Sourdough Fermentation Research Articles

Screening and Application of Novel Homofermentative Lactic Acid Bacteria Results in Low-FODMAP Whole-Wheat Bread

FODMAPs are fermentable oligo-, di-, monosaccharides, and polyols. The application of homofermentative lactic acid bacteria (LAB) has been investigated as a promising approach for producing low-FODMAP whole-wheat bread. The low-FODMAP diet is recommended to treat irritable bowel syndrome (IBS). Wheat flour is staple to many diets and is a significant source of fructans, which are considered FODMAPs. The reduction of fructans via sourdough fermentation, generally associated with heterofermentative lactic acid bacteria (LAB), often leads to the accumulation of other FODMAPs. A collection of 244 wild-type LAB strains was isolated from different environments and their specific FODMAP utilisation profiles established. Three homofermentative strains were selected for production of whole-wheat sourdough bread. These were Lactiplantibacillus plantarum FST1.7 (FST1.7), Lacticaseibacillus paracasei R3 (R3), and Pediococcus pentosaceus RYE106 (RYE106). Carbohydrate levels in flour, sourdoughs (before and after 48 h fermentation), and resulting breads were analysed via HPAEC-PAD and compared with whole-wheat bread leavened with baker’s yeast. While strain R3 was the most efficient in FODMAP reduction, breads produced with all three test strains had FODMAP content below cut-off levels that would trigger IBS symptoms. Results of this study highlighted the potential of homofermentative LAB in producing low-FODMAP whole-wheat bread.

Sourdough Fermentation Improves the Antioxidant, Antihypertensive, and Anti-Inflammatory Properties of Triticum dicoccum.

The fermentation process has been widely used to improve plant-based foods' nutritional and nutraceutical properties. This study aimed to investigate and compare the impact of sourdough fermentation on the bioactive content and profile, antioxidant and antihypertensive activities, as well as the anti-inflammatory properties of fermented (FS) and non-fermented (NFS) flour from Tuscan Triticum dicoccum wheat (spelt) on tumor necrosis factor-alpha (TNF-α)-inflamed human intestinal epithelial cells (HT-29). FS showed significantly higher total phenolic and flavonoid content, in vitro and ex vivo antioxidant activities, and ACE-inhibitory activities than NFS. Gallic acid was identified by HPLC-DAD as the most representative polyphenol, followed by rutin, trans-ferulic acid, iso-quercitrin, and quercetin, in the fermented spelt sample. Instead, rutin and gallic acid were identified as the predominant compounds in the non-fermented ones. Moreover, FS exhibited a better protective effect on inflamed HT-29 cells by significantly counteracting the TNFα-induced alterations, lowering the expression of IL-8, COX-2, and ICAM-1 inflammatory mediator while enhancing antioxidant enzyme HO-1 gene expression. In conclusion, sourdough fermentation positively affected the nutraceutical and functional properties of spelt, which may represent a valuable ingredient for the formulation of functional foods and a key product for managing hypertension and inflammatory intestinal diseases.

Sourdough Fermentation or Addition of Organic Acids or Corresponding Salts to Bread Improves Nutritional Properties of Starch in Healthy Humans

Postprandial blood glucose and insulin responses to barley bread containing organic acids or corresponding salts were evaluated in healthy human subjects. The satiety score and the rate and extent of in vitro starch digestion were also studied. Lactic acid was generated by use of a homofermentative starter culture or added to the dough. In addition, products were baked with Ca-lactate, or with Na-propionate at two different concentrations. Consumption of the product baked with a high concentration of Na-propionate significantly lowered the postprandial blood glucose and insulin responses, and significantly prolonged the duration of satiety compared with all other breads. When subjects consumed the breads baked with sourdough, lactic acid and Na-propionate, their glucose and insulin responses were reduced compared with the wholemeal bread alone. The rate of in vitro amylolysis was reduced only by ingestion of the breads containing lactic acid, suggesting that the beneficial impact of Na-propionate on metabolic responses and satiety was related to effects other than a reduced rate of starch hydrolysis. All bread products had a similar concentration of in vitro resistant starch of 1.3–2.1 g/100 g (starch basis). It is concluded that sourdough baking and other fermentation processes may improve the nutritional features of starch. The results also demonstrate that certain salts of organic acids may have metabolic effects.

Hierarchical Effects of Lactic Fermentation and Grain Germination on the Microbial and Metabolomic Profile of Rye Doughs.

