The contribution of P. acidilactici, L. plantarum, and L. curvatus starters and L-(+)-lactic acid to the acrylamide content and quality parameters of mixed rye - Wheat bread

Microbial Community Dynamics and Metabolite Changes during Wheat Starch Slurry Fermentation

Wheat starch fermentation slurry is the main substrate for producing Ganmianpi, a traditional Chinese fermented wheat starch-based noodle. In the present work, the microbial population dynamics and metabolite changes in wheat starch fermentation slurry at different fermentation times (0, 1, 2, 3, and 4 days) were measured by using high-throughput sequencing analysis and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS) methods. The texture and sensory properties of Ganmianpi made from fermented starch slurry are also evaluated. The results showed that Latilactobacillus curvatus and Leuconostoc citreum were the dominant bacteria in wheat starch fermentation slurry, while Saccharomyces cerevisiae and Kazachstania wufongensis were identified as the main species of fungi. With the extension of fermentation time, the reducing sugar content first increased and then decreased, when the titratable acidity content showed an increasing trend, and the nonvolatile acid was significantly higher than the volatile acid. A total of 62 volatile flavor compounds were identified, and the highest content is alcohols, followed by acids. Fermentation significantly reduced the hardness and chewiness of Ganmianpi, and increased its resilience and cohesiveness. Ganmianpi made from fermented starch slurry for two and three days showed a higher sensory score than other samples. The present study is expected to provide a theoretical basis for exploiting the strains with potential for commercial application as starter cultures and quality improvement of Ganmianpi.

Changes in Chemical Composition of Lentils, Including Gamma-Aminobutyric Acid and Volatile Compound Formation during Submerged and Solid-State Fermentation with Pediococcus acidilactici

The aim of this study was to evaluate and compare the characteristics of non-treated and fermented [via submerged (SMF) and solid-state (SSF) fermentation using Pediococcus acidilactici] lentils (Lens culinaris) grown either in pure stands (L) or relay intercropped with winter rye (LR). It was observed that the lentils were suitable substrate for lacto-fermentation. Most of the free amino acid concentrations increased in lentils after both fermentations. The highest concentration of γ-aminobutyric acid was found in SSF LR samples. However, fermentation led to higher biogenic amines (BA) content in lentils. The most abundant fatty acid in lentils was C18:2. SSF lentils showed more complex volatile compound (VC) profiles (with between nine and seventeen new VCs formed), whereas, in SMF samples, between two and five newly VCs were formed. When comparing lentil grown types, L contained significantly higher concentrations of Na, K, Ca, P, Mn, and Se, while LR contained significantly higher concentrations of Fe and Ni. To sum up, fermentation with lactic acid bacteria (LAB) contributed to the improved biological value of lentils; still, the quantity of BA needs to be considered. Further investigations into the P. acidilactici metabolism of certain compounds (such as phenolic and antinutritional compounds) in lentils during fermentation ought to be carried out.

Unlocking the potential of low FODMAPs sourdough technology for management of irritable bowel syndrome

Consumption of high FODMAP (Fermentable Oligo-, Di-, and Monosaccharides and Polyols) diet is the leading cause of alteration in the human gut microbiome, thereby, causing irritable bowel syndrome (IBS). Therefore, sourdough technology can be exploited for reduction of FODMAPs in various foods to alleviate the symptoms of IBS. Several microorganisms viz. Pichia fermentans, Lactobacillus fetmentum, Saccharomyces cerevisiae, Torulaspora delbrueckii, Kluyveromyces marxianus etc. have been identified for the production of low FODMAP type II sourdough fermented products. However, more research on regulation of end-product and volatilome profile is required for maximal exploitation of FODMAP-reducing microorganisms. Therefore, the present review is focused on utilisation of lactic acid bacteria and yeasts, alone and in synergy, for the production of low FODMAP sourdough foods. Moreover, the microbial bioprocessing of cereal and non-cereal based low FODMAP fermented sourdough products along with their nutritional and therapeutic benefits have been elaborated. The challenges and future prospects for the production of sourdough fermented low FODMAP foods, thereby, bringing out positive alterations in gut microbiome, have also been discussed.

