Use of sourdough fermented wheat germ for enhancing the nutritional, texture and sensory characteristics of the white bread

Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5, isolated from wheat germ and selected based on the kinetics of acidification, were used as starters for the manufacture of sourdough fermented wheat germ. A bread containing sourdough fermented wheat germ as an ingredient (SFWGB) was compared to breads made with (raw wheat germ bread, RWGB) or without (wheat flour bread, WFB) raw wheat germ. The higher concentration of free amino acids mainly differentiated SFWGB from WFB and RWGB. The in vitro protein digestibility of WFB was the highest, even if sourdough fermentation of wheat germ attenuated the difference. Phytase and antioxidant activities of SFWGB were highest. The specific volume and cell-total areas were also the highest for SFWGB. As determined by texture profile analysis, the values of hardness, resilience and fracturability of breads containing wheat germ were lower than those found in WFB. The crust lightness showed a decrease from WFB to SFWGB. As determined by sensory analysis, SFWGB had mainly acid taste and flavour and resulted more salty. Sourdough fermented wheat germ is an ingredient able to enhance nutritional, texture and sensory properties of bread.     

Exploitation of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours: Chemical characterization and their use for sourdough fermentation

This study aimed at characterizing the chemical and microbiological composition of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours and at exploiting their potential for sourdough fermentation. Both the flours had a gross composition similar to other cereals. As shown by two-dimensional electrophoresis analysis, Acha flour had a higher number of prolamins with respect to Iburu flour. The opposite was found for the number of glutelin spots. The concentration of total free amino acids of Iburu flour was higher than that of Acha flour (1348 ± 34 vs. 100 ± 20 mg/kg). Pediococcus pentosaceus was the dominant species in both the flours. Several isolates were used to ferment Acha or Iburu flours. After 8 h fermentation at 30 °C, pH ranged from 3.41 to 3.83 and from 4.20 to 4.66 for Acha and Iburu sourdoughs, respectively. The highest values of TTA and concentration of lactic acid were found in almost all Iburu sourdoughs. The synthesis of acetoin and γ-amino butyric acid (GABA) was only found in Iburu sourdoughs. Data from the kinetics of acidification, synthesis of lactic and acetic acids, acetoin, and liberation of total free amino acids were elaborated by Principal Component Analysis. Sourdoughs from Acha and Iburu flour were clearly differentiated.     

Use of selected sourdough strains of Lactobacillus for removing gluten and enhancing the nutritional properties of gluten-free bread

Forty-six strains of sourdough lactic acid bacteria were screened for proteolytic activity and acidification rate in gluten-free (GF) flours. The sourdough cultures consisted of Lactobacillus sanfranciscensis LS40 and LS41 and Lactobacillus plantarum CF1 and were selected and used for the manufacture of GF bread. Fermentation occurred in two steps: (i) long-time fermentation (16 h) and (ii) fast fermentation (1.5 h) using the previous fermented sourdough as inoculum (ca. 43%, wt/wt) with Saccharomyces cerevisiae (baker's yeast). GF bread started with baker's yeast alone was used as the control. Gluten was added to ingredients before fermentation to simulate contamination. Initial gluten concentration of 400 ppm was degraded to below 20 ppm only in the sourdough GF bread. Before baking, sourdough GF bread showed phytase activity ca. sixfold higher than that of GF bread started with baker's yeast alone. Atomic absorption spectrophotometric analysis revealed that the higher phytase activity resulted in an increased availability of free Ca2+, Zn2+, and Mg2+. The concentration of free amino acids also was the highest in sourdough GF bread. Sourdough GF bread had a higher specific volume and was less firm than GF bread started with baker's yeast alone. This study highlighted the use of selected sourdough cultures to eliminate risks of contamination by gluten and to enhance the nutritional properties of GF bread.     

Use of selected sourdough lactic acid bacteria to hydrolyze wheat and rye proteins responsible for cereal allergy

This work was aimed at showing the capacity of selected sourdough lactic acid bacteria to hydrolyze wheat and rye allergens. Hydrolysis was investigated after wheat sourdough fermentation and after treatment of wheat and rye sourdough breads with pepsin, trypsin and pancreatin, which mimicked the digestive process. As shown by immunoblotting with sera from allergic patients, wheat sourdough fermentation caused the disappearance of some IgE-binding proteins (albumins/globulins and gliadins mainly) with respect to the chemically acidified dough used as the control. The IgE-binding protein profile of wheat and rye sourdough breads differed from those of baker's yeast breads. The signals of the IgE-binding proteins contained in the sourdough breads disappeared after in vitro digestion with pepsin, trypsin and pancreatin. The same effect by digestive enzymes was not found for baker's yeast breads which showed persistent IgE-binding proteins. As shown by ELISA inhibition assays, the presence of IgE-binding low molecular weight proteins/peptides in sourdough breads significantly decreased with respect to baker's yeast breads. Proteolytic activity by selected sourdough lactic acid bacteria may have an importance during food processing to produce pre-digested wheat and rye dough which contains IgE-binding proteins degradable by digestive enzymes.     