A multi-omics approach was adopted to investigate the impact of lactic acid fermentation and seed germination on the composition and physicochemical properties of rye doughs. Doughs were prepared with either native or germinated rye flour and fermented with Saccharomyces cerevisiae, combined or not with a sourdough starter including Limosilactobacillus fermentum, Weissella confusa and Weissella cibaria. LAB fermentation significantly increased total titrable acidity and dough rise regardless of the flour used. Targeted metagenomics revealed a strong impact of germination on the bacterial community profile of sprouted rye flour. Doughs made with germinated rye displayed higher levels of Latilactobacillus curvatus, while native rye doughs were associated with higher proportions of Lactoplantibacillus plantarum. The oligosaccharide profile of rye doughs indicated a lower carbohydrate content in native doughs as compared to the sprouted counterparts. Mixed fermentation promoted a consistent decrease in both monosaccharides and low-polymerization degree (PD)-oligosaccharides, but not in high-PD carbohydrates. Untargeted metabolomic analysis showed that native and germinated rye doughs differed in the relative abundance of phenolic compounds, terpenoids, and phospholipids. Sourdough fermentation promoted the accumulation of terpenoids, phenolic compounds and proteinogenic and non-proteinogenic amino acids. Present findings offer an integrated perspective on rye dough as a multi-constituent system and on cereal-sourced bioactive compounds potentially affecting the functional properties of derived food products.

Impacts of Sourdough Technology on the Availability of Celiac Peptides from Wheat α- and γ-Gliadins: In Silico Approach

Celiac peptide-generating α- and γ-gliadins consist of a disordered N-terminal domain extended by an α-helical-folded C-terminal domain. Celiac peptides, primarily located along the disordered part of α- and γ-gliadin molecules, are nicely exposed and directly accessible to proteolytic enzymes occurring in the gastric (pepsin) and intestinal (trypsin, chymotrypsin) fluids. More than half of the potential celiac peptides identified so far in gliadins exhibit cleavage sites for pepsin. However, celiac peptides proteolytically truncated by one or two amino acid residues could apparently retain some activity toward HLA-DQ2 and HLA-DQ8 receptors in docking experiments. Together with the uncleaved peptides, these still active partially degraded CD peptides account for the incapacity of the digestion process to inactivate CD peptides from gluten proteins. In contrast, sourdough fermentation processes involve other proteolytic enzymes susceptible to the deep degradation of celiac peptides. In particular, sourdough supplemented by fungal prolyl endoproteases enhances the degrading capacities of the sourdough fermentation process toward celiac peptides. Nevertheless, since tiny amounts of celiac peptides sufficient to trigger deleterious effects on CD people can persist in sourdough-treated bread and food products, it is advisable to avoid consumption of sourdough-treated food products for people suffering from celiac disease. As an alternative, applying the supplemented sourdough process to genetically modified low gluten or celiac-safe wheat lines should result in food products that are safer for susceptible and CD people.

The Effect of Co-Fermentation with Lactobacillus plantarum HLJ29L2 and Yeast on Wheat Protein Characteristics in Sourdough and Crackers.

Sourdough fermentation has been widely used in food products. However, there has been limited study of the effect of co-fermentation with lactic acid bacteria and yeast on the dough and cracker products. In this study, the influence of co-fermentation with Lactobacillus plantarum HLJ29L2 (LP HLJ29L2) and yeast on wheat protein digestibility of cracker was studied, and the mechanism of the protein changes in sourdough during fermentation was further explored. Co-fermentation with LP HLJ29L2 and yeast (DN-1) strongly improved the protein digestibility of cracker. At the same time, the content of free amino acids in DN-1 crackers increased by 20%. Co-fermentation also had significant effect on the sourdough during fermentation. The SDS-soluble protein content in sourdough was increased, and large molecule proteins were significantly reduced in the DN-1 sourdough. This was due to the fact, that LP HLJ29L2 grew rapidly during co-fermentation and produced more organic acids, which led to an increase in protease activity in sourdough and promoted the degradation of protein by proteases. The results of this study provide an important theoretical basis for the application of lactic acid bacteria and yeast co-fermentation in crackers.

Probiotics in the Sourdough Bread Fermentation: Current Status

Sourdough fermentation is an ancient technique to ferment cereal flour that improves bread quality, bringing nutritional and health benefits. The fermented dough has a complex microbiome composed mainly of lactic acid bacteria and yeasts. During fermentation, the production of metabolites and chemical reactions occur, giving the product unique characteristics and a high sensory quality. Mastery of fermentation allows adjustment of gluten levels, delaying starch digestibility, and increasing the bio-accessibility of vitamins and minerals. This review focuses on the main steps of sourdough fermentation, the microorganisms involved, and advances in bread production with functional properties. The impact of probiotics on human health, the metabolites produced, and the main microbial enzymes used in the bakery industry are also discussed.

