Rheological and baking properties of cowpea and wheat flour blends

Effect of blending 50 to 250 g kg⁻¹ cowpea flour in wheat flour on rheological, baking and sensory characteristics of bread, chapati, cookies and muffins was studied. Farinograph water absorption, dough development time, mixing tolerance index and dough stability increased significantly with increased amount of cowpea flour. Incorporation of cowpea flour lowered gelatinisation time and peak viscosity. Loaf volume and overall acceptability scores of bread were reduced significantly beyond 150 g kg⁻¹ incorporation of cowpea flour. There were significant changes in specific volume and overall acceptability scores of muffins, registering an initial improvement up to 50 g kg⁻¹ and a significant decline thereafter. © 1999 Society of Chemical Industry     

Incorporation of dairy ingredients into wheat bread: effects on dough rheology and bread quality

 Dairy ingredients are used in breadmaking for their nutritional benefits and functional properties. The effects of the traditionally-used whole and skimmed milk powder, sodium caseinate, casein hydrolysate and three whey protein concentrates on dough rheology and bread quality were studied. Whole and skimmed milk powders improved sensory characteristics. Sodium caseinate and hydrolysed casein displayed beneficial functional properties in breadmaking including low proof time, high volume and low firmness. Both ingredients increased dough height measured with the rheofermentometer. Bread with 2% or 4% sodium caseinate added was rated highly in sensory evaluation. Incorporation of whey protein concentrates generally increased proof time, decreased loaf volume and decreased dough height measured with the rheofermentometer. Received: 6 April 1999 / Revised version: 13 July 1999     

Rheological behaviour of wheat flour dough in twin-screw extrusion cooking

A capillary-type viscometer was designed to measure the apparent viscosity of the cooked wheat flour dough on -line in a twin-screw extruder. The effect of mean residence time and specific energy were studied in the ranges 20–45s and 300–800 kJ kkg⁻¹, respectively. A viscosity model was developed which accounts for effects of wall shear rate, moisture content and specific energy. It was shown that the extent of the cooking reaction is largely determined by the specific energy applied.     

Lipid binding in flour,dough and bread

A study was made of the binding of lipids during dough and breadmaking, using yeasted and unyeasted doughs, and work input levels during doughmaking of 2 to 6 Wh/lb (0.16 to 0.48 h.p. min/lb; 16 to 48 MJ/kg). Incorporation of bakery fat into dough increased the ratio of (total) “free” to “bound” lipids as compared with corresponding doughs without fat and the distribution was not significantly influenced by the time of addition of the fat during doughmaking. There was no significant change in phospholipid distribution as a result of the incorporation of bakery fat into dough. Neither total work input nor rate of work input were found to affect lipid binding significantly in (air-mixed) dough or in bread, within the range of work levels likely to be encountered in commercial practice in the U.K. Differences in the distribution of total lipid cannot account for the essential requirement for fat in mechanical development processes, where work input is usually about 5 Wh/lb, as compared with conventional processes, with work inputs of about 2 Wh/lb, where fat is an optional ingredient.     

Effect of taro (Colocasia esculenta) flour addition on the functional and alveographic properties of wheat flour and dough

BACKGROUND: Taro is a plant widely produced in tropical areas for its underground corms. Taro corms are highly perishable owing to their high moisture content. In order to limit post‐harvest losses and improve the production and consumption, production and utilization of taro flour have been envisaged. In connection with this, the incorporation of taro flour into wheat‐based products has been reported to increase their keeping quality. Before consideration is given to taro flour as a substitute for wheat in bread manufacture, it is necessary to characterize the functionality of the composite flour and dough. The present study investigated the physicochemical and alveographic properties of wheat–taro composite flour. RESULTS: Three varieties of taro flour (WCN, RIN and KWN) were incorporated into wheat flour in proportions of 10%, 20% and 30% (w/w) and the water absorption capacity (WAC), retrogradation index (RI), foam capacity (FC) and other functional properties were measured. In addition, characteristics of dough rupture pressure (P), extensibility (L), elasticity index (Ie) and strength (W) of flour made from the different composites were measured using an alveograph. The results showed that WAC significantly increased from 132% (wheat flour) to 156% (30% composite flour), while RI significantly decreased from 38% to a mean value of 22%. Principal component analysis revealed that WAC and P formed a group of variables negatively correlated with a second group made of RI, FC, W, Ie and L. CONCLUSION: Incorporating taro flour up to a level of 10% had no significant effect on the functional and alveographic properties of the flours. This suggested that in order to guarantee the quality of bread made from wheat–taro composite the level of taro addition should not exceed 10%. Copyright © 2007 Society of Chemical Industry     

