Optimizing Lactic Acid Bacteria Proportions in Sourdough to Enhance Antifungal Activity and Quality of Partially and Fully Baked Bread.

The organic acids produced by lactic acid bacteria (LAB) during the fermentation of sourdoughs have the ability to reduce the growth of different molds. However, this ability depends on the LAB used. For this reason, in this study, the proportions of different LAB were optimized to obtain aqueous extracts (AEs) from sourdough to reduce fungal growth in vitro, control the acetic acid concentration, and obtain a specific lactic to acetic acid ratio. In addition, the optimized mixtures were used to formulate partially baked bread (PBB) and evaluate the mold growth and bread quality during refrigerated storage. Using a simplex-lattice mixture design, various combinations of Lactiplantibacillus plantarum, Lacticaseibacillus casei, and Lactobacillus acidophilus were evaluated for their ability to produce organic acids and inhibit mold growth. The mixture containing only Lpb. plantarum significantly reduced the growth rates and extended the lag time of Penicillium chrysogenum and P. corylophilum compared with the control. The AEs' pH values ranged from 3.50 to 3.04. Organic acid analysis revealed that using Lpb. plantarum yielded higher acetic acid concentrations than when using mixed LAB. This suggests that LAB-specific interactions significantly influence organic acid production during fermentation. The reduced radial growth rates and extended lag times for both molds compared to the control confirmed the antifungal properties of the AEs from the sourdoughs. Statistical analyses of the mixture design using polynomial models demonstrated a good fit for the analyzed responses. Two optimized LAB mixtures were identified that maximized mold lag time, targeted the desired acetic acid concentration, and balanced the lactic to acetic acid ratio. The addition of sourdough with optimized LAB mixtures to PBB resulted in a longer shelf life (21 days) and adequately maintained product quality characteristics during storage. PBB was subjected to complete baking and sensory evaluation. The overall acceptability was slightly higher in the control without sourdough (7.50), followed by bread formulated with the optimized sourdoughs (ranging from 6.78 to 7.10), but the difference was not statistically significant (p > 0.05). The sensory analysis results indicated that the optimization was used to successfully formulate a sourdough bread with a sensory profile closely resembling that of a nonsupplemented one. The designed LAB mixtures can effectively enhance sourdough bread's antifungal properties and quality, providing a promising approach for extending bread shelf life while maintaining desirable sensory attributes.

Quinoa snack elaborated with Lactiplantibacillus plantarum CRL 1964 sourdough increases the mineral bioavailability in mice.

BACKGROUND: Consumption of pseudocereal-based foods decreased in phytate concentration can provide better nutrition concerning mineral bioavailability. This study aimed to evaluate the mineral bioavailability of quinoa sourdough-based snacks in a murine model. The mice were divided into five groups. One group was fed with basal snacks; three control groups received quinoa-based snacks made from non-fermented dough, dough without inoculum, and chemically acidified dough; and the test group (GF) received quinoa snacks elaborated from sourdough fermented by a phytase-positive strain, Lactiplantibacillus plantarum CRL 1964. Food intake, body weight, and mineral concentration in blood and organs (liver, kidney, and femur) were determined. RESULTS: Food consumption increased during the feeding period and had the highest (16.2-24.5%) consumption in the GF group. Body weight also increased during the 6-weeks of trial. The GF group showed higher (6.0-10.2%) body weight compared with the other groups from the fifth week. The concentrations of iron, zinc, calcium, magnesium, and phosphorus in blood, iron and phosphorus in the liver, manganese and magnesium in the kidney, and calcium and phosphorus in the femur increased significantly (1.1-2.7-fold) in the GF group compared to the control groups. CONCLUSION: The diet that includes quinoa snacks elaborated with sourdough fermented by phytase-positive strain L. plantarum CRL 1964 increased the concentrations of minerals in the blood, liver, kidney, and femur of mice, counteracting the antinutritional effects of phytate. This study demonstrates that the diminution in phytate content and the consequent biofortification in minerals are a suitable tool for producing novel foods. © 2024 Society of Chemical Industry.

The effects of fermentation time on sourdough bread: An analysis of texture profile, starch digestion rate, and protein hydrolysis rate.

