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This study investigated the physicochemical properties, microbiological analysis, antifungal activity, and mycotoxin analysis of bread. Eight breads were prepared, including control Bread (CB), control Bread with calcium propionate (CPB), commercial sourdough breads (CCB), control bread made with oven-dried sourdough (SB), and bread baked with oven-dried sourdough fermented by Pediococcus pentosaceus TI6 (SB-TI6). These breads were contaminated with Aspergillus flavus and Penicillium verrucosum , and their shelf life was monitored over 7 days. The results indicated that incorporating sourdough powder into bread significantly extends the shelf life and reduces fungal contamination. This reduction resulted in lower levels of mycotoxins, with the use of dry sourdough fermented by P. pentosaceus TI6 leading to the lowest levels of aflatoxins. In the case of SB-TI6, minor levels of aflatoxin B1 (AFB1), B2 (AFB2), and G1(AFG1) were detected, with only 0.003 mg of AFG2/Kg of the product. Conversely, CB loaves exhibited the highest mycotoxin contamination levels, reaching values of 330 mg of AFB1/Kg. The findings suggested that incorporating dry sourdough in breadmaking served as a viable alternative to synthetic preservatives, effectively reducing mycotoxin levels and enhancing bread safety and shelf life. • Dried sourdough fermented by LAB showed antifungal activity against A. flavus and P. verrucosum. • Dried sourdough exhibited strong antimycotoxygenic properties and maintained bread quality. • Doughs and breads showed high lactic acid levels via HPLC, aiding preservation and flavor. • Moisture and water activity were assessed for shelf life and microbial growth insights. [ABSTRACT FROM AUTHOR]

The impact of egg white addition on structural and sensory qualities of gluten-free sourdough bread was investigated at three egg white-to-sourdough ratios: 25:75, 45:55, and 85:15, versus a sourdough-only control (0:100) Previously, egg white has replicated gluten-like networks, and sourdough addition improved structural and storage qualities in gluten-free breads. In this study, mild acidity from sourdough promoted gluten-like network formation in egg white-added breads, evidenced by significantly thicker cell walls versus control (p < 0.05), with the greatest improvement in samples with 45 % egg white and 55 % sourdough. Specific volume and textural parameters of breads with 45–85 % egg white were significantly improved versus control (p < 0.05). Principal Component Analysis showed positive multivariate correlations between egg white content and improved chewiness, area of cells and density. Positive correlations were identified between sourdough content and favourable acetic acid, phenylethyl alcohol and 6-methyl-5-heptan-2-one, and samples with egg white-to-sourdough ratios 45:55 contained positive flavour attributes throughout storage, with the greatest concentrations of acetic acid and phenylethyl alcohol by day six. This research demonstrated that the combination of egg white and sourdough in similar proportions promotes the formation of gluten-like networks, producing gluten-free breads with similar structural and sensory attributes to conventional breads, which are retained over storage. [Display omitted] • Mild acidity from sourdough stabilises foamed egg white networks in gluten-free batter. • Egg white positively contributes to bread structure, increasing specific volume and positive textural attributes. • Sourdough promotes generation of favourable flavour compounds, which are retained over storage. • Combined advantages of sourdough and egg white address common weaknesses of gluten-free products. [ABSTRACT FROM AUTHOR]

A number of studies have shown the effect of cereals and sourdough on bread nutritional and organoleptic quality, but the impact of the milling technique remains little studied. There are two main types of milling technic depending on the bread-making food chain. Industrial bakeries mainly use roller mills while artisanal bakeries may also use stone mill. We set up a participatory experiment with six millers and four bakers to study the impact of these two milling techniques on the quality of flours, sourdough microbiota and the quality of breads. Millers made twenty-two different flours from four different wheat grain varieties using either roller or stone mills. Each baker initiated and maintained sourdoughs with three roller-milled and three stone-milled flours during at least 32 backsloppings and then made bread. The analysis of flours revealed a typical granulometry profile linked to wheat hardness with higher particle sizes for stone-milled flours. Stone-milled flours also had a higher maltose content. However, the milling technic did not drive the composition of the sourdough microbiota. Moreover, the analysis of bread revealed that variation in bread protein fractions and in bread aroma compounds were more related to the specific baker microbial community than to the milling technique. Carbohydrate contents were clearly linked to the main LAB species metabolism. These results revealed that the sourdough microbial community shapes the organoleptic and nutritional quality of bread more than milling techniques. • Stone-milled flours have higher particle sizes and higher maltose content than roller-milled flours. • The differences in stone and roller-milled flour do not impact the microbial species composition of sourdough. • The milling technique has little influence on the nutritional and organoleptic quality of breads made with semi-whole flours. • Sourdough microbiota shape bread properties, metabolite and volatile contents. [ABSTRACT FROM AUTHOR]

The effects of microbial transglutaminase (mTG) on structure and loaf properties of gluten-free (GF) sourdough breads containing five different flours: chickpea, brown rice, white rice, oat, and quinoa. SDS-PAGE analysis revealed that white rice, brown rice, quinoa, and chickpea proteins are adequate substrates for mTG activity, while oat proteins, without the addition of exogenous proteins, lack the characteristics suitable for mTG action. Additionally, mTG engages in self-crosslinking. The utilization of mTG in GF sourdough bread applications was shown to improve some of the final bread characteristics of GF breads. White rice- and brown rice-GF sourdough loaves at 24 h showed a 28% and 13% decrease, respectively, in crumb firmness with the addition of 2 Units mTG per gram (U/g) of dough. Quinoa-GF sourdough breads at 24 h showed a 6% increase in specific volume with the addition of 1 U/g. Oat- and chickpea-GF sourdough loaves did not show improvements in loaf quality with mTG addition. [Display omitted] • Microbial transglutaminase (mTG) was tested in gluten-free (GF) flours and sourdough. • SDS-PAGE revealed rice, quinoa and chickpea flours support mTG cross-linking, oat does not. • White rice, brown rice and quinoa GF sourdough breads showed the most improvement. • Microbial transglutaminase (mTG) engages in extensive self-cross-linking. [ABSTRACT FROM AUTHOR]

In this study, freeze-dried highland barley sourdough powder containing inulin (SPN) was prepared, and its stability during storage, as well as the effects of SPN on dough network structure and bread quality, were investigated. Results showed that SPN retained a higher number of viable lactic acid bacteria and acid-producing ability in comparison to sourdough powder without inulin when stored at 4 °C for 60 d. The use of SPN was advantageous in the formation of gluten network structure in the dough. Bread prepared with SPN (B2) exhibited a larger specific volume and a softer texture than the highland barley-wheat (1:8, w/w) bread prepared without sourdough (B0) (P < 0.05) and the one prepared with fresh highland barley sourdough (B1) (P > 0.05). Sourdough usage decreased in vitro starch digestibility, yet increased protein digestibility and antioxidant activity, with no significant differences between B1 and B2. Ultimately, B2 showed the highest overall acceptability. The positive effects of SPN may provide insights into future innovations in this area. • Inulin maintained a higher number of LAB and acid-producing ability of sourdough powder. • Highland barley sourdough powder incorporating inulin enhanced bread dough gluten network. • Bread B2 exhibited a higher specific volume, softer texture, and lower baking loss rate. • The overall acceptability of bread B2 was the highest. [ABSTRACT FROM AUTHOR]

The importance of bread made from ancient wheat flours is currently increasing. In literature, several works examine the cultivation phase of ancient wheats, as well as their positive effects on human health. On a technological level, their bread-making process is hindered by the poor workability of these flours, but there are only few scientific studies aimed to enhance their technological performance. However, bakers developed several strategies to improve ancient wheat flour processability. We chose the semi-structured interview as instrument to investigate these strategies, evaluating them according to the existent literature. The study revealed that ancient wheats are usually stone milled, and processed as brown flours. Bread doughs are often prepared with flour blends, resulting from the cultivation of grain mixtures or obtained as flour mix. The choice of slow mixers, an accurate monitoring of the final leavening phase and the use of sourdough, as well as the selection of flour blends have been proposed as solutions to partially improve the technological performance of ancient wheat flours. Finally, ancient wheat varieties are usually processed following several "good working practices" (i.e. use of non-refined flours, sourdough, organic cultivations) which probably play a role in enhancing their beneficial effects on human health. • Ancient wheat flours are typically characterized by poor technological properties. • Ancient wheats are generally stone-milled and processed as brown flours. • Doughs are prepared with flour blends from mixed cultivations or flour mixtures. • Slow mixers and high viability sourdough improve flours' processability. • Monitoring the leavening step and bake in a temperature drop increase bread quality. [ABSTRACT FROM AUTHOR]

