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Succinic acid in levels produced by yeast (Saccharomyces cerevisiae) during fermentation strongly impacts wheat bread dough properties
... This fact can be further substantiated by water activity and moisture content results. The parameter of cohesiveness is representative of the sample's resistance to deformation before breaking, which can characterize the internal bond strength within a food matrix [44,45]. The addition of an aqueous ethanolic extract resulted in a reduction in cohesiveness values, which has been reported to induce the solubilization of gluten protein fractions [45,46]. ...
... The parameter of cohesiveness is representative of the sample's resistance to deformation before breaking, which can characterize the internal bond strength within a food matrix [44,45]. The addition of an aqueous ethanolic extract resulted in a reduction in cohesiveness values, which has been reported to induce the solubilization of gluten protein fractions [45,46]. Hence, upon solubilization, better swelling and expansion can be anticipated for the gluten network, which can subsequently result in the reduced cohesiveness of the dough system as a result of a decrease in the strength and amount of intermolecular secondary protein structures [44]. ...
... The cohesiveness in baked samples can be related to the moisture content and the network strength that surrounds the crumb cells, with lower cohesiveness values being associated with bread crumbling [44]. Therefore, it can be established that the addition of aqueous ethanol extracts in wheat dough matrices, which overall do not exceed the ethanol levels released during fermentation, inhibits yeast activity and can significantly impact the dough's texture, causing stiffer, harder-to-process doughs with a higher tendency to crumble [45]. ...
Sour and sweet cherries were evaluated as functional components in bread-making because of their bioactive microconstituent content. Five forms of enrichment for each fruit, including the hydroalcoholic extract, lyophilized pulverized fruit, lyophilized extract, and their combinations, were used for supplementation. The physicochemical (pH, color, moisture, rheology, and texture) and sensory properties of dough and bread were assessed in different environments (biological and chemical leavening). Sour cherry in pulverized and extract forms showed higher phenolic content than sweet cherry, especially in the pulverized form. The viscoelasticity of the doughs varied based on the proofing environment and the fortification form. Chemically leavened doughs exhibited higher moduli (G′, G″), complex viscosity (η*), and hardness. Biologically leavened doughs had a lower pH, influencing color, and swelling percentage, which is linked to the enrichment form and phenolic content. Extract-fortified doughs displayed increased G′, η*, and hardness compared to the control, whereas yeast-leavened doughs showed reduced swelling ability. Physicochemical changes were more significant in the yeast-leavened systems, which also scored higher on the sensory evaluations. Supplementing bakery products with bioactive fruit components enhances antioxidant status, but the enrichment form and proofing conditions significantly affect the physicochemical and sensory properties of the product.
... In addition to SA, fermenting dough included acetic and lactic acids. Apart from SA, acetic acid [137]. Thanks to the production of these acids and secondary compounds, the bread aroma profiles, and crumb structure are more distinctive, with compounds associated with sour aromas produced, and preferred by the sensory panel [131,132,138,139]. ...
... Table 2 reported the impact of bakery's yeast and sourdough on the technological and sensory properties of bread. Bread aroma profiles and crumb structure are more distinctive, due to sour aromas produced, and preferred by sensory panels produced [131][132][133][134][135][136][137][138] ↑: increase; ↓: reduction ...
The quality of bread is mainly affected by the three key phases of the production chain: kneading, leavening and baking. Each step contributes to the final rheological and sensory properties of the bread. However, especially during the mixing phase, the choice of ingredients and the optimization of processing parameters such as mixing time, dough temperature, mixing speed and total water content, affect the development and microstructure of the dough. In general, rheological tests measure the technological properties of doughs and represent the main analyses carried out in the bakery sector. Considering the heterogeneity and variability of raw materials and processing conditions, rheology aids in process control and in the simulation of the response of the dough to the complex deformation that it undergoes during its processing. The results obtained can be related to the final structure and the texture of the bread. Although the effects of mixing and rheological behaviour of wheat doughs have been systematically examined in the literature, there is no comprehensive review of the current knowledge about the effect of the processing on sensory quality and final texture characteristics. This paper aims to shed light on factors that affect the quality of bread, emphasizing both technological and sensory aspects.
... Comparing the mixing time leading to the maximal estimated specific volume of bread for different leavening strategies revealed a shorter mixing time when a type 1 sourdough was used. This was in line with earlier studies that reported a reduced optimal mixing time, determined with farinograph experiments, for more acidic doughs (Jayaram et al., 2014;Maher Galal et al., 1978;Wehrle et al., 1997). Interestingly, the larger quadratic effect of mixing time in the model of the specific volume of YB (M YB 2 = − 10.4 %), compared to SB and YSB (M SB 2 = − 5.4 %, M YSB 2 = − 5.8 %), indicated that deviations in mixing time had a larger influence on the specific volume of YB within the analysed design space. ...
... A possible explanation for the reduced mixing time could be found in the effect of the lower dough pH because of the addition of sourdough. Apart from an increase in the electrostatic repulsion between the gluten, the formation of free thiolate anion (S − ) groups may be reduced (Clarke et al., 2004;Delcour et al., 2012;Jayaram et al., 2014;Maher Galal et al., 1978;Rombouts et al., 2012;Schober et al., 2003). These negatively charged cysteine residues are required to execute the nucleophilic attack on a sulfur atom, leading to new intermolecular disulfide bonds during mixing. ...
The final quality of wholemeal wheat bread is determined by the process parameter settings and leavening strategy. We hypothesise that the used leavening strategy may influence the optimal process parameter settings and, as such, the specific volume of the bread loaf. To analyse this interaction, bread was leavened with (i) a type 1 sourdough (SB), (ii) a type 1 sourdough combined with baker's yeast (YSB), or (iii) baker's yeast (YB). For each leavening strategy, the specific volume of bread, in response to variations in mixing time (4-10/4-14 min), water absorption (60-85 %), and proofing time (1-7/1-3 h), was analysed using an I-optimal response surface experimental design. Data modelling identified a substantially lower maximal specific volume of SB (2.13 mL/g), compared to YSB (3.30 mL/g) and YB (3.26 mL/g). The proofing time and water absorption mostly influenced the specific volume of the SB and YSB, respectively. However, the mixing and proofing times mainly affected the specific volume of YB. The type 1 sourdough reduced the mixing time and water absorption required for an optimal specific volume of bread compared to baker's yeast. These results challenge the idea of yielding higher volumes upon using sourdough compared to baker's yeast and highlight the importance of optimisation of bread dough formulations and breadmaking processes.
... In our in-silico analysis, a strong interaction of histone with succinic acid was observed, which might lead to succinylation of histone. Furthermore, succinic acid was demonstrated to be the main contributor for the enhancement of wheat dough quality by acidification resulting in a dough pH drop (Jayaram et al. 2013(Jayaram et al. , 2014Reid et al. 2017). Succinic acid is assumed to be involved in protein unfolding resulting in increased interaction of the elongated strands and favor the formation of a more extended network (Clarke et al. 2002;Jayaram et al. 2014;Maher 1978). ...
... Furthermore, succinic acid was demonstrated to be the main contributor for the enhancement of wheat dough quality by acidification resulting in a dough pH drop (Jayaram et al. 2013(Jayaram et al. , 2014Reid et al. 2017). Succinic acid is assumed to be involved in protein unfolding resulting in increased interaction of the elongated strands and favor the formation of a more extended network (Clarke et al. 2002;Jayaram et al. 2014;Maher 1978). Furthermore, it was reported that succinic acid weakens the intermolecular interactions between gluten strands resulting in lower gluten aggregation. ...
Key message Proteomic, protein–protein and protein–metabolite interaction analyses in wheat inoculated with PGPB
and AMF identifed key proteins and metabolites that may have a role in enhancing yield and biofortifcation.
Plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) have an impact on grain yield and nutri�tion. This dynamic yet complex interaction implies a broad reprogramming of the plant’s metabolic and proteomic activities.
However, little information is available regarding the role of native PGPB and AMF and how they afect the plant proteome,
especially under feld conditions. Here, proteomic, protein–protein and protein–metabolite interaction studies in wheat trig�gered by PGPB, Bacillus subtilis CP4 either alone or together with AMF under feld conditions was carried out. The dual
inoculation with native PGPB (CP4) and AMF promoted the diferential abundance of many proteins, such as histones,
glutenin, avenin and ATP synthase compared to the control and single inoculation. Interaction study of these diferentially
expressed proteins using STRING revealed that they interact with other proteins involved in seed development and abiotic
stress tolerance. Furthermore, these interacting proteins are involved in carbon fxation, sugar metabolism and biosynthesis
of amino acids. Molecular docking predicted that wheat seed storage proteins, avenin and glutenin interact with secondary
metabolites, such as trehalose, and sugars, such as xylitol. Mapping of diferentially expressed proteins to KEGG pathways
showed their involvement in sugar metabolism, biosynthesis of secondary metabolites and modulation of histones. These
proteins and metabolites can serve as markers for improving wheat–PGPB–AMF interactions leading to higher yield and
biofortifcation
... The variability in organic acid synthesis across the strains presents intriguing opportunities for tailoring bread formulations. For instance, the balanced profiles of ACY158 are ideal for general-purpose bread, while higher acetic acid production in strains like ACY30 may cater to niche products such as sourdough or rye bread [31]. Organic acids not only impact flavor profiles but also contribute to microbial stability and texture during storage, potentially extending the shelf life of baked products. ...
