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Updated: Jul 11, 2026
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LERLIC-MS/MS for In-depth Characterization and Quantification of Glutamine and Asparagine Deamidation in Shotgun Proteomics
Published on: April 9, 2017
Glutamine deamidation by cereal-associated lactic acid bacteria.
N Vermeulen1, M G Gänzle, R F Vogel
1Technische Universität München, Technische Mikrobiologie, Weihenstephaner Steig, Freising, Germany.
Journal of Applied Microbiology
|September 28, 2007
Summary
Lactic acid bacteria like Lactobacillus sanfranciscensis convert glutamine to glutamate, enhancing their acid tolerance and significantly impacting wheat bread flavor. This highlights the complex role of sourdough in baking.
Area of Science:
- Food Microbiology
- Biochemistry
- Baking Science
Background:
- Lactic acid bacteria (LAB) are crucial in cereal fermentations.
- Glutamine deamidation is a metabolic process with potential implications in food production.
Purpose of the Study:
- To investigate glutamine deamidation by LAB from cereal fermentations.
- To determine the ecological and technological relevance of glutamine to glutamate conversion in baking.
Main Methods:
- Isolation and characterization of LAB from cereal fermentations.
- Assessing glutaminase activity in bacterial strains.
- Supplementing growth media and dough with glutamine/glutamate.
- Analyzing effects on bacterial growth, acid production, and bread flavor.
Main Results:
- Lactobacillus sanfranciscensis and Lactobacillus reuteri exhibited glutaminase activity.
- Glutamine supplementation increased cell yields and acid production in L. sanfranciscensis.
- Glutamate addition significantly altered bread flavor.
- Sourdough fermentation resulted in strain-dependent glutamate production (27-120 mmol/kg).
Conclusions:
- The conversion of glutamine to glutamate by L. sanfranciscensis and L. reuteri enhances LAB acid tolerance.
- This metabolic conversion plays a significant role in developing the characteristic flavor of wheat bread.
- Sourdough LAB interact with flour components, influencing their growth and contributing to unique fermented bread flavors compared to chemically acidified bread.
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