Effect of defatted maize germ flour addition on the physical and sensory quality of wheat bread

Maize (Zea mays L.) processing produces large quantities of defatted maize germ (DMG) that is being used mainly for animal feed. The objective of this study was to exploit use of this nutrient-rich by-product in bread by replacing wheat flour at 5-20 g/100 g levels. Breads prepared with wheat-DMG flour blends were analyzed for loaf volume, density, instrumental dough hardness and bread firmness, Hunter color (“L”, “a”, “b”, chroma, and hue angle), and selected sensory attributes. Loaf volumes decreased significantly, from 318.8 ml to 216.3 ml, as the DMG flour supplementation was increased from 0 to 20 g/100 g; a similar effect was observed for bread specific volume. Increase in dough hardness (7.56-71.32 N) was directly related to increase in DMG flour levels. Instrumental firmness values were significantly higher for breads containing DMG flours, 61.58 N in 20 g/100 g DMG bread versus 32.84 N for the control bread, made with wheat flour only. The control bread was lighter in color, as shown by higher “L” values, than those having DMG flour, with chroma and hue angle values significantly higher in treatment breads. In general, no differences were observed for the sensory attributes of crumb color, cells uniformity, aroma, firmness, mouthfeel, and off-flavor in breads with up to 15 g/100 g DMG flour, while the overall acceptability scores showed a mixed pattern. The results of this study demonstrated that acceptable quality bread could be made with DMG flour addition at ≤15 g/100 g.     

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.     

Bread quality by substituting normal and waxy hull-less barley (<Emphasis Type="Italic">Hordeum Vulgare</Emphasis> L.) flours

Substitution of regular and waxy hull-less barley flour was evaluated in pan breads prepared from the blends of barley cvs. Saessal (SSWB) and Saechalssal (SCWB) with wheat flour. Effect of barley type and barley flour level (10, 20, and 30%) was investigated on compositions, dough development, and bread qualities. Compared to 100% wheat flour, increasing barley flour increased ash from 0.36 to 0.67%, and β-glucan from 0.1 to 1.91%. Pasting viscosity exhibited higher peak viscosity, through, and breakdown in barley flour blends, showing higher viscosity in SSWB than SCWB. Optimum water absorption and mixing time were increased in barley-wheat flour blends. Substitution of 10% barley flour had no significant difference from wheat bread in bread volume and crumb firmness statistically (p<0.05). The SSWB showed better bread qualities in terms of bread volume and crumb firmness than SCWB. The β-glucan content was 0.13% in wheat bread, but ranged from 0.45 to 1.05% in barley breads.     

Wheat Germ Lipoxygenase: Its Effect on Dough Rheology,Microstructure, and Bread Making Quality

Extracted lipoxygenase from defatted wheat germ of commercial bread wheat along with raw and defatted germ were used to study their effect on rheological characteristics of wheat flour dough and bread making quality. The addition of 500 U and 1000 U of lipoxygenase increased the water absorption from 59.5 to 62.3 and 66.7%, respectively. The dough stability increased to 10.5 min, whereas mixing tolerance index values marginally decreased, and the addition of raw or defatted germ did not affect the mixing profile of the wheat flour dough. Breads with lipoxygenase were softer with a lower firmness value of 546 g when compared to the control (594 g) and had brighter crumb as seen in the reduction in ΔE values from 22.34 (control) to 19.04. The addition of gluten along with the lipoxygenase showed a synergistic effect. The specific volume of breads increased to 3.95 cc/g and the firmness values decreased to 538 g. Scanning electron micrographs at different stages of bread processing have shown improvement in the gluten network.     