The impact of yeast strain selection on bread quality was evaluated using a range of commercial Saccharomyces cerevisiae strains, typically employed in various alcoholic beverage productions, to determine their effectiveness in bread making. The final products made from these strains were compared to bread produced using the commercial baker’s strain S. cerevisiae ACY298. Key parameters, including specific volume, hardness, pH, residual sugars, and organic acids, were thoroughly assessed. Among the strains tested, S. cerevisiae ACY158 produced bread with a specific volume of 5.0 cm³/g and a Euclidean distance of 0.895, closely resembling ACY298. In contrast, S. cerevisiae ACY9, with a specific volume of 1.1 cm³/g and the highest Euclidean distance of 6.878, exhibited the greatest deviation from ACY298, suggesting it may be less suitable for traditional bread production. Furthermore, ACY158 displayed a balanced organic acid profile and minimal residual sugars, aligning well with consumer expectations for bread flavor and texture. These results underscore that certain alternative S. cerevisiae strains have the potential to match or exceed the performance of commercial baker’s yeast, offering opportunities to optimize bread quality and diversify industrial baking practices.
... Citric, quinic, and malic acids are correlated with the Y24 treatment. The higher concentration of these acids, especially in the NFY lot, may be related to the action of yeast, given that succinic acid originates in the reducing cycle of citric acid and also from the degradation of malic acid (Kitzberger et al., 2014); and acetic acid can be produced from fermentation of available sugars or from citric acid used as a source (Ho et al., 2018;Jayaram et al., 2014). ...
... Although ethanol has an impact on the properties of bread, most of it evaporates during baking. Furthermore, yeasts produce a small amounts of organic acids (acetic and succinic acid), which lower the pH of the bread dough and thus contribute to the taste of the bread (Jayaram et al., 2013(Jayaram et al., , 2014. ...
Sourdough technology is involved in bread making process for improving the sensory, rheological, nutritional and shelf life characteristics of bakery products. More than 540 volatile organic compounds (VOCs) and other flavour precursors belonging to the chemical classes, such as aldehydes, ketones, esters, acids, alcohols, terpenes and others, have been identified in sourdoughs and sourdough breads. The synthesis of VOCs is microbial species-specific, originating mainly from fermentation process. VOCs can be used as indicators to characterize microbial processes. Other additional sources of VOCs in sourdoughs are lipid oxidation and browning reactions, the latter of which occurs during the production of dried starter cultures. The purpose of this article is to provide an overview of the composition of VOCs and their effect on the sensory properties of sourdough bread, and to describe the most common extraction methods of VOCs used in the studies of sourdough and bread aroma profile. Long-term propagated sourdough VOCs have been less studied compared to volatiles found in bread crust and crumb or sourdoughs started with defined starter culture(s) due to their complexity and diversity in metabolic pathways, including sophistication of the analytical methodology of VOCs. The relation between sourdough microbiota and its volatile profile is not fully understood and therefore, their variability and precise role as a bread flavour enhancer is not yet known in detail.
... Although aromas can also result from the effects of Maillard reactions, which take place between amino acids and sugars during baking [10,11], and from oxidation of lipids [12], yeast metabolism is reported to be the main source of aromatic diversity in bread [7]. Besides its impact on the organoleptic quality of bread, several components released from yeast cells, such as glycerol, ethanol, organic acids, and glutathione, influence dough characteristics, such as dough strength, elasticity, and extensibility [13][14][15][16][17][18][19]. Despite these diverse functions of yeast in fermented bakery products, only a relatively homogenous group of S. cerevisiae yeast strains is widely used for dough Commercial wheat flour (protein content of 12.5 ± 0.0%, (dry matter (dm) base); moisture content of 13.7 ± 0.1%) was obtained from Paniflower (Merksem, Belgium). ...
Despite the diverse functions of yeast, only a relatively homogenous group of Saccharomyces cerevisiae yeasts is used in the baking industry. Much of the potential of the natural diversity of yeasts has not been explored, and the sensory complexity of fermented baked foods is limited. While research on non-conventional yeast strains in bread making is increasing, it is minimal for sweet fermented bakery products. In this study, the fermentation characteristics of 23 yeasts from the bakery, beer, wine, and spirits industries were investigated in sweet dough (14% added sucrose w/w dm flour). Significant differences in invertase activity, sugar consumption (0.78–5.25% w/w dm flour), and metabolite (0.33–3.01% CO2; 0.20–1.26% ethanol; 0.17–0.80% glycerol; 0.09–0.29% organic acids) and volatile compound production were observed. A strong positive correlation (R2 = 0.76, p < 0.001) between sugar consumption and metabolite production was measured. Several non-conventional yeast strains produced more positive aroma compounds and fewer off-flavors than the reference baker’s yeast. This study shows the potential of non-conventional yeast strains in sweet dough.
... For instance, the expansion of gluten-containing dough resulting from Saccharomyces cerevisiae or baker's yeast action was responsible for the increase of porosity and the change of alveolar structure stability [3]. The mixing step made the flour constituents homogenized with air bubbles and created intra-and intermolecular associations between flour constituents and moisture; while during proofing, nutrients, air, and moisture were utilized by microbes to produce metabolites, such as ethanol, organic acids, exopolysaccharides, etc., exerting great influence on gluten networks and eventually affecting dough rheology [7,8]. However, gluten has been identified as the cause of celiac disease, leading to the damage of intestinal mucosa and malabsorption of several important nutrients [9]. ...
Dough rheology, mainly enabled by gluten in the traditional dough, determines the end-products’ quality, particularly by affecting gas production and retention capacities during proofing. Gluten-free dough has quite different rheological performance compared with gluten-containing dough. To deepen the understanding of gluten-free dough, variations of rheology and moisture distribution of corn starch-hydroxypropylmethylcellulose (CS–HPMC) gluten-free dough in the process of proofing were studied. Significant differences were found in terms of soluble carbohydrate composition, moisture distribution, and rheology. Arabinose, glucose, fructose, and mannose were the main composition of soluble carbohydrates in CS–HPMC dough, out of which glucose was preferentially utilized during proofing. Non-freezable water content and third relaxation time decreased from 44.24% and 2171.12 ms to 41.39% and 766.4 ms, respectively, whereas the amplitudes of T23 increased from 0.03% to 0.19%, indicating reduced bounded water proportion and improved water mobility with proofing time. Frequency dependence and the maximum creep compliance increased, whereas zero shear viscosity reduced, suggesting decreased molecular interactions and flowability, but improved dough rigidity. In conclusion, the reduced soluble carbohydrates and improved water mobility decreased molecular entanglements and hydrogen bonding. Furthermore, yeast growth restricted a large amount of water, resulting in declined flowability and increased rigidity.
... Yeast growth is achieved by consuming essential compounds such as fermentable sugars, amino acids, vitamins, and minerals [30]. In coffee, yeast improves the quality of low-altitude coffees [24] and produces organic acids such as citric and succinic acid since they derive from the Krebs cycle [31]. According to Martinez et al. [32], S. cerevisiae in coffee can increase the citric acid content. ...
Coffee quality is achieved by performing good practices. This study aimed to evaluate coffees from different altitudes fermented with the self-induced anaerobic method (SIAF) and processed via natural (N) and pulped natural (PN). Molecular (PCR-DGGE), chemical (HPLC, ABTS, DPPH, ATR-FTIR, and GC-MS), and sensory analyses were performed. Leuconostoc predominated both processes and all altitudes. Hanseniaspora and Pichia predominated both processes at 800 and 1200 m. Acids were higher in N coffees for all altitudes. Acetic, malic acid and alcohols were the most abundant. Higher sensory scores were obtained in N (mainly at 1400 m—88.13). Floral and spices were perceived in all samples. ABTS capacity in roasted coffee increased with altitude in PN (2685.71, 2724.03, and 3847.14 µM trolox/g); meanwhile, the opposite was observed in N. High sensory scores were obtained in high altitudes. Alcohols and acids in roasted beans increase with altitude. Leuconostoc and Pichia showed potential as future coffee starters.