Influence of in-situ synthesized exopolysaccharides on the quality of gluten-free sorghum sourdough bread

The majority of gluten-free breads on the market are of poor sensory and textural quality. Exopolysaccharides (EPS) formed from sucrose during sourdough fermentation can improve the technological properties of gluten-free breads and potentially replace hydrocolloids. In this study, the influence of in situ formed EPS on dough rheology and quality of gluten-free sorghum bread was investigated. Dextran forming Weissella cibaria MG1 was compared to reuteran producing Lactobacillus reuteri VIP and fructan forming L. reuteri Y2. EPS containing bread batters were prepared by adding 10% and 20% of sourdough. As control served batters and bread containing sourdoughs fermented without sucrose and batters and bread without sourdough addition. The amount of EPS formed in situ ranged from 0.6 to 8.0 g/kg sourdough. EPS formed during sourdough fermentation were responsible for the significant decrease in dough strength and elasticity, with in situ formed dextran exhibiting the strongest impact. Increased release of glucose and fructose from sucrose during fermentation enhanced CO? production of yeast. Organic acids in control sourdough breads induced hardening of the bread crumb. EPS formed during sourdough fermentation masked the effect of the organic acids and led to a softer crumb in the fresh and stored sorghum bread. Among EPS, dextran showed the best shelf life improvements. In addition to EPS, all three strains produced oligosaccharides during sorghum sourdough fermentation contributing to the nutritional benefits of gluten-free sorghum bread. Results of this study demonstrated that EPS formed during sourdough fermentation can be successfully applied in gluten-free sorghum flours to improve their bread-making potentials.     

Study of the behaviour of Lactobacillus plantarum and Leuconostoc starters during a complete wheat sourdough breadmaking process

The acidification properties, metabolic activity and technological performance of four individual Lactobacillus plantarum or Leuconostoc freeze-dried starters were investigated during a complete wheat sourdough breadmaking process including 0.2 g/100 g baker's yeast. Microbiological contents (lactic acid bacteria and yeasts), acidification characteristics (pH and total titratable acidity), soluble carbohydrates (maltose, glucose and fructose) and fermentative end-products (lactic and acetic acids, ethanol) contents were evaluated during both sourdough and corresponding bread dough fermentation. Biochemical and technological analysis of the resulting bread products are also presented. Some differences among strains in acidification properties and soluble carbohydrates availability were outlined both in sourdough and bread dough. Each individual Leuconostoc or Lb. plantarum starter was able to produce a characteristic fermentation and was found to ensure the production of breads with overall satisfactory acceptance.     

乳酸菌冻干粉剂发酵全麦酸面包工艺优化及储藏特性分析

目的：为了利用植物乳杆菌冻干粉剂发酵制作全麦酸面团面包（Whole wheat sourdough bread,WWSB）,并优化其加工工艺以及分析其储藏特性。方法：在单因素实验基础上,选择全麦酸面团（Whole wheat sourdough,WWSD）添加量以及全麦酸面团发酵时间为影响因素,面包最终的pH、总酸度值（Total acidity,TTA）、比容、硬度、感官得分作为响应值,使用中心组合试验设计方法,对全麦酸面包的工艺配方进行优化。并在此基础上以普通小麦面包（Wheat bread,WB）和普通全麦面包（Whole wheat bread,WWB）为空白组及对照组,均于4℃进行为期一周的储藏,分别于第0、1、3、5、7 d时取样,分析三种面包的全质构特性以及水分迁移情况。结果：全麦酸面包的最佳工艺配方：全麦酸面团添加量18%,全麦酸面团发酵时间16 h,此时的全麦酸面包pH4.82、TTA 5.62 mL、比容3.47 mL/g、硬度5.59 N、感官得分83。在此加工条件下三种面包的储藏特性指标如下：WWSB在整个储藏期间的硬度增长速率在前期和后期（35.75%和21....     