To ensure the best quality bread, it is important to consider the speed of digestion of starch and proteins, as well as how time fermentation and storage time influence the rate of starch digestion and the texture of the bread. This study compared the effect of fermentation time and days of storage on the texture, physicochemical, protein and starch digestibility of sourdough bread. Texture profile analysis showed that the fermentation time in recently baked sourdough bread affects hardness, chewiness, and springiness. The electrophoretic profile showed a decrease in band thickness with increase in fermentation time, consistent with a higher percentage of protein digestion. While fermentation time did not significantly affect rapidly digestible starch (RDS) and slowly digestible starch (SDS), storage time resulted in a decrease in RDS and an increase in SDS. Sourdough breads had higher levels of resistant starch (RS). The digestibility characteristics of protein and starch, as well as texture properties, are significantly influenced by fermentation and storage time. The evidence suggests that sourdough bread has the potential to improve the digestion of protein and to effectively regulate the glycemic response, which is due to its higher levels of SDS and RS.

Influence of Limosilactobacillus fermentum IAL 4541 and Wickerhamomyces anomalus IAL 4533 on the growth of spoilage fungi in bakery products.

Fungi are the main microorganisms responsible for the spoilage of bakery products, and their control and subsequent reduction of food waste are significant concerns in the agri-food industry. Synthetic preservatives are still the most used compounds to reduce bakery product spoilage. On the other hand, studies have shown that biopreservation can be an attractive approach to overcoming food and feed spoilage and increasing their shelf-life. However, limited studies show the preservation effects on real food matrices. Therefore, this study aimed to investigate the influence of microorganisms such as lactic acid bacteria (LAB) and yeasts on the growth of spoilage filamentous fungi (molds) on bread and panettones. In general, on conventional and multigrain bread, treatments containing Limosilactobacillus fermentum IAL 4541 and Wickerhamomyces anomalus IAL 4533 showed similar results when compared to the negative control (calcium propionate) in delaying the fungal growth of the tested species (Aspergillus chevalieri, Aspergillus montevidensis, and Penicillium roqueforti). Different from bread, treatments with W. anomallus in panettones delayed the A. chevalieri growth up to 30 days, 13 days longer than observed on negative control (without preservatives). This study showed that biopreservation is a promising method that can extend bakery products' shelf-life and be used as an alternative to synthetic preservatives.

Consortia of lactic acid bacteria strains increase the antioxidant activity and bioactive compounds of quinoa sourdough - based biscuits.

The aim of this work was to use consortia (two or three strains) of lactic acid bacteria (LAB) [Lactiplantibacillus plantarum CRL 1964 and CRL 1973, and Leuconostoc mesenteroides subsp. mesenteroides CRL 2131] to obtain quinoa sourdoughs (QS) for further manufacturing of quinoa sourdough-based biscuits (QB). Microbial grow and acidification were evaluated in QS while antioxidant activity (AOA), total phenolic compounds (TPC) and total flavonoid compounds (TFC) were determined in QS and QB. QS inoculated with LAB consortia respect to monocultures showed higher growth and acidification, AOA (7.9?42.6%), TPC (19.9?35.0%) and TFC (6.1?31.6%). QB prepared with QS inoculated by LAB consortia showed higher AOA (5.0-81.1%), TPC (22.5?57.5%) and TFC (14.0-79.9%) than biscuits inoculated by monocultures sourdoughs. These results were attributed to a synergic effect from LAB consortia. Principal component analysis showed the highest scores of the evaluated characteristics for biscuits made with consortia sourdough of two (CRL1964?+?CRL2131) and three (CRL1964?+?CRL1973?+?CRL2131) strains.

Toward Sourdough Microbiome Data: A Review of Science and Patents.

Technological prospecting was performed on documents related to sourdough microbiota using SCOPUS, Web of Science, Google Scholar, Espacenet and Patent Inspiration databases. Scientific articles and patents were analyzed based on three different perspectives: macro (year of publication, country, and institutions), meso (categorization as different taxonomies according to the subject evaluated), and micro (in-depth analysis of the main taxonomies, gathering the documents in subcategories). The main subject addressed in patents was the starter and product preparation, while 58.8% of the scientific publications focused on sourdough starter microbiota (identification and selection of microorganisms). Most patents were granted to companies (45.9%), followed by independent inventors (26.4%) and universities (21.8%). Sourdough products are in the spotlight when the subject is the bakery market; however, a closer integration between academia and industry is needed. Such a collaboration could generate a positive impact on the sourdough market in terms of innovation, providing a bread with a better nutritional and sensory quality for all consumers. Moreover, sourdough creates a new magnitude of flavor and texture in gastronomy, providing new functional products or increasing the quality of traditional ones.