Exploiting the Native Microorganisms from Different Food Matrices to Formulate Starter Cultures for Sourdough Bread Production.

The use of sourdough for bread production involves fermentation, which is dominated by lactic acid bacteria (LAB) and yeast. Sourdough can be inoculated with a starter culture or through a food matrix containing microorganisms to initiate sourdough fermentation. Sourdough is used as leavening agent for bread making, and metabolites produced by LAB and yeast confer a specific aroma and flavor profile to bread, thus improving its sensory attributes. However, few publications report the effect of microorganisms from different food products and by-products on sourdough fermentation. This review focuses on using different starter cultures from various food sources, from wheat flour to starter cultures. Additionally, included are the types of sourdough, the sourdough fermentation process, and the biochemical transformations that take place during the sourdough fermentation process.

Ancient Wheat Varieties and Sourdough Fermentation as a Tool to Increase Bioaccessibility of Phenolics and Antioxidant Capacity of Bread.

This study aimed to determine the impact of ancient wheat varieties (emmer, spelt and khorasan) and spontaneous sourdough fermentation on the bioaccessibility of total phenolic content (TPC) and the DPPH antioxidant capacity evolution during breadmaking and in vitro digestion. Sourdough and yeast-fermented modern wheat breads were used as controls. After 6 h of fermentation, the total titrable acidity of the sourdough increased from 139 to 167%. The wheat variety, type of fermentation and processing affected TPC, antioxidant activity and bioaccessibility. Antioxidant activity and TPC were reduced by dough mixing, increased after sourdough fermentation and slightly decreased or remained the same after baking. Although wheat flour had the highest TPC, the modeling of TPC kinetic revealed that emmer and spelt sourdough exhibited a higher bound phenolics release rate due to the higher acidity, which contributed to increased phenolics solubility. Although wheat bread, both before and after digestion, had the lowest TPC, especially the one prepared with yeast, high TPC bioaccessibilities and antioxidant activities after the digestion suggested that, except phenolics, digestion process improved the release of additional compounds with different bioaccessibility and biological activity. The results of this study proved that the application of sourdough fermentation can increase the potential of ancient wheats in the developing of functional bakery products.

Modeling of Growth and Organic Acid Kinetics and Evolution of the Protein Profile and Amino Acid Content during Lactiplantibacillus plantarum ITM21B Fermentation in Liquid Sourdough.

The application of mathematical modeling to study and characterize lactic acid bacterial strains with pro-technological and functional features has gained attention in recent years to solve the problems relevant to the variabilities of the fermentation processes of sourdough. Since the key factors contributing to the sourdough quality are relevant to the starter strain growth and its metabolic activity, in this study, the cardinal growth parameters for pH, temperature (T), water activity (aw), and undissociated lactic acid of the sourdough strain Lactiplantibacillus plantarum ITM21B, were determined. The strain growth, pH, organic acids (lactic, acetic, phenyllactic, and hydroxy-phenyllactic), total free amino acids, and proteins were monitored during fermentation of a liquid sourdough based on wheat flour and gluten (Bio21B) after changing the starting T, pH, and inoculum load. Results demonstrated that the different fermentation conditions affected the strain growth and metabolite pattern. The organic acid production and growth performance were modeled in Bio21B, and the resulting predictive model allowed us to simulate in silico the strain performances in liquid sourdough under different scenarios. This mathematical predictive approach can be useful to optimize the fermentation conditions needed to obtain the suitable nutritional and technological characteristics of the L. plantarum ITM21B liquid sourdough.

Techno-Functional Performance of Emmer, Spelt and Khorasan in Spontaneously Fermented Sourdough Bread.