Abstract This work aimed to study the phenolic acid metabolism of sourdough lactic acid bacteria (LAB) in laboratory media, and in sourdough fermentation with single cultures and in co-fermentations. Lactobacilli were selected from isolates obtained from 35 sourdough samples. Isolates (114 strains) were screened for phenolic acid decarboxylase gene pdc and EPS production. Ferulic acid metabolism of the 18 pdc positive strains was evaluated in mMRS; all pcd positive strains converted ferulic acid by decarboxylation and/or reduction. Single whole wheat and rye malt dough fermentation fermented with lactobacilli or yeasts were characterized with respect to free, conjugated, or bound phenolic acids. Concentrations of free, conjugated, or bound phenolic acids were not altered substantially in chemically acidified sourdoughs, or in yeast fermented doughs. L. plantarum metabolized free ferulic acid in wheat and rye malt sourdoughs; L. hammesii DSM 16381 metabolized syringic and vanillic acids and reduced levels of bound ferulic acid in wheat sourdoughs. Co-fermentation of L. hammesii and L. plantarum achieved release of bound ferulic acid and conversion of the resultant free ferulic acid to dihydroferulic acid and volatile metabolites. Phenolic acid metabolism in sourdoughs was enhanced by co-fermentation with strains exhibiting complementary metabolic activities. Results may enable improvement of bread quality by targeted conversion of phenolic acids during sourdough fermentation. Highlights • Lactobacillus plantarum converts ferulic acid in sourdough. • Esterase activity of Lactobacillus hammesii releases bound ferulic acid in sourdough. • Co-culture of L. plantarum and L. hammesii enhances phenolic acid metabolism. [ABSTRACT FROM AUTHOR]

Abstract Aim of the study was to produce traditional and typical breads using stabilized sourdough starter without the addition of baker's yeast activator. To this end, the spray drying technique was investigated as an alternative tool to freezing, freeze drying and drying techniques to preserve sourdough starter. The stabilized sourdoughs were used in breadmaking to assess the ability to leaven and ferment the doughs and to evaluate the effect of their use on the sensory characteristics of the obtained breads. Positive and encouraging results were obtained mainly with the spray-dried sourdoughs that better preserved the vitality of both yeasts and lactic acid bacteria when compared to the traditional techniques. Furthermore, the results suggested that spray-dried sourdough, opportunely refreshed, can be successfully used for breadmaking without the use of baker's yeast activator, producing breads with sensory characteristics highly comparable to those produced using fresh sourdoughs. Highlights • Spray drying technique preserves good vitality of both yeast and LAB in sourdough. • Spray drying sourdough can be successfully used in breadmaking, without any added yeast. • Breads obtained with spray dried sourdough have high sensory characteristics. [ABSTRACT FROM AUTHOR]

Abstract The production of composite or double-layer (DL) bread was optimized to reduce the amount of the chemical preservative calcium propionate. It was validated using sourdough (SD) in the crust (0–80 g/100 g crust dough). Par-baked (PB) and fully baked (FB) breads were evaluated based on their shelf-life extending, bread technological and sensorial properties. The shelf-life of PB bread was increased with ≥60 g SD/100 g crust dough for air packaged and ≥20 g SD for modified atmosphere packaged (MAP) breads. Use of 60 g SD/100 g crust dough was sufficient to achieve the same level of preservation with or without MAP. Par-baked and fully baked bread were mould free for respectively 7 and 30 days using 60 g sourdough in 100 g crust dough. Specific volume decreased for PB bread containing 40–60 g SD/100 g crust dough and for FB bread with 80 g SD/100 g crust dough. Accordingly, crumb hardness was impaired under the latter conditions. Highlights • Method for the production of mould-free and double-layer bread was optimized. • Shelf-life of par-baked bread increased from 5 to 10 days with 60 g sourdough in crust dough. • With 20 or 40 g sourdough in bread crust, modified atmosphere packaging was necessary. • Modified atmosphere packaging had minor anti-mould effect with 60 g sourdough in crust dough. • Fully baked bread was mould free for 30 days using 60 g sourdough in crust dough. [ABSTRACT FROM AUTHOR]

This study focused on the performance of the dextran producer Leuconostoc citreum as starter culture during 30 days of wheat flour type I sourdough propagation (back-slopping). As confirmed by RAPD-PCR analysis, the strain dominated throughout the propagation procedure, consisting of daily fermentations at 20 °C. The sourdoughs were characterized by consistent lactic acid bacteria cell density and acidification parameters, reaching pH values of 4.0 and mild titratable acidity. Carbohydrates consumption remained consistent during the propagation procedure, leading to formation of mannitol and almost equimolar amount of lactic and acetic acid. The addition of sucrose enabled the formation of dextran, inducing an increase in viscosity of the sourdough of 2–2.6 fold, as well as oligosaccharides. The transcriptional analysis based on glucosyltransferases genes (GH70) showed the existence in L. citreum FDR241 of at least five different dextransucrases. Among these, only one gene, previously identified as forming only α-(1–6) glycosidic bonds, was significantly upregulated in sourdough fermentation conditions, and the main responsible of dextran formation. A successful application of a starter culture during long sourdough back-slopping procedure will depend on the strain robustness and fermentation conditions. Transcriptional regulation of EPS-synthetizing genes might contribute to increase the efficiency of industrial processes. [ABSTRACT FROM AUTHOR]

Germination is a biotechnological process helpful in obtaining new plants from grains. We tested the impact of processing condition (sprouting and dough yield) and flour composition on type I sourdoughs biochemical and nutritional parameters we here used four flour matrices and precisely: i) refined commercial wheat flour, ii) sprouted and iii) non-sprouted whole wheat flour and iv) a blend composed of sprouted whole wheat and sprouted lentils. We here compared a set of 24 samples based on different group stratifications including three different sampling times (starting, after 24h and at the 10th refreshment). Moreover, we inspected the microbiota and its relative taxa abundance by 16S rRNA target sequencing and qPCR absolute quantification. Our result highlighted how the sprouted process together with the dough yield influenced key substrate like raffinose and lead to a change of taxa composition as evinced for the increased relative abundances of Pediococcus genus. Other key taxa in the microbiota were shaped by tested conditions and the alpha and beta diversity evidenced how matrix impact the intergroup clustering. The presented results shed new light on the increased properties and the related health promoting effects of type I sourdough obtained with the sprouting process. • Germination is a traditional process helpful in obtaining new plants from grains. • The sourdough ecological niche is shaped by sprouting, dough yield and number of refreshments. • Statistically significant variables emerged from physicochemical and DNA sequencing data. • Potential health promoting effects may be associated with sprouted sourdoughs. [ABSTRACT FROM AUTHOR]

This study investigated the impact of in situ exopolysaccharides (EPS) on the properties of dough and quality of Chinese steamed bread (CSB). Sourdoughs were fermented with dextran-producing Weissella confusa QS813, with and without sucrose addition at 20 °C and 35 °C, respectively. The highest EPS content and lowest titratable acidity value were obtained in sucrose-enriched sourdough fermented at 20 °C (WS20+). Addition of WS20 + significantly improved proofing performance and induced glutenin macropolymer (GMP) particle agglomeration of dough. Microstructure results revealed a more continuous, connected network in WS20 + dough and better crumb structure in the corresponding CSB. The quality of CSB was enhanced upon addition of WS20+. Low EPS yield in sourdough without sucrose negatively affected dough and CSB quality. Increased acidification in sucrose-enriched sourdough fermented at 35 °C masked the beneficial effects of EPS. Therefore, both high EPS generation and mild acidification contributed to the beneficial effect of W. confusa sourdough on CSB quality. [ABSTRACT FROM AUTHOR]

