Partial-Baking Process on Gluten-Free Bread: Impact of Hydrocolloid Addition

The objectives of this work were to assess the impact of partial-baking process on gluten-free bread, and to study how carboxymethylcellulose (CMC) and xanthan gum addition affected this process. As different from the conventional baking which involves only one baking step (40 min), the part-baking process consisted in an initial-baking step (25 min), storage (7 days, 4°C), and final-baking step (15 min). Bread-specific volume (SV), crumb hardness, and image analysis were assessed on final products of both processes and intermediate products of part-baking process. Breads were stored at room temperature for 72 h and crumb firming and amylopectin retrogradation were monitored. Freezable water (FW) fraction was determined on fresh and stored samples by using differential scanning calorimetry. Part-baked breads showed lower SV and higher crumb hardness. No SV diminution was observed during cold storage. Hydrocolloids, especially CMC, had a positive effect on these parameters, and during bread storage at room temperature, the increase in crumb hardness was mitigated by hydrocolloid addition. Part-baked breads showed smaller cell area than full-baked ones. Overall, crumb structure was more homogeneous for CMC breads. FW showed no significant differences among processes, formulations, or storage time. Amylopectin recrystallization was higher for part-baked breads. Interrupted-baking process affected the final bread quality, but negative effects could be diminished by hydrocolloid addition. Part-baking process is suitable for obtaining gluten-free breads, stored for a week at 4°C, turning them appropriated for home consumption.     

Quality characteristics improvement of low‐phenylalanine toast bread

This study was designed to prepare and evaluate low‐phenylalanine toast bread made from gliadin‐free wheat flour and hydrocolloids. Wheat protein fraction (gliadin) rich in phenylalanine was extracted using aqueous alcohol solution for the production of low‐phenylalanine wheat flour. Pectin, gum arabic and carboxymethylcellulose (CMC) were used separately to improve the quality of bread at levels of 1, 2 and 3%. Chemical, rheological, organoleptic, baking, staling and microstructure of bread were studied. Phenylalanine content of gliadin‐free bread samples reduced by 43.2% compared with control. Separation of gliadin negatively affected the rheological properties of dough and baking quality of bread, while rheological properties, baking quality and staling were improved upon hydrocolloids addition. Microscopic examination of crumb structure revealed remarkable differences in control and treated breads. It was found that acceptable bread could be produced using gliadin‐free wheat flour with the addition of pectin or CMC up to 2 and 3%, respectively.     

Optimization of Gluten-Free Formulations for French-Style Breads

ABSTRACT:  The formulation of gluten-free bread, which will be suitable for patients with coeliac disease, was optimized to provide bread similar to French bread. The effects of the presence of hydrocolloids and the substitution of the flour basis by flour or proteins from different sources were studied. The added ingredients were (1) hydrocolloids (carboxymethylcellulose [CMC], guar gum, hydroxypropylmethylcellulose [HPMC], and xanthan gum), and (2) substitutes (buckwheat flour, whole egg powder, and whey proteins). The bread quality parameters measured were specific volume, dry matter of bread, crust color, crumb hardness, and gas cell size distribution. Specific volume was increased by guar gum and HPMC. Breads with guar gum had color characteristics similar to French bread. Hardness decreased with the addition of hydrocolloids, especially HPMC and guar. Breads with guar gum had the most heterogeneous cell size distribution, and guar gum was therefore selected for further formulations. Bread prepared with buckwheat flour had improved quality: an increased specific volume, a softer texture, color characteristics, and gas-cell size distribution similar to French bread. Bread with 1.9% guar gum (w/w, total flour basis) and 5% buckwheat flour (of all flours and substitutes) mimicked French bread quality attributes.     

Rheology and breadmaking performance of rice-buckwheat batters supplemented with hydrocolloids

The aim of this work was to investigate the effects of hydrocolloid addition on rheological properties and breadmaking performance of rice-buckwheat batter at different water levels. Xanthan gum (XG) and propylene glycol alginate (PGA) were added to rice-buckwheat blend (60:40) at levels of 0.5–1.5%. Batter rheological properties were investigated using dynamic measurements in the linear viscoelastic range (frequency sweep and time cure tests). The addition of both hydrocolloids significantly enhanced the storage modulus (G′) of batter. XG exerted greater effect on G′ than PGA. Different effects on starch gelatinisation were observed for the two hydrocolloids. PGA breads showed higher improvement in terms of increased specific volume (V_s), decreased crumb firmness and crumb structure than XG breads. Different technological behaviours were explained on the basis of batter rheological properties.     

