggle to effectively combine lactic acid and propionic acid bacteria due to differences in growth conditions, leading to limited propionic acid formation and potential spoilage, as lactic acid bacteria outcompete propionic acid bacteria, creating an acidic environment that inhibits their growth and allows unwanted microorganisms to thrive.
Innovation Solution
A two-step fermentation process where lactic acid bacteria are killed between fermentation steps, allowing for controlled conditions for propionic acid bacteria to thrive, ensuring optimal growth parameters and pH adjustment for enhanced propionic acid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lactic acid bacteria and propionic acid bacteria are used in a mixed culture, then both acid types are produced, but lactic acid bacteria outcompete propionic acid bacteria due to faster growth rate and acid tolerance, resulting in limited propionic acid formation
Solution Approach 1:
The fermentation process is divided into two separate sequential steps: first lactic acid fermentation, then propionic acid fermentation. This segmentation allows each bacterial type to operate under its optimal conditions without competition, ensuring reliable propionic acid production in the second step after the environment has been prepared by the first step.
Solution Approach 2:
The lactic acid fermentation is performed as a preliminary step to prepare the environment for propionic acid bacteria. The lactic acid bacteria first acidify the dough and produce necessary substrates, creating favorable conditions for the subsequent propionic acid fermentation step.
2Temperature
If neutralizing substance is added after lactic acid fermentation to adjust environment for propionic acid bacteria, then pH is adjusted to suitable range, but foreign germs such as clostridia or yeasts grow rapidly and spoil the dough
Solution Approach 1:
The harmful lactic acid bacteria are removed (killed) between the two fermentation steps through heat treatment or other elimination methods. This extraction of the dominant microorganism prevents them from competing with propionic acid bacteria in the second step while avoiding the need to add neutralizing substances that would allow foreign germs to thrive.
3Quantity of substance
If propionic acid bacteria are added to sourdough starter culture, then propionic acid formation is enabled, but the acid-tolerant lactic acid bacteria create an environment too acidic for propionic acid bacteria growth
Solution Approach 1:
The fermentation process is segmented into two independent sequential steps with different microbial populations. The first step uses lactic acid bacteria to acidify the environment and produce substrates, while the second step introduces propionic acid bacteria under controlled conditions where they can thrive and produce propionic acid without being outcompeted.
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
This process significantly increases propionic acid concentrations in sourdough, resulting in more intense flavor and extended shelf life of baked goods, with propionic acid concentrations of at least 1-8% in sourdough and 4-10% in sourdough concentrate, effectively preserving and enhancing the natural flavor of bread products.
Implementation Method 1
a first fermentation being carried out with lactic acid bacteria
Implementation Method 2
a step that kills the lactic acid bacteria is carried out between the first fermentation with lactic acid bacteria and the second fermentation with propionic acid bacteria. This can be autosterilization, pasteurization, drying, sterilization or heat treatment
Implementation Method 3
the second step being a fermentation by propionic acid bacteria
Data Source
Figure 1
AI summary
The invention concerns a method for enriching flavours and natural acids in sourdough, on the basis of two separate fermentation steps, the first step being fermentation by lactic acid bacteria and the second step being fermentation by propionic acid bacteria.