The aim of this study was to test the suitability of three different ancient wheat varieties (emmer, spelt and khorasan) to produce spontaneously fermented sourdough bread and to evaluate the impact on the dough rheological properties, ultrastructure and baking quality. Modern wheat sourdough bread and bakery yeast fermented bread were used as controls. Sourdoughs produced from modern and ancient wheats exerted different effects on dough viscoelastic properties, bread specific volume, texture, firming rate, colour and sensory properties, while there was no influence on bread water activity. Both khorasan sourdough, being characterised with the highest dough strength and dense gluten protein matrix, and emmer sourdough, with loose and thin gluten strands of low strength, yielded breads characterised by low specific volume and hard crumb texture. Spelt and modern wheat sourdough were characterised by foam-like dough structures with entrapped gas cells leading to breads of similar specific volume and texture. Although the yeast-fermented wheat flour exerted a higher specific volume and the lowest firmness, the sourdough wheat flour bread had a lower firming rate. A comparison of sourdough bread prepared with modern and ancient wheats revealed that breads based on ancient varieties possess a less noticeable sour taste, odour and flavour, thus contributing to more sensory-appealing sourdough bread.

Synergistic fermentation of Lactobacillus plantarum and Saccharomyces cerevisiae to improve the quality of wheat bran dietary fiber-steamed bread.

This investigation used the sourdough fermentation technique to ferment dough at different WBDF addition levels (0%, 3%, 6%, 9% & 12%) and to evaluate the quality of the finished steamed breads. The results show that WBDF addition promotes the hydrolytic behaviour of both GMP and SDS soluble proteins; especially for high molecular weight protein subunits (Mw=120-80kDa). MRI images clearly showed the water migration and escape behaviour in the fermented dough at different WBDF levels. Further, it was found that the specific volume of steamed breads increased from 3.75mL/g to 6.97mL/g (p<0.05); the DPPH· scavenging capacity of steamed breads increased from 4.46% to 9.68% (p<0.05). Finally, the GC-MS results demonstrated that the addition of WBDF significantly increased the 2-pentylfuran content in the steamed breads from 0.9 to 182.9 (p<0.05, in terms of relative peak area).

EFFECT OF STRUCTURE-FORMING AGENTS AND SPONTANEOUSLY FERMENTED BUCKWHEAT SOURDOUGH ON THE QUALITY OF GLUTEN-FREE BREAD

Gluten-free bread is a product with reduced nutritional value, since the amount of starch in its recipes ranges 50–90% of the mass of loose raw materials. A topical task is to improve the nutritional value of gluten-free products by including flour of cereal crops in the recipe as part of a growth medium of baking sourdoughs. Among the entire assortment of structure-forming additives, hydroxypropyl methylcellulose (HPMC) and xanthan gum still remain understudied as to their optimal dosage and effect on the technological process, whether separately or as a composition. Neither is there enough information on using cereal flours, structure-forming agents, and their combinations to manufacture bread with the minimum starch content. Baking tests in the laboratory have shown that in the technology of gluten-free bread with a high cereal flour content, it is advisable to use a combination of the structuring agents HPMC and xanthan gum in the amounts, respectively, 0.75% and 0.25% of the weight of the flour/starch mixture. This technological approach will allow achieving a high volume of bread, a smooth surface, and a well-developed, uniform, and thin-walled porosity of the crumb. Schemes of the dilution and production cycles of spontaneously fermented sourdough made from green buckwheat flour have been developed, and the specific features of preparation and the process parameters have been indicated. The sensory, biotechnological, and physicochemical characteristics of the quality of the finished sourdough have been investigated. Following the technological regulations developed, a high-quality semi-finished product was obtained, which could be further used in the production process. Laboratory tests in baking bread with the addition of the newly created spontaneously fermented buckwheat sourdough have shown results proving that it can be effectively used in the technology of gluten-free products. It has been established that the optimal percentage of sourdough in the recipe of buckwheat-rice gluten-free bread is 10–20% by weight of the flour/starch mixture. It has been proved that the sourdough can intensify acid accumulation processes in the dough and accelerate its maturation. The finished products had a pronounced taste and aroma as a result of the activity of lactic acid bacteria.

Production of high-value added exopolysaccharide by biotherapeutic potential Lactobacillus reuteri strain

Exopolysaccharides (EPS) are produced by various microbial groups including bacteria. EPS produced from Lactobacilli is gaining popularity as a new generation functional food to replace various chemically synthesized food additives. EPS production by strains of L. reuteri were reported previously in sourdough fermentation. The submerged cultivation of L. reuteri strain DSM 20016 T was optimised for crude EPS production. Initially, the factors controlling crude EPS generation were explored using one-at-a-time (OFAT). Among the investigated carbon sources, sucrose supplemented medium increased maximal crude EPS generation. Yeast extract was determined to be the greatest nitrogen source for increasing crude EPS and cell mass. Plackett-Burman experimental design (PBD) was employed to screen the important parameters impacting crude EPS production in the growing medium. Three important factors were identified: sucrose, yeast extract and sodium acetate. The RSM quadratic model for crude EPS generation was significant (R2:0.9373) and correlated with the observed response at roughly 94%. About 3.4 g L−1 crude EPS was produced under optimal fermentation conditions of sucrose (106.0 g L−1), yeast extract (30.0 g L−1) and sodium acetate (7.0 g L−1). This study shows the crude EPS synthesis of L. reuteri from sourdough can be used in submerged fermentation and biotechnological applications.