The lactic acid bacterial diversity of wheat sourdoughs collected in Ya'an city, Sichuan province was investigated by culture-dependent methods combined with 16S rRNA gene sequencing, and the exopolysaccharide (EPS) production characteristics of ropy lactic acid bacteria (LAB) strains from these sourdoughs were evaluated. Two hundred nineteen LAB strains were isolated, and genotypic characterization indicated that the isolated LAB strains included Lactobacillus plantarum ( L. plantarum ), L. pantheris , Leuconostoc citreum ( Leu. citreum ), Weissella viridescens , Leu. pseudomesenteroides , Lactococcus lactis ( L. lactis ), L. raffinolactis , and Leu. mesenteroides . All the isolates were found to harbor genes coding for EPS, and the yield of EPS produced by “ropy” LAB strains ranged between 2.3 and 229.5 mg/g wet cell weight. The present study enhances our knowledge about LAB diversity in Ya'an sourdoughs and provides information about the EPS-producing LAB strains in sourdough samples, which might be favorable for the application of specific LAB strains in sourdough technology. [ABSTRACT FROM AUTHOR]

Chickpea, a relevant legume worldwide, can be nutritional and functionally improved by fermentation with lactic acid bacteria (LAB). In order to select suitable autochthonous starter cultures, we isolated and identified LAB from kabuli chickpeas cultivated and consumed in northwestern Argentina, and screened their relevant techno-functional properties. Chickpeas were milled and spontaneously fermented with daily back-slopping at 37 °C for 6 days and evolution of microbial populations were followed by plate counting. Phenotypic and genotypic methods including (GTG) 5 -based PCR fingerprinting and 16S rDNA sequencing were used to differentiate and identify the isolates to species level. A marked increase of LAB counts was observed throughout fermentation raising from 0.88 ± 0.35 log CFU/g of unfermented flours to 9.61 ± 0.21 log CFU/g after 5 back-slopping steps with a concomitant pH decline from 6.09 ± 0.05 to 4.40 ± 0.03. Eighteen strains belonging to four LAB genera and six species: Enterococcus durans, E. mundtii, Lactococcus garvieae, Pediococcus pentosaceus , Weissella cibaria and W. paramesenteroides were identified in chickpea sourdoughs. Based on their abilities, Weissella cibaria CRL 2205 (acidification capacity), W. paramesenteroides CRL 2191 (proteolytic activity), Pediococcus pentosaceus CRL 2145 (gallate decarboxylase and peptidase activities), Lactococcus garviae CRL 2199 (α-galactosidase activity) and E. durans CRL 2193 (antimicrobial activity), were selected to design novel fermented chickpea products. [ABSTRACT FROM AUTHOR]

The present study was undertaken to isolate and characterize gluten hydrolyzing microbiota from locally fermented sourdoughs (Khamir) to evaluate their potential as a candidate for probiotics. Sixty autochthonous sourdough samples were collected from different areas of Pakistan. Nineteen bacterial and three yeast isolates were screened for the presence of gluten-degrading ability from sourdough samples. These isolates were sub-cultured on different media for presumptive pre-selection by biochemical assays. Five bacterial isolates were lactic acid bacteria and two were Bacillus sp among 19 bacterial isolates which were further characterized based on auto-aggregation, β-galactosidase activity, antibiotic susceptibility, anti-pathogenic activity, bile salts tolerance, pH tolerance, surface hydrophobicity and cholesterol assimilation. In this study Lactobacillus plantarum ATCC 14917 was used as control strain to compare the probiotic potential of isolated strains. Idetnfication based on 16S and 28S rRNA sequencing revealed the presence of four Enterococcus faecalis strains along with Enterococcus mundtii, Bacillus cereus and Bacillus megaterium strains. All yeast strains were identified as Wickerhamomyces anomalus. Among all microbial strains, E. mundtii QAUSD01 and W. anomalus QAUWA03 had the ability to tolerate low pH, bile salt properties and hydrophobicity compared to other gluten-degrading strains. These two strains exhibited the potential to be used as probiotic for sourdough fermentation. [ABSTRACT FROM AUTHOR]

In this study, sourdough samples were collected from different locations and lactic acid bacteria (LAB) and yeasts were isolated, identified and their phytic acid degradation capabilities were investigated. The isolated phytase positive LAB and yeast strains were identified by FTIR (Fourier Transform Infrared Spectroscopy) and LAB's 16s rRNA gene and yeast's 26s rRNA gene sequencings. Phytase positive strains were used as a starter culture in whole wheat bread production. In order to determine the culture effect on the quality parameters of whole wheat bread samples, some physicochemical, nutritional, sensory, and textural properties were characterized. The spectrophotometric phytase activity was calculated as 703.1–1153.8 U/mL for LAB isolates, and 352.2–943.4 U/mL for yeast isolates. Two different yeast species ( Saccharomyces cerevisiae , Pichia membranifaciens ) and five different LAB species ( Weissella viridescens , Pediococcus pentosaceus , Pediococcus acidilactici , Lactobacillus brevis , Lactobacillus parabuchneri ) were identified based on the FTIR-based identification and molecular subtyping methods. The phytic acid content significantly decreased in culture added whole wheat breads compared to control one produced with only commercial baker's yeast. The greatest reduction in phytic acid level (43.4%) was observed in the bread produced by S. cerevisiae + Pediococcus pentosaceus culture combination. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess whether wheat endophytic lactic acid bacteria (LAB) are able to dominate in sourdough ecosystem. To do that, a first experimental phase considered doughs produced under semi-sterile conditions and singly inoculated with different strains of endophytic LAB and Lactobacillus sanfranciscensis A4 isolated from sourdough. Notwithstanding the high frequency of Lactobacillus plantarum in the sourdoughs prepared in laboratory, only one of the starter strains, L. plantarum LB2, was detected after five days of back-slopping. Subsequently, the ability of this strain to dominate traditional sourdoughs was evaluated at bakery and laboratory level. Contamination of sourdoughs with L. plantarum LB2 caused an increased number of LAB and, accordingly, higher acidification, compared to the sourdoughs before this event. After six days of propagation, the wheat endophytic strain L. plantarum LB2 was retrieved as a component of the bacterial population, in all the sourdoughs and regardless of the place of propagation. In addition, the contamination event caused a modification of the lactic acid bacterium biota, which in turn influenced some sourdoughs biochemical features. In conclusion, this study showed that wheat endophytic LAB could represent a potential reservoir for selecting robust strains to be used as sourdough starters. [ABSTRACT FROM AUTHOR]

Interactions between microorganisms are key to their performance in food habitats. Improved understanding of these interactions supports rational improvement of food fermentations. This study aimed at identifying interactions between lactic acid bacteria and yeast during sourdough fermentation. Therefore, the lactic acid bacteria Lactobacillus plantarum and Lactobacillus sanfranciscensis were co-cultured with the yeast Saccharomyces cerevisiae in a newly developed medium, as well as in situ in a sourdough-like environment. L. sanfranciscensis was found to be stimulated by a secreted factor of S. cerevisiae in any tested in vitro situation, whereas L. plantarum and S. cerevisiae stimulated each other only in the presence of glucose, fructose and lactose as carbon source, but not with galactose, maltose, sucrose and starch. Moreover, it was demonstrated that L. sanfranciscensis is stimulated by CO 2 and another yet to be identified factor produced by yeast in a sourdough-like environment. In conclusion, S. cerevisiae produces growth factors stimulatory to lactic bacteria. The nature and the efficacy of these growth factors depend on the target species and on the supplied carbon source. [ABSTRACT FROM AUTHOR]