... Therefore, it could be inferred that 24 h crumbly dough fermentation might not be enough to change the internal crystal structure of starch, and enzyme/acidolysis mainly affects the amorphous region of starch because the amorphous region of starch is rich in amylose, and enzyme/acidolysis tends to hydrolyze amylose [15]. HN2, which also underwent 24 h of crumbly dough fermentation, did not show a more pronounced increase in relative crystallinity, probably because the enzymes produced by the yeast were mainly intracellular [25], and the erosive effect of the produced acids [35] on starch might not be sufficient to be detected by the instrument. Therefore, the starch from HN1, which only underwent 90 min of noodle fermentation, was less likely to produce changes that could be detected by the instrument. ...
Crumbly dough fermentation was applied to produce dried hollow noodles, with Lactobacillus plantarum, Koji and yeast as the main fermenting agents. The cooking, textural and digestive properties of the noodles were studied, followed by the morphological, crystalline and thermal properties of the starch. The results show that, compared to unfermented noodles, the optimal cooking time of Koji pre-fermented noodles (KJHN) decreased from 460 s to 253 s, and they possessed a higher percentage of weakly bound water and degree of gelatinization at the same cooking time. After cooking, KJHN had a softer texture and higher starch digestibility. In addition, the physicochemical properties of the KJHN and Lactobacillus plantarum pre-fermented noodles (LPHN) showed a decrease in pH and amylose content, and an increase in reducing sugars content. The starch extracted from KJHN and LPHN had significant superficial erosion and pore characteristics, and the gelatinization enthalpy, relative crystallinity and short-range order were all increased. These changes in the starch properties and the quality characteristics of noodles resulting from Koji fermentation might provide a reference for the development of easy-to-cook and easy-to-digest noodles.
... In combination with the smaller amounts of lipases used for brioche in comparison to the other cakes, both could explain the results. Another factor causing their inactivation could be the various fermentation products such as ethanol and succinic acid, which themselves are known to negatively impact baking properties of bread (Jayaram et al., 2014a;Jayaram et al., 2014b). ...
Lipases are commonly used as clean-label improvers for bread. However, their potential use in cakes with different formulations remains unknown. The aim was to analyze the effects of seven baking lipases on three different cake formulations (an eggless cake, a pound cake with eggs and a yeast-based cake) in comparison to a traditional emulsifier. Product density, water loss during baking and product texture were assessed. If and to what extent the product quality was improved depended on both the lipase and the cake formulation. Lipase-induced effects mostly exceeded those of the emulsifier and were most pronounced in formulations without intrinsic emulsifiers like eggs. The lipases differed in their extent of improvement, hinting at the importance of their specific reactivity patterns and the resulting range of interactions with macromolecules. Further research is needed to unravel the mechanistic background of baking quality improvement in cakes.
... has been identified as a major organic acid produced by yeasts during fermentation. It is created in both the reductive citric acid cycle and the glyoxylate cycle by oxidation of isocitrate (Jayaram et al., 2014). Citric, isobutyric, and isovaleric acids were also identified in wet fermentation employing yeast starters, in addition to succinic acid (Martinez et al., 2019). ...
Coffee is a significant agricultural commodity that is well-known and enjoyed all over the world for its distinct flavor and aroma. The quality of coffee is affected by various parameters. The existing coffee processes, which rely on natural microorganisms, are uncontrollable, resulting in product inconsistency. To overcome this problem, this study aimed to investigate the potential use of selected microbial inoculants in wet method processing and the effects of fermentation time and temperature on coffee quality. Selected yeasts, bacteria, and lactic acid bacteria, isolated from the coffee fermentation process, were used as the starter cultures. Twenty-four conditions were set. At the 0 and 24 h of fermentation, total bacterial and yeast counts, as well as pH, were measured and trend to change during fermentation. After fermentation, coffee beans were subjected to sensory evaluation by Quality-Arabica Graders. Results showed that specific microbial starter culture under controlled conditions successfully improved coffee quality. Ten of the twenty-four types coffee beans tested were classified as specialty coffee with distinct cupping characteristics. Scaling up experiment was done by a mixture of three strains of Pichia kluyveri and Wickerhamomyces anomalus (condition Y4-04) at Doi Saket District, Chiang Mai, Thailand. According to the flavor profile derived from Q-graders, the cupping results was related to the volatile and water-soluble compounds identified by GC-MS and 1H NMR analyses. It suggests that the coffee quality can be improved by using starter cultures and carefully managing fermentation settings.
... This yeast-mediated fermentation also yields secondary metabolites such as glycerol, organic acids and aroma compounds. These fermentation metabolites play an important role in dough properties and product quality characteristics [2][3][4]. Over the past decade, several during pastry making could offer opportunities to improve the production process or endproduct quality, whereas increasing our knowledge on the sugar release and consumption dynamics by yeast could help to design sugar reduction strategies. ...
Fermented pastry products are produced by fermenting and baking multi-layered dough. Increasing our knowledge of the impact of the fermentation process during pastry making could offer opportunities for improving the production process or end-product quality, whereas increasing our knowledge on the sugar release and consumption dynamics by yeast could help to design sugar reduction strategies. Therefore, this study investigates the impact of yeast fermentation and different sugar concentrations on pastry dough properties and product quality characteristics. First, yeasted pastry samples were made with 8% yeast and 14% sucrose on a wheat flour dry matter base and compared to non-yeasted samples. Analysis of saccharide concentrations revealed that sucrose was almost entirely degraded by invertase in yeasted samples after mixing. Fructans were also degraded extensively, but more slowly. At least 23.6 ± 2.6% of the released glucose was consumed during fermentation. CO2 production during fermentation contributed more to product height development than water and ethanol evaporation during baking. Yeast metabolites weakened the gluten network, causing a reduction in dough strength and extensibility. However, fermentation time had a more significant impact on dough rheology parameters than the presence of yeast. In balance, yeast fermentation did not significantly affect the calculated sweetness factor of the pastry product with 14% added sucrose. Increasing the sugar content (21%) led to higher osmotic stress, resulting in reduced sugar consumption, reduced CO2 and ethanol production and a lower product volume. A darker colour and a higher sweetness factor were obtained. Reducing the sugar content (7%) had the opposite effect. Eliminating sucrose from the recipe (0%) resulted in a shortened productive fermentation time due to sugar depletion. Dough rheology was affected to a limited extent by changes in sucrose addition, although no sucrose addition or a very high sucrose level (21%) reduced the maximum dough strength. Based on the insights obtained in this study, yeast-based strategies can be developed to improve the production and quality of fermented pastry.
... This could be because as the concentration of phosphate increased, the total charge increased, enhancing the electrostatic repulsion of biological macromolecules, stimulating the development of the gluten network and so allowing for more water to combine (M. Jayaram et al., 2014). ...
Noodles are usually made with flour, salt, and water. Developments in the noodle industry have led to the use of some inorganic salts such as NaCl, alkaline, and phosphate salts to improve the quality of noodle products. However, the physicochemical properties of dough and noodle characteristics may show different rheological and technological properties after salt addition depending on the salt content, type, and mixture. Therefore, understanding the role and mechanism of different salts in flour dough and the resulting noodles would be helpful in improving the quality of the final products. This review covers recent advances in the application of inorganic salts to noodle dough and the effects of such an addition on the final product. Addition of inorganic salts improves the elasticity and extensibility of gluten, improves the texture of noodles and gelatinization of starch, and enhances the processing performance of the dough and quality of the final product. However, the addition of excessive amounts of these salts leads to the deterioration of gluten and a decrease in the elasticity and extensibility of the resulting dough. Most alkaline salts and NaCl can increase the cooking loss of noodles, but phosphates can decrease this parameter. Addition of alkaline or NaCl decreases the nutritional quality of cooked noodles due to lysine losses and reduces protein digestibility. Overall, inorganic salts can enhance dough characteristics and noodle quality, but health of the consumer should not be overlooked, which should be added within the allowable range of production.
... Moreover, the free -SH can ionize and generate -S -(-SH anions) under certain conditions, where the -Sis more nucleophilic and reacts faster than free -SH (Koehler, 2003). The pK a of free -SH is about 8.50 (Jayaram et al., 2014), when the pH is low, the ionization of free -SH becomes disrupted. Therefore, with the decrease of pH value in FWNs, the content of -Sdecreases, which might result in the reduction of interchain disulfide bonds generated during cooking and thus affects the polymerization of proteins and the formation of gluten networks. ...
