Breadmaking performance and technological characteristic of gluten-free bread with inulin supplemented with calcium salts

The fortification of gluten-free bread containing inulin with different organic and non-organic calcium sources was investigated. Calcium lactate, calcium citrate, calcium chloride and calcium carbonate were used as calcium sources. Gluten-free bread composed of corn starch, potato starch, salt, yeast, pectin, sugar and sunflower oil was used as a reference. The calcium salts were supplemented to the gluten-free formula to provide equal content of elementary calcium (Ca⁺²). The Mixolab^? device was used to analyse the behaviour of gluten-free dough subjected to a dual mechanical shear stress and temperature constraint. Calcium salts significantly modified the dough behaviour during heating and cooling. The addition of calcium carbonate and calcium citrate provoked an increase in dough consistency during heating and cooling compared with the other salt-enriched samples. The specific volume and texture parameters of gluten-free breads varied with the calcium salt used, but calcium carbonate and calcium citrate showed improved values. The higher calcium content of the enriched breads, compared with the control, confirmed the fortification. Sensory evaluation of the calcium-fortified breads confirmed that calcium carbonate followed by calcium citrate was the most recommended salt for obtaining calcium fortification of gluten-free breads.     

Effect of dietary fibre enrichment on selected properties of gluten-free bread

The enrichment of gluten-free baked products with dietary fibre seems to be necessary since it has been reported that coeliac patients have generally a low intake of fibre due to their gluten-free diet. In the present study different cereal fibres (wheat, maize, oat and barley) were added at 3, 6 and 9 g/100 g level into a gluten-free bread formulation based on corn starch, rice flour and hydroxypropyl methyl cellulose (HPMC). Doughs were evaluated based on consistency, viscosity and thermal properties. Results showed that maize and oat fibre can be added to gluten-free bread with positive impact on bread nutritional and sensory properties. All breads with 9 g/100 g fibre increased the fibre content of control by 218%, but they were rated lower than those with 3 and 6 g/100 g fibre due to their powdery taste. The formulation containing barley fibre produced loaves that had more intense color and volume comparable to the control. During storage of breads a reduction in crumb moisture content and an increase in firmness were observed. The micrographs of the crumb showed the continuous matrix between starch and maize and/or oat fibre obtaining a more aerated structure.     

Rheological properties of gluten-free bread formulations

In this study, the rheological properties of rice bread dough containing different gums with or without emulsifiers were determined. In addition, the quality of rice breads (volume, firmness and sensory analysis) was evaluated. Different gums (xanthan gum, guar gum, locust bean gum (LBG), hydroxyl propyl methyl cellulose (HPMC), pectin, xanthan–guar, and xanthan–LBG blend) and emulsifiers (Purawave^™ and DATEM) were used to find the best formulation for gluten-free breads. Rice dough and wheat dough containing no gum and emulsifier were used as control formulations. The rice dough containing different gums with or without emulsifiers at 25 °C showed shear-thinning behavior with a flow behavior index (n) ranging from 0.33–0.68 (except pectin containing samples) and consistency index (K) ranging from 2.75–61.7 Pa sⁿ. The highest elastic (G′) and loss (G″) module were obtained for rice dough samples containing xanthan gum, xanthan–guar and xanthan–LBG blend with DATEM. When Purawave^™ was used as an emulsifier, dough samples had relatively smaller consistency index and viscoelastic moduli values compared to DATEM. The viscoelastic parameters of rice dough were found to be related to bread firmness. Addition of DATEM improved bread quality in terms of specific volume and sensory values.     

Rheological,textural and sensory properties of gluten-free bread formulations based on rice and buckwheat flour

Mixolab, as the rheological instrument, was utilized to create gluten-free products. According to obtained Mixolab profiles, mixtures of rice flour and husked buckwheat and rice flour and unhusked buckwheat flour expressed rheological properties similar to wheat flour. In both types of mixtures the ratio of rice flour to buckwheat flour was 90:10, 80:20 and 70:30. According to the Mixolab profiles of the investigated systems, gluten-free products containing unhusked buckwheat flour had higher water absorption values, lower stability and weaker protein network structure, as well as lower peak viscosity than those consisted of husked buckwheat flour.Increasing the amount of husked buckwheat flour from 10% to 20% resulted in both G′ and yield stress value increase, but further increase of the husked buckwheat flour on 30% resulted in both G′ and yield stress value decrease. However, increasing the amount of unhusked buckwheat flour from 10% to 20% resulted in significant decrease of G′ and yield stress value having no significant impact with the addition of 30% of unhusked buckwheat flour.Hardness, expressed as a work of compression of the final product, increased with the amount of both types of buckwheat flour. Samples containing UBF expressed not significantly higher values of hardness than those prepared with HBF. According to obtained results of sensory evaluation of the final products it can be concluded that all six combinations of tested gluten-free breads were sensory acceptable.     