小麦粉在不同粒度下其面团及馒头品质

为研究小麦粉在不同粒度下其面团及馒头品质的变化,通过控制研磨条件得到基本组分相同而粒度不同的6种粒度不同的小麦粉（分别全部穿过150 μm、137 μm、123 μm、112 μm、100 μm、88 μm,以下简称S150、S137、S123、S112、S100、S88）,对其色泽、基本理化特性、面团水分分布、发酵特性及馒头各项指标进行分析,从而探究粒度对面团特性及馒头品质的影响。结果表明：当小麦粉粒度减小时,其水分在粒度S112时较低,灰分、脂肪含量无显著性（p＜0.05）变化,粒度组成中D50从120.84 μm降至73.64 μm、湿面筋含量显著性（p＜0.05）降低,L*值、破损淀粉含量显著性（p＜0.05）增加;面团内深层结合水和自由水含量逐渐降低而弱结合水含量逐渐增加。在粒度为S123时,面团最大膨胀高度、漏气时间、产气量和持气率达到最大。随着小麦粉粒度减小,馒头的比容、L*值、弹性、内聚性、回复性整体呈先增加后降低趋势,硬度、胶着性、咀嚼性呈先降低后升高,宽高比在粒度为S112时最小。综上所述,粒度在S123～S112小麦粉适合制作馒头。     

发酵麦麸对面包面团生化特征及烘焙学特性的影响

采用马克斯克鲁维酵母(Marx Kluyveromyces)发酵麦麸,通过生化分析、流变特性测试及微观结构观察(Scanning electron microscope,SEM)等多种分析手段,研究其对面包面团生物化学特征和烘焙学特性的影响。结果表明:马克斯克鲁维酵母发酵麦麸中富含多种天然酶,主要包括纤维素酶、木聚糖酶和阿魏酸酯酶;水解酶在面包制作过程中持续作用,促进木聚糖溶解和酚类化合物释放,赋予面包较高的营养价值;与仅添加木聚糖酶的麦麸面包面团相比,马克斯克鲁维酵母发酵麦麸面包面团具有更好的持气性及连续的面筋网络结构,面包全质构特性和比容显著提升。研究结果显示,马克斯克鲁维酵母发酵麦麸可以作为一种天然面包功能配料。     

Effect of an enzyme preparation on wheat flour and dough color, mixing, and test baking

Bleaching flours with natural rather than chemical extracts is attractive because it reduces risks upon exposure and appeals to natural food consumers. This paper reports effects of a commercial proprietary blend of ‘natural’ bleaching enzymes on wheat flour and dough color, mixing behavior and test bake performance. Enzyme preparation did not improve whiteness (L*) and yellowness (b*) of flour system, but benzoyl peroxide sharply reduced b*. For whole wheat flour dough, L* increased for enzyme-treated dough after 2-h resting, ending higher than benzoyl peroxide and control dough. Yellowness increased in enzyme-treated dough. When enzyme application was during milling, resulting whole wheat flour dough had much higher L*. Mixograms of flours with increasing enzyme concentration showed severe dough weakness and rapid breakdown. Dialysis of the enzyme preparation in 3500 molecular weight cutoff (MWCO) tubes and freeze-drying prior to flour application recovered dough strength. l-cysteine in the enzyme mix was thought to adversely affect dough strength, and dialysis helped recover dough strength. However, pup loaf baking with dialyzed enzyme showed some loss of baking characteristics (loaf volume, loaf weight, and proof height) over the control. Although the natural enzyme extract addition enhanced whiteness for whole wheat dough, its effects on dough and baking properties were not favorable.     