Effects of two barley β-glucan isolates on wheat flour dough and bread properties

The effects of wheat flour fortification with two different molecular weight barley β-glucan isolates (1.00 × 10⁵, BG-100 and 2.03 × 10⁵, BG-200) on the rheological properties of dough and bread characteristics, using flours from two wheat cultivars that differ in their breadmaking quality, have been examined. The farinograph water absorption of doughs and the moisture content and water activity of the breads increased with increasing β-glucan content; the β-glucan isolate with the higher molecular weight (BG-200) exerted a greater effect than did BG-100. The addition of β-glucans to the dough formula increased the development time, the stability, the resistance to deformation and the extensibility of the poor breadmaking quality doughs, as well as the specific volumes of the respective breads, exceeding even that of the good breadmaking cultivar. Furthermore, the colour of the bread crumbs got darker and their structure became coarser, whereas the bread crumb firmness decreased with increasing level of β-glucan addition. Generally, the BG-200 was more effective in increasing the specific bread volume and reducing the crumb firmness, especially when used to fortify the poor breadmaking quality flour. The results further indicate a requirement for optimisation of the fortified doughs (level and molecular size of the β-glucan) to maximise bread quality attributes (loaf volume, texture, and staling events).     

Enzymes Action on Wheat–Soy Dough Properties and Bread Quality

High levels of soy flour added to wheat bread produce negative effects on gluten network formation, dough properties, and on bread final quality. The objective of this study was to assess the influence of three enzymes, transglutaminase (TG), glucose oxidase (GOX), and endoxylanase (XYL), on dough properties and final quality of high-protein breads. The addition of TG and GOX increased the mixing stability and maximum resistance of dough, decreased its extensibility, and produced stronger and more consistent dough samples. XYL incorporation produced opposite results. XYL addition and the lowest GOX dose increased bread volume significantly and decreased initial crumb firmness, while high doses of TG (0.3%) produced detrimental effects on bread volume and crumb firmness. In conclusion, XYL and GOX 0.001% addition improved the final quality of soy-fortified breads, but XYL was the best additive to improve dough properties, bread volume, and quality.     

Evaluation of viscoelastic properties and air-bubble structure of bread containing gelatinized rice

The impact of addition of gelatinized rice porridge to bread has been investigated on loaf volume, viscoelastic properties and air-bubble structure. We prepared four variety of bread: bread containing rice porridge (rice porridge bread), bread containing gelatinized rice flour (gelatinized rice flour bread), and wheat flour and rice flour breads for references. Instrumental analyses the bread samples were carried out by volume measurement of loaf samples, creep test and digital image analysis of crumb samples. Rice porridge bread showed the maximum specific volume of 4.51 cm³/g, and even gelatinized rice flour bread showed 4.30 cm³/g, which was larger than the reference bread samples (wheat and rice flour breads). The values of viscoelastic moduli of gelatinized rice flour bread and rice porridge bread were significantly smaller (p < 0.05) than those of wheat flour and rice flour breads, which indicates addition of gelatinized rice flour or rice porridge to bread dough encouraged breads softer. Bubble parameters such as mean air- bubble area, number of air-bubble, air-bubble area ratio (ratio of bubble area to whole area) were not significantly different among the bread crumb samples. Therefore, the bubble structures of the bread samples seemed to similar, which implied that difference of viscoelasticity was attributed to air-bubble wall (solid phase of bread crumb) rather than air-bubble. This study showed that addition of gelatinized rice to bread dough makes the bread with larger loaf volume and soft texture without additional agents such as gluten.     

Effect of Amino Acids and Peptides on Mixing and Frozen Dough Properties of Wheat Flour

Free amino acids, peptides, and vital wheat gluten were investigated to determine their effect on the mixing and frozen dough baking properties of wheat flour. Addition of 1% cysteine and aspartic acid decreased and glutamic acid, histidine, arginine, and lysine increased the mixing tolerance of flour. Cystine, methionine, tryptophan, and phenylalanine increased but isoleucine, histidine, glycine, arginine, glutamic acid, aspartic acid, and lysine decreased loaf volume of nonfrozen dough breads. However cystine, methionine, tryptophan, and phenylalanine did not increase loaf volume of bread prepared from frozen dough. Vital wheat gluten increased mixing tolerance and bread loaf volume only for the nonfrozen dough. However, wheat gluten hydrolysate, corn, and bonito peptides decreased mixing tolerance after optimum mixing time and were effective in increasing loaf volume for both frozen and nonfrozen dough. As the amount of corn and bonito peptide increased, specific loaf volumes also increased. Addition of 2.5% corn peptide was most effective in increasing loaf volume of frozen dough bread. Crust browning and crumb stickiness increased, whereas crumb softness decreased with addition of peptides. Addition of less than 1% peptide did not adversely affect the aftertaste and off‐flavor of bread. These results suggest that addition of peptides are effective for improving the baking quality of frozen dough, whereas amino acids and gluten have no effect.     

