Wheat bran particle size effects on bread baking performance and quality

Commercial hard red spring, hard red winter, soft white and durum wheat brans were used to evaluate the particle size effect of wheat bran on bread baking performance and bread sensory quality. Three different particle size bran samples were obtained from each bran by grinding, not by sifting, the bran samples. The bran samples were similar in chemical composition, but different in particle sizes. Results of baking experiments showed that breads containing fine bran had lower specific loaf volume and darker crumb colour than breads containing coarse or medium size bran. Sensory test panellists found that fine bran contributed smoother crust appearance and less gritty mouthfeel than the coarse bran. The sensory panel also indicated that breads containing soft white wheat bran had significantly better flavour and mouthfeel than breads containing hard red spring wheat bran. © 1999 Society of Chemical Industry     

添加改性麸皮对含麸皮面包结构及消化特性的影响

采用酶解-高压湿热处理对小麦麸皮进行改良,将改良后的小麦麸皮回添至高筋粉中获得不同麸皮含量的面粉,制作含麸皮面包,研究改良麸皮添加量对含麸皮面包的结构及消化特性的影响规律。结果表明：改良后的小麦麸皮中脂肪酶残余酶活降至0,不溶性膳食纤维含量从37.38%降低至15.64%,持水力升高了41.26%。与改良前的含麸皮面包相比,改良后的含麸皮面包香气浓郁,比容、硬度、弹性都得到了明显的改善。随着改良麸皮添加量增加,面包的老化程度降低、比容降低、硬度增加、弹性降低、感官品质降低。添加改良麦麸的含麸皮面包抗性淀粉含量增加,淀粉水解率降低。此外,改良麦麸显著降低了面包血糖生成指数。     

BREAD MAKING OF DURUM WHEAT WITH CHICKPEA SOURDOUGH OR COMPRESSED BAKER'S YEAST

Two ways of improving durum wheat bread-making quality were evaluated.
First, durum wheat (cultivar "Papadakis") was blended with bread wheat flour of good (A-flour) or medium (B-flour) quality (70% durum and 30% bread wheat flour). Durum wheat flour displayed the γ-gliadin 45 electrophoretic band and acceptable bread-making quality. Breads from flour blends had better volume, particularly the durum and A-flour blend. The addition of ascorbic and citric acid and malt flour improved dough rheological properties and thus bread volume, as well as staling rate and sensory characteristics. These were more pronounced in the blend of durum with B-flour.
Second, durum wheat flour alone was used to prepare chickpea sourdough-leavened bread, as flavor is important for consumer acceptance. With the addition only of salt, the chickpea sourdough-leavened durum wheat bread displayed acceptable loaf volume, distinguished flavor and longer shelf life compared with bread prepared with compressed baker's yeast.

PRACTICAL APPLICATIONS

One of the practical applications of this study is the possibility of using a common durum wheat cultivar instead of local varieties as is the case with traditional breads. Results of this work may be useful for promoting greater acceptance of durum wheat breads as well as expansion of the use of a traditional Mediterranean chickpea sourdough-leavened durum wheat bread with distinguished flavor and taste.
This work may serve as a guide for determining the quality of flours suitable for production of "home made" or "village" bread (which has high market value as specialty bread) by blending durum and bread wheat flours. Best results are obtained with good-quality bread wheat flour, regardless of the good quality of durum wheat cultivar used, together with the use of the dough improvers implemented in this work.     