Biofunctional soy-based sourdough for improved rheological properties during storage

Frozen dough storage, along with its thawing process, negatively affects the quality of the final product. Thus, fermentation with selected cultures and the enrichment of wheat-based dough using a specific soy powder could optimize the viscoelastic quality of frozen dough and increase its nutritional characteristics. Based on these aspects, the present study’s objective was to examine the effects of soy powder addition to wheat flour with single cultures of Fructilactobacillus florum DSM 22689 or Saccharomyces cerevisiae and coculture with these two microorganisms for 72 h of fermentation. Additionally, the fermentation process was monitored, and viscoelastic behavior and physical–chemical analyses of the fermented sourdough before and after frozen storage were assessed, as soy protein has been proposed to hinder water migration throughout frozen storage. As observed, soy powder, an essential functional ingredient, had a favorable impact on the water-starch-gluten system, and enhanced the viscoelastic behavior before and after 4 weeks of frozen storage.

Impact of sourdough fermentation on FODMAPs and amylase-trypsin inhibitor levels in wheat dough

FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols) and ATIs (Amylase-Trypsin inhibitors) have been reported to trigger intestinal symptoms in irritable bowel syndrome (IBS) patients and individuals with non-celiac wheat sensitivity (NCWS). The objective of this work was to investigate the FODMAP and ATI contents of 22 different wheat varieties grown in two locations in Minnesota, USA, and further study the effect of type I sourdough fermentation (4- and 12-h fermentation times) on the FODMAP and ATI levels in these varieties. FODMAPs and ATIs were quantified using High-performance anion-exchange chromatography (HPAEC) and High-performance liquid chromatography (HPLC), respectively. FODMAPs and ATIs were significantly influenced by variety as well as growing location. Longer sourdough fermentation time (12 h) caused up to 69%, 69%, and 41% reductions in fructans, raffinose, and ATIs, respectively, in the resulting sourdoughs. However, a substantial increase in mannitol (550%) was observed after sourdough fermentation. These results suggest that mannitol should be monitored in addition to other FODMAPs during type I sourdough fermentation, and strategies to reduce their levels during type I sourdough fermentation and in final products should be considered.

Understanding the influence of in situ produced dextran on wheat dough baking performance: Maturograph, biaxial extension, and dynamic mechanical thermal analysis

Rheological tests performed under conditions relevant to those experienced during proof and oven rise are necessary for understanding the mechanisms of dextran addition on wheat dough baking performance. This study evaluated the effect of a high molecular weight ( Mw ) dextran, produced in situ by Weissella confusa A16 or externally added, on wheat dough rheological properties including, (i) proofing behavior using a maturograph; (ii) bi-axial extensional profile using a dough inflation system; and (iii) viscoelastic characters (proof) and thermo-mechanical properties (simulated baking) by dynamic mechanical thermal analysis (DMA). The externally-added dextran increased dough elasticity, tenacity, and viscoelastic characters, but reduced dough extensibility at bubble rupture. DMA tests of doughs under dynamic heating conditions showed a sharp increase of elastic and loss moduli until maximum between 75 and 95 °C, accompanied by a drastic decrease of Tan δ (dough stiffening). Dextran addition exhibited a weakening effect on the dough thermal properties i.e., decreased peak moduli during heating. On the other hand, the mild acidic conditions during sourdough fermentation favored the activity of in situ produced dextran, conferring significantly improved thermal-mechanical properties and dough extensibility. This may explain the superior ability of in situ produced dextran to improve bread volume and crumb softness compared to the external-added dextran. By analyzing rheological parameters, we showed that the maximum proofing moduli in DMA, fermentation stability, dough level, and elasticity in maturogram were predictors of good baking quality. Overall, our study provides the mechanistic underpinning and optimum of dextran as a natural improver of bread quality. • Rheological properties of doughs are strongly associated with baking performance. • Dextran increases dough elasticity and tenacity but reduces dough extensibility. • Dextran added externally exhibits a thermal weakening effect on wheat dough. • Dextran produced in situ is preferred in improving dough rheology and bread quality. • Favorable effects of in situ -produced dextran are mediated by mild acidification.