The dietary fiber complex of cereal whole grain is an important source of host beneficial molecules, such as: beta-glucans, fructans, resistant starch and arabinoxylans. The bioavailability of these compounds from whole grain products is generally dependent to different physiological and technological issues, likewise: genotype and maturation stage, dough preparation, fermentation options and baking process. This study regards the production of breads from cereal whole grains, taking into account two wheat genotypes harvested at mature and immature stages and processed through different conditions, varying temperature, time of baking and fermentation parameters. The aim is to highlight the different impact of these aspects on the amount and the bioavailability of the aforementioned four bioactive molecules. Our results showed that the best product, in terms of content of beneficial compounds, is that obtained from the flour of advanced maturation stage processed with brewer's yeast fermentation. Given the great interest in finding better technological processes to increase the daily dietary fiber intake, our findings could be very useful for the food industry to design the exact formulation and best process for the increase of bio-active molecules concentration in cereal whole grains products. [ABSTRACT FROM AUTHOR]

Sourdough, a mixture of wheat flour and water, fermented by the action of lactic acid bacteria (LAB) and yeasts, presents some technological advantages, such as improvement in dough structure, flavor, aroma, bread texture, and shelf life. Few studies related to methods of preservation of sourdoughs are currently available. This work aimed to test the cryoprotective effect of trehalose on microorganism survival and its effect on freezing, freeze-drying and storage of freeze-dried sourdough, and to molecularly identify predominant bacteria and yeasts. Refined and whole wheat flour were used to prepare the sourdough. On the 14th day of production, varying amounts of trehalose were added (0, 10 and 15%) and the sourdough was freeze-dried. The cryoprotective effect of trehalose was evaluated before and after freezing, after freeze-drying, and after 15, 30 and 45 days of storage. Predominant microorganisms were molecularly identified through amplification and sequencing of rDNA fragments. Addition of trehalose promoted a cryoprotective effect survival of microorganisms, and it was more significant for LAB. Lactobacillus plantarum, Lactobacillus fermentum, Saccharomyces cerevisiae, Pichia anomala and Pediococcus pentosaceus, were the main species recovered. [ABSTRACT FROM AUTHOR]

The main objectives of this study were to investigate the antifungal activity of thyme essential oil ( Thymus zygis ) in-vitro and to validate its activity in par-baked wheat and sourdough bread ( in-vivo ) using the fungal strains Aspergillus niger and Penicillium paneum . The impact of thyme oil was evaluated in-vitro with the macro-dilution method with modified pH (4.8, 5.0, 5.5 & 6.0), a w (0.95 & 0.97) and temperature (22 & 30 °C) to mimic the conditions of wheat and sourdough par-baked bread stored at room temperature. Furthermore, the oil was applied in par-baked bread (0, 15 and 30 g sourdough/100 g dough). Challenge and shelf-life tests were performed to investigate the biopreservative potential of thyme oil in par-baked wheat and sourdough bread. Despite the promising in-vitro potential of thyme oil, no clear shelf-life extension was observed for par-baked bread which could be attributed to the oil. More research on food applications of essential oils is necessary to give the abundance of in-vitro studies industrial relevance. The use of sourdough, on the contrary, resulted in much more promising shelf-life extending properties. In both in-vitro as in-vivo assays, pH and a w showed no significant effect on fungal growth. [ABSTRACT FROM AUTHOR]

A sourdough for the industrial production of Colomba , a traditional Italian sweet-leavened baked good, was characterized in terms of microbiota composition, pH, a w , carbohydrates, organic acids, and VOCs. pH of the ripened sourdough was low (3.55), and the content of acetic acid limited (0.77 g/kg). A small biodiversity, in terms of both LAB and yeasts, was observed. Culture dependent analyses identified two biotypes of Lactobacillus sanfranciscensis and a dominant yeast species, Torulaspora delbrueckii. Metataxonomic analysis confirmed bacterial composition, whereas Candida humilis was the most represented yeast. The VOCs profile was strongly affected by bakers' yeast addition, resulting in higher amounts of acetaldehyde, acetoin, ethanol, and phenethyl alcohol. As a whole, a stable and abundant microbial community loosing competitiveness only after addition of S. cerevisiae was described. This robustness and simplicity can represent an advantage in terms of stable and easier propagation, allowing the production of more reproducible lots of Colomba . [ABSTRACT FROM AUTHOR]

The conversion of phenolic compounds by lactobacilli in food fermentations contributes to food quality. The metabolism of phenolics by lactobacilli has been elucidated in the past years but information on the contribution of specific enzymes in food fermentations remains scarce. This study aimed to address this gap by disruption of genes coding for the hydroxycimmanic acid reductase Par1, the hydroxycinnamic acid decarboxylase Pad, the hydrocinnamic esterase EstR, and strains with disruption of all three genes in Furfurilactobacillus milii FUA3583. The conversion of phenolics by Ff. milii and its isogenic mutants in sorghum fermentations was studied by LC-UV and LC-UV-MS/MS analyses. Ff. milii FUA3583 converted hydroxycinnamic acids predominantly with Par1. Vinylphenols were detected only in mutants lacking par1. A phenotype for the estR defective mutant was not identified. The formation of pyrano-3-deoxyanthocyanidins was observed only after fermentation with strains expressing Pad. Specifically, formation of these compounds was low with Ff. milii FUA3583, substantially increased in the Par1 mutant and abolished in all mutants with disrupted pad. Competition experiments with Ff. milii FUA3583 and its isogenic mutants demonstrated that expression of one of the two metabolic pathways for hydroxycinnamic acids increases the ecological fitness of the strain. Disruption of EstR in a Δ par1 Δ par2 Δ pad background improved ecological fitness, indirectly demonstrating a phenotype of the esterase in Ff. milii. The documentation of the functionality of genes coding for conversion of hydroxycinnamic acids may support the selection of starter cultures for improved quality of fermented cereal products. • The metabolism of phenolics by F. milii and 4 isogenic mutants was characterized. • Par1 and Pad mediate hydroxycinnamic acid metabolism by F. milii in sorghum. • Hydroxycinnamic acids are decarboxylated only if the reductase is deleted. • Vinylphenols converted 3-deoxyanthocyanidins to pyrano- and vinylphenol adducts. • Par1 or Pad were necessary for ecological fitness of F. milii in sorghum. [ABSTRACT FROM AUTHOR]

The possibility of using naked barley for food products is gaining popularity due to its dietary fibre content, especially β-glucans. The technological process (dough preparation, fermentation and baking) influences bread quality but also may contribute to degradation or preservation of valuable grain components. The aim of the study was to investigate the effects of different wholemeal barley flour share and bread production method on the quality of bread and non-starch polysaccharides content and solubility. Barley enriched bread contained more both soluble and insoluble dietary fibre and β-glucans, products of 40% barley share contained 67% more total dietary fibre and 160% more β-glucans than control. However, barley incorporation decreased the amount of soluble arabinoxylans. High barley contents contributed to the breads’ volume reduction by 14% and change in their crumb and crust colour. However, barley enriched breads gained higher ratings of taste than wheat bread. Barley sourdough fermentation improved breads’ volume, colour and sensory properties. Sourdough fermentation also resulted in higher concentration of dietary fibre, arabinoxylans and β-glucans. The beneficial effect of barley addition to wheat bread may be successfully enhanced by using barley wholemeal sourdough fermentation. [ABSTRACT FROM AUTHOR]

The effects of the substitution of wheat flour with faba bean flour and faba bean sourdough on the properties of composite bread were investigated. Bread was prepared by replacing wheat flour with 30% of faba bean flour, native or after sourdough fermentation. The addition of faba bean flour influenced the structure of the breads, causing a slight decrease of volume and higher hardness compared to wheat bread. However, when fermented faba bean flour was added, the crumb porosity of the bread was not affected. The addition of 30% of faba bean flour increased wheat bread protein content from 11.6 up to 16.5% of dry matter. The addition of native faba bean flour did not affect the in vitro protein digestibility, resulting similar to wheat bread (64%). On the contrary, faba bean sourdough bread showed higher protein digestibility (73%). Generally, the addition of native faba bean flour caused an improvement of the nutritional indexes of the composite bread, further enhanced when fermentation was carried out. The free amino acid profile, protein chemical score, and biological value index were the highest in faba bean sourdough bread. In addition, the predicted glycemic index was the lowest in faba bean sourdough bread. [ABSTRACT FROM AUTHOR]