Psyllium husk gel used as an alternative and more sustainable scalding technology for wheat bread quality improvement and acrylamide reduction

This study aimed at evaluating the influence of different amounts (5, 10, 15, 20, and 25%) of psyllium husk gel (PHG) on wheat bread (WB) characteristics - chiefly, overall acceptability (OA), porosity, specific volume (v), mass loss after baking (ML), shape retention coefficient, crust and crumb color coordinates, bread crumb hardness during storage, saccharides content, and acrylamide (AA) concentration. PHG was prepared by mixing 100 g of psyllium husk powder with 800 mL of warm water. It was established that the amount of psyllium husk gel is a significant factor in dough redness (a*) (p < 0.001). A moderate positive correlation (r) was found between acrylamide content in wheat bread and maltose concentration in dough (r = 0.567). The psyllium husk gel increased the overall acceptability and specific volume of wheat bread. Wheat bread porosity showed a moderate positive correlation with mass loss after baking (r = 0.567) and a strong positive correlation with texture hardness (r = 0.664). Lower acrylamide content was obtained in wheat bread prepared with 5, 10, 15, 20, and 25% of psyllium husk gel (1.53, 2.34, 3.80, 2.69, and 3.62 times lower than the control wheat bread, respectively). Acrylamide content showed a strong positive correlation with the porosity of wheat bread (r = 0.672), with crust brightness (L*), and yellowness/blueness (b*) coordinates, as well as with crumb brightness, redness, and yellowness coordinates. Overall, psyllium husk gel hydrocolloids reduced acrylamide formation in wheat bread and can be recommended for the quality improvement of wheat bread.

Formulation and Processing Strategies to Reduce Acrylamide in Thermally Processed Cereal-Based Foods

Acrylamide, a thermal process contaminant, is generated in carbohydrate-rich foods processed at high temperatures (above 120 °C). Since acrylamide indicates a human health concern, the acrylamide contents of various foods and the dietary exposure of the population to acrylamide are very well investigated. Commonly consumed foods in the daily diet of individuals such as bakery products, potato products and coffee are major dietary sources of acrylamide. In recent years, dietary exposure levels of the population and mitigation measures for reducing acrylamide in different food products have gained importance to decrease the public's exposure to acrylamide. Since the complete elimination of acrylamide in foods is not possible, various mitigation measures to reduce acrylamide to levels as low as reasonably achievable have been developed and applied in the food industry. Mitigation strategies should be applied according to the different product categories during agricultural production, formulation, processing and final consumer preparation stages. The aim of this review is to evaluate formulation and processing strategies to reduce acrylamide in various cereal-based food products and to discuss the applicability of mitigation measures in the food industry by taking into consideration the organoleptic properties, nutritional value, cost and regulations in the light of current knowledge.

The Contribution of Scalded and Scalded-Fermented Rye Wholemeal Flour to Quality Parameters and Acrylamide Formation in Semi-Wheat-Rye Bread

The aim of this study was to evaluate the influence of scalded (Sc) and scalded-fermented (FSc) (with Lactiplantibacillus paracasei No. 244 strain) rye wholemeal flour on the quality parameters and acrylamide formation in semi-wheat-rye bread. To that purpose, 5, 10 and 15% of Sc and FSc were used for bread production. Results showed that scalding increased fructose, glucose and maltose content in rye wholemeal. Lower concentrations of free amino acids were found in Sc when compared with rye wholemeal, but fermentation of Sc increased the concentrations of some amino acids (on average by 1.51 times), including gamma aminobutyric acid (GABA, by 1.47 times). Addition of Sc and FSc had a significant influence (p ≤ 0.05) on bread shape coefficient, mass loss after baking and most bread colour coordinates. Most of the breads with Sc or FSc showed lower hardness after 72 h of storage compared with the control (i.e., without Sc or FSc). FSc improved bread colour and flavour, as well as overall acceptability. Breads with 5 and 10% of Sc had a similar level of acrylamide to the control, while its level in breads with FSc was higher (on average, 236.3 µg/kg). Finally, different types and amounts of scald had varying effects on the quality of the semi-wheat-rye bread. FSc delayed staling and improved sensory properties and acceptability, as well as the GABA level of wheat-rye bread, while the same level of acrylamide as was seen in control bread could be reached when using between 5 and 10% of scalded rye wholemeal flour.