In this study, the effects of acidity regulators (ARs) on the shelf life, quality, and physicochemical characteristics of fresh wet noodles (FWNs) were investigated. The addition of ARs markedly reduced the pH value of FWNs with a prolonged microbial shelf life of 5–10 days. Moreover, the presence of ARs significantly (p < 0.05) decreased the hardness and tensile distance of cooked FWNs, while increasing the cooking loss of noodles significantly (p < 0.05). The results of confocal laser scanning microscope analysis showed that ARs inhibited the formation of gluten networks in cooked noodles. Sodium dodecyl sulfate-extractable protein (SDS-EP) and free –SH content increased significantly (p < 0.05) when ARs were added. ARs affected the polymerization of proteins by inhibiting the formation of interchain disulfide bonds during cooking. Moreover, X-ray diffraction results showed that the addition of ARs resulted in acid hydrolysis of the amorphous area of the starch in FWNs, decreasing the pasting temperature, peak and trough viscosities of the starch. The reduction in pH value was the main factor that affected the shelf life and quality of FWNs, but different types of ARs had no significant impact.
... Despite the increase observed at the end of drying for treatment 2SC, no significant difference was observed in any treatment during fermentation/drying (Fig. 2b). The succinic acid production by yeast is done mainly by the glyoxylate cycle and the citric acid reduction cycle (Jayaram, Cuyvers, Verstrepen, Delcour, & Courtin, 2014). These results suggested that only 2SC treatment followed this path. ...
Selected yeasts for coffee fermentation are correlated with changes in chemical compounds and beverage sensory characteristics. This work aimed to evaluate the chemical and sensory modifications of coffee fermented with one yeast (Saccharomyces cerevisiae CCMA 0543, Candida parapsilosis CCMA 0544, or Torulaspora delbrueckii CCMA 0684) and in co-inoculation (from two to two and the three together) by dry processing. Real-time PCR analyzes, total phenolic content and antioxidant activity (DPPH, ABTS, and FRAP), liquid and gas chromatography, and sensory analysis were performed. Caparaó coffees showed a higher C. parapsilosis (6.14 Log cell.g⁻¹) population followed by S. cerevisiae (5.85 Log cell.g⁻¹) and T. delbrueckii (4.64 Log cell.g⁻¹). The total phenolic content has a strong and positive correlation with the fermentation time and the roasted beans and a moderate and positive correlation with DPPH, FRAP, and ABTS. Coffee inoculated with T. delbrueckii reduced caffeine concentration during the fermentation process. In co-cultivation, the trigonelline concentration showed the most significant decrease (around 4 mg.g-1) when inoculated with S. cerevisiae and T. delbrueckii. Detection of some organic acids and volatile compounds during fermentation may indicate that the starter cultures used different metabolic routes. All co-inoculation treatments presented the best sensory scores (greater than 86 points). In the inoculated fermentation, fruity, citric, molasses, freshness, and wine notes appeared. The co-inoculated treatment with S. cerevisiae CCMA 0543, C. parapsilosis CCMA 0544, and T. delbrueckii CCMA 0684 was the best, considering the diversity of sensory notes descriptors and the final concentration of organic acids.
... The formation of glycerol from dihydroxy acetone phosphate generated by the EMP pathway as well as the formation of succinic acid through the reductive tricarboxylic acid (TCA) cycle further contribute to redox balancing (NAD + regeneration). In particular, the formation of carbon dioxide is important during dough fermentation and, hence, for the production of bread, although ethanol (that evaporates during the baking process), glycerol (produced as osmoprotectant and improving carbon dioxide retention), and succinic acid (causing a pH decrease) contribute to the formation of the gluten network and the rheological properties of the dough too (Jayaram et al. 2014a(Jayaram et al. , 2014bAslankoohi et al. 2015;Rezaei, Verstrepen, and Courtin 2015;Rezaei et al. 2016;De Vuyst, Van Kerrebroeck, and Leroy 2017). ...
Sourdough production is an ancient method to ferment flour from cereals for the manufacturing of baked goods. This review deals with the state-of-the-art of current fermentation strategies for sourdough production and the microbial ecology of mature sourdoughs, with a particular focus on the use of non-flour ingredients. Flour fermentation processes for sourdough production are typically carried out by heterogeneous communities of lactic acid bacteria and yeasts. Acetic acid bacteria may also occur, although their presence and role in sourdough production can be criticized. Based on the inoculum used, sourdough productions can be distinguished in fermentation processes using backslopping procedures, originating from a spontaneously fermented flour-water mixture (Type 1), starter culture-initiated fermentation processes (Type 2), and starter culture-initiated fermentation processes that are followed by backslopping (Type 3). In traditional recipes for the initiation and/or propagation of Type 1 sourdough productions, non-flour ingredients are often added to the flour-water mixture. These ingredients may be the source of an additional microbial inoculum and/or serve as (co-)substrates for fermentation. An example of the former is the addition of yoghurt; an example of the latter is the use of fruit juices. The survival of microorganisms transferred from the ingredients to the fermenting flour-water mixture depends on the competitiveness toward particular strains of the microbial species present under the harsh conditions of the sourdough ecosystem. Their survival and growth is also determined by the presence of the appropriate substrates, whether or not carried over by the ingredients added.
... Although fungi only account for a small part of the microbial community, 40% of the differential organic acids were related to them, suggesting that fungi played a vital role in serofluid dish (Li et al, 2017, Wei et al, 2020. Culture-based methods showed yeast could metabolize monosaccharides to ethanol and produce fragrance to improve the chemical composition and sensory properties (Jayaram, Cuyvers, Verstrepen, Delcour, & Courtin, 2014;Puertas et al., 2018), whereas correlation analysis of metabolomic profiles and ITS sequencing cannot directly reveal their functions. Thus, metagenomics and transcriptome provide us with powerful tools to elucide the functions of fungi based on direct evidence. ...
Serofluid dish is a popular fermented food in northwest China that contains abundant microorganisms. Advances of next-generation sequencing facilitate the elucidation of bacterial community composition, yet roles of fungi in serofluid dish need further exploration. Here, internal transcribed spacer (ITS) sequencing and metatranscriptomics were conducted and results showed that the dominant fungal communities belong to Candida and Saccharomyces. Additionally, fungal diversity, including phylogenetic diversity and species richness, was largely correlated with pH, the total organic carbon (TOC) and spatial distance. Multivariate regression tree and all-subsets regression analysis also identified them as strong predictors. Further gene annotations revealed that fungi exhibited higher participation in the carbohydrate metabolism, amino acid metabolism, translation and energy metabolism pathways, including sucrose and maltose metabolism and the production of acetate, fumarate and ethanol. Collectively, fungi in serofluid dish possess rich species diversity, and are affected by both environmental variation and geographical distance. In the fermentation process, fungi predominantly participated in the carbohydrate metabolism and genetic information processing.
... Alvarez-Martin et al. [20] found that propionic acid was produced during milk fermentation by several yeast strains belonging to the species Candida famata, Debaryomyces hansenii, Kluyveromyces lactis, Pichia fermentans, Pichia membranifaciens and Yarrowia lipolytica. Conversely, in doughs fermented by S. cerevisiae the main organic acids detected were acetic and butyric acids [70], and succinic acid [17,18]. Further studies will determine the fate of the high levels of propionic acid found in our doughs after baking, although no safety concerns have been detected when utilized as food additive [71]. ...
Traditional fermented foods are obtained by a complex consortium of autochthonous microorganisms producing a wide variety of bioactive compounds, thus representing a reservoir of strains with new functional properties. Here, doughs obtained using five different wholegrain flours were singly fermented with selected yeast strains, which were evaluated for their functional traits. Lactate, volatile fatty acids and conjugated linoleic acid isomers produced by fermented doughs were detected by HPLC, while dough anti-inflammatory capacity was measured on human peripheral blood mononuclear cells by flow cytometry. Yeast potential probiotic activity was assessed by evaluating their resistance to simulated gastric and intestinal fluids. For the first time we report evidence of yeast strains producing high levels of the conjugated linoleic acid (CLA) isomer CLA 10-12tc and propionic acid, which are known for their specific health benefits. Moreover, such yeast strains showed an anti-inflammatory capacity, as revealed by a significantly decreased production of the strongly pro-inflammatory cytokine IL-1β. All our Saccharomyces cerevisiae strains were remarkably resistant to simulated gastric and intestinal fluids, as compared to the commercial probiotic strain. The two strains S. cerevisiae IMA D18Y and L10Y showed the best survival percentage. Our novel yeast strains may be exploited as valuable functional starters for the industrial production of cereal-based innovative and health-promoting fermented foods.
... is inconsistency can be attributed to the decrease of the pH value. Increase in acidity of wheat flour would result in stiffer and more fragile dough [25]. e DDT and DST of three mixed 985.0 ± 1.4 c 726.5 ± 5.0 c 258.5 ± 3.5 bc 1472.5 ± 5.0 c 746.0 ± 10.0 b † Data were expressed as means ± SD. ...