Buckwheat sourdoughs supplemented with molasses as natural sucrose source were fermented with levan-producing Gluconobacter (G.) albidus TMW 2.1191 and Kozakia (K.) baliensis NBRC 16680. Cell growth, concomitant levan and low-molecular-weight metabolite production were monitored. Sourdough breads were prepared with different sourdoughs from both strains (24, 30 and 48 h fermentation, respectively) and analyzed with respect to bread volume, crumb hardness and sensory characteristics. During fermentation, levan, acetic and gluconic acids were increasingly produced, while spontaneously co-growing lactic acid bacteria additionally formed acetic and lactic acids. Sourdoughs from both strains obtained upon 24 h of fermentation significantly improved the bread sensory and quality, including higher specific volume as well as lower crumb hardness. Buckwheat doughs containing isolated levan, with similar molecular size and mass compared to in situ produced levan in the sourdough at 48 h, verified the positive effect of levan on bread quality. However, the positive effects of levan were masked to a certain extent by the impact from the natural acidification during fermentations. While levan-producing acetic acid bacteria are a promising alternative for the development of clean-label gluten-free breads without the need of additives, an appropriate balance between acidification and levan production (amount and structure) must be reached. [ABSTRACT FROM AUTHOR]

The bacterial communities of 4 dough fermentation starter samples, including Jiaozi A and D and sourdough B4 and B5 selected from Henan, Jiangsu, and Liaoning province of China were compared by high-throughput sequencing of 16S rRNA genes. The highest number of operational taxonomic units (OTUs) was found for the genus Acetobacter in Jiaozi A, but only OTUs adapted to dough conditions after 8 h (A8) and 24 h (A24) of fermentation using Jiaozi A as dough starter. Members belonging to the genus Pediococcus appeared to dominate in Jiaozi D, especially in the dough (D24) fermented for 24 h started by Jiaozi D. The genus Lactobacillus dominated in sourdough B5, A8, and A24. Weissella was the predominant genus in sourdough B4, and members of the genera Leuconostoc and Lactococcus were also identified. [ABSTRACT FROM AUTHOR]

From a microbiological perspective, sourdough is to be considered as a specific and stressful ecosystem, harboring yeasts and lactic acid bacteria (LAB), that is used for the production of baked goods. With respect to the metabolic impact of the sourdough microbiota, acidification (LAB), flavor formation (LAB and yeasts), and leavening (yeasts and heterofermentative LAB species) are most noticeable. Three distinct types of sourdough fermentation processes can be discerned based on the inocula applied, namely backslopped ones (type 1), those initiated with starter cultures (type 2), and those initiated with a starter culture followed by backslopping (type 3). A sourdough-characteristic LAB species is Lactobacillus sanfranciscensis. A sourdough-characteristic yeast species is Candida humilis. Although it has been suggested that the microbiota of a specific sourdough may be influenced by its geographical origin, region specificity often seems to be an artefact resulting from interpretation of the research data, as those are dependent on sampling, isolation, and identification procedures. It is however clear that sourdough-adapted microorganisms are able to withstand stress conditions encountered during their growth. Based on the technological setup, type 0 (predoughs), type I (artisan bakery firm sourdoughs), type II (industrial liquid sourdoughs), and type III sourdoughs (industrial dried sourdoughs) can be distinguished. The production of all sourdoughs, independent of their classification, depends on several intrinsic and extrinsic factors. Both the flour (type, quality status, etc.) and the process parameters (fermentation temperature, pH and pH evolution, dough yield, water activity, oxygen tension, backslopping procedure and fermentation duration, etc.) determine the dynamics and outcome of (backslopped) sourdough fermentation processes. [ABSTRACT FROM AUTHOR]

The technological and functional properties of 15 LAB species previously isolated from sourdough were determined in terms of antifungal and antibacterial activities, production of GABA as a functional component and phytase activity. All sourdough isolates were capable of producing GABA and Weissella paramesenteroides N-7 and Lactobacillus paralimentarius E-106 showed the highest and the lowest production levels as 18,43 mM and 3,39 mM, respectively determined by HPLC analysis. The antifungal activity of these strains were tested against Aspergillus niger and Penicillium chrysogenum and two strains Lactobacillus paraplantarum N-15 and L. paralimentarius E-106 showed significant inhibitory effects to these mould species. Generally, different levels of antibacterial activity of these species were observed against food-borne pathogens but only one strain showed low levels of inhibitory effect to Salmonella typhimurium but not the other strains. The PCR detection of several bacteriocin coding genes revealed that all strains were harboured at least one bacteriocin gene among the tested genes. Finally, all strains showed phytase activity but these activity was dependant on strain specific conditions. This study revealed some important techno-functional properties of sourdough LAB strains which can play crucial roles on sourdough technology. [ABSTRACT FROM AUTHOR]

The present work was carried out to retrieve the origin of lactic acid bacteria (LAB) in sourdough. To this purpose, wheat LAB were monitored from ear harvest until the first step of fermentation for sourdough development. The influence of the geographical area and variety on LAB species/strain composition was also determined. The ears of four Triticum durum varieties (Duilio, Iride, Saragolla and Simeto) were collected from several fields located within the Palermo province (Sicily, Italy) and microbiologically investigated. In order to trace the transfer of LAB during the consecutive steps of manipulation, ears were transformed aseptically and, after threshing, milling and fermentation, samples of kernels, semolinas and doughs, respectively, were analysed. LAB were not found to dominate the microbial communities of the raw materials. In general, kernels harboured lower levels of microorganisms than ears and ears than semolinas. Several samples showing no development of LAB colonies acidified the enrichment broth suggesting the presence of LAB below the detection limit. After fermentation, LAB loads increased consistently for all doughs, reaching levels of 7.0–7.5 Log CFU/g on M17. The values of pH (5.0) and TTA (5.6 mL NaOH/10 g of dough) indicated the occurrence of the acidification process for several doughs. LAB were phenotypically and genotypically differentiated by randomly amplified polymorphic DNA (RAPD)-PCR into eight groups including 51 strains belonging to the species Lactobacillus brevis , Lactobacillus coryniformis , Lactobacillus plantarum , Lactococcus lactis , Lactococcus garvieae , Enterococcus casseliflavus , Enterococcus faecium , Leuconostoc citreum , and Pediococcus pentosaceus . Lactobacilli constituted a minority the LAB community, while lactococci represented more than 50% of strains. Lower LAB complexity was found on kernels, while a richer biodiversity was observed in semolinas and fermented doughs. For broader microbiota characterisation in doughs before fermentation, the 16S rRNA gene fragment profiling was conducted on the unfermented doughs using MiSeq Illumina. LAB group was represented by Enterococcus , Lactococcus and members of Leuconostocaceae family whose relative abundances differed according to both geographical area and variety of wheat. The culture-independent approach confirmed that pediococci and lactobacilli constituted low abundance members of the semolina LAB microbiota and that although some strains may pass from wheat ear to fermented doughs, most are likely to come from other sources. [ABSTRACT FROM AUTHOR]

In the present study we evaluate the effect of honey on the growth and fermentative ability of two sourdough fermenting lactic acid bacteria (LAB), Pediococcus pentosaceus and Lactobacillus fermentum , and the impact that honey and LAB have on gluten microstructure. Growth kinetics and fermentative analyses were carried out through cell viability and potenciometry assays, respectively. Honey supplementation of sourdough increased LAB population. L. fermentum exhibited a higher growth rate, while P. pentosaceus was more acidifying. The fermentative profile of LAB was not altered by the presence of honey. The microstructure analyses were performed through scanning electron microscopy (SEM) and revealed that the microstructure of dough was modified by the fermenting activity of LAB, being involved in the development of gluten fibrils. In addition, honey induced changes in the microstructure of those dough whose pH value were higher than 4, disclosing a strong association between protein subunits. [ABSTRACT FROM AUTHOR]