Fibre-rich additives--the effect on staling and their function in free-standing and pan-baked bread

BACKGROUND: The use of dietary fibre in bread products is increasing because of consumer demand for healthier products. However, an increase in dietary fibre level changes the rheological properties of the dough and also the quality properties of the final bread product. In this study, effects on dough and bread staling were followed after replacing 3% of wheat flour by fibre‐rich additives (fine durum, oat bran, rye bran and wheat bran). Free‐standing and pan‐baked loaves were baked to compare the influence of baking method and loaf shape. RESULTS: All additives increased dough stability, with oat bran giving the greatest stability and longest development time. Parameters measured during storage were distribution, migration and loss of water, cutability, crumbliness, firmness and springiness. Furthermore, amylopectin retrogradation and amylase‐lipid complex formation were assessed. Oat bran provided similar or better results than the control for all staling parameters, while other additives gave no general improvements. Cutability reached a plateau when crumb firmness was ≥ 4 N. CONCLUSION: Small amounts of fibre‐rich additives had a significant influence on staling. However, the baking method (free‐standing or pan‐baked bread) had a greater impact on staling than the additives, thus displaying the importance of the baking method. Cutability was found to be related to firmness. Copyright © 2011 Society of Chemical Industry     

Optimisation of formulations and infrared–microwave combination baking conditions of chestnut–rice breads

The main objective of this study was to design gluten‐free breads containing chestnut and rice flour and xanthan–guar gum blend to be baked in infrared–microwave combination oven. Response surface methodology (RSM) was used to optimise gluten‐free bread formulations and processing conditions. Weight loss, firmness, specific volume and colour change of the breads were determined. Rice flour mixed with different proportions of chestnut flour and different emulsifier contents were used to prepare breads. The gluten‐free formulations were baked using different upper halogen lamp powers, microwave powers and baking time which were varied from 40% to 80%, 30% to 70% and 9 to 17 min, respectively. Gluten‐free breads and wheat breads baked in conventional oven were used for comparison. Breads containing 46.5% chestnut flour and 0.62% emulsifier and baked using 40% infrared and 30% microwave power for 9 min had statistically comparable quality with conventionally baked ones.     

Effects of wheat and rye bread structure on mastication process and bolus properties

Chemical composition, baking process and structure of breads influence their degradation in digestion leading to different postprandial responses. Rye bread has a very different structure as compared to wheat bread, and rye breads are known to induce lower postprandial insulin responses than wheat bread. The aim of this study was to find out potential differences in mastication and initial starch hydrolysis rate of rye and wheat breads. Three rye breads (wholemeal rye, endosperm rye and endosperm rye with gluten) and wheat bread were masticated by fifteen participants and the process was monitored using electromyography. The particle size distribution and initial in vitro starch hydrolysis of the bread boluses were analysed. Specific volume correlated negatively and closed porosity of breads correlated positively with work required for mastication. When compared to wheat bread, wholemeal rye bread required more work for mastication process (p = 0.004). Rye breads were degraded to smaller particles than wheat bread during mastication. There was a trend (p = 0.098) towards slower in vitro starch hydrolysis rate in rye bread boluses than in wheat bread boluses. The results indicate that the digestion process of rye breads differs from that of wheat bread already in the early phase of digestion. This may be one reason behind the unique postprandial responses reported for rye breads.     

Phytic acid content in milled cereal products and breads

Phytic acid was determined in cereal (brans, flours and milled wheat-products) and breads. The method was based on complexometric titration of residual iron (III) after phytic acid precipitation. The cereal flours showed values ranged between 3–4 mg/g for soft wheats, 9 mg/g for hard wheat and 22 mg/g for whole wheat. Corn, millet and sorghum flours reported a mean of 10 mg/g and oat, rice, rye and barley between 4 and 7 mg/g. Wheat brans had wide ranges (25–58 mg/g). The phytic acid for oat brans was half that of wheat bran (20 mg/g) and higher value (58 mg/g) than that for rice bran. The milling products (semolinas) from hard wheat exhibited 10 mg/g and soft wheat a mean of 23 mg/g. The breads made with single or mixture cereal flours exhibited ranges between 1.5 and 7.5 mg/g. The loss of phytic acid relative to unprocessed flours was between 20% for oat bread and 50% for white bread.     