Spontaneous sourdough processing of Chinese Northern-style steamed breads and their volatile compounds

The effect of amount of flour in the pre-fermented form (10%, 20%, and 30% flour in the pre-fermented form), fermentation time (12, 24, and 36 h), and amount of yeast (0.5%, 1.0%, and 1.5%) on acidity, specific volume, and crumb texture of Chinese Northern-style sourdough steamed breads were studied. Volatile compounds of the sourdough and non-sourdough steamed breads were also determined. The preferments were produced from spontaneous fermentation using all purpose (APF) and whole wheat flours (WWF). Specific volume was the highest at 20% preferment for APF sourdough steamed bread (ASSB) and 30% preferment for WWF sourdough steamed bread (WSSB). The softest texture was obtained with 20% preferment while at 30% preferment there was excessive gluten weakening due to high acidification. A total of 89 volatile compounds were identified in steamed breads with ethanol and 3-methyl-1-butanol being the most abundant compounds.     

Release of free ferulic acid and changes in antioxidant properties during the wheat and rye bread making process

Changes in the free ferulic acid (FFA) contents and antioxidant properties during bread making processes were determined. Experimental breads were produced from whole meal and white wheat and rye flours, and fermented using either baker’s yeast or sourdough starter. Sourdough fermented bread contained the highest content of FFA. Release of occurred mainly during dough fermentation. A further increase in the ferulic acid content in the bread crumb and a decrease in the crust was observed. Total antioxidant properties of sourdough bread, defined as the sum of lipophilic and hydrophilic compound activities, were significantly (p<0.05) higher than for yeast bread. Sourdough bread contained more methanol soluble phenolic compounds, proteins, tocochromanols, and oxidized products of fatty acids than yeast bread. The equilibrium between the anti- and pro-oxidative compound contents resulted in similar antioxidant properties for bread using both types of fermentation, and to results observed for the flour used for baking.     

Microbiological,chemical and sensory aspects of bread supplemented with different percentages of the culinary mushroom Pleurotus eryngii in powder form

Pleurotus eryngii (DC.) Quél. powder was used in bread production. Three dough trials (0, 5 and 10% of mushroom) were obtained with commercial baker's yeast. P. eryngii powder was first tested against several yeast species; 10% P. eryngii trial was characterised by the highest pH and total titratable acidity. P. eryngii did not influence negatively the fermentation process, since all trials reached yeast levels of 10⁸ CFU g⁻¹. Mushroom powder decreased bread height and softness, increased crust redness and crumb void fraction and cell density and, although the breads were scored diverse, the overall assessment was comparable. The final breads provided higher concentrations of thiamin, riboflavin and pantothenic acid than control breads and, mostly importantly, supplied biotin, cobalamin and cholecalciferol generally absent in wheat bread. P. eryngii can be cultivated on food residues. Thus, its inclusion in functional bread production represents an optimal strategy for the valorisation of food processing by-products.     

功能性乳酸菌发酵黑豆麦麸酸面团面包的营养及烘焙特性

将黑豆及麦麸作为发酵基质,分别以高产植酸酶的乳酸片球菌(Pediococcus acidilactici)L-19及产β-葡萄糖苷酶的戊糖片球菌(Pediococcus pentosaceus)J-28作为发酵剂制作酸面团面包.探究菌株的生长、酸化及产酶特性,分析体系中植酸与膳食纤维的变化,采用低场核磁共振及磁共振成像...     

Application of Bifidobacteria as Starter Culture in Whole Wheat Sourdough Breadmaking

This investigation is aimed at developing a new cereal-based product, with increased nutritional quality, by using Bifidobacterium pseudocatenulatum ATCC 27919 as starter in whole wheat sourdough fermentation and evaluating its performance. Four different sourdough levels (5%, 10%, 15%, and 20% on flour basis) in bread dough formulation were analysed. The effects of the use of bifidobacteria in sourdough bread were comparatively evaluated with controls (yeast and/or chemically acidified sourdough with antibiotics). The sourdough and dough fermentative parameters analysed were pH, total titratable acidity, d/l-lactic and acetic acids. Bread performance was evaluated by specific volume, slice shape, crumb structure and firmness, crust and crumb colour, pH, total titratable acidity, and d/l-lactic and acetic acids, phytate, and lower myo-inositol phosphate contents. The sourdough breads showed similar technological quality to the control sample, with the exception of specific bread volume (decreased from 2.46 to 2.22 mL/g) and crumb firmness (increased from 2.61 to 3.18 N). Sourdough inoculated with bifidobacteria significantly increased the levels of organic acids in fermented dough and bread. The Bifidobacterium strain contributed to the fermentation process, increasing phytate hydrolysis during fermentation owing to the activation of endogenous cereal phytase and its own phytase, resulting in bread with significantly lower phytate levels (from 7.62 to 1.45 μmol/g of bread in dry matter). The inclusion of sourdough inoculated with bifidobacteria made possible the formulation of whole wheat bread with positive changes in starch thermal properties and a delay and decrease in amylopectin retrogradation.     

