RETRACTED: Effect of wheat bran sourdough with exopolysaccharide producing Lactobacillus plantarum (NR_104573.1) on quality of pan bread during shelf life

Effects of lactic acid bacteria fermentation on the physicochemical and structural characteristics of starch in blends of glutinous and japonica rice

In this study, the effects of lactic acid bacteria (LAB) fermentation on the physicochemical and structural characteristics of mixed starches in blends of glutinous and japonica rice were investigated. Five starter cultures improved in varying degrees the hydration ability, transparency, and freeze-thaw stability of the mixed starches. Mixed starch I, prepared by fermentation of Lactobacillus acidophilus HSP001, exhibited optimal water-holding capacity, solubility, and swelling power. In comparison, mixed starches V and III involved fermentation of L. acidophilus HSP001 and Latilactobacillus sakei HSP002, using ratios of 2:1 and 1:1 to achieve higher transparency and freeze-thaw stability, respectively. The LAB-fermented, mixed starches exhibited excellent pasting properties due to their high peak viscosities and low setback values. Moreover, the viscoelasticity of mixed starches III-V, prepared by compound fermentation of L. acidophilus HSP001 and L. sakei HSP002 in ratios of 1:1, 1:2, and 2:1, respectively, proved superior to their single strain fermentation counterparts. Meanwhile, LAB fermentation resulted in reduced gelatinization enthalpy, relative crystallinity, and short-range ordered degree. Thus, the effects of five LAB starter cultures on mixed starches were inconsistent, but these results provide a theoretical basis for the application of mixed starches. PRACTICAL APPLICATION: Lactic acid bacteria was used to ferment blends of glutinous and japonica rice. Fermented mixed starch had better hydration, transparency, and freeze-thaw stability. Fermented mixed starch exhibited nice pasting properties and viscoelasticity. LAB fermentation corroded starch granules, leading to the decrease of ΔH. Relative crystallinity and short-range order of fermented mixed starch decreased.

Proteomic Analysis Explores Interactions between Lactiplantibacillus plantarum and Saccharomyces cerevisiae during Sourdough Fermentation

Sourdough is a fermentation culture which is formed following metabolic activities of a multiple bacterial and fungal species on raw dough. However, little is known about the mechanism of interaction among different species involved in fermentation. In this study, Lactiplantibacillus plantarum Sx3 and Saccharomyces cerevisiae Sq7 were selected. Protein changes in sourdough, fermented with single culture (either Sx3 or Sq7) and mixed culture (both Sx3 and Sq7), were evaluated by proteomics. The results show that carbohydrate metabolism in mixed-culture-based sourdough is the most important metabolic pathway. A greater abundance of L-lactate dehydrogenase and UDP-glucose 4-epimerase that contribute to the quality of sourdough were observed in mixed-culture-based sourdough than those produced by a single culture. Calreticulin, enolase, seryl-tRNA synthetase, ribosomal protein L23, ribosomal protein L16, and ribosomal protein L5 that are needed for the stability of proteins were increased in mixed-culture-based sourdough. The abundance of some compounds which play an important role in enhancing the nutritional characteristics and flavour of sourdough (citrate synthase, aldehyde dehydrogenase, pyruvate decarboxylase, pyruvate dehydrogenase E1 and acetyl-CoA) was decreased. In summary, this approach provided new insights into the interaction between L. plantarum and S. cerevisiae in sourdough, which may serve as a base for further research into the detailed mechanism.

Influence of fermentation temperature on in situ heteropolysaccharide formation (Lactobacillus plantarum TMW 1.1478) and texture properties of raw sausages

This study puts a focus on the influence of microbial in situ heteropolysaccharide (HePS) formation on the quality of raw fermented sausages (salami). Since exopolysaccharide-production is often triggered by sub-optimal growth conditions, the influence of different fermentation temperatures was also investigated. For this reason, the sausage batter was inoculated with (Lactobacillus plantarum TMW 1.1478) or without (L. sakei TMW 1.2037; control) a HePS-producing starter culture (inoculation concentration ~108 CFU/g), and the sausages fermented at either 10, 16, or 24°C (7 days), followed by a drying period at 14°C until the final weight loss of 31% was reached. Microbial growth, pH, and weight loss development were monitored and the products further characterized using texture profile analysis and a sensory test. HePS in the salami matrix were determined using confocal laser scanning microscopy and a semi-quantitative data interpretation approach. Sausages containing L. plantarum were found to be significantly (p < .05) softer compared with control samples, which was also confirmed in the sensory analysis. The different fermentation temperatures had an influence on the drying speed. Here, sausages produced with L. plantarum needed more time to reach the final weight loss of 31% as compared to control samples, which could be attributed to the presence of exopolysaccharides in the matrix (p < .05). Using HePS-forming starter cultures in raw fermented sausage manufacturing can lead to products with a softer texture (undesired in Europe) depending on the strain and processing conditions used, highlighting the importance of a suitable starter culture selection in food processing.