Effects of yeast and bran on phytate degradation and minerals in rice bread

ABSTRACT:  Rice bread is a potential alternative to wheat bread for gluten-sensitive individuals. Incorporation of rice bran into bread made from white rice flour adds flavor but also phytic acid, which can reduce the bioavailability of minerals. Breads with varied amounts of defatted bran and yeast were prepared to determine their effects on the phytate and mineral contents of the bread. A completely randomized factorial design was used with bran levels of 3.7%, 7.3%, and 10.5% of the dry ingredients and yeast levels of 1.6%, 3.2%, and 4.7%. Increasing the amount of bran decreased the phytate degradation from 42% at the lowest level of bran to 10% at the highest, and the amount of yeast had no significant effect. The bran contributed substantial amounts of magnesium, iron, and zinc. Breads with the lowest level of bran had phytate-to-zinc molar ratios between 5 and 10, which suggest medium zinc bioavailability. Rice bread is a tasty and nutritious food that is a good dietary source of minerals for people who cannot tolerate wheat bread.     

Effects of enzymes in fibre-enriched baking

The aim of the present study was to improve the quality of fibre-enriched wheat breads by enzymic treatment of the fibre fraction. The suitability of different enzymes in fibre-enriched baking and their effects on the dietary fibre content and the ratio of insoluble: soluble fibre content of the breads were studied. The enzyme preparations used were a hemicellulolytic culture filtrate of Trichoderma reesei, a specific (pI 9) xylanase of T reesei and Fermizyme, an α-amylase preparation containing a standardised level of hemicellulase activity. Rye bran was extracted in water (10% (w/w) suspension) to determine the solubilities of the β-glucans and pentosans. Addition of T reesei culture filtrate significantly increased the amount of extractable pentosan obtained from nonautoclaved rye bran. Rye bran supplementation (5%) of wheat flour increased the farinograph absorption and dough development time, but had little or no effect on stability and softening of the dough. The added enzymes decreased dough stability and increased softening. Addition of enzymes caused significant differences in the stickiness of the wheat doughs both with (P<0·003) and without (P<0·001) rye bran. Fermizyme significantly increased the stickiness of wheat doughs both with and without rye bran. The baking results of the fibre-enriched breads were improved by the added enzymes. Addition of T reesei culture filtrate increased the specific volume of the wheat breads both with and without rye bran by almost 20%. Enzyme mixtures were more efficient than individual xylanase in softening the bread crumb and reducing the staling rate of wheat breads both with and without rye bran. Incorporation of enzymes reduced the total dietary fibre content of the breads, but at least doubled the amount of soluble pentosan. The proportions of fluorescent cell walls in the breads were detected by microscopical image analysis. Enzyme addition caused the surface area of insoluble cell walls originating from wheat flours to decrease, suggesting that the enzymes exert more effects on wheat endorsperm cell walls than on bran particles. © 1998 SCI.     

发酵麦麸对面包膳食纤维组成及烘焙特性的影响

采用马克斯克鲁维酵母发酵麦麸制得富含天然酶的功能配料,分析麦麸发酵过程中纤维素酶活力变化,比较制作的麦麸面包(B₁)、发酵麦麸面包(B₂)、木聚糖酶麦麸面包(B₃)和复合麦麸面包(B₄)的膳食纤维组成及烘焙特性的差异。结果表明:马克斯克鲁维酵母具有较强的胞外β-葡萄糖苷酶生产能力,其酶活为6.98 U/g;在48 h麦麸发酵过程中,外切葡聚糖酶和β-葡萄糖苷酶的酶活不断提高,其酶活分别增加至6.06和21.70 U/g,不溶性膳食纤维(IDF)也持续降解至38.30 g/100 g。面团搅拌、醒发过程中,还原糖含量不断增加,且添加发酵麦麸的面包效果最明显。相比未发酵麦麸面包,添加发酵麦麸的面包体积、弹性及持水力都显著提升(p<0.05),气孔结构更加细腻。制作的4种面包中总膳食纤维(TDF)和阿拉伯木聚糖(AX)含量没有显著差异,而添加发酵麦麸及木聚糖酶都能促进面包中IDF和AX溶解。     