In this study changes during fermentation of spontaneously fermented modern and ancient (spelt, emmer, and khorasan) wheat sourdoughs and their feasibility to act as leavening agents in breadmaking were evaluated. During 6 h of fermentation, sourdough was characterized for lactic acid bacteria and yeasts counts, pH, total titratable acidity (TTA), proteolytic activity, rheological and electrophoretic profiles. The effects of 25 and 50 g/100g sourdough addition on physico-chemical and sensory properties of refined wheat flour bread were also investigated. Although in all sourdoughs a pH drop, increase in proteolytic activity, gliadin and glutenin degradation with fermentation were recorded, due to different flour composition and microbial activity, tested sourdoughs significantly differed in rheological properties and breadmaking quality. Wheat sourdough being characterized by the highest acidification, increase in proteolytic activity, and the most extensive hydrolysis of gliadins, resulted in bread with the lowest specific volume and hardest crumb texture. Emmer sourdough, having the highest TTA, ash and wet gluten content, exhibited the highest extensibility, the least pronounced changes in proteolytic activity and the electrophoretic pattern which produced bread with the highest volume and softest texture. In general, ancient wheat varieties have shown great potential in sourdough breadmaking in comparison to modern wheat. • Ancient wheat varieties were used to prepare spontaneously fermented sourdoughs. • Wheat, spelt, emmer and khorasan sourdough behaved differently during fermentation. • Wheat sourdough had increased proteolytic activity and high gliadins hydrolysis. • Emmer sourdough exhibited high extensibility and low changes in gluten structure. • Unlike wheat, emmer resulted in bread with the highest volume and softest texture. [ABSTRACT FROM AUTHOR]

This study aimed at understanding the effect of additional ingredients (baker’s yeast, macerated pears, grape must, honey, or water from macerated pears) on the microbiota and biochemical characteristics of durum wheat-based sourdough. One dough prepared using only flour was used as the control (control-dough). Compared to the control-dough, doughs containing additional ingredients showed higher ( P < 0.05) cell numbers of lactic acid bacteria after the first fermentation. Constant pH of ca. 4.0 was found after two (macerated pears or water pears-doughs) to seven (control-dough) back-slopping steps. The use of additional ingredients caused lower microbial diversity, after the first fermentation and in mature sourdoughs. Regardless of the type of ingredient used, OTU belonging to the genus Lactobacillus represented more than 95% of the total Firmicutes in mature sourdoughs. Some metabolic capacities of microbial community of the mature sourdoughs were linked to the additional ingredient. Based on culture-dependent method, Lactobacillus plantarum and Saccharomyces cerevisiae dominated in all the sourdoughs. However, the sourdoughs showed different strains of these two species. Other lactic acid bacterium species were associated to baker’s yeast, grape must and macerated pears. The different microbial composition was correlated ( r > 0.7, P < 0.05) with several biochemical characteristics of the sourdoughs (e.g., free amino acids and their derivatives). [ABSTRACT FROM AUTHOR]

Cardiovascular disease, including hypertension, is the leading cause of preventable death worldwide. Sodium chloride (NaCl) associated with its excessive consumption is linked to hypertension while the global dietary NaCl intake has increased extensively. Thus, limitations on sodium (Na) consumption were recommended by the WHO and further international health agencies (<2 g Na/day). Bread and other cereal products contribute about 30% to the daily intake of sodium in the western human diet. Although it may sound simple, salt reduction in foods is not as straight forward since salt impacts the processability during the production and the quality characteristics of the final bakery products. To achieve the final reduction goals long-term strategies and reformulation of recipes are required. Numerous different techniques have been proposed to reduce the sodium chloride content. Other approaches include salt replacers or enhancers. These are summarized with special attention given to recent developments over the last 5 years. One of the promising strategies to reduce salt has been the addition of sourdough to bakery goods. Sourdough can counteract some of the negative impacts salt reduction has on bread (e.g., flavour, shelf life) improving the overall quality. The present review describes and assesses the impact of NaCl reduction on a range of bakery products, including dough characteristics, sensory properties and shelf-life. It further outlines the progress that has been made in salt reduction and indicates existing problems in the bakery sector. [ABSTRACT FROM AUTHOR]

Aim of the study was to evaluate the effect of respiratory metabolism of Lactobacillus casei species on qualitative characteristics of sourdough. For this purpose, the respiration-competent strain L. casei N87, grown both in anaerobic (AN) and respiratory (RS) condition, was used as starter culture, in combination with the yeast (Y), in model wheat dough fermentation. Three mixed starter cultures were designed for dough fermentation, namely, L. casei RS + Y, L. casei AN + Y, and Y; a control sample C was produced without starter. At time zero and after 6 and 24 h of fermentation the doughs were analyzed for pH, total titratable acidity, lactic acid bacteria and yeast concentration, volatile organic compounds production by SPME-GC/MS and the changes in albumin/globulin, gliadin and glutenin fractions by SDS-PAGE. The respirative strain L. casei N87 affected significantly the characteristics of the dough showing major acidification, increased biomass, and different volatile (higher production of diacetyl, acetic acid, acetoin, ethyl acetate) and proteolytic profiles compared to the anaerobic culture L. casei N87. The findings proved the significant role for respiratory cells of L. casei N87 in the definition of acidification, aroma and proteolysis during dough fermentation suggesting a potential role in influencing flavor and structure of baked goods. [ABSTRACT FROM AUTHOR]

Sourdough plays an important role in improving product quality. In this study, single-strain and mixed fermentation of Lactobacillus paracasei LG0260, Lactobacillus plantarum LG1034, Lactococcus lactis LG0827, Saccharomyces cerevisiae J2815 and Saccharomyces cerevisiae J8202 were used to prepare type II sourdough, which was used to evaluate the ability of mixed fermentation to improve the quality of sourdough and increase volatile flavor compounds. In sourdough, mixed fermentation reduced the number of lactic acid bacteria (LAB) and yeasts colonies, accompanied by a decrease in acidity. However, the organic acid analysis found that mixed fermentation increased the content of acetic acid and reduced the content of lactic acid. Mixed fermentation enhanced the degradation of phytic acid. It was found that sourdough MY1L3 degrades up to 96.6% of phytic acid. In addition, the total polyphenol content of mixed fermentation was decreased, but the DPPH free radical scavenging ability was enhanced. It was found by HS-SPME-GC-MS that mixed-fermented sourdough had more complex flavor compounds, such as acids, aldehydes, and esters. The differences in the metabolic properties of different starter cultures in sourdough will provide a theoretical reference for the improvement of sourdough quality. • Microbial colonies in mixed fermentation sourdough reduced, accompanied by a decrease in acidity. • Mixed fermentation increased acetic acid content and reduced lactic acid content in sourdough. • Mixed fermentation showed the strong ability to degrade phytic acid. • Mixed-fermented sourdough had more complex flavor compounds. [ABSTRACT FROM AUTHOR]

Four obligate heterofermentative lactic acid bacteria (LAB) strains ( Weissella cibaria PON10030 and PON10032 and Leuconostoc citreum PON 10079 and PON10080) were tested as single strain starters, mono-species dual strain starters, and multiple strain starter for the preparation and propagation of sourdoughs for the production of a typical bread at industrial level. The kinetics of pH and TTA during the daily sourdough refreshments indicated a correct acidification process for all trials. The concentration of lactic and acetic acid increased consistently during fermentation. The resulting molar ratios between these two organic acids in the experimental trials were lower than those observed in the control trial. The microbiological investigation showed levels of approximately 10 9 CFU/mL in almost all sourdoughs and the comparison of the genetic polymorphisms of the dominating LAB with those of the pure cultures evidenced the persistence of the added strains over time. The resulting breads were evaluated for several quality parameters. The breads with the greatest height were obtained with the quadruple combination of leuconostocs and weissellas. The highest softness was registered for the breads obtained from fermentations performed by W. cibaria PON10032 alone and in combination. The different inocula influenced also the color, the void fraction, the cell density and the mean cell area of the breads. Different levels of acids, alcohols, aldehydes, esters, hydrocarbons, ketones, terpenes, furans and phenol were emitted by the breads. The sensory tests indicated the breads from the sourdoughs fermented with the seven LAB inocula as sweeter and less acidic than control breads and the breads from the trials with the highest complexity of LAB inoculums were those more appreciated by tasters. A multivariate approach found strong differences among the trials. In particular, control breads and the breads obtained with different starter LAB were quite distant and a more strict relation was found among the productions carried out by W. cibaria strains. This study proved the suitability of the selected strains of L. citreum and W. cibaria for industrial-scale level applications in sourdough bread production. [ABSTRACT FROM AUTHOR]