Incorporation of several additives into gluten free breads: Effect on dough properties and bread quality

The objective of this work was to assess the effect of emulsifiers, hydrocolloids and enzymes on gluten-free dough rheology and thermal properties and bread quality, while relating dough properties parameters to bread technological quality. Breads were based on rice flour, cassava starch and full-fat active soy flour, with 65% or 75% (flour-starch basis) of water incorporation. Additives used were emulsifiers (diacetyl tartaric acid ester of monoglycerides – DATEM and sodium stearoyl lactylate – SSL), enzymes (glucose oxidase and α-amylase) and hydrocolloids (xanthan gum, carboxymethylcellulose, alginate and carrageenan). Results showed that additive incorporation modified dough behavior, evidenced by different calorimetric and rheological properties. Besides, the electrophoretic pattern of dough extracted proteins changed with glucose oxidase addition. These modifications resulted in breads with different characteristics, such as specific volume, firmness and firming rate, and crumb structure. Nonetheless, they did not necessarily show better quality parameters than the control bread. The control dough displayed good performance for obtaining gluten-free breads of acceptable volume, crumb structure and, principally, with lower hardening rate during storage. Contrary to widespread opinion, this work shows that the presence of additives is not essential for gluten-free bread production. This fact provides new perspectives to the gluten free market at the moment of selecting raw materials and technological parameters, reducing production costs and facilitating gluten free products development.     

Functional effects of xanthan gum on composite cassava-wheat dough and bread

The use of composite flour for bread making is gradually gaining prominence worldwide due to some economic and nutritional reasons. However, studies on the application of functional ingredients purposely to improve composite bread quality are very few. This paper examines the functional role of xanthan gum (XG) on the properties of dough and bread from composite cassava-wheat flour. The viscoelastic properties of dough and gas retention characteristics of batter as well as the fresh and storage properties of bread from the composite flour (90% wheat plus 10% cassava) were studied. The crumb cell structure was also studied using digital image analysis technique. Inclusion of XG had significant effects on the dough tenacity and extensibility and sensory acceptability of fresh composite bread. The oven spring, specific volumes of bread loaf and crumb softness were higher at 1% XG content. Also, addition of XG made the composite bread samples had more open crumb structure and better sensory acceptability. However, moisture loss and crumb firming during bread storage were best reduced when 1% XG was added to bread formulation.     

Effect of zein protein and hydroxypropyl methylcellulose on the texture of model gluten‐free bread

The influence of zein protein and hydroxypropyl methylcellulose (HPMC) on the texture and volume of gluten‐free bread was investigated. The addition of HPMC to starch affected the dough viscoelasticity and it improved the bread volume during baking since it acts as an emulsifier. The addition of zein protein to gluten‐free bread increased the crumb firmness and reduced the crust hardness within the range of concentrations investigated. No zein protein network could be observed in the bread crumb. The zein protein, cold mixed at low concentration, did not enhance the dough elasticity. Due to the lack of a protein network noncovalent interactions may stabilize the bubble structure stabilization within the crumb, rather than covalent links of the protein chain. With an optimized amount of zein protein and HPMC hydrocolloid, the gluten‐free bread showed similar texture and staling behavior to that of model wheat bread. The optimized recipe, compiled into a spreadsheet, is available in the supporting information. The microstructural observations suggest that zein could be replaced with another protein for this recipe resulting in a similar bread texture.     

Effects of bread making methods,lupin variety and gluten powder on the quality of bread enriched with high percentage of lupin flour

Lupin is an economical source of protein, fibre and bioactive compounds, and to obtain these health and nutritional benefits lupin flour has been used in bread production. However, addition of more than 10% lupin flour markedly reduces bread quality mainly due to gluten dilution. The main aim of this research was to retain lupin bread quality enriched with higher percentages of lupin flour (20%) by addition of vital gluten powder (0%, 2%, 3.5% and 5%), investigating the effects of lupin variety (Lupinus albus and L. angustifolius) and two baking systems (rapid and sponge & dough). Impact on bread staling qualities was also determined through texture analysis of samples over a 72-h storage period. Compared to lupin bread with nil gluten addition, significant improvements in loaf volume and crumb texture were observed with addition of gluten powder especially at 5% which increased loaf volume by an average of 20% across lupin sources and baking methods, and crumb softness by 30–50%. Differences were observed between the lupin flour sources. L. angustifolius had a reduced weakening effect when blended with the base flour compared with L. albus. The Sponge & Dough process was found to be more suitable to the inclusion of lupin flour than the rapid process.     