Antifungal Capacity of Poolish-Type Sourdough Supplemented with Lactiplantibacillus plantarum and Its Aqueous Extracts In Vitro and Bread.

This study aimed to evaluate the antifungal capacity of the aqueous extracts (AE) of poolish-type sourdoughs fermented with Lactiplantibacillus plantarum NRRL B-4496 on broth, agar, and bread. The aqueous extracts were obtained by centrifugation and separating the supernatant from the poolish sourdoughs once the fermentation time had ended. The aqueous extracts inhibited 80% of the growth of Penicillium chrysogenum and Penicillium corylophilum and <20% of Aspergillus niger in broth. The AEs delayed the radial growth rate and increased the lag time for the three molds tested. The addition of poolish-type sourdoughs inhibited fungal growth in bread for ten days. The extracts' fungistatic capacity was primarily attributed to lactic and acetic acids and probably the antifungal peptides occurring in the AE. The L. plantarum sourdough is an alternative to calcium propionate as an organic antifungal agent.

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.

Influence of Preferments on the Physicochemical and Sensory Quality of Traditional Panettone.

In Peru, panettones are consumed in July and December. The main ingredient of panettones is wheat flour, which can be replaced with substitute flours to improve their nutritional, textural and sensory properties. This study aimed to evaluate the physicochemical, textural and sensory characteristics of panettones produced with three preferments, namely, biga (PB), sourdough (PMM) and sponge (PE), with the substitution of red quinoa flour and amaranth compared with a commercial product (PC). A completely randomized design with four experimental treatments was used to evaluate the total carbohydrate content, ash, total energy, fat, moisture, protein, color and texture profile. In addition, sensory characteristics were evaluated by 80 consumers using the CATA method; the purchase intention and preference ranking were also investigated. The results showed better sensory characteristics of panettones produced with preferments compared with a commercial product with similar characteristics. The sponge preferment presented better sensory characteristics with a profile of sweet, spongy, vanilla odor and moist texture, along with greater acceptability, preference and purchase intention, followed closely by the biga. It was concluded that the sponge preferment presented better sensory properties, which were correlated with its texture profile as manifested by an intermediate hardness, good elasticity and cohesiveness, which translated into greater acceptability, preference and purchase intention.

Consumption of sourdough bread and changes in the glycemic control and satiety: A systematic review.

The aim of this study was to carry out a systematic review of clinical trials followed by meta-analysis, to evaluate the effect of sourdough bread on glycemic control and appetite and satiety regulators such as leptin, ghrelin, GLP-1 (glucagon-like peptide-1), GLP-2 (glucagon-like peptide-2), NPY (neuropeptide Y), AgRP (agouti-related protein), PYY (peptide YY), and GIP (glucose-dependent insulinotropic polypeptide). Clinical trials compared the intake of sourdough bread to that of an industrially fermented one or control glucose solution in adults over 18 years of age. This systematic review included all randomized, parallel, or crossover trials published up to June 2021 in the EMBASE, MEDLINE, Scopus, and Web of Science databases. After the selection process, 18 studies were included. The analysis of the final average difference of the change in serum glucose after 60 minutes for the intervention indicated that the consumption of sourdough bread has a lower impact on blood glucose compared to that of industrial bread or glucose (MD = -0.29, IC 95% = [-0.46; -0.12]; I2 = 0%). The evaluation of blood glucose 120 minutes after the consumption of the intervention also indicated a lower increment in blood glucose when compared to the consumption of other types of bread or the same amount of glucose (MD = -0.21, IC 95% = [-0.32; -0.09]; I2 = 0%). The certainty of evidence varied from low to very low. The results showed that sourdough is effective in reducing the increment of postprandial glycemia, especially when prepared with whole wheat flour, although it does not reduce fasting serum insulin, nor does it change plasma PYY.