Overozonized wheat flour was added to unozonized wheat flour at three different ratios (M1: 1 : 1; M2: 1 : 2; and M3: 1 : 3), and the mixed flour was evaluated for quality properties, including pH, protein component, dough property, pasting property, and steamed bread quality. The pH of the mixed flour gradually increased as the addition content of overozonized flour decreased. The three mixed flour had higher insoluble polymeric protein (IPP) content than unozonized flour. Compared with overozonized flour, M1 and M2 flour did not show a significant difference in IPP content, but M3 flour exhibited a decreased IPP content. Three mixed flour had higher dough development time and dough stability time than both unozonized and overozonized flour, and there was no significant difference among three mixed flour in these two dough parameters. Peak, trough, and final viscosities of the three mixed flour were between those of unozonized and overozonized flour. Steamed bread of three mixed flour had larger specific volume and better texture than that of overozonized flour, with steamed bread of M3 flour showing the best attributes. Among the three mixed flour, M1 flour was the closest to overozonized flour in volatile compounds of steamed bread. These results suggested overozonized flour can be mixed with unozonized flour to decrease the deterioration of overozonization on the dough and food-making properties of wheat flour, but the mixing ratio should be taken into consideration to obtain a better quality.
... Yeasts can produce succinic acid through the oxidization of isocitrate via the glyoxylate cycle and the reductive citric acid cycle (Jayaram et al., 2014). M. caribbica (CCMA 0198), S. cerevisiae (CCMA 0543), and C. parapsilosis (CCMA 0544) possibly used this biochemical route in the PN treatments. ...
Starter cultures during fermentation of Coffea arabica var. Mundo Novo processed in open stainless-steel vessels by natural and pulped natural methods were studied. The yeasts Meyerozyma caribbica (CCMA 0198), Saccharomyces cerevisiae (CCMA 0543), Candida parapsilosis (CCMA 0544), and Torulaspora delbrueckii (CCMA 0684) were inoculated separately in two different coffee processes: natural and pulped natural. The qPCR (real-time quantitative polymerase chain reaction) was used as a culture-independent method to monitor the inoculum's permanence. Changes in microbial metabolites (organic acids and volatile) production were evaluated by high-performance liquid chromatography (HPLC) and gas chromatograph-mass spectrometry (GC–MS), respectively. The sensory analysis was assessed in roasted beans. The fermentation lasted 27 h, and the coffee temperature ranged from 16.5 to 24 °C. The starter culture population was dominant throughout fermentation. S. cerevisiae (CCMA 0543) and T. delbrueckii (CCMA 0684) presented a higher population in natural processing. However, in pulped natural processing, M. caribbica (CCMA 0198) and C. parapsilosis (CCMA 0544) were the dominant populations. Citric, malic, and succinic acids were naturally present in coffee. Lactic, isobutyric, and isovaleric acids were detected at the end of the fermentation in different treatments. Lactic acid was detected in samples at the end of fermentation in Control and CCMA 0198 treatment. NAT coffee inoculated with CCMA 0684 presented isobutyric acid and isovaleric acid concentrations. Volatile compounds, such as 2,6-diethylpyrazine was detected in treatments inoculated with yeasts, but not in Controls. 2-acetoxymethylfuran was only detected in samples inoculated with CCMA 0198 from both NAT and PN methods. Samples fermented with S. cerevisiae (CCMA 0543) presented the highest sensorial scores in both processing (84.75 and 84.92). The inoculated coffee beans showed higher scores of sweetness, long aftertaste, and greater complexity. The starter cultures influenced the sensorial profiles through the synthesis of specific volatile constituents. However, considering all parameters analyzed, S. cerevisiae (CCMA 0543) would be the most suitable yeast for the var. Mundo Novo processed by both fermentation methods.
... 21 The impact of different yeast and lactobacilli ratios on the specific volume of WWB might have been due to different microbial metabolites, including acids, aroma precursors, and reducing agents. 23 For WWB Sac:Lac = 0:1 , SSF with lactobacilli caused acidification of WB (as shown in Appendix table 1), which resulted in the moderate proteolysis of gluten and hydrolysis of starch, leading to a weak network structure of the dough and reduced specific volume of the WWB. 20 For WWB Sac:Lac = 1:0 , the lower specific volume might have been related to the presence of higher reducing agents such as glutathione (γ-glutamylcysteinylglycine) produced by individual yeast fermentation, which weakens the gluten network and impairs the baking quality of the WWB. ...
BACKGROUND
The addition of wheat bran (WB) could improve the nutritional quality of whole wheat bread (WWB); however, it also caused many negative effects on the quality of bread. To improve the physico‐chemical properties of WB and the quality of WWB, WB was solid‐state fermented with different ratios of commercially available S. cerevisiae and L. plantarum, and utilized to prepare WWB.
RESULTS
The physico‐chemical properties of WB including dietary fiber content and its components, amino acid composition, and antioxidant activities were determined. After solid‐state fermentation, the physico‐chemical properties of WB were improved. WBSac:Lac = 2:1 showed higher antioxidant activity (only the total antioxidant activity was slightly lower than WBSac:Lac = 1:1), and greater concentration of soluble dietary fiber (9.22%) and essential amino acids / total amino acids (42.04) than the other WB samples. Whole wheat bread quality was investigated by measuring specific volume, porosity, texture, aroma, and volatile compounds. The WWB made with WBSac:Lac = 2:1 showed a higher specific volume, more uniform porosity structure, better texture, and more volatile compounds than the other samples.
CONCLUSION
Using a ratio of yeast and lactobacilli of 2:1, the solid‐state fermentation maximally improves the processing properties of WB, and prepares WWB with the best quality. © 2021 Society of Chemical Industry
This study presents a potential approach to produce effervescent tablets with yeast probiotic and bio-converted mangosteen pericarp juice (MPEj), aiming to deliver both multifunctional health benefits and appealing color. The process involved fermenting MPEj with Saccharomyces cerevisiae var. boulardii to modify its composition and increase the yeast population. Subsequently, the bio-converted MPEj and yeast cells were separated to generate powdered forms for producing effervescent tablets. Through response surface methodology, varying MPEj and nitrogen source concentrations revealed the optimal condition: 20% MPEj and 0.5% nitrogen source, yielding a yeast viability of 8.67 ± 0.24 CFU/mL When scaling up yeast fermentation, both flask and bioreactor demonstrated similar trend, with bioreactor exhibiting notably enhanced growth rates in MPEj as well as significant changes in TSS, TTA, and pH during fermentation. After fermentation, MPEj displayed increased antioxidant activity, altered phenolic content, increased isoleucine levels, and presence of propionate, indicating biotransformation driven by yeast. Effervescent tablets met quality standards and demonstrated enhanced yeast survival in simulated gastrointestinal conditions. Moreover, surface property testing, specifically hydrophobicity, revealed improved adherence to intestinal cells, suggesting the potential for prolonged gastrointestinal retention. This study underscores promising application of MPEj fermentation with yeast probiotic in developing functional probiotic tablets with enhanced health benefits.
With the rapid development of animal husbandry, forage resources are increasingly scarce. Improving the utilization rate of forage products and silage efficiency of planting is an urgent problem to be solved. This experiment used high moisture alfalfa at the budding stage with a water content of 71.4% from saline-alkali and non-saline-alkali soils as raw materials, setting up four experimental groups: non-saline-alkali alfalfa without additives (HNS-CK), non-saline-alkali alfalfa with compound lactic acid bacteria (Lactobacillus plantarum + Lactobacillus buchneri + Pediococcus pentosaceus + Lactobacillus kimchi, HNS-L4), saline-alkali alfalfa without additives (HS-CK), and saline-alkali alfalfa with compound lactic acid bacteria (HS-L4). After 60 days of silage, the quality and microbial diversity of the silage were tested. The results showed that the dry matter (DM) and lactic acid (LA) of the HNS-L4 group were significantly higher than those of the HS-L4 (P < 0.05), while there was no significant difference in crude protein (CP) between the HNS-L4 group and the HS-L4 (P < 0.05). The neutral detergent fiber (NDF), acid detergent fiber (ADF), pH of the HNS-L4 group were all lower than those of the HS-L4. The results of the microbial community showed that compared with the non-additives group, the Shannon index decreased and the Simpson index increased in the compound lactic acid bacteria group, indicating a significant reduction in microbial diversity in the silage environment (P < 0.05). The dominant bacteria in the HNS-CK and HS-CK groups were Enterobacteriaceae, while the dominant bacteria in the HNS-L4 and HS-L4 groups were Lactobacillus. At the phylum level, the dominant bacteria in alfalfa after lactic acid bacteria treatment were Firmicutes, which were significantly higher than the control group (P < 0.05). Therefore, compound lactic acid bacteria can improve the quality of alfalfa silage in both saline alkali and non-saline-alkali soils, with saline-alkali soils being better than non-saline-alkali soils, and both can reduce microbial diversity.