A Comparative Study of Commercial Modified Celluloses as Bread Making Additives

The effect of commercial modified celluloses: microcrystalline cellulose, carboxymethyl cellulose, and hydroxypropylmethyl cellulose on bread quality attributes and their potential protective effect with respect to bread staling were analyzed. Two levels of gums were assayed (0.5 and 1.5 g/100 g flour). The best performance was obtained with carboxymethyl cellulose and hydroxypropylmethyl cellulose F 4 M at both levels; these gums led to higher specific volumes and a better crumb texture as measured by texture profile analysis. In general, crumbs were softer, more cohesive, and resilient and exhibited lower chewiness values. Other gums like microcrystalline cellulose and hydroxypropylmethyl cellulose F50 did not improve bread quality on the same extent. Mechanical spectra obtained by dynamic mechanical analysis assays indicated a marked change in molecular mobility when carboxymethyl cellulose was present. Bread staling was evaluated by texture profile analysis, moisture loss, and calorimetric assays. Gums did not avoid retrogradation and even exhibited an accelerating effect, probably due to changes in water retention and migration during storage. However, in most cases, final crumb hardness in samples with hydrocolloids was lower than that in the control sample.     

Creep‐recovery parameters of gluten‐free batter and crumb properties of bread prepared from pregelatinised cassava starch,sorghum and selected proteins

The effect of egg white, skim milk powder, soy protein isolate and soy protein concentrate on creep‐recovery parameters of gluten‐free batter made from sorghum and pregelatinised cassava starch was studied. Batter treated with egg white had the highest deformation and compliance parameters and lowest zero shear viscosities and differed significantly (P < 0.05) from the other treatments. However, this batter recovered its elasticity sufficiently and its elastic portion of maximum creep compliance did not differ significantly (P < 0.05) from the other treatments. Unlike the other treatments, egg white did not decrease bread volume and exhibited the lowest crumb firmness and staling rate. Optimisation of the amount of egg white with diacetyl tartaric acid esters of mono and diglycerides (DATEM) showed that creep‐recovery parameters and crumb hardness were affected by the linear, quadratic and interaction effects of the input variables. Treatment with 6% and 0.1% w/w fwb egg white and DATEM, respectively, gave gluten‐free batter with the least elastic portion of maximum creep compliance (J_e/J_max = 11.65%) which corresponded to the lowest crumb firmness (790.8 g).     

INFLUENCE OF GUMS ON DOUGH PROPERTIES AND FLAT BREAD QUALITY OF TWO PERSIAN WHEAT VARIETIES

The effects of separate mixing of two hydrocolloids carboxymethylcellulose (CMC) and hydroxypropylmethylcellulose (HPMC) at 0.1, 0.3 and 0.5% levels with Sardary and Sorkheh wheat flours (two native Persian varieties) were studied. Chemical and rheological (Farinograph and Extensograph) tests, staling and sensory evaluations were performed on the two flours, their dough and the resulting Lavash flat bread, respectively. On the basis of split‐plot experiment in a complete random design and using the Duncan's multiple range tests, the data were evaluated and the average of replicates was compared at the statistical level of 1% (α = 0.01). Although the CMC and HPMC gums enhanced significantly the dough quality of the two wheat varieties by increasing water absorption and reducing resistances after 90 and 135 min (compared with control), the effect of HPMC was more pronounced than CMC. Anti‐staling properties of HPMC were better than CMC, especially for Sardary flour. Separate addition of 0.5% CMC and HPMC gums to Sorkheh and Sardary flours significantly delayed the staling process of the resulting Lavash bread by more than 45 and 42%, respectively. Additionally, sensory evaluation scores of the Lavash bread made from either Sorkheh flour containing 0.3% CMC or HPMC or Sardary flour containing 0.5% HPMC were 50 and 120% higher than control bread samples, respectively.     

High-Legume Wheat-Based Matrices: Impact of High Pressure on Starch Hydrolysis and Firming Kinetics of Composite Breads

The significance of high hydrostatic pressure (HHP) processing on the physico-chemical—techno-functional and firming kinetics—parameters and nutritional properties—nutritional composition and “in vitro” starch digestibility—of highly replaced wheat flour breads by chickpea, pea and soybean flours was investigated, and the power/effectiveness of HHP in partially replacing structural agents (gluten and/or hydrocolloids) was discussed. Incorporation of pressured legume slurries (350 MPa, 10 min) at 42% of wheat replacement into bread formulation provoked a general increase in initial crumb hardness and browning of the crust with a concomitant explicit reduction of moisture, whiteness of the crumb and bread specific volume, but a slower in vitro starch digestibility with prominent formation of slowly digestible starch and resistant starch, compared to their counterparts prepared by using a conventional gluten/carboxymethyl cellulose (CMC)-added breadmaking recipe/process. Pressured breads with no gluten but 3% CMC in the formulation kept higher sensory ratings, softer initial texture and lower firming profiles on ageing than pressured breads with no gluten nor CMC. HHP has proven to be an effective technology to partially replace structuring agents (CMC and/or gluten) in high-legume wheat-based matrices providing sensorially acceptable breads with medium physico-chemical quality profile but enhanced formation of nutritionally relevant starch fractions and slower crumb firming kinetics on ageing.     