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.

Parámetros de incubación del starter de Lactobacillus para su aplicación en pan campesino / Incubation parameters of the Lactobacillus starter for application in sourdough bread

RESUMEN El fermento natural o starter es un insumo panadero, que se ha revalorizado, en la actualidad, por sus beneficios y por su aporte de sabor. En este estudio, se determinaron los parámetros de cultivo del starter espontáneo de Lactobacillus, a partir de harina integral, para aplicarlo en la elaboración de pan campesino, en función de sus características sensoriales y mecánicas. Se elaboraron tres starters, para lo cual, se mezcló harina integral con agua, en una proporción de 45,5 y 54,5%, respectivamente; posterior a ello, se fermentaron, espontáneamente, a 20, 24 y 28°C, hasta un pH final de 4, a partir de los cuales, se elaboraron panes campesinos. Los panes fueron evaluados sensorialmente, por un panel de expertos (07), mediante una escala lineal no estructurada de 5 puntos, en cuanto a la forma ovalada, apariencia de la costra, masticabilidad de miga, gusto ácido y apariencia de los alveolos. El pan elaborado con el fermento a 24°C fue seleccionado por los panelistas, debido a que presentó puntajes superiores (p<0,05), en los atributos de apariencia de la costra (4,24), masticabilidad de la miga (5,0), gusto ácido (4,67) y apariencia de los alveolos (4,0). El fermento empleado presentó 79 x 107 UFC g-1 de bacterias acidolácticas. Finalmente, la textura del pan campesino seleccionado fue caracterizada instrumentalmente en términos de dureza (102,09N), gomosidad (43,02N), masticabilidad (37,36N), elasticidad (0,87) y cohesividad (0,42), perfil que se puede emplear como parámetro de calidad, para pan campesino y otras variedades similares.

ABSTRACT The natural ferment or sourdough starter is a bakery input that has been revalued nowadays for its benefits and flavour improve. In this study, the incubation parameters of the spontaneous Lactobacillus starter made with wholemeal flour were determined to be applied in sourdough bread production depending on its sensory and mechanical characteristics. Three starters were made with wholemeal flour mixed with water in a proportion of 45.5 and 54.5% respectively, then were fermented spontaneously at 20, 24 and 28°C until a final pH of 4, from which sourdough breads were produced. The breads were sensory evaluated by a panel of experts (07), using a 5-point unstructured linear scale, in terms of oval shape, crust appearance, crumb chewiness, sourness and alveoli appearance. The bread made with the starter at 24°C was selected because of the higher scores (p<0.05) in the attributes of crust appearance (4.24), crumb chewiness (5.0), sourness (4.67) and alveoli appearance (4.0). The starter used exhibit 79 x 107 CFU g-1 of lactic acid bacteria. Finally, the texture of the selected sourdough bread was characterized in terms of hardness (102.09N), gumminess (43.02N), chewiness (37.36N), springiness (0.87) and cohesiveness (0.42), a profile that can be used as a quality parameter for sourdough bread and other similar varieties.

Biodiversity and technological-functional potential of lactic acid bacteria isolated from spontaneously fermented chia sourdough.

Chia, is a gluten-free, rich in proteins, oilseed that is "on trend" as an alternative ingredient in food production, adding nutritional value. As a reservoir of natural biodiversity, lactic acid bacteria development, during spontaneous chia flour fermentation (sourdough) for 10 days, were investigated by culturing and high throughput sequencing (HTS). Culture-dependent analysis showed a rapid increase in total LAB numbers from the second day of sourdough refreshment. Taxonomical identification of LAB isolates by rep-PCR and further 16S rRNA sequencing was performed. Besides Among identified LAB by culture-dependent approach, species from genus Enterococcus were the most abundant; Lactococcus (Lc. lactis), Lactobacillus (L. rhamnosus) and Weissella (W. cibaria) species were also isolated. By HTS, twelve OTUs belonging to LAB genera were identified during chia sourdough fermentation with an increased Lactobacillus diversity. Enterococcus (E.) faecium, E. mundtii, W. cibaria and L. rhamnosus were detected as dominant species in the final propagation stages while Bacillus and Clostridium were mostly present during first fermentation stages. The investigation of biotechnological and safety traits (acidification ability, protein hydrolysis, exopolysaccharides production, antimicrobial activity and antibiotic resistance) of 15 representative LAB strains was performed. Strains characterization led to the selection of Lc. lactis CH179, L. rhamnosus CH34 and W. cibaria CH28 as candidates to be used as novel functional starter culture for gluten-free chia fermented products. As far as we know, this is the first study providing information on the molecular inventory of LAB population during spontaneous fermentation of chia sourdough.