Physiological Responses of Rats to High Fiber Bread Diets Containing Several Sources of Hulls or Bran

Fiber-supplemented breads, prepared by replacing 7.5% of the hard wheat flour with field pea, flax or sunflower hulls, wheat bran or microcrystalline cellulose, were evaluated for breadmaking characteristics and physiological effects on rats. Cellulose-supplemented dough and bread resembled the straight-grade wheat bread while pea hull and wheat bran breads were similar to whole wheat bread. Flax and sunflower hulls had adverse effects on dough mixograph properties, loaf volume and crumb characteristics while sunflower hulls also contributed grittiness and aftertaste in taste panel evaluations. The fiber-supplemented breads, when fed to weanling rats, gave similar feed consumptions, weight gains and serum cholesterol levels as rats fed the whole wheat bread. Pea hulls increased daily fecal weight and, with coarse sunflower hulls, decreased dry matter digestibility. Fine wheat bran and fine sunflower hulls in the bread diets were associated with low fecal weight, low fecal volume, high fecal density and high digestibility of dry matter.     

Effect of Rice, Corn and Soy Flour Addition on Characteristics of Bread Produced from Different Wheat Cultivars

Preparation and consumption of bread enriched with flours that contain appreciable amounts of protein, lysine, dietary fiber, and minerals will provide a healthy alternative to consumers and also a lowering of bread making cost in countries where wheat is not a major domestic crop. Addition of rice, corn, and soy flour to bread and durum wheat flours at 10, 20, 30, 40, 50% levels was carried out to examine the effects on the baking (specific volume, color, firmness) and sensory characteristics of bread. Dough rheological properties were also studied using Brabender Farinograph and Extensograph. Results of the present study suggest that incorporation of rice, corn, and soy in bread wheat flour up to a level of 10% (flour basis) and in durum wheat flour up to 20% produces bread without any negative effect in quality attributes such as color, hardness, and flavor and reasonable acceptance offering promising nutritious and healthy alternative to consumers. Increasing levels of substitution (30 and 50%) resulted in decreasing dough strength, extensibility, and loaf volume, due to the replacement of gluten by the added protein. Overall acceptability scores of these breads were found to be very low. The durum flour can be substituted with nongluten flours up to 10% more than the bread wheat flour because of its stronger gluten matrix and better dough rheological characteristics.     

Fermentation Process and Grain Structure of Baked Breads from Frozen Dough Using Freeze-Tolerant Yeasts

The fermentation process for frozen doughs using freeze‐sensitive (Saccharomyces cerevisiae, Kyowa for sweet bread; S. cerevisiae, FC for white bread) and freeze‐tolerant (S. cerevisiae, YF for sweet bread) yeasts was traced by magnetic resonance imaging (MRI). Grain network structures of baked breads were also visualized by MRI. Prefermentation before freezing, punching and remolding, or resheeting and molding treatments increased loaf volume by 10 to 110% for the baked breads using freeze‐tolerant yeast, while these treatments decreased loaf volume by 70% using freeze‐sensitive yeast. The first fermentation before freezing and the second fermentation with punching or resheeting after thawing are useful for obtaining good quality breads from frozen dough using freeze‐tolerant yeast.     

Quality and antioxidant properties of bread containing turmeric (Curcuma longa L.) cultivated in South Korea

Turmeric (Curcuma longa L.) powder was used to substitute 0%, 2%, 4%, 6% and 8% of wheat flour for making turmeric wheat breads. Proximate composition, physical quality, functional components (curcumin and total phenols) and antioxidant properties of breads containing turmeric were analysed and compared with those of wheat bread. Hardness, crumb colour a and b values, curcumin content and total phenolic contents of breads significantly increased with the addition of turmeric powder. Water activity, specific volume and crumb colour L value of breads decreased with the addition of turmeric powder. Breads containing turmeric powder also showed good antioxidant activity as tested by the β-carotene-linoleate bleaching assay. A 4% substitution of wheat flour with turmeric powder showed acceptable sensory scores which were comparable to wheat bread. Breads containing turmeric powder can thus be developed as a health-promoting functional food.     