Effect of low lactose dairy powder addition on the properties of gluten-free batters and bread quality

Different low lactose dairy ingredients including sodium caseinate (SC), milk protein isolate (MPI), whey protein isolates (WPIS and WPIM) and whey protein concentrate (WPC) were tested in a gluten-free bread formulation and compared to controls with the addition of no dairy ingredient (C) and one dairy ingredient containing lactose, skim milk powder. Rheological characterisation (frequency sweep and creep-recovery) of the batters at 90% water level (WL) suggested that the addition of WPIS, WPIM and WPC significantly decreased G′ and G″ values. SC and MPI had the opposite effect with a significant increase in both these parameters being found (p < 0.05). The WL of the batters was adjusted in order to obtain the same consistency of the batter C at 90% WL. A Power Law model was used to predict the new WL based on single frequency measurements of G* for each sample. The baking analysis demonstrated that the correction of the WL did not show a strong impact in the quality of the breads. Nevertheless, whey proteins demonstrated the ability to increase significantly the specific volume of the breads and decrease the hardness over time (p < 0.05). SC had a negative impact on the specific volume, which led to an increase in crumb hardness (p < 0.05).     

水溶性胶体对无麸质面包焙烤特性的影响

研究了水溶性胶体对无麸质面包(米粉、红薯淀粉)比容、硬度、色泽及感官品质的影响。结果表明,添加1%的羧甲基纤维素、果胶、刺槐豆胶、瓜尔多胶、羟丙基甲基纤维素可改善面包的品质,面包比容增大,结构松软,气孔更加均匀,硬度降低,色泽改善,感官品质提高。综合来看,添加羟丙基甲基纤维素无麸质面包品质改善最为明显,添加量为1%、2%时,比容分别增加12.7%、22.3%,硬度分别降低6.8%、7.3%(24h),面包色泽明显改善,感官品质显著提高。     

Effect of structurally different microbial homoexopolysaccharides on the quality of gluten-free bread

The effect of structurally different bacterial homoexopolysaccharides on gluten-free bread quality and their properties to act as hydrocolloids was investigated. Furthermore, exopolysaccharides (EPS) were analyzed structurally by asymmetrical flow field flow fractionation and methylation analysis. Breads were made of buckwheat and rice flour with EPS of Lactobacillus (L.) curvatus TMW 1.624, L. reuteri TMW 1.106, L. animalis TMW 1.971, and L. sanfranciscensis TMW 1.392 or hydroxypropylmethylcellulose (HPMC) at 1?% w/w flour base. Water-holding capacity, specific volume, crumb analysis, baking loss, moisture content, and crumb hardness were determined. Only HPMC and the glucan of L. curvatus TMW 1.624 retained water, and all supplements increased the specific volume. Furthermore, crumb hardness was decreased by additives to different extents. The moisture content, baking loss, and crumb firmness were improved most by dextran of L. curvatus TMW 1.624. Structure analysis of EPS revealed that L. animalis TMW 1.971 produces a fructan and a glucan and that the dextran of L. curvatus TMW 1.624 had highest molecular weight of analyzed EPS, ranging from 118 to 242 MDa. A methylation analysis demonstrated differences in branching. Dextran of L. reuteri TMW 1.106 is branched in position 4 (18?C19?%), whereas dextran of L. curvatus TMW 1.624 is branched in position 3 (8?C9?%). Overall, this study gives insight into structure function relations of different EPS. A structure function relation is suggested in which high weight average molar mass (Mw) and branching at position 3 of the glucose monomer foster a compact conformation of the molecule, which enables an increased water-binding capacity and promotes superior (structural) effects in gluten-free breads. The dextran of L. curvatus TMW 1.624 was the most promising candidate for applications in gluten-free bread quality improvements as it retains its size distribution and root mean square even with increasing Mw and forms an increasingly compact molecule.     

Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread

The importance of polyunsaturated fatty acids (PUFA) in health and nutrition is well recognised. Flaxseed (Linum usitatissimum) has recently gained a lot of attention as functional food because of its unique nutrient profile. In the present work efforts were made to develop omega-3 enriched functional bread using raw and roasted ground flaxseed flour. Initially optimisation of each bread ingredient viz., salt, sugar, and shortening, GMS, yeast and water was carried out on the basis of sensory overall acceptability score. The standardised bread was incorporated with raw and roasted ground flaxseed (5, 10, and 15 g/100 g) flour. The effect of flaxseed incorporation on bread dough rheology parameters viz., dough stickiness and water absorption was studied. Increase in water absorption and dough stickiness was observed with increased flaxseed level. Further breads were evaluated for sensory parameters, colour and texture. The crumb softness increased with increase in flaxseed level. Bread was optimised at 10(g/100 g) flaxseed level based on sensory evaluation.     

Influence of modified starches on properties of gluten-free dough and bread. Part I: Rheological and thermal properties of gluten-free dough

The aim of this study was to analyze the influence of chemically modified starches (HDP and ADA) and high amylose corn starch (HACS) on the rheological and thermal properties of gluten-free dough based on corn and potato starches with pectin and guar gum. The results indicate that the dough with the addition of modified starch behaves as weak gel, the value of storage modulus G′ significantly depends on the frequency and the values of tan δ = G″/G′ range from 0.32 to 0.49. Significant influence of hydroxypropylated distarch phosphate (HDP) on the viscoelastic properties of dough was observed. The share of modified starch in the system caused a decrease of the instantaneous and viscoelastic compliance. It also influenced the retardation time and zero shear viscosity. The application of modified starches (HDP and ADA) for dough preparation did not have much impact on the pasting characteristics. However, significant reduction of the onset and end viscosities were found for high amylose starch (HACS). Thermograms obtained for individual dough systems were characterized by the presence of two peaks, associated with the existence of two different starches in the system. No significant effect of modified starch on the onset temperature (T_O) and only a slight effect of HACS starch on gelatinization enthalpy were observed. However, the level of addition of individual starch affected peak and end (T_E) temperatures, depending on the type of preparation.     

Baking properties and microstructure of pseudocereal flours in gluten-free bread formulations

In the present study, the baking properties of the pseudocereals amaranth, quinoa and buckwheat as potential healthy and high-quality ingredients in gluten-free breads were investigated. Scanning electron micrographs were taken of each of the flours. The pasting properties of these flours were assessed using a rapid visco analyser. Standard baking tests and texture profile analysis were performed on the gluten-free control and pseudocereal-containing gluten-free breads. Confocal laser scanning microscopy (CLSM) images were also obtained from the baked breads and digital image analysis was conducted on the bread slices. Bread volumes were found to significantly increase for the buckwheat and quinoa breads in comparison with the control. In addition, the pseudocereal-containing breads were characterised by a significantly softer crumb texture effect that was attributed to the presence of natural emulsifiers in the pseudocereal flours and confirmed by the confocal images. No significant differences were obtained in the acceptability of the pseudocereal-containing gluten-free breads in comparison with the control.     

Influences of lactic acid bacteria on technological, nutritional, and sensory properties of barley sour dough bread

Barley bread was baked with and without admixture of barley sour doughs, individually fermented with seven starter cultures containing lactic acid bacteria (including two with β-glucanase activity).

The aim of the study was to investigate how starter cultures influenced the baking-technological, nutritional and sensory properties of barley bread. Could degradation of β-glucans caused by sour dough admixture result in bread that was more easy to chew?

The starter culture influenced the volume yield, the total titratable acidity (S °) and the sensory properties. The amounts of lactate and acetate ranged from 0.20 to 0.26 and 0.03 to 0.08 g/100 g sour dough bread, respectively. The total titratable acidity in the sour dough breads varied between 4.1 and 5.4 ml 0.1 N NaOH/10 g bread. There were negative correlations between barley taste and total titratable acidity (S °). The acidulous taste of the sour dough breads seemed to mask the barley taste. The phytate of the barley sour dough breads was reduced below 0.5 μ mol/g, which does not inhibit mineral absorption, irrespective of starter culture. There was no significant difference in the total content of β-glucans between bread made with and without admixture of sour dough, irrespective of starter culture, rejecting the hypothesis that barley bread made with sour dough would be more easy to chew.     