Stability, sensory attributes and acceptance of panettones elaborated with Lactobacillus fermentum IAL 4541 and Wickerhamomyces anomallus IAL 4533.

This work aimed to elaborate sourdough panettones with Lactobacillus fermentum (LF) and Wickerhamomyces anomallus (WA) evaluating their microbiological stability, physical and chemical characteristics as well as the impact of these microorganisms on sensory aspects and consumer acceptance. For characterization, panettones were elaborated by long fermentation, using two selected microorganisms, LF and WA in different proportions; and control panettones were formulated using commercial yeast with and without preservative. For sensory analyses, LF, WA, LF/WA (1:1), control with calcium propionate and commercial panettones were compared. Regarding the pH values and total titratable acidity (TTA), a similar behavior was observed among panettones elaborated with the selected strains (LF, WA and mixtures). On the other hand, panettones elaborated with commercial yeast showed a higher pH and lower TTA. Until the 112nd day of storage, the water activity (aw) was similar among all panettones, but in the following analyses, it dropped in all panettones. Panettones elaborated with sourdough maintained better their softness during the storage, when compared with the controls. Regarding microbial stability, control panettones with and without preservative became moldy faster; while sourdough panettones (WA and LF/WA) remained stable throughout all the monitored storage. Sensory evaluation by CATA allowed distinguishing between sourdough and commercial yeast panettones. Desirable characteristics such as nice aroma, pleasant taste and uniform color were checked more often for LF and WA elaborated panettones, whereas yeast flavor was checked more often for the Commercial. Moreover, according to the descriptors used, panettones were grouped into 3 groups: LF/WA, LF + WA and controls. The panettones elaborated with the specific microorganisms of this study were well-accepted sensorially, proving to be very competitive with respect to control and commercial panettone. So, the use of selected microorganisms as a starter for sourdough is a promising alternative for producing panettones with good technological quality, microbiological stability, sensorially differentiate and well accepted by consumers; and, additionally, with the appeal of no added preservative.

Survival and stability of Lactobacillus fermentum and Wickerhamomyces anomalus strains upon lyophilisation with different cryoprotectant agents.

The stability of microorganisms along the time is important for allowing their industrial use as starter agents, improving fermentation processes. This study aimed to evaluate the survival and maintenance of the cell viability of the lactic acid bacteria Lactobacillus fermentum IAL 4541 and the yeast Wickerhamomyces anomalus IAL 4533, both isolated from wheat sourdough, after lyophilisation with different cryoprotectant and storage at room temperature along a year. Treatments involved adding control solution (S1 = 0.1% peptone water), and four cryoprotectant solutions S2 (10% sucrose), S3 (5% trehalose), S4 (10% skim milk powder) and S5 (10% skim milk powder plus 5% sodium glutamate) to the microbial cells previously of freeze drying processing. To verify the effect of lyophilisation on the number of microbial cells recovered, microbiological analyses were performed and cell viability was calculated before and after lyophilisation and regularly during a storage period of 365 days at room temperature. Viability after freeze-drying was influenced by the cryoprotectant agent employed, as well the microbial stability conferred along the storage. Differences on the microorganism response to some protectors were observed between the lactic acid bacteria and the yeast evaluated. W. anomalus was more affected by absence of cryoprotectant (S1) during freeze drying processing, but this microorganism was more stable than L. fermentum along the storage without the presence of protectant agents. For L. fermentum, S5 was the best protectant, allowing the recovering of 100% of the bacterial cells after lyophilisation and 87% of cell viability was observed after one year storage, followed by S4 (96 and 74%, respectively). S4 and S5 were the best protectant to W. anomalus (viability >80% after 1 year), but no increase in the yeast cell viability was conferred by addition of glutamate (S5) to skim milk. After 1 year of storage, trehalose was much more effective on protection of the yeast than bacteria (72% and 7% of viability, respectively). S2 was the less protectant agent among the tested, and their effectiveness was higher in L. fermentum (allowing 14% of cell recovering up to 120 days of storage) if compared to W. anomalus (25% of viability until 90 days of storage). Our results demonstrate that freeze-drying is a realistic technology for the stability and maintenance of the potential sourdough starter L. fermentum and W. anomalus for long time; however, the choice of cryoprotectant will influence the process effectiveness.

