Isolation, identification, and stability of sourdough microbiota from spontaneously fermented Norwegian legumes.

Fermentation has recently been rediscovered as an attractive technique to process legumes, as it can improve the nutritional quality and value of the end product. This study investigated the dynamics and stability of the microbial communities in spontaneously fermented sourdoughs made from flours of two cultivars of faba beans and two cultivars of peas. Sourdoughs were established by the backslopping technique, and the microbial development at 22 °C and 30 °C was followed by culture dependent and culture independent methods. The utilization of substrates and formation of metabolites were also determined by high-performance liquid chromatography. A stable pH was reached in all the sourdoughs after 11-15 days of daily backslopping. Lactic acid bacteria and yeast from pH stable sourdoughs were isolated, characterized and identified. The fermentation temperature influenced the development of the microbial community and the substrate utilization during spontaneous fermentation. In the 30 °C fermentations, one species dominated (Lactiplantibacillus plantarum/pentosus), a lower pH was achieved, and the available substrates were more extensively converted. The 22 °C fermentation resulted in a more diverse microbial community (Lactiplantibacillus, Leuconostoc, Pediococcus), a higher pH, and more residual substrates were available after fermentation. Yeasts were only detected in one of the pea sourdoughs fermented at 30 °C, with Saccharomyces cerevisiae being the dominant species. Nearly all sourdoughs were depleted of maltose after 24 h fermentation cycles, and higher levels of lactic and acetic acid were detected in 30 °C fermen-tations. This research adds to our understanding of the autochthonous microbial community present in faba beans and peas as well as their natural capacity to establish themselves and ferment legume flours. These findings enhance the possibilities of utilizing and improving plant based protein sources.

Tailor-made fermentation of sourdough reduces the acrylamide content in rye crispbread and improves its sensory and nutritional characteristics.

Thirty strains of lactic acid bacteria (LAB) and Saccharomyces cerevisiae E8.9 (wild type) were used to formulate fifteen combinations of starters by mixing two or three LAB with the yeast (ratio LAB: yeast, 10: 1). Such combinations were used to prepare rye sourdough and their performance in term of acidification and biochemical characteristics during fermentation at two temperatures (30 and 37 °C) and duration (4 and 8 h) were screened. The best thirteen sourdough formulations were selected and used for rye crispbread making. The analysis of acrylamide concentration demonstrated that 11 out 13 formulations resulted in significant decreases of concentration compared to the baker's yeast (control), with reductions up to 79.6 %. The rye sourdough crispbreads showed also higher amount of volatile organic compounds (VOCs) compared to the baker's yeast control. Two rye sourdough crispbreads, selected to represent the opposite extremes within the thirteen formulations in term of VOC profiles and fermentation performances, demonstrated better sensory and nutritional features, such as phytic acid reduction (up to 47.3 %), and enhanced total free amino acid compared to the control. These evidences suggest the potential of tailored sourdough fermentations as alternative and suitable biotechnological strategy for lowering acrylamide levels in rye crispbread.

Mechanism of carbohydrate and protein conversion during sourdough fermentation: An analysis based on representative Chinese sourdough microbiota.

Sourdough fermentation is attracting growing attention because of its positive effects on properties of leavened baked good. However, the changes in dough features and the mechanisms behind them are not well understood, which limits its widespread use. In this study, we assessed the effects of representative lactic acid bacteria in sourdough monoculture or co-culture with yeasts on dough characteristics. Physicochemical analysis identified increased proteolysis and enhanced nutritional properties of co-culture groups. However, a reduction in organic acids contents of co-culture groups compared to monoculture was detected, and this effect was not limited by the yeast species. The RNA sequencing further demonstrated that the presence of yeast enhanced the protein metabolic activity of lactic acid bacteria, while decreased its organic acid biosynthetic activity. Moreover, the proteomic analysis revealed that endogenous metabolic proteins of flour, such as pyruvate kinase, glucosyltransferase and pyruvate dehydrogenase play a key role in carbohydrate metabolism during fermentation. This study uncovered the influence of typical microorganisms and endogenous enzymes on dough characteristics based on different aspects. Bacteria-mediated consumption of proteins and increased proteolysis in co-culture groups may underlie the improved digestibility and nutritional effects of sourdough fermented products, which provides an important basis for nutrient fortified bread making with multi-strain leavening agent.

