Effect of barley flour addition on the physico-chemical properties of dough and structure of bread

The effects of different percentages of barley flour (i.e. 0–25%) in wheat flours on the physico-chemical properties and structure of dough and bread were investigated. As the percentage of barley flour in mixed flour was increased, its protein and gluten contents decreased whereas the ash content and enzyme activity increased. The rheological characteristics of the four dough mixes were studied using Farinograph, Extensograph and Alveograph. The water absorption (p < 0.01) and stability (p < 0.05) decreased significantly as the percentage of barley flour increased, while no changes were observed in the extensibility and maximum heights. Significant differences were observed in the structural and physical properties as well as in the image analysis of breads. With the increase in the percentage of barley flour, the crumb apparent density decreased (p < 0.1) whereas the porosity (i.e., fraction to total volume) increased (p < 0.1). Overall, the shape and pore structure at 10% barley flour (W90B10) were similar to the pure wheat flour bread, while addition at 15 and 25% of barley flour (W85B15 and W75B25) showed more non-uniform and larger pores.     

Effect of wheat germ flour addition on wheat flour,dough and Chinese steamed bread properties

Wheat germ flour (WGF) has been developed as a functional food ingredient with high nutritional value. In this study, WGF was applied in steamed bread-making in order to improve the quality of Chinese steamed bread (CSB). Partial substitution of wheat flour with WGF at levels of 3%, 6%, 9% and 12% (w/w) was carried out to investigate physicochemical properties of blends and their steaming performance. Falling number (FN) values of composite flours ranged from 199 to 223 s. Viscosity analysis results showed that wheat flour mixed with WGF had higher pasting temperature and lower viscosities. Dough rheological properties were also investigated using farinograph and extensograph. The addition of WGF diluted the gluten protein in dough and formed weak and inextensible dough, which can be studied by scanning electron microscope (SEM) analysis. CSB made with WGF had significantly lower volume, specific volume and higher spread ratio. The sensory acceptability and physicochemical quality of CSB were improved with the application of a low level of WGF (3% and 6%). However, results showed that a high level of WGF over 9% is not recommended because of unsatisfactory taste. As a whole, addition of appropriate level of WGF in wheat flour could improve the quality of CSB.     

Prediction of selected rheological characteristics of wheat based on Glutopeak test parameters

The GlutoPeak®-Test, a new rapid small-scale technique, was proposed as an alternative method for evaluation of wheat grain and tool for predicting the wheat flour quality. Samples obtained from an industrial mill were analyzed by a GlutoPeak test (whole grain flours) as well as by farinograph and extensograph tests (refined flours). Firstly, linear correlation coefficients between water absorption, dough stability, dough energy and defined parameters of GlutoPeak were calculated. Next, a sequential multiple quadratic regression analysis (backward, forward and stepwise), a logistic regression analysis and a PLSR analysis were applied. The correlation between the flour water absorption and most of the parameters obtained from the GlutoPeak test were strong (r ≥ 0.74, p < 0.001). For stability, the r value was 0.40, while for energy it was 0.44. Based on the obtained results it could be state that in the case of water absorption, the best fit was the sequential regression model, for dough stability sequential regression model and the PLSR model had the best fit, whereas logistic regression model was the best fitted to the energy. Unfortunately, after cross validation it was found that the last model is not good enough for energy prediction.     

燕麦粉对强筋面粉品质特性及其面包品质的影响

面包逐渐成为中国人营养早餐的选择,但面包中膳食纤维含量较低。燕麦是一种食疗兼备的特色杂粮作物,富含膳食纤维。为拓宽燕麦的应用范围、提高面包的营养价值,以优质强筋小麦品种藁优2018和燕麦粉为材料,研究了燕麦粉对小麦面粉面团流变学特性及淀粉糊化特性的影响,并进行了燕麦面包实验室制作和质构分析。结果表明,随着燕麦粉添加比例的增加,面团吸水率逐渐增加,面团稳定时间和粉质质量指数先减小后增加;面团拉伸能量、拉伸长度、拉伸阻力、最大拉伸阻力均逐渐减小。说明燕麦粉对面团拉伸特性各参数均有弱化作用。在藁优2018小麦面粉中添加10%的燕麦粉,既能保证面包的感官品质,又能满足面包营养最大化。     