The role of buckwheat and HPMC on the breadmaking properties of some commercial gluten-free bread mixtures

Although the food industry has risen to the formulation challenges associated with removing gluten from dough, and a number of gluten-free (GF) products are now commercially available, many GF bread formulations are still based on pure starches, resulting in low technological and nutritional quality. The aim of this research was to evaluate the role of buckwheat and HPMC on the breadmaking properties of two commercial GF bread mixtures. A dehulled (DBF) and a puffed (PBF) buckwheat flour were used, and high substitution levels (40%) were tested, with the aim of improving the nutritional value of the final GF breads without decreasing their technological quality. Ten mixtures (2 commercial, 8 experimental) were evaluated. The inclusion of 40% DBF was demonstrated not to reduce but actually improve the baking performances of the commercial GF mixtures. Moreover, the presence of a small amount of PBF, as well as of HPMC, turned out to be useful in limiting both the diffusion and the loss of water from the bread crumb and the interactions between starch and protein macromolecules, resulting in a softer GF bread crumb and reduced staling kinetics during storage.     

Effects of soy protein isolate and egg white solids on the physicochemical properties of gluten-free bread

Gluten-free formulations are often supplemented with proteins to improve their quality. To determine the effects of alternative proteins on a hydroxypropyl methylcellulose (HPMC)-treated gluten-free dough system, soy protein isolate was added at 1%, 2% and 3% while egg white solids were investigated at 5%, 10% and 15%. The formulated doughs were analysed using thermoanalytic and rheological techniques to determine the role of water and subsequent flow behaviour upon hydrocolloid addition. The baked loaves were measured for specific loaf volume and tensile strength to determine bread quality. The addition of soy protein isolate and egg white solids (5% and 10%) reduced dough stability by suppressing HPMC functionality, reducing available water, weakening HPMC interactions with the starch matrix and reducing foam stability. At 15% addition, egg white solids became the primary protein scaffolding in the dough and overcame negative interactions with HPMC, improving the loaf volume. However, this formulation may need further optimisation to meet full consumer acceptability.     

Effect of fortification of defatted soy flour on sensory and rheological properties of wheat bread

The objective of this study was to determine the effects of soy-fortified bread on the sensory and rheological properties. Ground defatted soy flour was blended with wheat flour at 3%, 7% and 12%. The organoleptic characteristics of soy-fortified wheat breads were carried out by taste panel. The effect of this fortification on the rheological properties of the resulting dough was investigated using farinograph and extensograph for quality assessment of the final product. The ash and protein contents of 3% and 7% wheat–soy bread blends increased compared with control. The results revealed that organoleptic characteristics score such as bendability, appearance, flavour and taste, crust texture and overall acceptability properties of bread containing 3% defatted soy flour was highest even though it is not significantly different. Therefore, we conclude that adding 3% or 7% defatted soy flour actually gives as good a loaf of bread as the 100% wheat bread with higher nutritional quality and acceptable consumer attitude with rheological and sensory characteristics.     

Effect of cellulose-derivatives and emulsifiers on creep-recovery and crumb properties of gluten-free bread prepared from sorghum and gelatinised cassava starch

The effect of cellulose-derivatives and emulsifiers on the creep-recovery behaviour of gluten-free dough prepared from gelatinised cassava starch and sorghum was studied. Cellulose treated doughs, except the treatment with 2.4% w/w fwb CMC, had lower resistances to deformation (range 10–33%) than emulsifier-treated doughs (range 3–13%). The higher elastic recovery of emulsifier-treated doughs corresponded to lower compliances and higher zero shear viscosities than for doughs treated with cellulose-derivatives. Addition of egg white powder (6.7% w/w fwb) eliminated several textural defects associated with gluten-free bread. Cellulose-derivatives did not decrease crumb firmness or staling rate when compared to the control. Though increasing emulsifier concentration (from 0.4% to 2.4% w/w fwb) decreased crumb firmness, crumbs treated with 2.4% w/w fwb emulsifiers, except diacetyl tartaric acid esters of mono- and diglycerides, were weak and difficult to handle after slicing. Nevertheless, all gluten-free breads treated with 2.4% w/w fwb emulsifiers staled at a slower rate than the control.     