The rise of the sourdough: Genome-scale metabolic modeling-based approach to design sourdough starter communities with tailored-made properties.

Sourdough starters harbor microbial consortia that benefit the final product's aroma and volume. The complex nature of these spontaneously developed communities raises challenges in predicting the fermentation phenotypes. Herein, we demonstrated for the first time in this field the potential of genome-scale metabolic modeling (GEMs) in the study of sourdough microbial communities. Broad in-silico modeling of microbial growth was applied on communities composed of yeast (Saccharomyces cerevisiae) and different Lactic Acid Bacteria (LAB) species, which mainly predominate in sourdough starters. Simulations of model-represented communities associated specific bacterial compositions with sourdough phenotypes. Based on ranking the phenotypic performances of different combinations, Pediococcus spp. - Lb. sakei group members were predicted to have an optimal effect considering the increase in S. cerevisiae growth abilities and overall CO2 secretion rates. Flux Balance Analysis (FBA) revealed mutual relationships between the Pediococcus spp. - Lb. sakei group members and S. cerevisiae through bidirectional nutrient dependencies, and further underlined that these bacteria compete with the yeast over nutrients to a lesser extent than the rest LAB species. Volatile compounds (VOCs) production was further modeled, identifying species-specific and community-related VOCs production profiles. The in-silico models' predictions were validated by experimentally building synthetic sourdough communities and assessing the fermentation phenotypes. The Pediococcus spp. - Lb. sakei group was indeed associated with increased yeast cell counts and fermentation rates, demonstrating a 25 % increase in the average leavening rates during the first 10 fermentation hours compared to communities with a lower representation of these group members. Overall, these results provide a possible novel strategy towards the de-novo design of sourdough starter communities with tailored-made characterizations, including a shortened leavening period.

Sourdough starters exhibit similar succession patterns but develop flour-specific climax communities.

The microbial fermentation behind sourdough bread is among our oldest technologies, yet there are many opportunities for sourdough science to learn from traditional bakers. We analyzed 16S rRNA sequences in R to assess the bacterial community structure and performance of 40 starters grown from 10 types of flour over 14 days, and identified six distinct stages of succession. At each stage, bacterial taxa correlate with determinants of bread quality including pH, rise, and aromatic profile. Day 1 starter cultures were dominated by microorganisms commonly associated with plants and flour, and by aromas similar to toasted grain/cereal. Bacterial diversity peaked from days 2-6 as taxa shifted from opportunistic/generalist bacteria associated with flour inputs, toward specialized climax bacterial communities (days 10-14) characterized by acid-tolerant taxa and fruity (p < 3.03e-03), sour (p < 1.60e-01), and fermented (p < 1.47e-05) aromas. This collection of traits changes predictably through time, regardless of flour type, highlighting patterns of bacterial constraints and dynamics that are conserved across systems and scales. Yet, while sourdough climax communities exhibit similar markers of maturity (i.e., pH ≤ 4 and enriched in Lactobacillus (mean abundance 48.1%), Pediococcus (mean abundance 22.7%), and/or Gluconobacter (mean abundance 19.1%)), we also detected specific taxa and aromas associated with each type of flour. Our results address important ecological questions about the relationship between community structure and starter performance, and may enable bakers to deliberately select for specific sourdough starter and bread characteristics.

A chestnut-hemp type-II sourdough to improve technological, nutritional, and sensory properties of gluten-free bread.