Effects of Sourdough on FODMAPs in Bread and Potential Outcomes on Irritable Bowel Syndrome Patients and Healthy Subjects.

Background: Fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) are an heterogeneous group of compounds that can be poorly digested and may have a range of effects on gastrointestinal processes. FODMAPs are found in a wide variety of foods, including bread. FODMAPs' intake is associated with the onset of symptoms of irritable bowel syndrome (IBS). On the other hand, some FODMAPs contribute to the healthy maintenance of intestinal microbiota. Volume increase of bread dough commonly relies on the use of two biological leavening agents, sourdough and baker's yeast and, in some cases, a combination of both. Scope and Approach: The main objective of this review is to discuss the association between FODMAPs and IBS, beneficial effects of FODMAPs on healthy subjects and potential impact of biological leavening agents on FODMAPs content of bread. Key Findings and Conclusion: Given that yeasts and lactic acid bacteria, the dominant microorganisms in sourdough, may degrade FODMAPs, it would be possible to modulate the FODMAPs concentration in bread, thus positively affecting consumers' health.

Molecular identification and technological characterization of lactic acid bacteria isolated from fermented kidney beans flours (Phaseolus vulgaris L. and P. coccineus) in northwestern Argentina.

Legumes are an important protein source in developing countries and their flours represent an attractive alternative for the manufacture of gluten free products. In the present study, 4 kidney bean varieties (Alubia, Pallar, Black and Red beans) commonly cultivated in northwestern Argentina, were milled and spontaneously fermented in order to isolate and select autochthonous lactic acid bacteria (LAB) with relevant technological and functional properties for usage as starter cultures. Twelve doughs were fermented with daily back-slopping at 37°C for 6days and evolution of total mesophiles, lactic acid bacteria, and yeasts and molds populations were followed by plate counting. A combination of phenotypic and genotypic methods including (GTG)5-based PCR fingerprinting and 16S rRNA gene sequencing were used to differentiate and identify the isolated LAB to species level. LAB counts ranged from around 0.89±0.81 to 8.74±0.03logcfu/g with a pH decline from 6.4 to 3.9 throughout fermentation. Four genera and nine species of LAB: Enterococcus durans, E. faecium, E. mundtii, E. casseliflavus; Lactobacillus rhamnosus, Lactococcus garvieae, Weissella cibaria and W. paramesenteroides were found on kidney beans. Twenty five LAB strains were assessed for their abilities to grow on kidney bean extracts, acidifying capacities (pH and acidification rates), amylolytic, proteolytic, tannase and gallate decarboxylase activities as well as pathogens inhibition by antimicrobials. Based on these properties E. durans CRL 2178 and W. paramesenteroides CRL 2182 were inoculated singly and combined in Alubia kidney bean flour and fermented for 24h at 37°C. LAB strains were beneficial for removing trypsin inhibitors and tannins from sourdoughs and for improving amino acids and phenolics contents, increasing the antioxidant activities of kidney bean matrices. Selected strains have potential as starter cultures for obtaining fermented bean products with high nutritional and functional quality.

Lactic Acid Fermentation Improved Textural Behaviour, Phenolic Compounds and Antioxidant Activity of Chia (Salvia hispanica L.) Dough.