This study evaluated the impact of germination time and cereal type on nutrient content and sensory attributes of bread using germinated flours as a natural starter culture. Wheat varieties (Ashehan and Global) and oats were soaked for 12 hours, and then germinated for 48, 72, and 96 hours. After drying (27–30°C) for 48 hours, grains were milled into whole flour. Breads made from these germinated flours were analyzed for proximate composition, minerals, and sensory qualities. Bread made with Ashehan germinated flour (48–96 hours) showed fat (2.91–3.08%), protein (13.79–14.38%), carbohydrate (61.08–62.13%), and energy (328.03–331.49 kcal/100g) content. Global wheat showed similar trends, while oats had higher values, with fat (4.36–4.59%), protein (16.18–19.26%), and energy (336.48–359.99 kcal/100g). Germination significantly increased protein, energy, and mineral contents, especially in oats germinated for 96 hours (calcium 24.51 mg/100g, zinc 1.85 mg/100g, iron 2.44 mg/100g). Sensory tests indicated that germination at 72 hours improved bread acceptability, particularly in taste, with Ashehan, Global, and oats achieving the highest scores. Non-germinated (yeast-fermented) samples were least preferred. This study suggests that germination, especially at 72 hours, enhances bread quality and could be effective in traditional starter development.
In this study, the fermentation characteristics and functional properties of lactic acid bacteria-malted vinegar (LAB-MV) were investigated during the fermentation period. Changes in the components (organic acids, free sugars, free amino acids, β-glucan, and gamma-aminobutyric acid (GABA)) of MV (BWAF0d, BWAF10d, BWAF20d) and LAB-MV (LBWAF0d, LBWAF10d, LBWAF20d) were analyzed according to the fermentation time. The amounts of β-glucan and GABA in LBWAF20d were greater than those in BWAF20d (122.00 μg/mL, 83.06 μg/mL and 531.00 μg/mL, 181.31 μg/mL, respectively). The ACE1 and HMG-CoA reductase inhibitory activities of LBWAF20d were 98.16% (1/20 dilution factor, DF) and 91.01% (1/25 DF), respectively. The lipid accumulation ratio and total cholesterol levels in HepG2 cells treated with LBWAF20d (1/200 DF) were reduced by 45.85% and 54.48%, respectively, compared to those in the untreated group. These results suggest that LAB-MV, which comprises barley wine manufactured from LAB and yeast, may improve hepatic lipid metabolism.
Chapati is unleavened flat bread originated from Indian sub-continent and is considered as staple product in everyday meals. Its quality attributes are dependent on number of factors including the wheat used, ingredients added and processing parameters. The study was aimed to observe the effect of yeast addition on functional, rheological, and sensory characteristics on whole wheat flour and chapati at varying percentage (0.25–1.0). All the experiments conducted were compared with a control flour/chapati without yeast addition. The results showed that all the attributes were favourably affected with yeast addition when compared with control samples. It was noticed that the peak viscosity, setback, breakdown and final viscosity decreased with yeast addition and the paste obtained had higher gel strength. Alveogragh results also depict the increase in tensile strength and decrease in extensibility of dough on yeast incorporation. Textural and sensory studies revealed that yeast concentration upto 0.75% w/w in whole wheat flour resulted in chapati with good overall acceptability.
Banana plays a vital role in the nutrition and well-being of millions of people. With the change in lifestyle, people prefer convenient foods and pizza is one among it. In this study, pizza base was prepared by partial replacement of semolina with banana based composite flours, viz., green-banana flour (GBF), banana modified-starch (BMS) and banana peel-flour (BP). Addition of GBF, BMS and BP increased the ash and crude-fibre content of formulated dough. Pizza base prepared with banana based composite flour recorded positive effect on nutritional profile with 19–27% reduction in calories. Increase in higher level of substitution decreased the spread-ratio and specific volume after baking. Low gluten content (up to18-24%) in developed product is a positive outcome of substitution. The presence of total carotenoids in the GBF influenced the colour property of the final product with improved yellowness index (YI) values. Addition of BMS attributed to increased firmness values in composite pizza base. Sensory evaluation showed that formulation with 10% GBF, 0.4% BMS and 0.6% BP was preferred with acceptable colour, firm crumb and taste next to control. Therefore, the addition of nutritionally rich GBF, BMS and BP, can possibly be a choice to develop fibre enriched, low gluten pizza base with commercial feasibility and functional health benefits.
Yeasts are unicellular fungi found in many fermented foods. They play an important role in sourdough, by producing CO2 allowing the dough to rise as well as formation of aroma. This chapter describes yeasts usually found in sourdough, including their ecology, evolution, and metabolism.KeywordsYeastBiodiversityEcologyEvolutionMetabolism
Yeasts are important microorganisms used in different fermentation processes. The cocoa beans must go through a correct fermentation process to obtain good quality chocolate, which involves the action of yeasts and bacteria, and yeasts play a crucial role since they act in the first days of fermentation. In coffee, several studies have shown that the microbiota in the fruits is also a relevant factor. The fermentation process (regardless of the processing type) improves the beverage's quality. In this sense, studies using starter cultures in these two raw materials are important for better control of the process, and optimization of fermentation time, in addition to the improvement and diversification of volatile and non-volatile compounds produced by yeasts. Thus, this review discusses the importance and role of yeasts during fermentation, their metabolism, the produced compounds, and how yeast and the different chemical reactions help increase the quality of chocolate and coffee.
Fermentation is a commonly concerned topic in starch scientific research and is widely utilized in the food and pharmaceutical industry. Although massive papers on starch fermentation have been published in the past 10 years (2012‐2022), reviews of the overall knowledge structure of the discipline are relatively rare. Research in this area progresses rapidly. To stay current with the emerging trends, this review used a bibliometric analysis method based on CiteSpace software to analyze, review, and briefly comment on selected articles published in the field of starch fermentation over the past 10 years. The research progress and emerging trend of starch fermentation were discussed. A total of 4943 references were used for analysis on CiteSpace. The results showed that from 2012 to 2022, the rate of published articles and the number of citations had increased. China was in first place by number of publications. Jiangnan University was the most prolific institutions, and the author with the most prolific was Akihiko Kondo. Among the category collaboration, “Agriculture”and “Food Science and Technology” were the first between two five years. The keyword “ethanol” showed the highest burst strength level. In addition, food fermentation and clean energy research were the main areas of concern in this field. This review aims to provide new insights for promoting the industrialization development and clinical application of starch fermentation technology. This article is protected by copyright. All rights reserved
Many food companies try to reduce the sugar content in their products. For yeasted cereal-based products, knowledge about the sugar production and consumption dynamics during processing, including sucrose hydrolysis, and its impact on product quality is key in achieving this. We showed before that in fermented pastry, sucrose is entirely hydrolysed into glucose and fructose by yeast invertase and that the contribution to sweetness of glucose, partly consumed by yeast, is negligible compared to that of fructose. Therefore, this study investigated the possibility of using fructose instead of sucrose in fermented pastry to decrease end product total sugar content. Fermentation dynamics, product height and sweetness factor were compared for recipes with 14% sucrose, 14% fructose and 10% fructose (dry matter flour base). Sucrose replacement had a small impact on fermentation dynamics and no significant impact on product height. Fermented pastry samples made with 10% fructose did not have significantly more fructose in the end product than those made with 14% sucrose. Moreover, samples made with 10% fructose had the same sweetness factor as samples made with 14% sucrose, while the end product contained 33% less sugar. It would be interesting to explore these findings in other fermented high-sugar bakery products.
This study compared the deterioration of pre-fermented frozen dough in 1–90 days frozen storage (FS) and 1–4 times of freeze–thaw cycles (FT) by analysing the characteristics of steamed bread, its dynamic rheology and rheofermentation properties, gluten aggregation, yeast viability, cell microstructure and yeast metabolites. The results showed that the specific volume and hardness of steamed bread after 25 days of FS and 1 FT were unacceptable. The decrease in the elasticity modulus and the increase in the viscosity modulus caused by FT were more obvious than those caused by FS. The rheofermentation results indicated that both FS and FT decreased the gas retention and gas production ability, but more significant negative effect was observed during FT than during FS. Further investigation of the gluten aggregation showed that the glutenin macropolymer decreased during FS and FT whether yeast was added or not to the dough, and the yeast increased the decline rate from 0.24 to 0.52 when FT was conducted, which indicated that the yeast had a negative effect on gluten aggregation. The yeast viability and microstructure showed no significant difference during FS and FT, whereas the yeast metabolites results demonstrated that the glucose and fructose contents increased during FS but decreased during FT, which indicate a difference in yeast metabolism. Fructose and glucose could be the indicators of the difference in the deterioration mechanism of FS and FT based on the factor analyses. This study provided novel insights on the deterioration mechanism of pre-fermented frozen dough.