Physicochemical and sensory attributes of gluten-free sourdough breads produced from underutilised African cereal flours and flour blends

To seek potential alternative(s) for imported wheat in the African baking industry, the physicochemical parameters and sensory attributes of sourdough breads developed from locally sourced underutilised cereals and their blends were assessed. Processed sorghum (Sorghum bicolour), finger millet (Eleusine coracana) and pearl millet (Pennisetum glaucum) and their composites (50:50) were used to produce sourdough. Sourdough and flour-sourdough blends (30% sourdough) were used in making gluten-free breads. The protein content of the breads ranged from 16.29% to 39.26%, whereas the fat, crude fibre, ash and carbohydrate contents fell between 14.02–18.80%, 0.55–1.22%, 1.90–3.32% and 42.16–65.61%, respectively. The calculated energy value of the gluten-free breads (405.99–446.39 Kcal per 100 g) exceeded that of wheat bread (396.43 Kcal per 100 g), while the specific loaf volume varied from 1.46 to 1.80 cm³ g⁻¹. Although the produced gluten-free breads have improved nutritional content compared to conventional wheat bread, they were at best moderately liked. This is perhaps due to the non-cohesive nature of the crumbs and psychological preference for known products. Further research targeted at improving the organoleptic properties of these sourdough breads is recommended.     

Application of bioprocessing techniques (sourdough fermentation and technological aids) for brewer's spent grain breads

A comprehensive study into the potential of bioprocessing techniques (sourdough fermentation and technological aids) for improving the technological, sensory, and nutritional properties of breads made using brewer's spent grain (BSG) was undertaken. Xylanase and dough conditioner altered the mixing and pasting properties of the flours, improved the specific volume and texture of breads and delayed staling in BSG breads when added to both sourdough and non-sourdough BSG breads. The aromatic properties were determined by volatile analysis and were influenced by sourdough fermentation. Ferulic and 4-coumaric acids were the main phenolic acids found in insoluble bound form in BSG flour, while the phenolic profile was different for the free extracts. Sourdough fermentation and the use of enzymes increased the antioxidant capacity of breads.     

Evaluation of Leuconostoc citreum HO12 and Weissella koreensis HO20 isolated from kimchi as a starter culture for whole wheat sourdough

Leuconostoc citreum HO12 and Weissella koreensis HO20 isolated from kimchi were evaluated as starter cultures in the making of whole wheat sourdough bread. After 24 h of fermentation at 25 °C, both lactobacilli grew to the final cell numbers of ca. 10⁹ cfu/g dough, and both doughs had similar pHs and total titratable acidities. In addition, the fermentation quotient of the dough with Lc. citreum HO12 was slightly lower than that of the dough with W. koreensis HO20 (1.6 versus 2.8). Sourdoughs and bread with 50% sourdough produced with the starter cultures exhibited consistent ability to retard the growth of bread spoilage fungi (Penicillium roqueforti and Aspergillus niger) and rope-forming bacterium (Bacillus subtilis). Sourdough breads underwent a significant reduction in bread firming during storage. It seems that both lactobacilli have the potential to improve the shelf-life of wheat bread. The results indicate that the selected lactobacilli have unique fermentation characteristics and produce sourdough breads with overall satisfactory quality.     

酵母菌对自然发酵酸面团面包中风味物质影响的研究

以添加不等量酵母菌（0，1，2，3g酵母菌／200g自然发酵剂）的自然发酵酸面团面包及非酸面团面包为研究对象，采用固相微萃取（SPME）技术分别提取样品中的挥发性风味物质，然后通过气相色谱-质谱（GC-MS）联用法进行鉴定：结果表明，44种挥发性物质存在于至少两种样品中，其中主要为醇类、酸类、醛类、酯类、烷烃类、酮类、烯类、芳香族化合物和杂环及含氮化合物。酸面团面包含一些独有的物质，如乙酸甲酯、4-丁酸丁交酯、1，2-苯二酸二乙酯和蚁酸丙酯等：酵母菌对自然发酵酸面团面包中主要挥发性风味物质有较大影响．如酸类物质的相对含量有所下降，醛类的含量增加，添加酵母菌的酸面团面包风味物质中酯类的比例低于不添加酵母菌的．     