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     

Microflora of the sour dough of wheat flour bread IX. Biochemical characteristics and baking performance of wheat doughs elaborated with mixtures of pure microorganisms

Summary Changes in mono- and disaccharides and acetic and lactic acid production of six different straight doughs elaborated with combinations of pure strains of yeastsSaccharomyces cerevisiae andCandida boidinii and lactic acid bacteriaLactobacillus plantarum andStreptococcus sp have been investigated, as well as the baking quality of the resulting breads. The type and proportion of the fermentative microorganisms were found to influence the biochemical activity of the doughs. The sugar levels after mixing reached different proportions, depending on the type of sugar and the type of microorganisms used. After proofing, the glucose and fructose content of the doughs decreased to 0.01%–0.02% db and maltose decreased to 0.45%–0.11 % db. Acetic and lactic acids underwent variable changes during fermentation, depending on the type of dough. Lactic acid showed higher levels than acetic acid. Bread made from these doughs had different sensory characteristics, texture, edibility and overall acceptance, as well as different lactic and acetic acid contents, depending on the mixture of microorganisms inoculated.

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Biochemische Merkmale und Leistungsfahigkeit der mit Mischungen reiner Mikroorganismen hergestellten Weizenbackteige

Zusammenfassung Die Forschungsaufgabe befaßte sich mit den Veranderungen der Mono- und Disaccharide, mit der Entstehung von Essig- und Milchsaure in sechs Teigen, die mit Kombinationen reiner HefekulturenSaccharomyces cerevisiae undCandida boidinii und MilchsäurebakterienLactobacillus plantarum undStreptococcus sp hergestellt waren und mit den sich daraus ergebenden Qualitätsmerkmalen der Brote. Die Art und Anteile der Mikroorganismen übten einen entscheidenden Einfluß auf die biochemische Aktivität der Teige aus. Nach dem Knetvorgang konnten unterschiedliche Gehalte gemäß der eingesetzten Saccharide und Mikroorganismen festgestellt werden. Der Glucose- und Fructoseanteil der fermentierten Teige verringerte sich auf 0,01–0,02% t. g., der Maltoseanteil auf 0,45-0,11% t.g. In den einzelnen Teigen veranderten sich wahrend der Garung die Essig-und Milchsauregehalte unterschiedlich. Bei der Milchsaure konnte eine grbBere Zunahme und somit höhere Endgehalte als bei der Essigsaure festgestellt werden. Die mit diesen Teigen hergestellten Brote erreichten verschiedene Textureigenschaften (Weichheit der Krume) und sensorische Merkmale, insbesondere Kaufahigkeit und Geschmack Bowie einen, entsprechend der Mikroorganismenmischung, höheren oder geringeren Milch- und Essigsäuregehalt.

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Presented at the 8th International Cereal and Bread Congress, Lausanne, Switzerland, June 1988.

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This paper is a part of a doctoral thesis     

Hearth bread baking quality of durum wheat varying in protein composition and physical dough properties