Whole wheat flour dough (WWFD) has a high content of dietary fibres that causes a negative influence on the dough rheology, resulting in undesirable quality for whole wheat bread (WWB). Therefore, to devise the processing strategies for overcoming the quality issues for WWB is of remarkable significance. The cooperative fermentation by yeast and lactic acid bacteria (CFYL) has been proposed as a powerful processing technology to modify the dough rheology, retention and stabilization of gas cells for a WWFD. The breadmaking performance of WWFD has been modified due to the CFYL-induced changes in the structure of wheat bran, gluten proteins and wheat starch. CFYL mitigated the negative influence of wheat bran on gluten network. CFYL also strengthened the intermolecular interactions between proteins and starch. During CFYL, exopolysaccharides (EPSs), enzymes and organic acids were produced which modified the dough rheology and led to an improvement in the bread quality. Moreover, CFYL contributed to an increase in the water-extractable arabinoxylans and soluble wheat proteins but a decrease in the starch granule sizes. This results in a higher strain hardening and a stronger liquid film of the dough for improving the retention and stabilization of gas cells in a WWFD during breadmaking. As such, CFYL has a good potential use for WWB manufacturing to achieve the products with desirable overall quality and satisfactory consumer acceptability.
This study evaluated the inoculation of Meyerozyma guilliermondii and Bacillus licheniformis, separately or in co-culture, in wet-processed conilon coffee. Wet fermentation was conducted for 48 hours. Mesophilic bacteria, lactic acid bacteria, yeasts, and filamentous fungi were counted during fermentation. The inoculation of B. licheniformis and M. guilliermondii stimulated the multiplication of lactic acid bacteria. Acetic, citric, lactic, oxalic, malic, succinic, tartaric acids, glucose, and fructose were identified in all treatments at different concentrations. Methyl salicylate, 2-heptanol, 2-nonanol, and heptanone were found during fermentation. Methylpyrazine, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, and 3-ethyl-2,5-dimethylpyrazine identified after roasting notes of “almond” and “chocolate” to the beverages. All treatments were classified as “premium,” with the B. licheniformis treatment receiving the highest score. Bacillus licheniformis obtained better performance in fermentation, increasing coffee score and producing volatile compounds that provided positive sensory notes to the beverage.
There is increased interest in research on yeasts as potential phytopathogen biocontrol agents due to increasing restrictions in the use of chemical pesticides. Yeast strains from a range of genera and species have been reported to inhibit postharvest decay in different fruits. However, the mechanisms behind these yeast biocontrol capacities have not been completely deciphered because they are complex and act synergistically. In this study, we performed a thorough untargeted analysis of the exometabolome generated in a co-culture of the fungal plant pathogen Botrytis cinerea with four antagonistic yeast strains: Pichia fermentans (two strains), Issatchenkia terricola and Wickerhamomyces anomalus. As a result, general and strain-specific antifungal mechanisms and molecules were identified. The P. fermentans strains secreted the highest number of differential metabolites to the extracellular medium when co-cultured with B. cinerea. In vitro antagonistic and in vivo pathogen protection assays were performed with the selected metabolites. Among a plethora of 46 differentially secreted metabolites related to yeast-fungus competitive interaction, the phenylpropanoid trans-cinnamic acid and the alkaloid indole-3-carboxaldehyde were identified as the best antagonistic metabolites against gray mold infection under in vivo protection assays. Both metabolites caused damage to the fungal membrane and increased ROS generation in spores of B. cinerea. In addition, enhanced yeast secretion to the extracellular medium of oxylipins, dipeptides, alkaloids or antibiotics deserve to be further investigated as signaling or antagonistic molecules. This study opens the door to future investigations of roles of these molecules in yeast metabolism and application of this knowledge for biotechnological purposes.
Sourdough starters for making traditional steamed bread are rich in microbes. Studies have shown that, in addition to yeast and lactic acid bacteria (LAB), acetic acid bacteria (AAB) are other functional species in sourdough, but the influences of AAB on the properties of sourdough and steamed bread were rarely reported. This study aimed to assess the effects of a selected strain of acetic acid bacterium on the properties of sourdough and steamed bread. Sourdoughs and steamed breads were prepared from five different starter cultures, marked as CK (control, with no starters), Y (only yeast), YL (yeast+LAB), YA (yeast+AAB) and YLA (yeast+LAB+AAB), and their properties were determined. The results of sourdough properties showed that the YLA sourdough had the highest total titratable acid of 14.6 mL and the lowest pH of 3.87 compared with the other groups after fermentation to 8 h; and the YLA sourdough had the greatest elasticity and viscosity. The results of quality properties of steam bread revealed that the L* value (88.40 ± 0.09) of the YA steamed bread was significantly higher than those of the YLA and YL steamed breads; the YLA steamed bread had the highest specific volume and the highest sensory score 89.6 ± 3.31 in comparison to those of the other groups; the hardness and chewiness of YLA and YA steamed breads were significantly lower than those of the other groups. Volatile compounds in the steamed breads were also determined by SPME-GC–MS. A total of 42 flavor substances were detected, including 3 kinds of alcohols, 8 kinds of aldehydes, 7 kinds of ketones, 2 kinds of acids, 15 kinds of esters, 1 furan, and 6 kinds of other types of compounds, mainly alkanes and esters, followed by alcohols and aldehydes. The YLA steamed bread was richer in esters, aldehydes, and acids than those from the other treatment groups. By contrast, alkanes and aldehydes were dominant in the Y and YL steamed breads. Therefore, the flavor and quality of the steamed bread made from the YLA sourdough could be improved obviously. These results could provide references for the application of AAB in dough fermentation and the improvement of new kinds of starters.
ε−poly−L−lysine treated yeast (PTY) helps to enhance the freeze-thaw tolerance of frozen dough. This study explored the effect of PTY on the aggregation and the gas-retention of frozen dough after steaming for 2, 5, 10, and 20 min. Gas-cell images showed that PTY reduced the loss of gas-retention ability caused by 4 times of freeze-thaw. The results of sodium dodecyl sulfate extractability and subunit distribution of gluten showed that, after the same heat time, frozen dough with PTY has higher degree of covalent crosslinking with better aggregation ability of α−, γ−gliadin, and low molecular weight glutenin subunits than frozen dough with yeast. Chemical analysis and chain morphology results demonstrated that the levels of acidity, NH2, and free sulfhydryl in dough were decreased, and the protein molecules aggregated into longer chains when using PTY instead of yeast, indicating that PTY reduced acid-mediated hydrolysis and increased the disulfide bonds-mediated gluten polymerization.
The effects of three phosphate salts (PS) on the secondary structure, microstructure of gluten, rheological properties of dough and water status of noodles were investigated to determine the mechanisms underlying the changes in the quality of noodles. Changes in the secondary structure detected were the increased number of β-sheet and decreased number of random coil structures. PS reduced the content of free sulfhydryl (SH) and increased the content of disulfide (SS) bonds. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that the band density of the high molecular regions of the gluten was reduced. The results showed that adding PS induced a more compact microstructure and improved the G′ and G′′ values of the dough. After adding PS, the water-solids interaction in noodles was enhanced by the decreased water mobility. It was concluded that PS promoted the water holding capacity of the noodles and strengthened the gluten network.
Cereal Chem. 75(5):612-616 Baker's yeast, Saccharomyces cerevisiae, has a well-known effect on dough rheology during breadmaking. During a 3-hr fermentation, hydrogen peroxide (H2O2) produced by yeast (0.76%, fwb) increased from 1.09 to 2.32 μmol/g of flour. The spread test, a measure of a dough's rheological properties, showed that yeast had an effect on dough rheology similar to that of H2O2, an oxidant that makes flour-water dough more elastic. In addi- tional experiments (spread test and H 2O2 measurement), glucose oxidase, an enzyme that produces H2O2, gave results similar to those with yeast. The fact that catalase, an enzyme that destroys H 2O2, reversed the rheo- logical effect of added H 2O2 but did not reverse the effect of either yeast or glucose oxidase suggested that either wheat flour contains an inhibitor to catalase or H2O2 was not the active component. A series of experiments, inclu- ding use of defatted flour, remixing, and mixing dough under nitrogen, all indicated that catalase was inhibited by peroxides in the lipid fraction of flour. These results also suggested that H 2O2 is responsible for the effects of yeast and glucose oxidase on dough.
Network formation of wheat gluten proteins, containing monomeric gliadin and polymeric glutenin, is essential for many wheat-based food products. The mechanisms of protein polymerization depend on processing conditions. Gluten disulfide cross-linking determines end product quality of many if not all wheat-based food products. Non-disulfide cross-links can be derived from dehydro amino acids after -elimination of cystine upon heating under alkaline conditions. In addition, isopeptide bonds can be induced during heating at neutral pH and under dry conditions, and Maillard cross-links can be formed when reducing sugars are heated in presence of primary amino groups. The production of hard pretzels involves a heat/alkali treatment and subsequent baking and drying to a final moisture content of 2%. It induces disulfide, dehydroalanine-derived, and Maillard-derived cross-links.