Changes in the physicochemical parameters and microbial community of a new cultivar blue wheat cereal wholemeal during sourdough production

Changes in the characteristics of a new cultivar (DS8472-5) of blue wheat during wholemeal fermentation with Pediococcus acidilactici (LUHS29), Liquorilactobacillus uvarum (LUHS245), and Lactiplantibacillus plantarum (LUHS122), including acidity, microbiological and chromaticity parameters, free amino acid (FAA), gamma-aminobutyric acid (GABA), and biogenic amine (BA) contents, macro- and micro-element concentrations and fatty acid (FA) and volatile compounds (VC), were evaluated. In addition, a metagenomic analysis was performed. The lactic acid bacteria (LAB) strains used for fermentation was a significant factor in wholemeal fermentation sample pH, redness (a*) and LAB counts (p ≤ 0.05). In most of the samples, fermentation increased the FAA content in wheat wholemeal, and the highest concentration of GABA was found in DS8472-5 LUHS122 samples. Phenylethylamine (PHE) was found in all wheat wholemeal samples; however, spermidine was only detected in fermented samples and cadaverine only in DS8472-5 LUHS122. Fermented samples showed higher omega-3 and omega-6 contents and a higher number and variety of VC. Analysis of the microbial profile showed that LAB as part of the natural microbiota present in cereal grains also actively participates in fermentation processes induced by industrial bacterial cultures. Finally, all the tested LAB were suitable for DS8472-5 wheat wholemeal fermentation, and the DS8472-5 LUHS122 samples showed the lowest pH and the highest LAB viable counts (3.94, 5.80°N, and 8.92 log10 CFU/g, respectively).

The Potential of Traditional ‘Gaja’ and New Breed Lines of Waxy, Blue and Purple Wheat in Wholemeal Flour Fermentation

The aim of this study was to analyse and compare the acidity, microbiological and colour characteristics, fatty (FA) and amino (AA) acid profiles, biogenic amine (BA) and gamma-aminobutyric acid (GABA) concentrations, and macro- and microelement contents in non-treated (non-fermented) and fermented wholemeal cereal flours of ‘Gaja’ (traditional wheat) and new breed lines DS8888-3-6 (waxy wheat), DS8548-7 (blue wheat) and DS8535-2 (purple wheat). Independent fermentations were undertaken with selected strains of Pediococcus acidilactici, Liquorilactobacillus uvarum and Lactiplantibacillus plantarum. The results revealed that all the wholemeal cereal flours of the analysed wheat varieties are suitable for fermentation with the selected strains because all the fermented samples showed lactic acid bacteria (LAB) viable counts higher than 8.00 log10 CFU/g and desirable low pH values. In most of the cases, fermentation increased the concentration of essential amino acids in the wholemeal cereal samples, and the LAB strain used for fermentation proved to be a significant factor in all the essential amino acid content of wholemeal wheat (p ≤ 0.0001). When comparing the non-fermented samples, the highest GABA content was found in ‘Gaja’ and waxy wheat samples (2.47 µmol/g, on average), and, in all the cases, fermentation significantly increased GABA concentration in the wholemeal cereals. On the other hand, total levels of biogenic amines in wholemeal samples ranged from 22.7 to 416 mg/kg. The wheat variety was a significant factor in all the analysed macro- and microelement contents (p ≤ 0.0001) in the wholemeal cereals. Furthermore, fermentation showed to be a significant factor in most of the FA content of the wholemeal cereal samples. Finally, fermentation can also contribute to improving the biological and functional value of wholemeal wheat flours (by increasing essential amino acids and GABA concentrations); however, safety parameters (e.g., biogenic amines) also should be taken into consideration when optimizing the most appropriate technological parameters.