Effects of different formulations on the quality of microwave baked breads

Effects of different amounts of gluten, fat, emulsifier, and dextrose on the quality of breads baked in the microwave oven were investigated. Response surface methodology was used to optimize the formulation of microwave baked breads. Firmness, specific volume, and weight loss of the breads were determined. Breads formulated with low gluten flour were softer and had higher volume. Volume of these breads can be comparable with the volume of conventionally baked breads. For breads formulated with flour containing low gluten, the increase in fat and emulsifier contents decreased the firmness and increased the specific volume of breads. Fat, emulsifier, and dextrose contents were found to be the significant factors to reduce the weight loss of microwave baked breads.     

A study on the effects of different gums on dielectric properties and quality of breads baked in infrared-microwave combination oven

In this study, the effects of different gums on dielectric properties of doughs and breads baked in infrared-microwave combination oven were investigated. In addition, the quality parameters of breads formulated with different gums baked in infrared-microwave combination oven were determined. The gums used were xanthan, guar, xanthan-guar blend and κ-carrageenan. The gums were added to the formulation at 0.5% concentration. The dielectric properties and quality parameters of breads baked in infrared-microwave combination oven were found to be dependent on gum type. κ-carrageenan resulted in undesirable final bread quality, while xanthan-guar blend addition improved bread quality (high specific volume and porosity, low hardness values). The dielectric properties of bread samples formulated with κ-carrageenan were found to be the highest among the other gum types.     

IMPROVEMENT OF THE WHEAT AND CORN BRAN BREAD QUALITY BY USING GLUCOSE OXIDASE AND HEXOSE OXIDASE

The effects of addition of wheat (10, 20 and 30%) and corn bran (10 and 20%) on rheological and bread making properties of flour were examined. To improve dough and bread properties, glucose oxidase (GO) and hexose oxidase (HO) (15–30 and 45 mg/kg) were used separately in each bran-wheat flour formula with L-ascorbic acid at 75 mg/kg, glucose at 0.5% and vital gluten at 9.2%. Water absorption and development time increased as the amount of wheat and corn bran increased, while dough stability, maximum resistance to extension, extensibility, energy and loaf volume decreased. Corn bran was found to be more detrimental to dough rheology and bread characteristics than wheat bran. Corn bran and wheat bran could be used at bread making up to levels of 10 and 20%, respectively. Addition of 30 mg/kg of HO in combination with constant additives was most effective in improving dough and bread characteristics and GO with its 15 mg/kg usage level followed it. Further increasing of enzyme levels led to over oxidizing of doughs and breads.

PRACTICAL APPLICATIONS

Corn bran up to 10% and wheat bran up to 20% levels can be used in bread making. To improve dough and bread quality, besides L-ascorbic acid (75 mg/kg) and vital gluten (as a percentage of added bran weight), GO (15 mg/kg) or HO (30 mg/kg) could be incorporated into wheat flour-bran mixtures. However, the amount of enzyme should be carefully chosen because when they are used above the mentioned levels, they cause overoxidation of doughs and small loaf volumes are obtained. As a conclusion; by using the corn bran, which is a by-product of the starch industry, not only could it be possible to offer healthy alternative breads which contain high amounts of dietary fiber to consumers, but it could also be possible to obtain economical value by evaluating such a by-product in the bread industry.     