The nutritional quality of gluten-free (GF) products is usually improved by using flours derived from alternative grains (e.g., pseudocereals and legumes), additives and hydrolysates, leading to long ingredient lists in the labels, that conflict with current customer expectations. In this work, chestnut, carob, and hemp flours were used as mixed ingredients for making a gluten-free type-II sourdough. Three exopolysaccharides-producer lactic acid bacteria, belonging to Leuconostoc mesenteroides, Weissella cibaria, and Leuconostoc pseudomesenteroides, were used, and the fermentation processes (6 log10 cfu/g, 25 °C, 16 h) optimize to maximize the EPS synthesis (15.70 ± 2.1 mg/kg). The chestnut-hemp (70:30) type-II sourdough was included in a rice/corn gluten-free bread recipe also containing psyllium flour as structuring agent. Although the fortification with unfermented flours already led the achievement of 6 g/100 g of fiber (high fiber, Regulation EC n. 1924/2006) and content of magnesium higher than the daily reference intakes, the use of type-II sourdoughs led to a further structural, sensory, and nutritional improvements (e.g., decreasing the main anti-nutritional factor phytic acid). This work demonstrated that the use of ad-hoc selected ingredients and optimized protocol can be used to produce a GF and "clean label" bread with optimal nutritional features and appreciable sensory and structural properties.

NMR-Based Metabolomic Study on Phaseolus vulgaris Flour Fermented by Lactic Acid Bacteria and Yeasts.

In recent years, fermented foods have attracted increasing attention due to their important role in the human diet, since they supply beneficial health effects, providing important sources of nutrients. In this respect, a comprehensive characterization of the metabolite content in fermented foods is required to achieve a complete vision of physiological, microbiological, and functional traits. In the present preliminary study, the NMR-based metabolomic approach combined with chemometrics has been applied, for the first time, to investigate the metabolite content of Phaseolus vulgaris flour fermented by different lactic acid bacteria (LAB) and yeasts. A differentiation of microorganisms (LAB and yeasts), LAB metabolism (homo- and heterofermentative hexose fermentation), LAB genus (Lactobacillus, Leuconostoc, and Pediococcus), and novel genera (Lacticaseibacillus, Lactiplantibacillus, and Lentilactobacillus) was achieved. Moreover, our findings showed an increase of free amino acids and bioactive molecules, such as GABA, and a degradation of anti-nutritional compounds, such as raffinose and stachyose, confirming the beneficial effects of fermentation processes and the potential use of fermented flours in the production of healthy baking foods. Finally, among all microorganisms considered, the Lactiplantibacillus plantarum species was found to be the most effective in fermenting bean flour, as a larger amount of free amino acids were assessed in their analysis, denoting more intensive proteolytic activity.

Effect of oil exposure stages on the heat resistance of Salmonella enterica serovar Enteritidis phage type 30 in peanut flour.

The oil in low-moisture foods (LMFs) shows protective effects on bacteria during thermal processing. However, the circumstances under which this protective effect strengthens remain unclear. This study aimed to understand which step of the oil exposure to bacterial cells (inoculation, isothermal inactivation, or recovery and enumeration step) in LMFs can enhance their heat resistance. Peanut flour (PF) and defatted PF (DPF) were selected as the oil-rich and oil-free LMF models. Salmonella enterica Enteritidis Phage Type 30 (S. Enteritidis) was inoculated into four designated PF groups representing different oil exposure stages. It was isothermally treated to obtain heat resistance parameters. At a constant moisture content (aw,25°C = 0.32 ± 0.02) and controlled aw,85°C (0.32 ± 0.02), S. Enteritidis exhibited significantly high (p < 0.05) D values in oil-rich sample groups. For instance, the heat resistance values of S. Enteritidis in the PF-DPF and DPF-PF groups were D80°C of 138.22 ± 7.45 min and 101.89 ± 7.82 min; however, the D80°C in the DPF-DPF group was 34.54 ± 2.07 min. The oil addition after the thermal treatment also helped injured bacterial recovery in the enumeration. For instance, the D80°C, D85°C, and D90°C values in the DFF-DPF oil groups were 36.86 ± 2.30, 20.65 ± 1.23, and 7.91 ± 0.52 min, respectively, which were higher than those in the DPF-DPF group at 34.54 ± 2.07, 17.87 ± 0.78, and 7.10 ± 0.52 min. We confirmed that the oil protected S. Enteritidis in PF in all three stages: desiccation process, heat treatment, and recovery of bacterial cells in plates.

Nutritional benefits of sourdoughs: A systematic review.