Improvement of Sourdough and Bread Qualities by Fermented Water of Asian Pears and Assam Tea Leaves with Co-Cultures of Lactiplantibacillus plantarum and Saccharomyces cerevisiae

Qualities of sourdough and sourdough bread using fermented water from Asian pears and Assam tea leaves with Lactiplantibacillus plantarum 299v and Saccharomyces cerevisiae TISTR 5059 as starter cultures were evaluated. Changes in the growth of lactic acid bacteria and yeast, pH, sourdough height, total phenolic contents (TPCs) and antioxidant activities detected by ORAC, FRAP and DPPH radical scavenging assays were monitored during sourdough production. Mature sourdough was achieved within 4 h after 18 h retard fermentation and used for bread production. The bread was then analyzed to determine chemical and physical properties, nutritional compositions, TPCs, antioxidant activities and sensory properties as well as shelf-life stability. Results showed that fermented water significantly promoted the growth of yeast and increased TPCs and antioxidant activities of sourdough. Compared to common sourdough bread, fermented water sourdough bread resulted in 10% lower sugar and 12% higher dietary fiber with improved consumer acceptability; TPCs and antioxidant activities also increased by 2–3 times. The fermented water sourdough bread maintained microbial quality within the standard range, with adequate TPCs after storage at room temperature for 7 days. Fermented water from Asian pears and Assam tea leaves with L. plantarum 299v and S. cerevisiae TISTR 5059 as starter cultures improved dough fermentation and bread quality.

Comparison Study of Nontreated and Fermented Wheat Varieties 'Ada', 'Sarta', and New Breed Blue and Purple Wheat Lines Wholemeal Flour

The aim of this study was to analyze and compare the acidity, microbiological, and chromaticity parameters; fatty acid (FA) and volatile compound (VC) profiles; and biogenic amine (BA), macro- and microelement, and mycotoxin concentrations in nontreated ‘Ada’, ‘Sarta’, and new breed blue (DS8472-5) and purple (DS8526-2) wheat lines wholemeal (WW) with those fermented with lactic acid bacteria (LAB) possessing antimicrobial/antifungal properties, isolated from spontaneous sourdough: Pediococcus acidilactici-LUHS29, Liquorilactobacillus uvarum-LUHS245, Lactiplantibacillus plantarum-LUHS122). All the fermented WW showed >8.0 log10 CFU/g of LAB count, and the type of LAB was a significant factor in the WW acidity parameters. Phenylethylamine was the predominant BA in WW, and the wheat variety (WV), the type of LAB, and their interaction were significant factors on the BA formation. Despite the fact that some differences in trace element concentrations in WW were obtained, in most of the cases fermentation was not a significant factor in their content. The main FAs in WW were palmitic acid, all-cis,trans-octadecenoic acid, and linoleic acid. Fermented WW showed a more diverse VC profile; however, the influence of fermentation on deoxynivalenol in WW was varied. Finally, further studies are needed to indicate the technological parameters that would be the most effective for each WV, including the lowest BA formation and mycotoxin degradation.

Mathematical Modeling and Optimization of Lactobacillus Species Single and Co-Culture Fermentation Processes in Wheat and Soy Dough Mixtures

To improve food production via fermentation with co-cultures of microorganisms (e.g., multiple lactic acid bacteria-LAB strains), one must fully understand their metabolism and interaction patterns in various conditions. For example, LAB can bring added quality to bread by releasing several bioactive compounds when adding soy flour to wheat flour, thus revealing the great potential for functional food development. In the present work, the fermentation of three soy and wheat flour mixtures is studied using single cultures and co-cultures of Lactobacillus plantarum and Lactobacillus casei. Bio-chemical processes often require a significant amount of time to obtain the optimal amount of final product; creating a mathematical model can gain important information and aids in the optimization of the process. Consequently, mathematical modeling is used to optimize the fermentation process by following these LAB’s growth kinetics and viability. The present work uses both multiple regression and artificial neural networks (ANN) to obtain the necessary mathematical model, useful in both prediction and process optimization. The main objective is to find a model with optimal performances, evaluated using an ANOVA test. To validate each obtained model, the simulation results are compared with the experimental data.