Usage of in situ exopolysaccharide-forming lactic acid bacteria in food production: Meat products-A new field of application?

In the meat industry, hydrocolloids and phosphates are used to improve the quality attributes of meat products. However, latest research results revealed that the usage of exopolysaccharide (EPS)-forming lactic acid bacteria (LAB), which are able to produce EPS in situ during processing could be an interesting alternative. The current review aims to give a better understanding of bacterial EPS production in food matrices with a special focus on meat products. This includes an introduction to microbial EPS production (homopolysaccharides as well as heteropolysaccharides) and an overview of parameters affecting EPS formation and yield depending on LAB used. This is followed by a summary of methods to detect and characterize EPS to facilitate a rational selection of starter cultures and fermentation conditions based on desired structure-function relationships in different food matrices. The mechanism of action of in situ generated EPS is then highlighted with an emphasis on different meat products. In the process, this review also highlights food additives currently used in meat production that could in the future be replaced by in situ EPS-forming LAB.

Evaluating the traditional bread properties with new formula: Affected by triticale and cress seed gum

During recent years, composite bread is more popular among consumers due to its functional and nutritional properties. Among cereals, triticale has been studied, along with careful observation of its characteristics. In addition, hydrocolloids can be replaced as an appropriate resource due to a decrease in the gluten content. The present study aimed to evaluate the effect of triticale flour replacement at the levels of 0, 100, 150, and 250 g/kg, and cress seed gum at the concentrations of 0, 3, 6, and 10 g/kg on the rheological parameters of dough and physicochemical, textural, microstructural, and sensory properties of bread. Based on the results, formula including composite flour (150 g/kg triticale flour+850 g/kg wheat flour) and cress seed gum at 6 g/kg was the best formulation for improving the texture, color parameters, and general acceptance of both types of bread (Barbari and Lavash). Regarding the Iranian Barbari bread, cress seed gum increased the specific volume, porosity, and brightness, while reduced the hardness compared to the control. Besides, sensory evaluation manifested that 150 g/kg of wheat flour could be replaced with triticale flour for providing a good quality of bread. In conclusion, the addition of 150 g/kg of triticale and 6 g/kg of cress seed gum into composite flour and bread formulations had positive effects on all properties measured in both types of bread.

Exploitation of Lactic Acid Bacteria and Baker's Yeast as Single or Multiple Starter Cultures of Wheat Flour Dough Enriched with Soy Flour

Sourdough fermentation presents several advantageous effects in bread making, like improved nutritional quality and increased shelf life. Three types of experiments aimed to evaluate comparatively the efficiency of two Lactobacillus (Lb.) strains, Lb. plantarum ATCC 8014 and Lb. casei ATCC 393, to metabolize different white wheat flour and soybeans flour combinations to compare their efficiency, together with/without Saccharomyces cerevisiae on sourdough fermentation. For this purpose, the viability, pH, organic acids, and secondary metabolites production were investigated, together with the dynamic rheological properties of the sourdough. During sourdough fermentation, LAB presented higher growth, and the pH decreased significantly from above pH 6 at 0 h to values under 4 at 24 h for each experiment. Co-cultures of LAB and yeast produced a higher quantity of lactic acid than single cultures, especially in sourdough enriched with soy-flour. In general, sourdoughs displayed a stable, elastic-like behavior, and the incorporation of soy-flour conferred higher elasticity in comparison with sourdoughs without soy-flour. The higher elasticity of sourdoughs enriched with soy-flour can be attributed to the fact that through frozen storage, soy proteins have better water holding capacity. In conclusion, sourdough supplemented with 10% soy-flour had better rheological properties, increased lactic, acetic, and citric acid production.

Effect of microbial exopolysaccharide on wheat bran sourdough: Rheological, thermal and microstructural characteristics

Rheological, thermal and microstructural properties of wheat bran sourdough (WBS) containing different levels of microbial exopolysaccharide (EPS) extracted from Lactobacillus plantarum were investigated. All sourdough samples showed pseudoplastic behavior and the highest apparent viscosity was achieved at 1.5% EPS. The values of consistency coefficient of 1 and 2.5% EPS were significantly lower than for the dough without EPS. Increasing EPS in WBS produced a decrease in the storage, loss, and complex moduli of the sourdough, except that made with 1.5% EPS. This can be attributed to the microbial EPS structure and its ability to bind with water. It can be concluded, due to high hygroscopicity of EPS, WBS containing EPS had a lower access to water and other dough constituents. Thermal and microstructural results showed that EPS strongly modified starch gelatinization by prohibiting water access to amorphous parts of the granules and stabilized crystalline regions of starch causing an increase of end set temperature.