Rheology and bread‐making performance of gluten‐free formulations affected by different levels of sugar beet fibre,hydroxypropylmethylcellulose and water

This study investigated the application of hydroxypropylmethylcellulose (HPMC) (2%, 3%, 4%), sugar beet fibre (SBF) (3%, 5%, 7%) and water (210%, 220%, 230%) into maize‐based gluten‐free (GF) formulations and their effects on the GF batter rheology and bread quality. HPMC incorporation in higher amounts reduced the compliance values of GF batter samples and increased the values of dynamic moduli indicating an improvement in the GF batter elastic characteristic. The same course of action with a less pronounced influence on mentioned rheological parameters had SBF addition. GF bread quality evaluation in terms of specific loaf volume and crumb texture (hardness, cohesiveness and springiness) reveals that HPMC and SBF incorporation at higher levels enhanced these quality parameters. The inclusion of HPMC and SBF coupled with adequate water content can improve the nutritional value of GF bread without negative influence on bread quality.     

Physical properties of breads containing hydrocolloids stored at low temperature. I. Effect of chilling

Different bread types, some of them containing also hydrocolloid stabilizers, were cold stored for evaluating the final quality of breads after storage. Dough (DB), semi-baked products (SB) and full-baked (FB) breads were used. After storage their physical characteristics were measured, data grouping was performed using PCA analysis and correlations among the properties measured were found. Fresh samples presented some similarities to DB or SB breads, but FB breads had a completely different behaviour. Crust characteristics were found to be important for the quality characterization of breads, as crust textural characteristics; its colour and moisture content were correlated to other properties. Furthermore, crust viscoelastic characteristics gave an indication of bread staling. Porosity was the only physical property not correlated to other bread characteristics. Differences were noticed according to the bread type before storage and the hydrocolloid used, but the main differences were determined by the baking stage before storage. Furthermore, hydrocolloids addition could result in different final bread properties according to the baking stage before storage. The crumb of FB breads was relatively viscous despite of hydrocolloid addition. Hydrocolloids seem to be more effective as stabilizers in DB and SB breads.     

Influence of Gluten-free Flours and their Mixtures on Batter Properties and Bread Quality

Gluten is a major component of some cereals and is responsible for flour technological characteristics to make bakery products. However, gluten must be eliminated from the diet of celiac patients because its ingestion causes serious intestinal damage. The objectives of this study were to assess the effect of different flours and their mixtures on thermal and pasting properties of batters, and to study the quality parameters and staling rate of gluten-free breads. Starch gelatinization temperatures and enthalpies depended on batter composition. Soy flour addition had a higher effect on rice than on corn starch, indicating some differential interaction between starch and proteins. Inactive soy flour incorporation improved all bread quality parameters in both corn- and rice-based breads. Higher batter firmness of formulations with soy addition (extrusion force was doubled in rice/soy and rice/corn/soy batters with regard to rice and rice/corn batters) partially explained higher specific volume (rice breads: 1.98 cm³/g; rice/soy 90:10 2.51 cm³/g, corn/soy 90:10: 2.05 cm³/g, whereas corn/soy 80:20: 2.12 cm³/g), as these batters retained more air during proofing. The staling rate was decreased by soy flour incorporation on rice (staling rate of rice breads with 10% soy diminished 52%, and with 20% of soy addition, 77%, both regarding to 100% rice breads) and corn formulation (the staling rate of corn/soy 80:20 breads was 5.9% lower than corn/soy 90:10) because of the high water-holding capacity of soy proteins and the interactions established with amylopectin that could retard the retrogradation process. Breads made with rice, corn, and soy flours showed the best quality attributes: high volume, good crumb appearance, soft texture, and low staling rate.     