In vitro fermentation of polysaccharides of rye,wheat and oat brans and inulin by human faecal bacteria

The in vitro fermentabilities of rye, wheat and oat brans and of a commercial fibre preparation, inulin, were compared. The brans were first digested enzymatically to remove starch and protein. The digested brans and inulin were then fermented with human faecal inoculum. The progress of fermentation was studied by following the consumption of carbohydrates and the production of short‐chain fatty acids and gases. Inulin, a short fructose polymer, was consumed significantly faster than the more complex carbohydrates of cereal brans. Carbohydrates of oat bran (rich in β‐glucan) were consumed at a higher rate than those of rye and wheat brans (rich in arabinoxylan). In all brans, glucose was consumed faster than the other main sugars, arabinose and xylose, and arabinose was degraded only slightly. The total production of short‐chain fatty acids was slightly higher with oat bran than with rye and wheat brans and inulin. In the fermentation of inulin, relatively more butyric acid and less propionic acid were produced than in the fermentation of brans. The decrease in pH was also greater in the case of inulin. Wheat bran led to a slightly slower gas formation than rye and oat brans. Formation of gases was fastest and greatest in the case of inulin. In conclusion, rye, wheat and oat brans were fermented in a rather similar way. Fermentation of the brans was different from that of inulin. Cereal brans might serve as a more balanced source of dietary fibre supplement than gas‐producing, readily fermentable polysaccharides such as inulin. © 2000 Society of Chemical Industry     

High-Amylose Resistant Starch as a Functional Ingredient in Breads: a Technological and Microstructural Approach

Resistant starches (RS) are important functional fibers with high potential for the development of healthy foods. The technological, nutritional, and commercial possibilities of introducing type 2 RS in white breads were studied. Four levels of maize RS (HM) as wheat flour replacement were evaluated: 0%, 10%, 20%, and 30% (control, HM10, HM20, and HM30, respectively). Thermal transitions experiments were assessed on doughs prior to breadmaking. The bread quality was studied by specific volume, color of crust and crumb, porosity, and texture of the crumb. The microstructure of the crumb was analyzed by environmental scanning electron microscopy (ESEM). Proximate composition and in vitro starch digestibility were performed to characterize the nutritional profile of breads and estimate the glycemic index (GI). Consumer acceptability of breads was also evaluated. Breads with HM showed great performance up to 20% replacement in the specific volume, the crumb porosity, and the texture. Replacement up to 30% caused major damage to those parameters. Differential scanning calorimetry runs demonstrated that HM starch did not gelatinize under the baking conditions, as confirmed by ESEM. The presence of increasing levels of native starch is thought to have the greatest influence on reducing the crust browning, increasing the crumblier texture and decreasing starch digestibility. With respect to the control, a high and progressive reduction in the estimated GI and an outstanding increase of fiber with increasing levels of HM were found. The sensory evaluation of HM20 bread showed that this level of substitution has great consumer acceptance, giving it the chance to become a healthy substitute of white bread.     

Characterization of the Bread Made with Durum Wheat Semolina Rendered Gluten Free by Sourdough Biotechnology in Comparison with Commercial Gluten‐Free Products

Durum wheat semolina was fermented with sourdough lactic acid bacteria and fungal proteases aiming at a complete gluten hydrolysis. The gluten‐free (GF) semolina, added with naturally GF ingredients and structuring agents, was used to produce bread (rendered GF bread; rGFB) at industrial level. An integrated approach including the characterization of the main chemical, nutritional, structural, and sensory features was used to compare rGFB to a gluten‐containing bread and to 5 commercial naturally GF breads. High‐performance liquid chromatography was used for free amino acids (FAAs), organic acids, and ethanol analysis. A methanolic extract was used for determining total phenols and antioxidant activity. The bread characterization also included the analysis of dietary fibers, mycotoxins, vitamins, and heavy metals. Beyond chemical analysis, nutritional profile was evaluated considering the in vitro protein digestibility and the predicted glycemic index, while the instrumental texture profile analysis was performed to investigate the structure and the physical/mechanical properties of the baked goods. Beyond the huge potential of market expansion, the main advantages of durum wheat semolina rendered GF can be resumed in the high availability of FAAs, the high protein digestibility, the low starch hydrolysis index, and the better technological properties of bread compared to the commercial GF products currently present on the market. Vitamins, minerals, and dietary fiber profiles are comparable to those of gluten‐containing wheat bread. Also the sensory profile, determined by a panel test, can be considered the most similar to those of conventional baked goods, showing all the sourdough bread classic attributes.