A total of 249 Lactic Acid Bacteria (LAB) isolates were found in traditional Turkish wheat sourdoughs from Eastern Black Sea region of Turkey. Genotypic characterization of these isolates revealed the presence of 47 distinct LAB strains belonging to 11 different species: Lactobacillus plantarum , Lactobacillus paraplantarum , Lactobacillus curvatus , Lactobacillus rossiae , Lactobacillus sanfranciscensis , Lactobacillus brevis , Lactobacillus paralimentarius , Weissella paramesenteroides , Leuconostoc mesenteroides , Leuconostoc pseudomesenteroides and Weissella cibaria . The sourdough LAB microbiota differed depending on the sample origin and the collection period and heterofermentative LAB were dominant. The number of different species within a sourdough varied from 3 to 6 with the association of different hetero- and homofermentative LAB species. Exopolysaccharide (EPS) production characteristics of the isolates were determined and strain specific properties appeared to be important for the final EPS yields. Genes required for homopolysaccharide ( gtf and lev ) and heteropolysaccharide ( epsA , epsB , p-gtf ) production were PCR detected and several distribution patterns were observed. Results of this study confirmed the biodiversity of LAB species in traditional Turkish sourdough and highlighted the importance of EPS production in sourdough LAB strains. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria were isolated and identified from quinoa flour, spontaneously fermented quinoa dough, and type I quinoa sourdough. Strains were further selected based on acidification and proteolytic activities. Selected Lactobacillus plantarum T6B10 and Lactobacillus rossiae T0A16 were used as mixed starter to get quinoa sourdough. Compared to non-fermented flour, organic acids, free amino acids, soluble fibers, total phenols, phytase and antioxidant activities, and in vitro protein digestibility markedly increased during fermentation. A wheat bread was made using 20% (w/w) of quinoa sourdough, and compared to baker's yeast wheat breads manufactured with or without quinoa flour. The use of quinoa sourdough improved the chemical, textural, and sensory features of wheat bread, showing better performances compared to the use of quinoa flour. Protein digestibility and quality, and the rate of starch hydrolysis were also nutritional features that markedly improved using quinoa sourdough as an ingredient. This study exploited the potential of quinoa flour through sourdough fermentation. A number of advantages encouraged the manufacture of novel and healthy leavened baked goods. [ABSTRACT FROM AUTHOR]

This work studies the influence of the addition of teff flour (5, 10 and 20%) and different dried (buckwheat or rice) or fresh (with Lactobacillus helveticus ) sourdoughs on the sensory quality and consumer preference of GF breads. A set of 10 GF breads combining these ingredients was submitted to sensory descriptive analysis performed by a trained panel. The four breads with the most promising sensory profile were evaluated by celiac consumers to look for attributes driving product acceptability. The combination of teff (10%) with cereal sourdough (rice or buckwheat) enhanced bread aroma, increasing the fruity, cereal and toasty notes. High levels of teff (20%) and Lb. helveticus sourdough induced a decrease on the loaf area. The visual appearance of breads with 20% teff was highly appreciated by consumers, while bread combining 10% teff and rice sourdough was preferred in terms of flavour. The bitter taste of buckwheat sourdough was generally considered as a negative attribute. However, a group of consumers liked bitter bread as they associated it to a traditional, artisan, “malty-like” product. This work highlights the great potential of combining teff and selected sourdoughs to obtain GF breads with target attributes and improved sensory profile. [ABSTRACT FROM AUTHOR]

This study aimed at understanding the extent of contamination by lactic acid bacteria (LAB) and yeasts from the house microbiotas during sourdough back-slopping. Besides sourdoughs, wall, air, storage box, dough mixer and flour of four bakeries were analyzed. Based on plate counts, LAB and yeasts dominated the house microbiota. Based on high throughput sequencing of the 16S rRNA genes, flour harbored the highest number of Firmicutes , but only few of them adapted to storage box, dough mixer and sourdough. Lactobacillus sanfranciscensis showed the highest abundance in dough mixer and sourdoughs. Lactobacillus plantarum persisted only in storage box, dough mixer and sourdough of two bakeries. Weissella cibaria also showed higher adaptability in sourdough than in bakery equipment, suggesting that flour is the main origin of this species. Based on 18S rRNA data, Saccharomyces cerevisiae was the dominant yeast in house and sourdough microbiotas, excepted one bakery dominated by Kazachstania exigua . The results of this study suggest that the dominant species of sourdough LAB and yeasts dominated also the house microbiota. [ABSTRACT FROM AUTHOR]

Molecular markers are valuable tools for assessing the genetic variation in yeast. Here, we investigated the utility of SCoT markers for the genetic characterization of yeast strains at inter and intraspecies levels. A total of 345 endogenous yeast strains were isolated from 65 Type I sourdough samples collected from six different regions of Turkey. The seven SCoT primers produced 221 bands, of which 95.47% were polymorphic. Each primer could successfully differentiate species, supported by PIC and RP values. The ITS sequencing of isolates selected from the UPGMA dendrogram revealed that Saccharomyces cerevisiae predominated the microflora, followed by Kazachstania servazzii , K. humilis , Wickerhamomyces anomalus , Torulaspora delbrueckii , and Pichia kudriavzevii , respectively. The AMOVA revealed a high genetic variation between (49%) and within populations (51%) for S. cerevisiae. The high gene flow observed among S. cerevisiae populations suggests that it may have contributed to the geographical evolution of S. cerevisiae via the transportation of the sourdough samples. The different geographical origins were most likely to group separately on the UPGMA and PCoA. Saccharomyces cerevisiae strains from more distant populations generally displayed more significant genetic variation. SCoT markers can successfully be used alone or with the other existing DNA markers for DNA fingerprinting and analyzing the genetic variation between and within species. • S. cerevisiae was the predominant yeast species in Type I Turkish sourdough. • Each of seven SCoT primers differentiated yeast species. • SCoT markers were useful to analyze genetic diversity in yeast. • More distant S. cerevisiae populations displayed greater genetic variation. [ABSTRACT FROM AUTHOR]

The quality evaluation of food products using electrical measurements has gathered the attention of food scientists because of its simplicity and being nondestructive. In this study, the electrical resistance variation during the fermentation process of three types of Iranian local bread doughs, namely, Taftan, Lavash, and Sangak, was measured at two electrical frequencies of 120 and 1000 Hz and statistically evaluated using the D-optimal design. The results showed that there is a meaningful correlation between the electrical resistance and the type of dough and fermentation time. The dough samples had different amounts of some ingredients, e.g., yeast and sourdough, which resulted in different levels of microorganism activity. Moreover, the effects of frequency on the sample response were not significant during the experiments. Furthermore, having the type of bread dough, fermentation time, and electrical frequency, the artificial neural network (ANN) could predict the electrical resistance of the dough samples with an MSE of 0.007. Food scientists who work on the bread dough quality can use the apparatus introduced in this study to determine the quality of bread doughs during the fermentation process based on their electrical properties. Increasing the quality of bread dough leads to better durability, longer freshness and better digestion. [Display omitted] • The electrical resistance during fermentation process was measured in different local bread doughs. • There is a meaningful correlation between electrical resistance of dough and the yeast value. • There was no effect of the electrical frequency on the measured electrical impedance of dough. [ABSTRACT FROM AUTHOR]