Carob Flour Addition to Sourdough: Effect of Sourdough Fermentation, Dough Rheology and Bread Quality

Carob flour (CF) has been widely used in bakery formulations since containing various bioactive compounds, high percentage of fibre, protein, vitamins and minerals. Sourdough fermentation is considered as a promising tool to improve sensorial, textural and nutritional features of baked goods. The aim of this study is to investigate the potential usage of Type I sourdough incorporated with carob flour in bread making .Empirical rheological measurements were also performed in the flour blended with carob flour (0%, 2%, 4%, 6%, 8%, and 12%). Water absorption capacity and dough development time increased significantly with the increase of carob flour (P ≤ 0.05). Energy and extensibility value of the samples decreased according to control sample (P ≤ 0.05). Yeast number of sourdough decreased with the increase of carob flour addition to sourdough (P ≤ 0.05). The stimulation of Lactic acid bacteria growth were determined by the addition of carob flour when compared to the control (P&amp;gt;0.05) but no significant differences were observed among sourdoughs with the increasing level of carob flour. Usage of carob flour via sourdough fermentation increased the quality properties of bread with sourdough as compared to the commercial baker’s yeast bread including same level of carob flour. Highest concentration of the CF (8% and 12%) in formulation caused the raise of hardness (P ≤ 0.05), which in turn was associated with the decrease in the specific volume of the bread. CF addition of yeasted bread samples (CFYB) decreased the lightness (L*) of the bread crust (P ≤ 0.05). Sourdough fermentation was also improved the sensory acceptance of carob flour incorporated breads. Low level of carob flour usage (from 2% to 6%) in sourdough making was not detrimental to any of the sensory parameters in this study.

Role of lactic acid bacteria and yeasts in sourdough fermentation during breadmaking: Evaluation of postbiotic-like components and health benefits.

Sourdough (SD) fermentation is a traditional biotechnological process used to improve the properties of baked goods. Nowadays, SD fermentation is studied for its potential health effects due to the presence of postbiotic-like components, which refer to a group of inanimate microorganisms and/or their components that confer health benefits on the host. Some postbiotic-like components reported in SD are non-viable microorganisms, short-chain fatty acids, bacteriocins, biosurfactants, secreted proteins/peptides, amino acids, flavonoids, exopolysaccharides, and other molecules. Temperature, pH, fermentation time, and the composition of lactic acid bacteria and yeasts in SD can impact the nutritional and sensory properties of bread and the postbiotic-like effect. Many in vivo studies in humans have associated the consumption of SD bread with higher satiety, lower glycemic responses, increased postprandial concentrations of short-chain fatty acids, and improvement in the symptoms of metabolic or gastrointestinal-related diseases. This review highlights the role of bacteria and yeasts used for SD, the formation of postbiotic-like components affected by SD fermentation and the baking process, and the implications of functional SD bread intake for human health. There are few studies characterizing the stability and properties of postbiotic-like components after the baking process. Therefore, further research is necessary to develop SD bread with postbiotic-related health benefits.

Effects of Bifidobacteria Fermentation on Physico-Chemical, Thermal and Structural Properties of Wheat Starch.

Lactic acid bacteria have been considered to be a very important species during sourdough fermentation. In order to explore the effects of bifidobacteria fermentation on thermal, physico-chemical and structural properties of wheat starch during dough fermentation, starch granules were separated from the fermented dough at different fermentation times, including 0 h, 2 h, 6 h, 9 h and 12 h. The results showed that the morphology of starch granules was destroyed gradually as the fermentation time increased, which appeared as erosion and rupture. With the increase in fermentation time, the solubility showed a significant increase, which changed from 8.51% (0 h) to 9.80% (12 h), and the swelling power was also increased from 9.31% (0 h) to 10.54% (12 h). As for the gelatinization property, the enthalpy was increased from 6.77 J/g (0 h) to 7.56 J/g (12 h), indicating a more stable thermal property of fermented starch, especially for the longer fermentation. The setback value was decreased with short fermentation time, indicating that the starch with a longer fermentation time was difficult to retrograde. The hardness of the gel texture was decreased significantly from 50.11 g to 38.66 g after fermentation for 12 h. The results show that bifidobacteria fermentation is an effective biological modification method of wheat starch for further applications.