Thirty durum wheat genotypes from ten countries of origin were grown in field plots for two consecutive years. Three of the genotypes were γ‐gliadin 42 types and the remainder were γ‐gliadin 45 types. Among the γ‐gliadin 45 types, six high‐molecular‐weight glutenin subunit (HMW‐GS) patterns were identified: 6 + 8, 7 + 8, 7 + 16, 14 + 15, 20 and 2*, 20. All the γ‐gliadin 42 genotypes contained low amounts of unextractable polymeric protein (UPP) and exhibited low gluten index values and weak gluten properties. The γ‐gliadin 45 genotypes exhibited a wide range of UPP, gluten index and dough strength. HMW‐GS 20 genotypes were generally weak, whereas HMW‐GS 6 + 8 and 7 + 8 genotypes were generally strong. When baked by a lean formulation, long‐fermentation straight‐dough hearth bread process, the durum wheat genotypes exhibited a wide range of baking quality. Loaf volume and bread attributes were strongly correlated with UPP and gluten index. Some of the genotypes exhibited bread attributes and loaf volume equal or slightly superior to those of a high‐quality bread wheat flour. However, even the strongest durum wheat genotypes exhibited inferior fermentation tolerance to the bread wheat flour, as seen by a requirement for lower baking absorption during dough handling and more fragile dough properties when entering the oven. Among the HMW‐GS groups, HMW‐GS 7 + 8 and 6 + 8 exhibited the best and HMW‐GS 20 the poorest baking quality. Farinograph, alveograph and small‐scale extensigraph properties demonstrated that a combination of dough elasticity and extensibility was needed for superior durum wheat baking performance. Copyright © 2007 Society of Chemical Industry     

Binding and extractability of wheat flour lipid after dough formation

Observations that lipids normally extracted from flour with nonpolar solvents become bound upon dough or gluten formation have been confirmed. Lipids bound in this way can be extracted by solvents of high dielectric constant and by mixtures of some alcohols with solvents containing donor hydrogen atoms. Low molar volume of solvent, in general associated with high dielectric constant, also leads to good extraction of bound lipid. Ethanol/ether/water (2:2:1) was the most efficient of the solvents tried and appeared to give almost complete extraction of lipid from flour. The reported reduction of lipid bound in dough containing salt has been investigated further and it was found that lipid binding decreased with added salt up to about 4% of flour weight. Doughing and lipid-binding occur when flour is mixed with solvents of high dielectric constant as well as with water.     

藜麦粉对小麦面团、面包质构特性及品质的影响

研究藜麦粉对小麦面团及面包质构特性的影响,为开发藜麦焙烤食品提供理论依据。在对藜麦粉中蛋白组分含量系统研究的基础上,利用质构仪的TPA模式测定添加藜麦粉对小麦面团硬度、弹性和黏性的影响,藜麦粉对面包硬度和弹性的影响。结果表明,随着藜麦粉添加量的增加,面团的硬度呈先减小后增加的趋势,添加量为15%时硬度最小;弹性呈先增大后减小的趋势,在藜麦粉添加量15%时达到最大值,黏性呈逐渐增大的趋势。随着藜麦粉添加量的增加,面包的硬度逐渐增大,弹性逐渐减小,感官评分先增大后减小,在15%时达到最大值。因此,藜麦粉的添加改变了小麦面团和面包的质构特性,且面团的质构特性与面包质构特性、面包感官品质间具有一定相关性。     

Characterization of bread dough: Rheological properties and microstructure

The change in rheological and microstructural properties of wheat flour dough as a function of water and yeast content, and with addition of hydrocolloids is described. The rheological properties vary with the size of the bubbles and measurements were made on controlled shear/stress rheometer. Confocal laser scanning microscope (CLSM), accompanied with image analysis technique, was used to obtain microstructure of the dough. It was found that with an increase in water content the moduli values decreased and the mean bubble diameter increased. As concentration of yeast increased, the bubbles became smaller and the moduli values increased. Addition of hydrocolloids like sodium alginate and xanthan gum led to increased moduli values and generally caused the bubbles in the dough to shift towards narrower distributions. An inverse relation between bubble size and storage modulus is found.     