Food fermentation using sourdough-i.e., consortia of lactic bacteria and yeasts-is increasingly considered among the public as a natural transformation yielding nutritional benefits; however, it is unclear whether its alleged properties are validated by science. The aim of this study was to systematically review the clinical evidence related to the effect of sourdough bread on health. Bibliographic searches were performed in 2 different databases (The Lens and PubMed) up to February 2022. Eligible studies were randomized controlled trials involving adults, healthy or not, given any type of sourdough bread compared with those given any type of yeast bread. A total of 573 articles were retrieved and investigated, of which 25 clinical trials met the inclusion criteria. The 25 clinical trials included a total of 542 individuals. The main outcomes investigated in the retrieved studies were glucose response (N = 15), appetite (N = 3), gastrointestinal markers (N = 5), and cardiovascular markers (N = 2). Overall, it is currently difficult to establish a clear consensus with regards to the beneficial effects of sourdough per se on health when compared with other types of bread because a variety of factors, such as the microbial composition of sourdough, fermentation parameters, cereals, and flour types potentially influence the nutritional properties of bread. Nonetheless, in studies using specific strains and fermentation conditions, significant improvements were observed in parameters related to glycemic response, satiety, or gastrointestinal comfort after bread ingestion. The reviewed data suggest that sourdough has great potential to produce a variety of functional foods; however, its complex and dynamic ecosystem requires further standardization to conclude its clinical health benefits.

Fate of salmonella and shiga-toxin producing Escherichia coli on wheat grain during tempering.

Outbreaks of Salmonella and Shiga-toxin producing Escherichia coli (STEC) linked to wheat flour led to increased interest in characterizing the fate of Salmonella and STEC on wheat during processing. Tempering is the stage of wheat processing where water is added to toughen the bran prior to milling, which has the potential to influence pathogen behavior on the kernels. This study aimed to quantify changes in the numbers of STEC and Salmonella inoculated onto soft red winter wheat, and to observe potential changes in the distribution of the pathogens on the surface of kernels during tempering. Lab-scale tempering experiments were conducted to quantify the water activity of and bacterial populations on wheat grain at various time points during 16 h of tempering. The highest water activity observed throughout 16 h of tempering was 0.88. There was no significant change (p > 0.05) in numbers of Salmonella, STEC, or native mesophiles. Using confocal microscopy, observation of Salmonella and STEC cells expressing mCherry on wheat kernels showed an even distribution of inoculated cells, though the localization of cells on kernels did not change significantly after tempering. Even though the environment was not favorable for pathogen replication on grain, the population remained stable, suggesting that disinfection of the kernels prior to milling could reduce food safety concerns in flour.

Liquid sourdough from stone-ground soft wheat (Triticum aestivum) flour: Development and exploitation in the breadmaking process.

The aim of the study was to set up a liquid sourdough obtained using stone-ground soft wheat (Triticum aestivum) flour to be exploited in breadmaking. Therefore, a Type II sourdough (dough yield = 350) was developed from a stable stone-ground wheat Type I sourdough (dough yield = 156) used as inoculum. Both sourdoughs were analyzed for lactic acid bacteria (LAB) viable counts, pH and total titratable acidity (TTA), LAB biodiversity by a combined culture-dependent and -independent approach (PCR-DGGE) and they were tested for their breadmaking ability. In addition, the chemical and rheological features and volatile organic compounds of the stone-ground soft wheat flour used in the experiment were investigated. The flour had a high protein content, good bakery properties and it also presented a rich aroma pattern characterized not only by the prevalence of green grass, flowery, and sweet aromas but also nutty, roasted and popcorn aromas. The sourdoughs I and II used in the trial were characterized by viable LAB counts, pH and TTA values typical of mature sourdoughs, i.e., approximately 9 log cfu gr-1 and mL, pH 3.9 and 10 mL 0.1 N NaOH. In addition, Levilactobacillus brevis and Companilactobacillus paralimentarius species represented the LAB stable microbiota of both sourdoughs. Both sourdoughs efficiently produce acceptable experimental breads characterized by different volatile profiles thus indicating that the type of sourdough fermentation significantly influenced the features of the final products. Overall, for the first time in the present study stone-ground wheat flour and bread have been characterized for their volatile aroma profile and sensory properties.