Effect of Butternut (Cucurbita moschata Duchesne ex Poiret) Fibres on Bread Making, Quality and Staling

The effect of different enriched fibre products obtained from butternut (Cucurbita moschata Duchesne ex Poiret) on bread making and bread quality was evaluated through the study of bread yield, quality parameters (specific volume, crumb firmness, crumb and crust colour) and bread shelf life. Fractions tested were obtained from butternut mesocarp through ethanolic treatment (fraction AIR) or through dehydration (fraction S) or from the ethanolic treatment of peel (fraction C). These fractions were incorporated in a bread formula, at levels of 5, 10 and 15 g of fibre fraction per kilogram of wheat flour. The study of crumb through digital imaging and thermal analysis was also performed in order to better understand the effects observed. An important influence of water absorption kinetics and chemical composition of the fibre fractions studied was observed in the results obtained. Lower bread firmness was determined 24 h after baking when 10 g of C or either 10 or 15 g of S was present per kilogram of wheat flour used. Breads made with flour containing 10–15 g of S or 5 g of C per kilogram of wheat flour tended to be softer, while 10 g of C per kilogram of flour produced significantly softer breads along 9 days storage.     

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.     

Techno‐functional properties of wheat flour‐resistant starch mixtures applied to breadmaking

Resistant starch can be used to reduce the availability of carbohydrates in baked products. In this study, the effect of type 4 resistant wheat starch (RS₄) on wheat flour dough and breads was evaluated. Wheat flour was substituted by RS₄ at 10%, 20% and 30% w/w (RS10, RS20 and RS30, respectively). Rheological and thermal behaviours of dough were evaluated. Besides, bread quality, starch digestibility and bread staling were analysed. All substituted dough exhibited viscoelastic behaviour but lower elastic and viscous moduli. Regarding to bread quality, specific volume and crumb texture were negatively affected in samples with RS₄. However, all samples were technologically acceptable. During storage, crumb hardening was observed in breads without and with RS₄ but amylopectin retrogradation was not particularly affected. The in vitro digestibility of bread with RS showed a lower release of reducing sugars and a lower estimated glycaemic index, suggesting a healthier profile for these breads.     

Use of Enzymes to Minimize Dough Freezing Damage

The purpose of this investigation was to study the effect of pentosanase (Pn), glucose oxidase (Gox), and transglutaminase (TG) on frozen dough (−18 °C) and their influence on minimizing the damage caused by frozen storage. Bread characteristics were analyzed on day 0; after 3 and 9 weeks of frozen storage, specific loaf volume, crust color, and crumb texture and structure were analyzed. Dough expansion capacity and dough stickiness, extensibility, and viscoelasticity were determined. Frozen dough with high levels of Gox developed a larger bread volume than control dough (without added enzyme). The damage percentage caused by frozen storage in Gox samples was lower than in control samples, indicating that Gox increased dough strength and counteracted the depolymerization effect of gluten produced by ice crystal formation and the release of reducing substances from dead yeast cells during freezing. Samples with Pn developed a large bread volume after 9 weeks of frozen storage because of the formation of smaller pentosans, which result from Pn enzyme action. These pentosans were located in protein–starch–CO₂ matrix interfaces and increased dough expansion capacity without gas loss, thus allowing a higher expansion during proofing. The intermediate level of TG was the only one to present a larger bread volume from frozen dough than control. The new isopeptidic bonds introduced by TG in the gluten proteins helped to mitigate the damage caused by dough freezing.     