脱皮率对小麦粉、面团及馒头品质的影响

对小麦籽粒进行脱皮处理,研究脱皮率对小麦粉、面团及馒头品质的影响。结果表明:随脱皮率的增加,小麦粉的蛋白质和可溶性膳食纤维含量呈先上升后下降的趋势,在脱皮率为6%时达到最高值;面团的黏度崩解值下降,回生值和蒸煮稳定性升高,扫描电镜图显示面筋网络的排列更均匀致密;馒头的综合感官评分增加,硬度、胶着性和咀嚼度下降,内聚性和回复性上升。脱皮率为0%～6%时面团和馒头的品质明显改善,在6%～12%时其品质提升幅度减缓。6%脱皮率能有效保留小麦粉的营养物质,改善馒头的品质,是较理想的脱皮程度。     

Towards the development of peanut–wheat flour composite dough: Influence of reduced‐fat peanut flour on bread quality

The effect of partial substitution of wheat flour with reduced‐fat peanut flour at different levels (10, 20, 30, 40, and 50%) on physical parameters, proximate composition, sensory profile, and shelf stability of bread were investigated. Loaf volume, specific volume, and crumb density were significantly (p ≤ .05) reduced with increasing level of substitution with the peanut flour. Peanut flour had significant (p ≤ .05) improvement on the protein content and reduction in carbohydrate content of loaves. Consumers preferred the taste aroma and color of the peanut–wheat flour composite loaves at ≥20% peanut flour inclusion. Freshly baked composite peanut–wheat bread loaves with 10% level of peanut substitution had higher overall acceptability than 100% wheat flour formulation but less microbial stability during storage. Reduced fat‐peanut has potential application for improving the nutritional quality and shelf stability of wheat flour bread.

Practical applications

The demand for convenient alternative to conventional foods is on the increase with the dynamics of the world's social values, lifestyles, and demographic trends. Having peanut incorporated into dough (as one food system) will offer convenience to consumer and therefore add value to bread variety on market shelves. Assessing the influence of the peanut flour on bread quality provides first‐hand information that can facilitate optimization of the baking process toward commercial production of peanut–wheat flour bread.     

不同酵母在青麦馒头面团中的发酵特性及品质对比分析

以馒头专用粉及青麦粉制作青麦馒头,采用发酵仪和流变仪对不同酵母种类(彩虹牌即发干酵母,安琪高活性干酵母,梅山即发干酵母,新良即发高活性干酵母)、不同质量分数的青麦粉(0%、5%、10%、15%、20%)制成的馒头面团的发酵特性和流变特性进行研究,并对此面团制成的馒头的比容、感官品质和质构特性进行分析。结果表明:4种酵母中安琪牌酵母面团的发酵特性(产气量、持气率、面团开始漏气时间)最好,弹性模量与黏性模量较大;加入青麦粉后,安琪牌酵母制作的馒头比容较大,感官评分较高,硬度、咀嚼性较小,弹性较大;在青麦粉添加量为质量分数10%时,馒头比容和质构指标适中,感官评分与普通馒头相差不大,膳食纤维含量较高。因此,选择安琪即发高活性干酵母发酵、添加质量分数10%青麦粉制作成的馒头品质较好,营养丰富。     

Rheological,microstructural and sensorial properties of durum wheat bread as affected by dough water content

In this paper the influence of water content on the rheological, microstructural and sensorial properties of durum wheat bread was evaluated. In order to evaluate bread quality, oscillation measurements, stress relaxation test and creep–recovery measurements were performed on dough samples, whereas tomographic and sensorial analyses were performed on baked bread samples. Results of the rheological analysis highlighted that both the storage and loss moduli (G′, G″) showed a descending trend with the increase of the water content. This is also confirmed by stress relaxation tests. Creep–recovery tests for strong doughs (with low water content), recorded greater resistance to deformation, therefore a smaller creep strain than the softer doughs. These results were reflected in the microstructural properties of the bread; an increase in water content caused an increase in the percentage volume of pores. Regarding the sensorial properties, the overall acceptability of the investigated bread samples was low for both the lowest and the highest water contents, and this was due primarily to the compact crumb with small bubbles and high crust firmness for the former and to the loaf volume collapsed with irregular distribution of very large bubbles for the latter. Therefore, the bread samples with intermediate water content were preferred by the panelists.