不同发酵基质的酸面团对酵母面团体系面包烘焙及老化特性的影响

应用分离自我国传统酸面团的区域特色乳酸菌--旧金山乳杆菌分别发酵小麦粉和小麦麸皮基质制成（小麦/麦麸）酸面团,研究了两种不同发酵基质的酸面团及其添加量对酵母面团体系面包烘焙及老化特性的影响。结果表明：与小麦粉制作的空白组面包相比,小麦酸面团可以明显改善面包的比容和感官品质;添加未发酵麦麸制作的非酸面团麦麸面包品质低于空白组,但引入麦麸酸面团（10%、20%、30%）后面包比容和感官评定得分均高于相对应的非酸面团麦麸面包。小麦酸面团和麦麸酸面团以及小麦麸皮均可以改善面包的老化特性,在相同贮藏期内,酸面团面包和麦麸面包的硬度增加量、水分迁移量和老化焓值都低于空白组,并且添加麦麸酸面团的面包其硬度和老化焓值都低于相对应的非酸面团麦麸面包。     

Sourdough fermentation as a tool for the manufacture of low-glycemic index white wheat bread enriched in dietary fibre

Three Lactobacillus strains were selected and used together as sourdough starter. Sourdough performances were evaluated for 30 days. Three breads were manufactured: wheat sourdough bread (WSB), WSB enriched with oat and rye fibres (WSB-DF) and wheat yeasted bread (WYB) fermented with baker’s yeast alone. WSB-DF and WSB showed higher specific volume and lower firmness than WYB. Sensory analysis showed that WSB-DF and WSB were preferred due to acidulous smell, taste and aroma. Compared to WYB and WSB, WSB-DF had high level of dietary fibre (DF). WYB was used as the control to estimate the hydrolysis index (HI = 100). WSB-DF had values of HI lower than WSB (59 vs. 86%). As estimated on 20 volunteers, the value of GI for WSB-DF was ca. 41%. WSB-DF bread manufactured at industrial plant combined low-GI with physiologically significant supply of DF and high standard structure and sensory features.     

Optimization of sourdough process for improved sensory profile and texture of wheat bread

The aim of the study was to determine optimum sourdough process conditions for improved flavour and texture of wheat bread. The influence of process conditions and the starter culture on the characteristics of wheat sourdough bread was established by using response surface methodology. Influence of fermentation temperature (16-32 °C), ash content of flour (0.6-1.8 g/100 g), and fermentation time (6-20 h) were considered as independent factors and their effects were studied in sourdough bread fermented with Lactobacillus plantarum, Lactobacillus brevis, Saccharomyces cerevisiae or with a combination of yeast and lactic acid bacteria. Intensity of sensory attributes, specific volume and bread hardness were considered as the main responses. Ash content of flour and fermentation time were the main factors determining the intensity of sensory attributes. The possibility to enhance intensity of overall flavour, aftertaste and roasted flavour without excessive pungent flavour and without reduced fresh flavour in wheat bread containing 20 g sourdough/100 g of wheat dough was demonstrated by choosing e.g. Lb. brevis for a starter and by utilization of high ash content of flour, long fermentation time and reduced temperature. Bread specific volume was improved 0.2-0.5 ml/g and hardness was reduced (after 4 days of storage) up to 260 g by using low ash content of flour and by optimizing fermentation time according to the microbial strain. Lactic acid fermentation had more profound influence on both desired and undesired flavour attributes, as well as textural features of bread in comparison with yeast fermentation.     

Effects of several starter cultures on the anti-mold activity and sensory attributes of a traditional flat bread (Sangak) from Iran

Effects of 8 different sourdoughs and their replacement levels at 10, 20, and 30%(w/w) on the volume (of dough), crust hardness, organoleptic, and anti-mold properties of Iranian sangak bread were investigated. Saccharomyces cerevisiae, Lactobacillus plantarum, Lactobacillus acidophilus, and Leuconostoc mesenteroides were selected for the preparation of sourdough samples. The highest dough volume was achieved when sourdough (those having S. cerevisiae) was used at 30%. The highest taste scores were found with the bread sample using the above-mentioned starters at 30% sourdough replacement level. Considering the chewing, appearance, and overall quality of the new products, most of the samples maintained the favorite sensory aspects of sangak bread. Use of lactic acid bacteria and yeast strains as part of the sourdough formulation (followed by the use of sourdough in the dough formulation) resulted in improved crust properties and greater anti-mold activities.