Effect of fermentation time and addition amount of rice sourdoughs with different microbial compositions on the physicochemical properties of three gluten-free rice breads.

This study aimed to better understand the impact of microbial growth and metabolism on rice sourdough and their relationship with quality characteristics of rice breads. Therefore, this research determined the microbial compositions and biochemical characteristics of indica rice (IR), japonica rice (JR) and waxy rice (WR) sourdough within 72 h fermentation. And the effects of different fermentation time and dosage of rice sourdough on rheology of rice doughs, quality characteristics of rice breads were studied. The results showed that the dominant bacteria Leuconostoc changed the processing properties of rice doughs through producing organic acids and reducing sugars. Adding 30 % rice sourdough had the best effect on improving specific volume of rice breads. And IR and JR breads with sourdough fermented 48 h had the highest chewiness, cohesiveness, resilience and the lowest hardness, while WR breads had high viscosity and poor overall structure, which was not suitable for making gluten-free bread.

Thermal Inactivation of Salmonella enterica and Nonpathogenic Bacterial Surrogates in Wheat Flour by Baking in a Household Oven.

ABSTRACT: Wheat flour has been implicated in recalls and outbreaks linked to Salmonella and pathogenic Escherichia coli. An instructional online video posted on a popular YouTube channel with over 20 million subscribers claimed that safe raw cookie dough could be made from flour baked in a household oven at 177°C (350°F) for 5 min, but no evidence in support of that claim was provided. This study was conducted to assess thermal inactivation of two Salmonella strains, as well as Enterobacter aerogenes and Pantoea dispersa in wheat flour during home oven baking. Wheat flour was inoculated with Salmonella Enteritidis PT 30, Salmonella Typhimurium PT 42, or their potential surrogates at high concentrations (4.8 to 6.1 log CFU/g) before baking in a consumer-style convection oven (toaster oven) at 149, 177, and 204°C (300, 350, or 400°F) for up to 7 min. Flour was heated in an aluminum tray, with a maximum depth of ∼2 cm. Heated wheat flour samples (5 g each) were enumerated in triplicate, and the microbial concentration was expressed in log CFU per gram. Thermal profiles of the geometric center of the wheat flour pile and air in the oven during the baking were recorded. Water activity of wheat flour samples was also measured before and after baking. The water activity of wheat flour decreased, as baking temperature and time increased. Water activity values ranged from 0.30 to 0.06 after 7 min, as oven temperature increased from 149 to 204°C. Thermal inactivation kinetics were linear until counts approached the limit of detection for all microorganisms. D-values for Salmonella and potential surrogate strains ranged from 1.86 to 2.13 min at 149°C air temperature, 1.66 to 1.92 min at 177°C air temperature, and 1.12 to 1.38 min at 204°C air temperature. Both Salmonella strains and surrogates showed similar inactivation patterns. Baking of wheat flour in household toaster ovens has potential as an inactivation treatment of pathogenic bacteria in consumer homes, despite its low water activity.

Thermal death kinetics of Salmonella Enteritidis PT30 in peanut butter as influenced by water activity.

It has been a challenge in developing effective thermal pasteurization processes for foods with high-fat and low-moisture contents like peanut butter, due to a general lack of reliable data on thermal resistance of pathogens in those food matrices. Recent studies on low-moisture foods like wheat flour and almond flour suggest that temperature and water activity (at the process temperatures) are two key factors that influence thermal inactivation of bacteria. In this study, we measured high-temperature water activities of peanut butter of two moisture content (MC), 3.1% and 5.6% (dry basis), and investigated the thermal death kinetics of Salmonella enterica Enteritidis PT 30 (S. Enteritidis) in those samples at 70, 80, 90, and 100 °C. The results indicated that the water activity of peanut butter increased with increasing temperature, e.g., from 0.33 and 0.53 at 23 °C, up to 0.39 and 0.59 at 100 °C, respectively. The thermal death of S. Enteritidis in peanut butter followed the first-order kinetics. Overall, higher moisture content and a higher treatment temperature led to a smaller D-value (decimal reduction time of the survival population) of S. Enteritidis. The maximum D-value was 102.6 ± 15.2 min at MC 3.1% and 70 °C, and the minimum D-value was 0.3 min (predicted) at MC = 5.6% and 100 °C. The log D-value reduced linearly with temperature at a given aw, with Z-values equal to 15.4 °C (for MC = 3.1%) and 12.6 °C (for MC = 5.6%). Based on this study, the first-order kinetic model can be employed for developing and validating thermal pasteurization processes for peanut butter. The moisture content of peanut butter and the process temperature are two key parameters that need to be controlled for sufficient lethality.