Development of gluten free bread containing carob flour and resistant starch

Gluten free bread from rice flour substituted with carob flour and resistant starch (RS) was investigated. RS and protein amount added were optimized in model gluten free breads (MGFB's) containing rice flour using Response Surface Methodology (RSM). RS addition did not influence MGFB's crumb firmness, but it acted as an elastifying agent. A MGFB with soft and elastic crumb was produced with 10 g protein/100 g flour and 15 g RS/100 g flour. MGFB recipe was further improved by adding carob flour. Its addition raises the water content needed for the breadmaking procedure, but did not significantly affect any of the textural and structural parameters measured. Water amount increase diminished crumb firmness and contributed to the development of an open crumb cell structure. The design allowed the determination of the optimum formulation for obtaining gluten-free bread with low crumb firmness and improved porosity values by combining 15 g carob flour/100 g flour, 15 g RS/ 100 g flour, 10 g protein/ 100 g flour and 140 g water/ 100 g flour. The use of carob flour and RS constitutes a promising approach in producing fibre-rich formulations of high quality characteristics in order to fulfil population deficiency of dietary fibre intake.     

STEAMED BREADS MADE FROM COLORADO GROWN WHITE WHEATS

Seven Colorado grown white wheats and a commercial all-purpose flour were used to prepare Chinese steamed bread. Steamed bread doughs were made from 41.8% flour (200g per batch), 0.7% instant active dry yeast, and 57.5% water. Steamed breads were evaluated for specific volume (cm³/g), color of crumb and crust, texture using a texture analyzer, and by a subjective sensory evaluation.
Specific volume of steamed bread ranged from 3.3 to 3.6 cm³/g. There was no statistical significant difference in crust and crumb color among breads from all flour samples. Low peak force and area texture measurements which indicate softness, were correlated with high specific volume. Overall, the flours from Colorado grown white wheats were desirable for making steamed bread with one exception. The all-purpose commercial flour was found to be desirable for making steamed bread.     

Influence of Cephalaria Syriaca Addition on Physical and Sensorial Properties of Wheat Bran Bread

The effect of different Cephalaria syriaca products (CSP) (whole Cephalaria syriaca flour (WCSF) and defatted Cephalaria syriaca flour (DCSF)) on the final quality of bran breads was investigated. Five levels of Cephalaria syriaca products (0.16, 0.50, 0.84, 1.17, and 1.51 g/100 g bread) were used in this study. Results of this study showed that addition of CSP (WCSF and DCSF) to wheat bran bread had significant positive impact on bread specific volumes, crumb firmness and bread sensory characteristics, although addition levels (0.16, 0.50, 0.84, 1.17, and 1.51 g/100 g bread) were very low. In general, specific volume, yield of volume, and some sensory characteristics of the bran bread increased when the addition levels of WCSF and DCSF increased, except for the level of 1.51 g/100 g bread CSP addition, in which a slight decrease was observed. Bran breads containing WCSF had significantly higher loaf specific volume, softness of breadcrumb and sensory characteristics than those of breads containing DCSF at all addition levels. Especially, the addition of 1.17 g WCSF significantly improved the quality of bran breads. This study indicates that these two CSP can be used as additives in bran bread production in order to improve the quality of bread.     

Effect of Extruded Wheat Germ on Dough Rheology and Bread Quality

Wheat germ, a by-product of the milling industry, has interesting nutritional properties. However, it has limited use due to a high risk of rancidity, which could be reduced by using certain thermal treatments such as extrusion. The aim of this study was to investigate how wheat germ extrusion affects the changes induced by its addition to bread dough. For this purpose, different quantities of extruded or raw wheat germ (2.5, 5, 7.5, 10, and 20?g/100?g flour) were added to bread dough. Rheological characteristics of the dough and final quality characteristics of the bread were analysed from both the physical and the sensory points of view. Wheat germ addition increased water absorption and development time but decreased stability after over-kneading, dough tenacity, extensibility, and dough alveographic strength. The addition of extruded wheat dough improved stability and decreased extensibility and strength. Bread made from dough with added wheat germ presented decreased volume, cohesiveness, and elasticity and increased firmness. However, extrusion increased the volume of breads with added wheat germ and improver and decreased firmness. All breads obtained positive acceptability scores in sensory analysis, although wheat germ addition (10?g/100?g flour) slightly decreased texture, appearance, and overall acceptability scores of breads. Germ extrusion therefore improves dough rheology and bread quality and constitutes a suitable treatment to stabilise wheat germ in bread dough.     