Influence of unicellular protein on gluten-free bread characteristics

The objective of this work was to study the characteristics of three gluten-free bread formulations and the effect of the inclusion of unicellular protein. Bread recipes were starch-based, starch-vegetable-based and flour-based and the same recipes with added unicellular protein. Flour-based breads had lower specific volume values (2.2–2.3 cm³/g) than starch-based breads (3.1–3.3 cm³/g). Starch-based and starch-vegetable-based formulations with unicellular protein showed less bake loss (18.3 and 17.8%) than their counterparts (21.1 and 19.6%) probably due to increased water retention caused by unicellular protein. Flour-based recipes resulted in the firmest crumb, mainly caused by the high content in dietary fiber. The addition of unicellular protein resulted in a darker crumb color, and significant differences were also found in crumb color because of ovalbumin addition. Confocal scanning laser microscopy results showed a more compact microstructure in flour-based recipes compared with starch-based and starch-vegetable-based formulations. Starch-vegetable-based formulations without unicellular protein were the most preferred by consumers, followed by starch-vegetable-based formulations with added protein. Main differences detected by consumers were related to texture attributes. No major changes in shelf-life could be attributed to differences in formulation.     

Impact of quinoa bran on gluten-free dough and bread characteristics

Besides an appealing texture and taste, gluten-free products should feature a well-balanced nutrient profile, since celiac disease or chronic inflammations are likely to induce malnutrition for involved patients. Due to their composition, pseudocereals represent a promising ingredient to improve nutrient profile of gluten-free bread. The objective of this study was to investigate the impact of quinoa bran on gluten-free bread quality, focusing on volume, pore size and sensory acceptance. The impact of quinoa bran was studied in a gluten-free bread formulation. Five different quinoa bran and two whole grain flour concentrations were evaluated and compared to a control formulation based on rice and corn flour. The rheological properties of quinoa bran as well as the effect on dough development up to a replacement level of 80 % were investigated. Baking tests were carried out, and loaf volume, crumb firmness and sensory characteristics were determined. Quinoa fractions significantly increased carbon dioxide formation (p < 0.05) due to a higher substrate availability. Gas retention was reduced by increasing bran levels (p < 0.05). Oscillation measurements indicated a firming impact of quinoa bran which might have caused a more permeable dough structure, promoting the release of carbon dioxide. With regard to the specific loaf volume significant differences were found across the quinoa milling fractions and the applied levels (p < 0.05). Overall this study demonstrated that 10 % bran improved the bread volume by 7.4 % and enhanced the appearance without compromising the taste.     

Effects of protein and transglutaminase on the preparation of gluten-free rice bread

Effects of transglutaminase (TGase) and proteins such as whey protein, caseinate, and soy protein on the preparation of gluten-free rice breads using non-waxy rice flour were investigated. Rice flour (about 12% moisture content) was prepared from dry milling of dried grain after rice got soaked. Unlike general dry milled flour, newly developed rice flour increased water binding capacity (WBC), swelling power, and peak viscosity. Soy protein increased WBC but other proteins slightly decreased with the increase of levels. Lightness decreased and yellowness increased with the addition of whey and soy protein. All pasting viscosities decreased with the addition of protein. The TGase improved the network structure of rice batter. The 2^nd proof time of rice batter with protein was shortened by 4–9 min with the addition of TGase. The specific volumes of rice breads with whey and soy protein also increased. TGase and protein additions decreased the hardness of rice bread. Sensory test showed that roasted flavor, volume, air cell homogeneity, and overall quality were significantly different (p<0.05) with protein and TGase additions.     

The effects of maltodextrins on gluten-free dough and quality of bread

The aim of the study was to check if maltodextrins of various dextrose equivalents (DE) could be used to improve stability and quality of gluten-free bakery products, and effectively reduce starch retrogradation. The maltodextrins, which were used for partial replacement of starch in the recipe for gluten-free dough, were characterised by DE 3.6, 15.3, 18.0 and 21.8. Basing on the obtained results it was concluded, that the addition of applied maltodextrins significantly influences starch gelatinisation, by increasing pasting temperature and reducing viscosity of the obtained pastes. Rheological properties of the obtained dough are also modified by maltodextrins, which weaken its structure and increase deformation sensitivity. The addition of maltodextrins with low DE (3.6) diminishes loaf volume and causes deterioration of bread quality. Maltodextrins with higher DE, especially 18.0 and 21.8, positively influence bread volume and have a beneficial influence on crumb hardening during storage. Maltodextrin with the highest DE is also an effective factor reducing recrystallisation enthalpy of amylopectin.