Development of a Wet-Granulated Sourdough Multiple Starter for Direct Use

The search for sourdough starters for the direct production of baked goods with all the advantages of biological sourdough fermentation is still a crucial issue. In this study, 43 Lactic Acid Bacteria strains isolated from mature sourdoughs were evaluated for features of technological interest and tested for fermentation ability. Three microbial combinations were selected and used to produce bread. Based on GC-MS and sensory analysis, bread made by using the three combinations of strains was characterized by a more complex aroma profile with the prevalence of VOCs typical of sourdough bread. To set up the best way to keep microbial viability upon drying, the three combinations were subject to freeze-drying and wet granulation, with the latter being used for the first time for food starters’ stabilization. Wet granulation ensured optimal strains’ viability. Surprisingly, the height attained by mature sourdoughs when inoculated with wet granulated starters was constantly higher than the height reached by sourdoughs made with the same starters as fresh cells. The microbial combination E75-B72 exhibited the best performances and may represent a starter able to ensure sourdough bread production in 16 h of fermentation at 28 °C.

Amaranth selective hydrolyzed protein influence on sourdough fermentation and wheat bread quality

Amaranth selective hydrolyzed protein (ASPH) may improve sourdough properties and bread quality. In this regard, this study focused on investigating the influence of protein hydrolysates on sourdough fermentation and bread properties. Based on the findings, ASPH further increased Lactobacillus plantarum and Saccharomyces cerevisiae growth in sourdough compared with amaranth protein isolates and amaranth flour. ASPH at 5 g/kg resulted in sourdough with higher pH and total titratable acidity (TTA) after 20 h of fermentation at 30°C. The prepared sourdough using APH (S-ASPH) at 3 g/kg increased the specific volume (4.57 ml/g) and TTA (4.76 ml) while decreasing water activity, hardness, cohesiveness, and chewiness of the bread (S-ASPH-B) compared with the control. Moreover, transition temperature and enthalpy reduced whereas sensory properties and shelf life represented an increase with S-ASPH addition. Overall, the obtained data indicated the improvement of bread quality by S-ASPH sourdough.

Nutritional Contributions and Health Associations of Traditional Fermented Foods

The growing interest in the consumption and study of traditionally fermented food worldwide has led to the development of numerous scientific investigations that have focused on analyzing the microbial and nutritional composition and the health effects derived from the consumption of these foods. Traditionally fermented foods and beverages are a significant source of nutrients, including proteins, essential fatty acids, soluble fiber, minerals, vitamins, and some essential amino acids. Additionally, fermented foods have been considered functional due to their prebiotic content, and the presence of specific lactic acid bacterial strains (LAB), which have shown positive effects on the balance of the intestinal microbiota, providing a beneficial impact in the treatment of diseases. This review presents a bibliographic compilation of scientific studies assessing the effect of the nutritional content and LAB profile of traditional fermented foods on different conditions such as obesity, diabetes, and gastrointestinal disorders.

New Insight into Bacterial Interaction with the Matrix of Plant-Based Fermented Foods

Microorganisms have been harnessed to process raw plants into fermented foods. The adaptation to a variety of plant environments has resulted in a nearly inseparable association between the bacterial species and the plant with a characteristic chemical profile. Lactic acid bacteria, which are known for their ability to adapt to nutrient-rich niches, have altered their genomes to dominate specific habitats through gene loss or gain. Molecular biology approaches provide a deep insight into the evolutionary process in many bacteria and their adaptation to colonize the plant matrix. Knowledge of the adaptive characteristics of microorganisms facilitates an efficient use thereof in fermentation to achieve desired final product properties. With their ability to acidify the environment and degrade plant compounds enzymatically, bacteria can modify the textural and organoleptic properties of the product and increase the bioavailability of plant matrix components. This article describes selected microorganisms and their competitive survival and adaptation in fermented fruit and vegetable environments. Beneficial changes in the plant matrix caused by microbial activity and their beneficial potential for human health are discussed as well.