Effects of flour from different barley varieties on barley sour dough bread

Twenty flours from 16 different barley varieties cultivated in 1990 and 1992, and a Swedish reference flour, were fermented by Lactobacillus plantarum A1 to sour doughs. Barley breads (40% barley/60% wheat flour) from each flour type were baked with and without an admixture of barley sour dough in order to investigate how the sour dough admixture would affect the baking properties. A trained panel carried out sensory evaluation by conventional profiling on breads made from three of the barley varieties and the Swedish reference flour, made with and without sour dough admixture.

The barley varieties influenced both the sour dough properties and the properties of the barley bread. The pH of bread with sour dough ranged from 4.6 to 4.8 as compared to 5.4 to 5.6 in bread without sour dough. The acidity of the breads with sour dough ranged from 4.1 to 5.0 ml NaOH/ 10 g bread crumb as compared to 2.4 to 3.6 in breads without sour dough. In 14 of the twenty bread types an addition of sour dough lowered the bread volume. Breads with a sour dough admixture scored higher for total taste and acidulous taste than breads without sour dough. The β-glucan content of the flours had no significant influence on the sour dough or the sensory characteristics of the bread, except for the breadcrumb colour.     

Effect of flaxseed and wheat flour blends on dough rheology and bread quality

The rheological and baking properties of flaxseed/wheat composite flours were studied. Flaxseed flour was used to replace 50, 100, 150 and 200 g kg^?1 of wheat flour in bread. Farinographic studies showed that water absorption, dough development time and mixing tolerance index increased as the amount of flaxseed flour increased, while dough stability decreased at 100, 150 and 200 g kg^?1 of flaxseed flour substitution. The extensographic energy of dough also decreased at 150 and 200 g kg^?1 flaxseed levels. The addition of increasing amounts of flaxseed flour caused a decrease in extensibility. Doughs containing 100, 150 and 200 g kg^?1 flaxseed flour showed resistance to extension comparable to that of control dough. The specific volume of flaxseed flour breads was similar to that of control bread. Crust L, a, b values of breads with flaxseed flour were lower than those of control bread. Breads with flaxseed flour gave lower crumb L and b values and higher a values than control bread. The sensory properties showed that an acceptable bread could be produced using flaxseed flour up to a level of 200 g kg^?1. Copyright © 2007 Society of Chemical Industry     

Influence of the Enzymatic Modification of the Nonstarchy Polysaccharide Fractions on the Baking Properties of Reconstituted Rye Flour

The effect of the nonstarchy polysaccharide (NSP)-hydrolases on the properties of rye bread was established by enzymatic modification of the enriched soluble and insoluble NSP fractions, followed by flour recombination and bread baking (20g flour per minibread). Two microbial enzyme preparations were used for the modification (incubation 2 hr at 28°C, 15 min at 75°C, and 10 min at 95°C; pH 4.6). Modification of the insoluble NSP decreased crumb firmness and increased specific volume. Hydrolysis of the soluble NSP decreased the specific volume. Treatment of both fractions improved crumb structure, decreased crumb firmness and increased the width/height ratio of the minibreads.     

Application of Response Surface Methodology to the Development of Rice Flour Yeast Breads: Objective Measurements

A gluten-free wheat bread replacement was developed from rice flour (80%) and potato starch (20%). Using objective measurements as responses, response surface methodology was utilized to find carboxymethylcellulose (CMC)-hydroxypropylmethylcellulose (HPMC)-water combinations which could successfully replace gluten in the rice flour yeast breads from each of three rice flours. CMC and water had the greatest effect on the responses measured; HPMC had the least. Rice bread formulations were found that resulted in breads which met wheat (white) bread reference standards for specific volume, crumb and crust color, Instron firmness and % moisture.