In this work, autochthonous lactic acid bacteria (LAB) were isolated from chia (Salvia hispanica L.) dough and selected on the basis of the kinetics of acidification and proteolytic activity. Strain no. C8, identified as Lactobacillus plantarum C8, was selected and used as starter to obtain chia sourdough. Lactic acid fermentation increased the organic acid mass fractions (lactic, acetic and phenyl lactic acids to 12.3 g, 1.0 g and 23.8 µg per kg of dough respectively), and antioxidant activities, which increased by approx. 33-40% compared to unfermented chia flour dough. In addition, total phenolic content increased 25% and its composition was strongly modified after 24 h of fermentation by L. plantarum C8. Chlorogenic acid was only found in the fermented dough (2.5 mg/g), while ferulic acid was detected from the beginning of fermentation, being 32% higher in chia sourdough (5.6 mg/g). The use of fermented chia sourdough improved the overall characteristics of white bread, including physical (e.g. reduced hardness and chewiness of the crumb) and antioxidant properties (25% on average), compared to the white bread. These results indicate that the use of chia sourdough could be a promising alternative to improve the technological and antioxidant properties of wheat bread. In addition, this work has shown, for the first time, that lactic acid bacterium is able to ferment chia dough, improving its overall characteristics.

Biodiversity and technological potential of lactic acid bacteria isolated from spontaneously fermented amaranth sourdough.

UNLABELLED: Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence of autochthonous lactic acid bacteria (LAB) predominating microbiota. The doughs were fermented with daily backslopping on a laboratory scale at 30°C for 10 days. LAB counts ranged from 2·60 to 8·54 log CFU g(-1) with a pH declined from 6·2 to 3·8 throughout fermentation. The combined use of randomly amplified polymorphic DNA (RAPD)-PCR analysis and sequence analysis of 16S rRNA was applied for LAB intraspecies differentiation and taxonomic identification, respectively. Enterococcus, Pediococcus and Lactobacillus species were present in amaranth sourdoughs (AS). After the first refreshment step, Lactobacillus plantarum dominated AS until the end of fermentation. In coincidence, when DGGE analysis was performed, the occurrence of a progressive change in bacterial communities allowed the selection of Lact. plantarum as a dominant species. Moreover, technological, functional and safety characteristics of representative RAPD-biotypes were investigated. Lact. plantarum CRL1898 was selected as a potential candidate for gluten-free amaranth sourdough starter. SIGNIFICANCE AND IMPACT OF THE STUDY: Nowadays, there is an increasing interest in ancient noncereal gluten-free (GF) crops such as amaranth, due to their reported nutritional and health benefits. However, the use of these grains is still limited to traditional foods and bread making processes that are not yet well standardized. Results on the dynamics of autochthonous lactic acid bacteria (LAB) microbiota during laboratory spontaneous amaranth sourdoughs (AS) fermentation will contribute to overcome challenges for GF-fermented products development. In addition, knowledge about LAB diversity involving Enterococcus, Pediococcus and Lactobacillus species, with Lactobacillus plantarum predominating during AS fermentation, and their technological and functional properties provides the basis for the selection of autochthonous strains as starters cultures for novel gluten-free bakery products with enhanced nutritional, sensory and/or safety quality.

Biodiversity and technological-functional potential of lactic acid bacteria isolated from spontaneously fermented quinoa sourdoughs.

AIMS: To analyse lactic acid bacteria (LAB) diversity and technological-functional and safety properties of strains present during spontaneous fermented quinoa sourdoughs. METHODS AND RESULTS: Fermentation was performed by daily backslopping at 30°C for 10 days. Autochthonous LAB microbiota was monitored by a biphasic approach combining random amplified polymorphic DNA (RAPD)-PCR and rRNA gene sequencing with PCR-denaturing gradient gel electrophoresis (DGGE) analysis. Identification and intraspecies differentiation allowed to group isolates within nine LAB species belonging to four genera. A succession of LAB species occurred during 10-days backslopping; Lactobacillus plantarum and Lactobacillus brevis were detected as dominant species in the consortium. The characterization of 15 representative LAB strains was performed based on the acidifying capacity, starch and protein hydrolysis, γ-aminobutyric acid and exopolysaccharides production, antimicrobial activity and antibiotic resistance. CONCLUSION: Strains characterization led to the selection of Lact. plantarum CRL1905 and Leuconostoc mesenteroides CRL1907 as candidates to be assayed as functional starter culture for the gluten-free (GF) quinoa fermented products. SIGNIFICANCE AND IMPACT OF THE STUDY: Results on native LAB microbiota present during quinoa sourdough fermentation will allow the selection of strains with appropriate technological properties to be used as a novel functional starter culture for GF-fermented products.