FODMAP Fingerprinting of Bakery Products and Sourdoughs: Quantitative Assessment and Content Reduction through Fermentation

Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are associated with digestive disorders and with diseases such as irritable bowel syndrome. In this study, we determined the FODMAP contents of bread, bakery products, and flour and assessed the effectiveness of sourdough fermentation for FODMAP reduction. The fermentation products were analyzed to determine the DP 2-7 and DP >7 fructooligosaccharide (FOS) content of rye and wheat sourdoughs. FOSs were reduced by Acetobacter cerevisiae, Acetobacter okinawensis, Fructilactobacillus sanfranciscensis, and Leuconostoc citreum to levels below those in rye (-81%; -97%) and wheat (-90%; -76%) flours. The fermentation temperature influenced the sourdough acetic acid to lactic acid ratios (4:1 at 4 °C; 1:1 at 10 °C). The rye sourdough contained high levels of beneficial arabinose (28.92 g/kg) and mannitol (20.82 g/kg). Our study contributes in-depth knowledge of low-temperature sourdough fermentation in terms of effective FODMAP reduction and concurrent production of desirable fermentation byproducts.

Acrylamide in bread: a review on formation, health risk assessment, and determination by analytical techniques

Acrylamide is a water-soluble toxicant found in high-protein and carbohydrate-containing foods exposed to high temperature like bread as the staple foodstuff. This toxicant is mainly formed via Maillard reaction. The potential adverse effects of acrylamide especially possible carcinogenicity in human through dietary exposure necessitate its monitoring. Regarding the existence of its precursors in wheat bread formulation as well as extreme consumption of bread by most population and diversity of bread types, its acrylamide level needs to be investigated. The indicative value for acrylamide in wheat bread is set at 80 μg/kg. Consequently, its determination using liquid chromatography-tandem mass spectrometry (LC-MS/MS), gas chromatography-mass spectrometry (GC-MS), or capillary electrophoresis can be helpful considering both the risk assessment and quality control aspects. In this respect, methods based on LC-MS/MS show good recovery and within laboratory repeatability with a limit of detection of 3-20 μg/kg and limit of quantification of 10-50 μg/kg which is suitable for the immediate requirements for food product monitoring and calculation of consumer exposure.

The function and mechanism of lactic acid bacteria in the reduction of toxic substances in food: a review

N-nitrosamines, heterocyclic amines, polycyclic aromatic hydrocarbons, biogenic amines, and acrylamide are widely distributed and some of the most toxic substances detected in foods. Hence, reduction of these substances has attracted worldwide attention. Lactic acid bacteria (LAB) inoculation has been found to be an effective way to reduce these toxic substances. In this paper, the reduction of toxic substances by LAB and its underlying mechanisms have been described through the review of recent studies. LAB aids this reduction via different mechanisms. First, it can directly decrease these harmful substances through adsorption or degradation. Peptidoglycans on the cell wall of LAB can bind to heterocyclic amines, acrylamide, and polycyclic aromatic hydrocarbons. Second, LAB can indirectly decrease the content of toxic substances by reducing their precursors. Third, antioxidant properties of LAB also contribute to the reduction in toxic substances. Finally, LAB can suppress the growth of amino acid decarboxylase-positive bacteria, thus reducing the accumulation of biogenic amines and N-nitrosamines. Therefore, LAB can contribute to the decrease in toxic substances in food and improve food safety. Further research on increasing the reduction efficiency of LAB and deciphering the mechanisms at a molecular level needs to be carried out to obtain the complete picture.