Fifteen sourdoughs produced in western Sicily (southern Italy) were analysed by classical methods for their chemico-physical characteristics and the levels of lactic acid bacteria (LAB). pH and total titratable acidity (TTA) were mostly in the range commonly reported for similar products produced in Italy, but the fermentation quotient (FQ) of the majority of samples was above 4.0, due to the low concentration of acetic acid estimated by high performance liquid chromatography (HPLC). Specific counts of LAB showed levels higher than 10 8 CFU g −1 for many samples. The colonies representing various morphologies were isolated and, after the differentiation based on phenotypic characteristics, divided into 10 groups. The most numerous group was composed of facultative heterofermentative isolates, indicating a relevance of this bacterial group during fermentation. The genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR, 16S rRNA gene sequencing and species-specific PCRs identified 33 strains as Lactobacillus plantarum , Lactobacillus curvatus and Lactobacillus graminis . Due to the consistent presence of L. plantarum , it was concluded that this species codominates with obligate heterofermentative LAB in sourdough production in this geographical area. In order to evaluate the performances at the basis of their fitness, the 29 L. plantarum strains were investigated for several technological traits. Twelve cultures showed good acidifying abilities in vitro and L. plantarum PON100148 produced the highest concentrations of organic acids. Eleven strains were positive for extracellular protease activity. Bacteriocin-like inhibitory substances (BLIS) production and antifungal activity was scored positive for several strains, included L. plantarum PON100148 which was selected as starter for experimental sourdough production. The characteristics of the sourdoughs and the resulting breads indicated that the best productions were obtained in presence of L. plantarum PON100148. [ABSTRACT FROM AUTHOR]

Despite its potential health benefits, the integration of wheat bran into the food sector is difficult due to several adverse technological and sensory properties such as bitterness and grittiness. Sourdough fermentation is a promising strategy to improve the sensory quality of bran without inducing severe changes to the bran matrix. Therefore, identification of species/strains with potential for industrial sourdough fermentations is important. We compared the effects of different representatives of species of lactic acid bacteria (LAB) on wheat bran. Lactobacillus plantarum , Lactobacillus pentosus , Lactobacillus brevis , Lactobacillus sanfranciscensis and Fructobacillus fructosus produced highly individual fermentation patterns as judged from carbohydrate consumption and organic acid production. Interestingly, fructose was released during all bran fermentations and possibly influenced the fermentation profiles of obligately heterofermentative species to varying degrees. Except for the reduction of ferulic acid by L. plantarum and L. pentosus , analyses of phenolic compounds and alkylresorcinols suggested that only minor changes thereof were induced by the LAB metabolism. Sensory analysis of breads baked with fermented bran did not reveal significant differences regarding perceived bitterness and aftertaste. We conclude that in addition to more traditionally used sourdough species such as L. sanfranciscensis and L. brevis , also facultatively heterofermentative species such as L. plantarum and L. pentosus possess potential for industrial wheat bran fermentations and should be considered in further investigations. [ABSTRACT FROM AUTHOR]

Six Albanian soft and durum wheat cultivars were characterized based on chemical and technological features, showing different attitudes for bread making. Gliadin and glutenin fractions were selectively extracted from flours, and subjected to two-dimensional electrophoresis. Linja 7 and LVS flours showed the best characteristics, and abundance of high molecular weight (HMW)-glutenins. Type I sourdoughs were prepared through back slopping procedure, and the lactic acid bacteria were typed and identified. Lactobacillus plantarum and Leuconostoc mesenteroides were the predominant species. Thirty-eight representative isolates were singly used for sourdough fermentation of soft and durum wheat Albanian flours and their selection was carried out based on growth and acidification, quotient of fermentation, and proteolytic activity. Two different pools of lactic acid bacteria were designed to ferment soft or durum wheat flours. Sourdough fermentation with mixed and selected starters positively affected the quotient of fermentation, concentration of free amino acids, profile of phenolic acids, and antioxidant and phytase activities. This study provided the basis to exploit the potential of wheat Albanian flours based on an integrated approach, which considered the characterization of the flours and the processing conditions. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the free amino acid profile, including gamma-aminobutyric acid (GABA) and ornithine, as well as the biogenic amine and acrylamide content in three types of breads that differed in their baking process and type of fermentation. Eleven commercial breads and twelve artisan sourdough breads from supermarkets and artisan bakeries, respectively, in Barcelona (Spain) were analyzed and compared with experimental bread designed to lower blood pressure and developed at a pilot plant. The experimental bread contained 21% of sourdough rich in GABA (98.2 mg/100 ml) with potassium citrate (0.13%) to partially replace common salt. Significant differences ( p < 0.05) were found between the two groups of breads in pH value, total titratable acidity, GABA concentration, total free amino acid content and acrylamide level. The highest synthesis of GABA (24.2 ± 0.87 mg/100 g) and the presence of tyramine (41.8 mg/kg), which was the only biogenic amine found, were observed in the experimental sourdough bread. [ABSTRACT FROM AUTHOR]

Pandoro is a traditional Italian sweet-leavened baked product, usually consumed at Christmas. It is manufactured according to specific procedures and preparation starts from a sourdough called ‘‘madre’’ (mother sponge) continuously refreshed. This sourdough is the result of a complex microbial association including yeasts and lactic acid bacteria (LAB) and its use can improve sensory quality and shelf-life of the resulting products. The aim of this work was to evaluate the effect of the use of two different sourdoughs matured at different temperature (13 and 19 °C) on some metabolites, which can affect the organoleptic characteristics of Pandoro . Different samples, taken throughout the 19 h of process, were analysed for the determination of yeast and LAB counts, pH, a w , carbohydrates, organic acids content and volatile profile. The results showed that, at the end of fermentation process, the sourdough propagated at 19 °C reached lower pH values than that at 13 °C. This was probably due to higher LAB counts (1 log unit higher), resulting also in higher lactic acid concentration and faster sugars depletion. On the contrary, temperature of dough during maturation did not affected yeast concentrations. Different production processes strongly affected also the volatile profile, both of sourdough at the end of fermentation and of the final products. [ABSTRACT FROM AUTHOR]

Abstract: Candida milleri, together with Candida humilis, is the most representative yeast species found in type I sourdough ecosystems. In this work, comparison of the ITS region and the D1/D2 domain of 26S rDNA gene partial sequences, karyotyping, mtDNA-RFLP analysis, Intron Splice Site dispersion (ISS-PCR) and (GTG)5 microsatellite analyses, assimilation test of different carbohydrates, and metabolome assessment by FT-IR analysis, were investigated in seventeen strains isolated from four different companies as well as in type strains CBS6897T and CBS5658T. Most isolates were ascribed to C. milleri, even if a strong relatedness was confirmed with C. humilis as well, particularly for three strains. Genetic characterization showed a high degree of intraspecific polymorphism since 12 different genotypes were discriminated. The number of chromosomes varied from 9 to 13 and their size ranged from less than 0.3 to over 2 Mbp. Phenotypic traits let to recognize 9 different profiles of carbon sources assimilation. FT-IR spectra from yeast cells cultivated in different media and collected at different growth phases revealed a diversity of behaviour among strains in accordance with the results of PCR-based fingerprinting. A clear evidence of the polymorphic status of C. milleri species is provided thus representing an important feature for the development of technological applications in bakery industries. [Copyright &y& Elsevier]

Abstract: Sprouted seeds possess potential to stimulate the growth and acidifying activity of lactic acid bacteria. Simultaneous enrichment of the sprouted seeds in deficient selenium may create a multifunctional additive to sourdough fermentation with consequent supplementation of human diet. Bread being a staple diet seems to be a perfect carrier of this micronutrient. In the study germinating seeds revealed high ability to accumulate selenium from watering solution, up to 188 mg Se/kg of dried sprouts in the case of lentil. The process of selenium accumulation strongly depended on the plant species resulting in total Se content in soy and lentil biomass twice as high as in rye or wheat sprouts. A high correlation (R 2 = 0.97) between selenium concentration in water and Se accumulation in biomass was observed. Raising of pH from 7.0 to 8.0 increased 2.5 times selenium uptake. The addition of Se-enriched plant biomass had stimulating effect on the sourdough fermentation process allowing to shorten it by 8–16 h, depending on the dose and temperature. Se fortified rye sprouts used in amounts 2.5 g/100 g of flour did not deteriorate sensory quality of bread and raised five times selenium content in it. [Copyright &y& Elsevier]