Bio-based succinic acid is receiving increasing attention, as it could provide a cost-effective, ecologically sustainable alternative to the current petrochemical production process, thus promising a significantly higher market potential. The yeast Saccharomyces cerevisiae is a robust and well-established industrial production organism exhibiting an extraordinarily high acid- and osmotolerance. These features in conjunction with the sophisticated toolbox for genetic engineering make it particularly suitable for succinic acid production. The high tolerance towards acidity is a major advantage over previously established bacterial succinic acid production hosts, since it makes the use of neutralisation salts dispensable and thus enormously facilitates the downstream process. By constructing yeast strains capable of producing significant amounts of succinic acid, we have recently established S. cerevisiae as a promising host for succinic acid production. Our metabolic engineering strategy relied on the implementation of an oxidative production route using the glyoxylate cycle. We here discuss theoretical and practical aspects of oxidative and reductive succinic acid production routes in S. cerevisiae.
A negative relationship between dough strength and dough extensibility would pose a problem for breeding hard wheats, as both dough strength and dough extensibility are desirable. We derived 77 recombinant inbred lines (RIL) from a cross between hard red spring wheat cultivars McNeal and Thatcher. McNeal produces flour with stronger dough and lower extensibility than does Thatcher. RIL were evaluated for strength-related properties using mixograph analysis and extensibility parameters using the Kieffer attachment to the TA.XT2 texture analyzer. Additionally, the RIL were test baked. Measurements using the mixograph and the Kieffer attachment were highly heritable. Maximum dough extensibility (Ext(max)) was negatively correlated with resistance to extension (R(max)) (r = -0.74) and with mixograph tolerance (r = -0.45). Loaf volume was correlated with both R(max) (r = 0.42) and area under the extensigraph curve (r = 0.44) based on partial correlation analysis adjusted for protein differences. Ext(max) was negatively correlated with loaf volume (r = -0.26). The McNeal allele for polymorphism at the Gli1-B1 locus on chromosome 1BS caused high dough-mixing tolerance and low dough extensibility. Our results suggest that traditional selection criteria in hard red spring wheat, including tolerance to dough mixing and high loaf volume, may result in reduced dough extensibility.
The rheological attributes of polymers as wheat dough are strongly related to its microstructure. To quantify dough protein microstructure confocal laser scanning microscopy combined with image analysis was used. The effect of three experimental factors pH (addition of lactic acid and sodium hydroxide), water addition, and sodium chloride (NaCl) addition on empirical and fundamental rheological properties as well as microstructural protein properties were studied and modeled by applying a response surface methodology. The obtained models revealed high correlations between the experimental factors and the complex shear modulus (R
2 = 0.97), dough resistance (Rmaxk; R
2 = 0.91) and stickiness (R
2 = 0.93). Furthermore it was possible to determine microstructural attributes as the area fraction (R
2 = 0.88) and Feret’s diameter (R
2 = 0.86) as a function of pH, water and NaCl addition. Especially measures of Rkmax revealed highly significant correlations with the protein microstructure as the branching index (r = 0.79).
For the characterization of wheat quality, micro-extension tests for dough and gluten and a micro-baking test were developed using comparable dough compositions, the same mixing temperature and cultivar-specific mixing times. By means of these methods, the flours of 26 wheat samples were studied for dough development time, maximum resistance and extensibility of dough and gluten and loaf volume of the baked products. Standard methods (rapid-mix-test, gluten index determination) were used for comparison. The results indicated that the rheological properties of dough and gluten as well as the gluten index are correlated higher with the optimised micro-baking test than with the standard baking test. If flour protein or wet gluten content is included in the correlations, the extension test of gluten, which can be performed easily and reproducibly, allows a reliable prediction of the loaf volume obtained by the micro-baking test.
BACKGROUND: In order to explore the differences in rheological behaviour of full formula and flour/water doughs due to mixing, small-amplitude oscillatory strain (SAOS) rheological measurements were made on fully developed nonyeasted and inactivated yeasted dough formulations mixed at various speeds using the Brabender Farinograph and the Bohlin ReoMixer. These results were compared with large-strain empirical rheological results (including Kieffer rig uniaxial extension) as well as baking test results to determine differences due to mixer speed and/or flow distribution.
RESULTS: The uniaxial extension and baking tests detected mixing speeds with incomplete dough development. Above those speeds, energy input to peak development was relatively constant in the Farinograph. Extensibility trends showed increases with speed in the yeasted dough samples, which were attributed to variation in fermentation time during mixing to peak torque at different speeds. While SAOS results did not show differences due to mixing speed, they did detect differences between the yeasted and nonyeasted dough formulations, as well as significant differences (P < 0.01) between yeasted doughs mixed in the two different mixers.
CONCLUSION: The results indicate that known differences in the distribution of elongational and shear flows in the two mixers impact the development of dough structure during mixing. Copyright
The course of the sedimentation test for evaluation of gluten quality was investigated using light microscopy. Flour particles swelled up reversibly in the sedimentation solutions, as did single strands of the gluten network, the swelling being greater in sodium dodecyl sulphate (SDS)-sedimentation solution than in Zeleny reagent. Investigation of gliadin and glutenin showed only glutenin to be capable of swelling, whereas gliadin dissolved completely.Der Ablauf des Sedimentationstests zur Kleberqualittsbestimmung wurde am Lichtmikroskop untersucht. Mehlpartikel quellen in den Sedimentationslsungen reversibel auf. Eine Quellung wurde auch bei einzelnen Strngen des Klebernetzwerks beobachtet, wobei die SDS-Sedimentationslsung zu einer strkeren Quellung fhrte als das Zeleny-Reagens. Die Untersuchung von Gliadin und Glutenin zeigte, da nur das Glutenin zur Quellung befhigt ist, whrend das Gliadin vollstndig gelst wird.
Model studies were conducted in order to study the influence of acid and NaCl, as occurring in wheat sourdough bread, on fundamental rheological properties of wheat gluten. Gluten was divided into pieces and subjected to a swelling period in lactate buffer of pH 3.9, with or without added NaCl (3g/100ml). The respective controls were unbuffered NaCl solution and pure water. The microstructure of the gluten pieces was studied by laser-scanning confocal microscopy and the recombined pieces were examined using fundamental rheology. The combination of buffer (pH 3.9) and NaCl in comparison to unbuffered NaCl solution caused a denser, but partially dissolved fibrillar microstructure. Further to this, swelling of the gluten was reduced (62.0% versus 65.9% moisture) and an increase in firmness and elasticity was observed: in comparison with unbuffered NaCl solution, the absolute value of the complex dynamic modulus (|G*|) was higher, while the phase angle was lower in dynamic oscillatory measurements at 30C and dynamic temperature sweeps (30–95C), while in creep tests at 30C and 95C strain values were lower and relative recovery higher. In contrast, pH 3.9 buffer without added NaCl caused softer rheological behaviour than water and a film-like microstructure.
The influence of process parameters during the dough formation step on wheat flour gluten agglomeration and composition in a laboratory scale gluten–starch separation process was studied. In the process, in which a dough was transformed into a batter then poured over a set of vibrating sieves (400, 250 and 125 μm), increasing water contents, mixing times and speeds during dough development all had a positive effect on gluten agglomeration as indicated by an increased gluten protein recovery on the 400 μm sieve. This showed the importance of optimal gluten hydration and development at the dough making stage of the process. The total level of gluten recovered on the three sieves was not affected significantly by the variables. Changes in gluten agglomeration behaviour coincided with changes in the carbohydrate composition of the gluten fractions. When the gluten protein recovery on the 400 μm sieve increased, the arabinose and xylose contents of the fractions decreased, while the starch content increased.
Sourdough has been used since ancient times and its ability to improve the quality and increase the shelf-life of bread has been widely described. During sourdough fermentation, lactic acid bacteria (LAB) produce a number of metabolites which have been shown to have a positive effect on the texture and staling of bread, e.g. organic acids, exopolysaccharides (EPS) and/or enzymes. EPS produced by LAB have the potential to replace more expensive hydrocolloids used as bread improvers. Organic acids affect the protein and starch fractions of flour. Additionally, the drop in pH associated with acid production causes an increase in the proteases and amylases activity of the flour, thus leading to a reduction in staling. While improving the textural qualities of bread, sourdough fermentation also results in increased mineral bioavailability and reduced phytate content. In this review we will be discussing the effect of sourdough on wheat and rye bread as well as the potential of sourdough to improve the quality of gluten-free bread.
Official methods of analysis
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Studies of dough during fermentation and overmixing
- L C Kivett
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KS: Kansas State University.
A ten gram mixograph for determining and predicting functional properties of wheat flours. Baker's Digest
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Das Getreide. II. Teil. Das Getreide und seine Untersuchung
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