Lactic Acid Bacteria Isolation from Spontaneous Sourdough and Their Characterization Including Antimicrobial and Antifungal Properties Evaluation

This research effort aimed at isolating and phenotypically characterizing lactic acid bacteria (LAB) isolates from a spontaneous rye sourdough manufactured following traditional protocols, as well as at evaluating their antimicrobial and antifungal properties as key features for future industrial applications. Thirteen LAB strains of potential industrial interest were isolated and identified to species-level via PCR. Most of the sourdough isolates showed versatile carbohydrate metabolisms. The Leuconostoc mesenteroides No. 242 and Lactobacillus brevis No. 173 demonstrated to be gas producers; thus, revealing their heterofermenter or facultative homofermenter features. Viable counts higher than 7.0 log10 (CFU/mL) were observed for Lactobacillus paracasei No. 244, Lactobacillus casei No. 210, L. brevis No. 173, Lactobacillus farraginis No. 206, Pediococcus pentosaceus No. 183, Lactobacillus uvarum No. 245 and Lactobacillus plantarum No. 135 strains, after exposure at pH 2.5 for 2 h. Moreover, L. plantarum No. 122, L. casei No. 210, Lactobacillus curvatus No. 51, L. paracasei No. 244, and L. coryniformins No. 71 showed growth inhibition properties against all the tested fifteen pathogenic strains. Finally, all LAB isolates showed antifungal activities against Aspergillus nidulans, Penicillium funiculosum, and Fusarium poae. These results unveiled the exceptionality of spontaneous sourdough as a source of LAB with effective potential to be considered in the design of novel commercial microbial single/mixed starter cultures, intended for application in a wide range of agri-food industries, where the antimicrobial and antifungal properties are often sought and necessary. In addition, metabolites therefrom may also be considered as important functional and bioactive compounds with high potential to be employed in food and feed, as well as cosmetic and pharmaceutical applications.

Defined co-cultures of yeast and bacteria modify the aroma, crumb and sensory properties of bread

AIMS

Yeast and bacterial communities inhabit a sourdough starter to make artisanal bread. This study shows whether the interactions of micro-organisms derived from Australian sourdough starters provide some of the positive flavour, and aroma properties to bread by using defined sourdough cultures as the sole leaven in bread production.

METHODS AND RESULTS

An investigation of Australian sourdough starters found that they contained Saccharomyces cerevisiae and Kazachstania exigua yeasts. When these yeasts were inoculated alone to ferment wheat flour in an extended fermentation, the bread had a heterogeneous crumb structure, a deeper colour and a distinctive chemical aroma profile than those made with commercial baker's yeast. When bread was made combining these yeasts individually and in combinations with lactic acid bacteria also isolated from these sourdough starters, including Lactobacillus plantarum, L. brevis, L. rossiae, L. casei, the bread aroma profiles and crumb structure were more distinctive, with compounds associated with sour aromas produced, and preferred by sensory panels.

CONCLUSIONS

The use of defined mixed cultures as the leaven in bread making, by exploiting the microbial diversity of artisanal Australian starters, can produce bread with distinctive and attractive aromas.

SIGNIFICANCE AND IMPACT OF THE STUDY

Understanding and identifying the community ecosystems found in sourdough cultures and using them as the sole leaven in bread production provide novel insights into microbial interactions and how they affect food quality by removing the effects of commercial yeast strains.

Effect of selected strains on physical and organoleptic properties of breads

The use of selected Saccharomyces cerevisiae PS7314, Lactobacillus rossiae NOS7307, Lactobacillus brevis NOS7311, and Lactobacillus plantarum NOS7315 as mono-culture or co-culture for production of sourdoughs, their breads showed different physical and organoleptic properties. The pH of breads fermented with sourdoughs incubated with mono-culture or co-culture all decreased. An opposite trend was found for TTA. The use of single lactobacillus for the dough fermentation decreased the specific volume of bread, which was 4.15-19.10% lower than that of control bread (CB). However, the synergetic fermentation helped the improvement of bread quality. Compared to CB, the mixed culture 4 sourdough remarkably decreased the hardness by 52.08%, increased the specific volume by 5.29%, improved porosity of final product by 24.90%, and gave a preferable sensory characteristic to bread. Thus, the MC4 could be recommended for replacing spontaneous sourdough for improving the quality of bread.