不同食品胶对面包烘焙特性的影响研究

研究了不同食品胶(海藻酸钠、黄原胶、羧甲基纤维素钠、刺槐豆胶和羟丙基甲基纤维素)对面包烘焙特性的影响。结果表明,添加适量的食品胶可以有效提高面包的焙烤品质,增大面包的比容,提高面包的整体接受度,改善面包的质构特性,增加面包的弹性和内聚性,显著降低面包的硬度和咀嚼性,有较好的抗老化效果,延长产品的货架期。海藻酸钠和羟丙基甲基纤维素改善效果最好,黄原胶改良效果最差。     

Extensional flow,viscoelasticity and baking performance of gluten-free zein-starch doughs supplemented with hydrocolloids

Viscoelastic doughs of zein and starch were prepared at 40 °C, above the glass transition temperature of zein. The effects of hydrocolloid supplementation with hydroxypropyl methylcellulose (HPMC) or oat bran with a high content of β-glucan (28%) were investigated by dynamic measurements in shear, confocal laser scanning microscopy (CLSM) and Hyperbolic Contraction Flow. Zein-starch dough without hydrocolloids exhibited rapid age-related stiffening, believed to be caused by cross-links between peptide chains. A prolonged softness was attributed to doughs containing hydrocolloids, with the oat bran exhibiting the most pronounced reduction in age-related stiffening. Moreover, CLSM-images of dough microstructure revealed that a finer fibre network may be formed by increased shearing through an addition of viscosity-increasing hydrocolloids, a reduction in water content in the dough or the use of appropriate mixing equipment. The Hyperbolic Contraction Flow measurements showed that doughs containing hydrocolloids had high extensional viscosities and strain hardening, suggesting appropriate rheological properties for bread making. Zein-starch dough without hydrocolloids showed poor bread making performance while hydrocolloid additions significantly improved bread volume and height. Although the hydrocolloid supplemented doughs had similar extensional rheological properties and microstructures, a fine crumb structure was attributed only to bread containing HPMC, marking the importance of surface active components in the liquid-gas interface of dough bubble walls. Zein could not mimic the properties of gluten on its own, but hydrocolloids did positively affect the structural and rheological properties of zein, which yielded dough similar to wheat dough and bread with increased volume.     

嗜热真菌耐热木聚糖酶对面包品质的改善

研究了纯化的耐热木聚糖酶对面包品质及老化的影响，探讨了耐热木聚糖酶影响面包发酵及烘烤过程的作用机理。适量添加木聚糖酶的面包体积显著增加且面包芯的组织结构优良，同时老化变缓：本试验条件下，添加纯酶1．5mg／kg为最适酶添加量，体积增加43％，硬度减小44％，老化速度放缓近一半。     

Effects of milk proteins and gums on quality of bread made from frozen dough

BACKGROUND: Mixtures of milk proteins and gums incorporated into bread formulations may enhance the quality of bread and retard the deterioration of frozen dough. Our objective was to investigate the effects of mixtures of milk proteins (casein (C) and whey protein (W)) and gums (sodium alginate (A) and κ‐carrageenan (K) on the quality of bread made from frozen dough. We hypothesized that bread containing milk proteins and gums would be of improved quality. Milk proteins improve texture, moisture retention and specific volume, and reduce the size of ice crystals, while gums incorporated into the bread improve moisture retention, control water mobility and prevent the growth of ice crystals, so we hypothesized milk proteins and gums would suppress the quality deterioration of bread during frozen storage. RESULTS: We found that mixtures of milk proteins and gums proved effective with regard to the maintenance of the baking quality of frozen dough. Breads containing CA had a higher specific loaf volume than the control bread. The addition of WK enhanced crumb firmness during extended frozen storage. In sensory evaluation, the addition of WA and CA contributed to the improvement of baking quality, taste, texture and acceptability. CONCLUSION: These findings are consistent with the hypothesis that mixtures of milk proteins and gums improved baking quality by reducing the deterioration of frozen dough. These results indicate that the addition of CA and WA improved the bread quality and WK could effectively be used as an anti‐staling agent in bread. Copyright © 2009 Society of Chemical Industry     

Effect of chitosan on physical and chemical processes during bread baking and staling

The objective of this research was to investigate the effect of chitosan on the interaction of water with bread ingredients and on the rate of staling. The changes in freezable bound water and total water contents in bread crumb were assessed by differential scanning calorimetry from water melting and evaporation endothermic peak areas. It was found that freezable water content and total water content in bread crumb decrease during staling more rapidly in the presence of chitosan. The weak interaction of freezable water with protein and starch polymeric chains in bread crumb becomes stronger, but the interaction of nonfreezable bound water with protein and starch molecules in bread crumb becomes weaker in the course of staling during bread storage. Two stages of bread crumb staling were indicated. Chitosan increases the rate of bread staling during both stages. It was suggested that during bread staling chitosan increases water migration rate from crumb to crust, prevents amylose-lipid complexation, and increases dehydration rate both for starch and gluten.