Influence of Several Process Parameters on Sourdough Fermentation

Wick, M.; Stolz, Peter; Böcker, Georg; Lebeault, J. M.

doi:10.1002/abio.200390008

Cited by 24 publications

(11 citation statements)

References 11 publications

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“…In our study, 18 bakers used the same flour to make a single starter each and then, using the same ingredients, a single loaf of bread each. The yeasts and bacteria in starters can differ due to differences in flour type and condition (19,20) and the additional ingredients made using a starter (21). We sought to minimize the influence of these factors, focusing instead on how differences in baker identity and location may impact otherwise standardized starters.…”

Section: Discussionmentioning

confidence: 99%

Influences of Ingredients and Bakers on the Bacteria and Fungi in Sourdough Starters and Bread

Reese

Madden

Joossens

et al. 2020

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Sourdough starters are naturally occurring microbial communities in which the environment, ingredients, and bakers are potential sources of microorganisms. The relative importance of these pools remains unknown. Here, bakers from two continents used a standardized recipe and ingredients to make starters that were then baked into breads. We characterized the fungi and bacteria associated with the starters, bakers’ hands, and ingredients using 16S and internal transcribed spacer (ITS) rRNA gene amplicon sequencing and then measured dough acidity and bread flavor. Starter communities were much less uniform than expected, and this variation manifested in the flavor of the bread. Starter communities were most similar to those found in flour but shared some species with the bakers’ skin. While humans likely contribute microorganisms to the starters, the reverse also appears to be true. This bidirectional exchange of microorganisms between starters and bakers highlights the importance of microbial diversity on bodies and in our environments as it relates to foods. IMPORTANCE Sourdough starters are complex communities of yeast and bacteria which confer characteristic flavor and texture to sourdough bread. The microbes present in starters can be sourced from ingredients or the baking environment and are typically consistent over time. Herein, we show that even when the recipe and ingredients for starter and bread are identical, different bakers around the globe produce highly diverse starters which then alter bread acidity and flavor. Much of the starter microbial community comes from bread flour, but the diversity is also associated with differences in the microbial community on the hands of bakers. These results indicate that bakers may be a source for yeast and bacteria in their breads and/or that bakers’ jobs are reflected in their skin microbiome.

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Section: Discussionmentioning

confidence: 99%

Influences of Ingredients and Bakers on the Bacteria and Fungi in Sourdough Starters and Bread

Reese

Madden

Joossens

et al. 2020

mSphere

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“…The establishment and stability of microbial consortia in sourdoughs depends on the microbial communities within the raw materials, the chemical composition of the raw materials, and interactions between the microorganisms, together with fermentation parameters such as temperature, inoculum size, dough yield, and fermentation length [12] – [16] . Previous studies on the dynamics of microbial communities in spontaneously started sourdoughs have stated that the establishment of a stable consortium occurs through a three-stage evolution process within a few days during which one may observe the prevalence of sourdough-atypical LAB, sourdough-typical LAB, and highly adapted sourdough-typical LAB [2] , [8] , [10] – [11] .…”

Section: Introductionmentioning

confidence: 99%

Evolution of Bacterial Consortia in Spontaneously Started Rye Sourdoughs during Two Months of Daily Propagation

et al. 2014

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The evolution of bacterial consortia was studied in six semi-solid rye sourdoughs during long-term backslopping at different temperatures. Each rye sourdough was started spontaneously in a laboratory (dough yield 200), propagated at either 20°C or 30°C, and renewed daily at an inoculation rate of 1∶10 for 56 days. The changes in bacterial diversity over time were followed by both DGGE coupled with partial 16S rRNA gene sequencing and pyrosequencing of bar-coded 16S rRNA gene amplicons. Four species from the genus Lactobacillus (brevis, crustorum, plantarum, and paralimentarius) were detected in different combinations in all sourdoughs after 56 propagation cycles. Facultative heterofermentative lactic acid bacteria dominated in sourdoughs fermented at 30°C, while both obligate and facultative heterofermentative LAB were found to dominate in sourdoughs fermented at 20°C. After 56 propagation cycles, Kazachstania unispora (formerly Saccharomyces unisporus) was identified as the only yeast species that dominated in sourdoughs fermented at 20°C, while different combinations of strains from four yeast species (Kazachstania unispora, Saccharomyces cerevisiae, Candida krusei and Candida glabrata) were detected in sourdoughs propagated at 30°C. The evolution of bacterial communities in sourdoughs fermented at the same temperature did not follow the same time course and changes in the composition of dominant and subdominant bacterial communities occurred even after six weeks of backslopping.