Industrial production of sourdoughs for the baking branch - An overview

Sourdoughs are produced both in artisanal and industrial size. Sourdough manufacturers deliver the baking branch either with starters for production of in-house sourdoughs or with fully fermented sourdough products. In the latter case sourdough production is separated in time and space from the bread production. A big part of this convenience products are dried sourdoughs, which are mainly produced from rye and wheat flour, but also from other starch containing plants, like pseudocereals or legumes. The requirements regarding the raw materials used differ from that used for baking bread. The most applied drying techniques for sourdoughs are drum and spray-drying. Compared with other foods, sourdough and sourdough products have only a low risk regarding food safety due to pH < 4.2, however formation of biogenic amines or acrylamide has taken into account. More tools for sourdough authentication are needed but, before developing and validating methods, it would be necessary to include different sourdough products in a clear regulatory framework.

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.

The Influence of Scalded Flour, Fermentation, and Plants Belonging to Lamiaceae Family on the Wheat Bread Quality and Acrylamide Content

The aim of this study was to investigate the influence of additives such as plants belonging to Lamiaceae family (Thymus vulgaris, Carum carvi, Origanum vulgare, Ocimum basilicum, and Coriandrum sativum), scalded flour (SF) or scalded flour fermented with Lactobacillus plantarum LUHS135 (SFFLp) on the quality and acrylamide formation in wheat bread. The formation of acrylamide and bread quality significantly depended on the king of plants used and the amount of SF and SFFLp used. The additives of T. vulgaris and SF increased the content of acrylamide by 3.4-fold in comparison with bread prepared without SF, whereas the addition of SFFLp significantly reduced the content of acrylamide in bread, especially using 5% of SFFLp supplemented with O. vulgare and 15% of SFFLp supplemented with C. sativum (respectively by 40% and 29.4%) therefore could be recommended for safer bread production.

PRACTICAL APPLICATION

The addition of 5% (from total wheat flour content) of scalded wheat flour fermented with Lactobacillus plantarum LUHS135 strain (SFFLp) with Origanum vulgare addition, and 5% or 10% of SFFLp prepared with Ocimum basilicum, and 15% of SFFLp prepared with Coriandrum sativum significantly reduce the content of acrylamide in wheat bread, therefore could be recommended for safer bread production.

Effect of heat treatment to sweet potato flour on dough properties and characteristics of sweet potato-wheat bread

The effect of heat treatment at 90, 100, 110 and 120 ℃ for 20 min to sweet potato flour on dough properties and characteristics of sweet potato-wheat bread was investigated. The lightness (L*) and a* of sweet potato flour samples after heat treatment were increased, while the b* were decreased significantly, as well as the particle size, volume and area mean diameter ( p < 0.05). A slight change of the microstructures of sweet potato flour was observed, where the number of irregular granules increased as the temperature increased from 90 to 120 ℃. Compared with sweet potato flour samples without heat treatment and with heat treatment at 90, 100 and 120 ℃, the gelatinization temperature and enthalpy change of sweet potato flour at 110 ℃ were the lowest, which were 77.94 ℃ and 3.67 J/g, respectively ( p < 0.05). After heat treatment, gas retention of the dough with sweet potato flour increased significantly from 1199 ml without heat treatment to 1214 ml at 90 ℃ ( p < 0.05). In addition, specific loaf volume of sweet potato-wheat bread with sweet potato flour after heat treatment increased significantly, which was the largest at 90 ℃ (2.53 cm3/g) ( p < 0.05). Thus, heat treatment at 90 ℃ to sweet potato flour could be potentially used in wheat bread production.