Sourdough performances of the golden cereal Tritordeum: Dynamics of microbial ecology, biochemical and nutritional features.

The novel cereal 'Tritordeum' was employed in sourdough fermentation for bread making using a traditional backslopping procedure over 10 days. Culture-dependent and culture-independent approaches were used to characterize microbial ecology during sourdough preparation and propagation. Sourdough reached the highest microbial diversity after three days of propagation. Microbial diversity decreased as sourdough reached maturity (day 5). Microbiota dominance shifted from Weissella to Lactiplantibacillus genera after 5 days of propagation. Lactic acid bacteria (LAB) showed a constant increase throughout the propagations starting from 3.9 ± 0.24 log CFU g-1 on day 0 up to 8.0 ± 0.39 log CFU g-1 on day 5. Weissella confusa/cibaria and Weissella paramesenteroides were the most prevalent LAB species until day 5 of propagation, while Lactiplantibacillus plantarum was the most prevalent thereafter. Yeasts were present in low cell density (2.0 ± 0.11 log CFU g-1) until the fourth backslopping (day 4) and then gradually increased until day 10 (5.0 ± 0.29 log CFU g-1), with Saccharomyces cerevisiae being the most prevalent and dominant species. Lactic and acetic acid concentrations increased throughout Tritordeum sourdough propagations, indicative of a proportional decrease of fermentation quotient (lactic acid/acetic acid) from 13.54 ± 1.29 to 4.08 ± 0.15. Utilization of glucose, fructose and sucrose was observed, followed a progressive increase in mannitol concentrations beginning from day 4. The nutritional potential (total phenol content, antioxidant activity, dietary fiber content and total free amino acids) remained elevated during sourdough propagations. Antinutritional factors (phytic acid and raffinose) were reduced to minimal concentrations by day 10. Finally, texture analysis of Tritordeum sourdough bread was demonstrated to have better cohesiveness, resilience and firmness compared to baker's yeast bread, confirming its potential to improve functionality and use in sourdough biotechnology.

Delayed lactose utilization among Shiga toxin-producing Escherichia coli of serogroup O121.

Two outbreaks of Shiga toxin-producing Escherichia coli O121:H19 associated with wheat flour, in the United States of America and Canada, involved strains with an unusual phenotype, delayed lactose utilization (DLU). These strains do not ferment lactose when initially cultured on MacConkey agar (MAC), but lactose fermentation occurs following subculture to a second plate of MAC. The prevalence of DLU was determined by examining the ß-galactosidase activity of 49 strains of E. coli O121, and of 37 other strains of E. coli. Twenty four of forty three O121:H19 and one O121:NM displayed DLU. Two strains (O121:NM and O145:H34) did not have detectable ß-galactosidase activity. ß-glucuronidase activity of O121 strains was also determined. All but six DLU strains had normal ß-glucuronidase activity. ß-glucuronidase activity was suppressed on MAC for 17 of 23 O121 non-DLU strains. Genomic analysis found that DLU strains possessed an insertion sequence, IS600 (1267 bp), between lacZ (ß-galactosidase) and lacY (ß-galactoside permease), that was not present in strains exhibiting normal lactose utilization. The insert might reduce the expression of ß-galactoside permease, delaying import of lactose, resulting in the DLU phenotype. The high probability of DLU should be considered when using lactose-containing media for the isolation of STEC O121.

Fermentation of chickpea flour with selected lactic acid bacteria for improving its nutritional and functional properties.