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“…For instance, fructose-to-mannitol and arginineto-ornithine conversion favor ATP generation and/or acid stress (16). Also, interactions between sourdough LAB and yeasts have been studied in detail (9, 21).The microbial growth and activity of LAB in sourdough are influenced by endogenous factors (e.g., flour carbohydrates and enzymes); process parameters (e.g., water content and temperature); and interactions between LAB, yeasts, and other bacteria (21,28,44,71). Despite changes in raw material or the bakery environment, the sourdough microbiota is often remarkably stable, even for several years (17, 54).…”

mentioning

confidence: 99%

“…The microbial growth and activity of LAB in sourdough are influenced by endogenous factors (e.g., flour carbohydrates and enzymes); process parameters (e.g., water content and temperature); and interactions between LAB, yeasts, and other bacteria (21,28,44,71). Despite changes in raw material or the bakery environment, the sourdough microbiota is often remarkably stable, even for several years (17,54).…”

mentioning

confidence: 99%

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

Meulen

Scheirlinck

Schoor

et al. 2007

Appl Environ Microbiol

188

149

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Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination of various chromatographic methods including liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The establishment of a stable microbial ecosystem occurred through a three-phase evolution within a week, as revealed by both microbiological and metabolite analyses. Strains of Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rossiae, Lactobacillus brevis, and Lactobacillus paraplantarum were dominating some of the sourdough ecosystems. Although the heterofermentative L. fermentum was dominating one of the wheat sourdoughs, all other sourdoughs were dominated by a combination of obligate and facultative heterofermentative taxa. Strains of homofermentative species were not retrieved in the stable sourdough ecosystems. Concentrations of sugar and amino acid metabolites hardly changed during the last days of fermentation. Besides lactic acid, ethanol, and mannitol, the production of succinic acid, erythritol, and various amino acid metabolites, such as phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid, was shown during fermentation. Physiologically, they contributed to the equilibration of the redox balance. The biphasic approach of the present study allowed us to map some of the interactions taking place during sourdough fermentation and helped us to understand the fine-tuned metabolism of lactic acid bacteria, which allows them to dominate a food ecosystem.Sourdough is a mixture of ground cereals (e.g., wheat or rye) and water that is spontaneously fermented. Sourdough fermentations improve dough properties, enhance both bread texture and bread flavor, and delay bread spoilage (28). Lactic acid bacteria (LAB) and yeasts play a key role in sourdough fermentation processes (9,21,26,28,29,55). Sourdough LAB have been intensively studied with respect to their carbohydrate metabolism (16,24,60), proteolysis and amino acid metabolism (16,23,58,69), lipid metabolism (16), and production of volatile compounds (7,31,32). Besides these general metabolic traits, specific metabolic properties have been recognized in sourdough LAB, such as the use of alternative electron acceptors (59, 61), the production of antifungal compounds (38,45,57), the biosynthesis of exopolysaccharides (36, 63, 64), and arginine catabolism (8, 53). These metabolic traits of sourdough LAB highlight their adaptation to the sourdough environment. For instance, fructose-to-mannitol and arginineto-ornithine conversion favor ATP generation and/or acid stress (16). Also, interactions between sourdough LAB and yeasts have been studied in detail (9, 21).The microbial growth and activity of LAB in so...

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Influence of Several Process Parameters on Sourdough Fermentation

Cited by 24 publications

References 11 publications

Influences of Ingredients and Bakers on the Bacteria and Fungi in Sourdough Starters and Bread

Influences of Ingredients and Bakers on the Bacteria and Fungi in Sourdough Starters and Bread

Evolution of Bacterial Consortia in Spontaneously Started Rye Sourdoughs during Two Months of Daily Propagation

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

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