AIMS: To improve the nutri-functional quality of chickpea flour by fermentation with selected lactic acid bacteria (LAB) to formulate functional legume-derived products. METHODS AND RESULTS: A Randomized Complete Block Design was carried out to assess the influence of experimental conditions (presence/absence of Lactiplantibacillus plantarum CRL2211 and/or Weissella paramesenteroides CRL2182, temperature, time and dough yield) on LAB population, acidification, antinutritional factors and total phenolic contents (TPCs) of chickpea flour. Fermentation with both strains for 24 h at 37°C produced an increase in LAB (up to 8.9 log CFU/g), acidity (final pH 4.06), TPC (525.00 mg GAE/100 g) and tannin and trypsin inhibitor removal (28.80 mg GAE/100 g and 1.60 mg/g, respectively) higher than the spontaneously fermented doughs. RAPD and Rep-PCR analysis revealed that fermentation was dominated by L. plantarum CRL2211. Molecular docking and dynamics simulations were useful to explain LAB enzyme behaviour during fermentation highlighting the chemical affinity of LAB tannases and proteinases to gallocatechin and trypsin inhibitors. Compared with other processing methods, fermentation was better than soaking, germination and cooking for increasing the techno-functional properties of chickpea flour. Fermented doughs were applied to the manufacture of crackers that contained 81% more TPC and 64% more antioxidant activity than controls. CONCLUSIONS: Fermentation for 24 h at 37°C with selected autochthonous LAB was the best method for improving the quality of chickpea flour and derived crackers type cookies. SIGNIFICANCE AND IMPACT OF STUDY: Chickpea is suitable for the development of novel functional foods. Fermentation with selected LAB would improve the final product quality and bioactivity. The combination of experimental and simulation approaches can lead to a better understanding of the fermentation processes to enhance the properties of a food matrix.

Thermal inactivation of Salmonella during hard and soft cookies baking process.

This study validated a simulated commercial baking processes for hard and soft cookies to control Salmonella, and determined D- and z-values of 7-serotype Salmonella (Newport, Senftenberg, Tennessee, Typhimurium, and three isolates from dry pet food) cocktail in cookie doughs. Cookie doughs were prepared using flour mist-inoculated with the Salmonella cocktail. Hard and soft cookies were baked at 185 °C for 16 min and 165.6 °C for 22 min, respectively, followed by 30 min of ambient air cooling. D-values of the cocktail in cookie doughs were determined using thermal-death-time disks. Studies were designed as randomized complete blocks with three replications as blocks (α = 0.05). Salmonella populations decreased by > 5 log CFU/g in hard and soft cookies at 11.5 and 20.5 min of baking, respectively. Salmonella was not detected in hard cookies at the end of baking (as determined by enrichment), whereas in soft cookies, 0.6 log CFU/g Salmonella was present at the end of baking and cooling. Salmonella D-values in hard cookie dough at 60, 65 and 70 °C were 59.6, 28.1 and 11.9 min, respectively; while in soft cookie dough they were 62.3, 28.6 and 14.4 min, respectively. The Salmonella z-values in hard and soft cookie doughs were 14.5 and 15.8 °C, respectively.

Investigating the growth kinetics in sourdough microbial associations.

In this study we investigated the effect of the single strain in stabilization of type I sourdough microbial associations by crossing six different Fructilactobacillus sanfranciscensis with five Kazachstania humilis strains. Furthermore, we compared three predictive models, Zwitwering based on Gompertz's equation, Baranyi and Roberts' function and Schiraldi's function to evaluate which one best fitted the experimental data in determining the behaviour of co-cultivated microorganisms. Specific growth rates (µm) and lag time (λ) values for each mixed population were assessed. Results showed that the different F. sanfranciscensis strains significantly steer the growth kinetics within the pair and affect the ratio bacterial/yeast cells, as data analysis confirmed, whereas K. humilis accommodates to the bacterial strain. To compare the growth models, Root Mean Square (RMS) values were calculated for each predicted curve by implementing an algorithm based on an iterative process to minimize the deviation among observed and calculated data. Schiraldi's function performed better than the others, revealing, on average, the smallest RMS values and providing the best fitting for over 70% of co-cultivation experiments. Models prove to be consistent in predicting growth kinetics of microbial consortia too.