新疆冬小麦品种品质性状与面包、馒头、面条加工品质的关系

为了给优质面包、馒头、面条专用品种选育提供品质辅助选择指标,以30份新疆冬小麦品种(包括自育品种和引进品种)为材料,分析了新疆冬小麦品种品质性状与面包、馒头、面条加工品质的关系.回归分析结果表明,小麦籽粒性状、面粉品质、面团特性、淀粉糊化特性以及面粉色泽对新疆冬小麦品种面包、馒头和面条加工品质均有显著影响;面粉灰分、湿面筋、稀懈值、亮度和红度是影响面包、馒头和面条加工品质的共同品质性状;形成时间、稳定时间、延展度是影响面包和面条加工品质的共同品质性状;而籽粒性状仅对新疆冬小麦品种馒头加工品质有显著影响.相关分析结果表明,千粒重、形成时间、稳定时间、拉伸面积、最大拉伸阻力、红度和黄度与面包总分呈显著相关关系,相关系数分别为0.460、0.516、0.537、0.719、0.707、0.534和-0.403;籽粒蛋白质含量、面粉蛋白含量和湿面筋含量与馒头总分呈显著相关关系,相关系数分别为-0.397、-0.458和-0.552,面团延展度、稀懈值与面条总分呈显著相关关系,相关系数分别为0.438和0.432.从以上结果可以看出,面包与面团流变学特性,馒头与蛋白质和面筋数量,面条与面团流变学特性及淀粉糊化特性的关系更为密切,这些品质性状可以作为新疆冬小麦品种面包、馒头、面条加工品质改良时的辅助选择指标.     

Dough and bread made from high- and low-protein flours by vacuum mixing: Part 2. Yeast activity,dough proofing and bread quality

The combined effects of reduced mixer headspace pressure and mixing duration on the yeast activity, proofing and quality of dough and bread made from both high-protein flour (HPF) and low-protein flour (LPF) were addressed in this study. Rheofermentometer analysis showed that a reduction in mixer headspace pressure up to 0.08 MPa did not affect the overall gassing power of yeast in either of the two dough matrices. An increase in mixing duration sped up the mass transfer rate of CO₂ at the initial stage of fermentation, leading to a faster expansion of dough volume at the beginning. Moreover, an increase in mixing time promoted dough development and gas inclusion, which resulted in a increased volume of dough and bread, as well as a softer texture of both baked bread and steamed bread. In general, reduced headspace pressure produced baked bread of smaller volume, denser structure and harder texture. On the other hand, vacuum mixing produced steamed bread with softer texture without significantly changing the bread’s volume and porosity.     

The relationship between rheological characteristics of gluten-free dough and the quality of biologically leavened bread

The rheological characteristics of gluten-free doughs and their effect on the quality of biologically leavened bread were studied in amaranth, chickpea, corn, millet, quinoa and rice flour. The rheological characteristics (resistance to extension R, extensibility E, R/E modulus, extension area, stress at the moment of dough rupture) were obtained by uniaxial dough deformation. Specific loaf volume of laboratory prepared gluten-free breads was in significant positive correlation with dough resistance (r = 0.86), dough extensibility (r = 0.98) and peak stress at the moment of dough rupture (r = 0.96). Even if the correlation between R/E modulus and the characteristics of loaf quality were not significant, the breads with the highest specific loaf volume were prepared from flours with R/E closer to the wheat check sample (18 N?mm-1). The results showed, in general, good baking flours exhibited stronger resistance to extension and greater extensibility, but differences found were not directly related to the results of baking tests.     

中麦175馒头和面条品质稳定性分析

为给优质小麦育种和生产提供参考依据,以优质小麦新品种中麦175于2010-2011年度在河北和北京14个地点的样品为材料,分析了磨粉品质、面粉和面片颜色、面团流变学和淀粉糊化特性、馒头和面条加工品质。结果表明,中麦175为馒头和面条兼用型优质品种,特点是软质、中偏弱的面筋强度、面粉颜色白,多数品质性状较稳定,籽粒硬度、PPO活性、面片a*值、稳定时间、拉伸面积、延展性和最大抗延阻力的变异系数较大,馒头加工品质地点间变异大于面条。磨粉品质和面团流变学参数对馒头加工品质有显著影响,籽粒硬度和出粉率对馒头表面颜色有显著负向影响,相关系数分别为-0.82(P<0.01)和-0.58(P<0.05);面粉L*值高,馒头加工品质好,二者相关系数为0.72(P<0.01);吸水率与馒头总分呈显著负相关(r=-0.84,P<0.01),稳定时间、拉伸面积、延展性和最大抗延阻力与馒头总分呈显著正相关,相关系数分别为0.85(P<0.01)、0.77(P<0.01)、0.62(P<0.05)和0.70(P<0.01)。降低PPO活性和吸水率,提高蛋白质含量、出粉率和黄色素含量可以改善面粉和面片颜色的亮白度,增加部分黄度,形成消费者可接受的奶白色。淀粉糊化特性对馒头和面条加工品质无显著影响。上述信息对改良小麦品质的稳定性有重要意义。     

小偃22小麦粉馒头加工技术研究

为了提高馒头的加工品质,满足中国馒头加工业的迫切要求,以小偃22小麦粉为材料,研究其馒头加工的加水量、和面时间以及大豆蛋白、小麦胚芽、卵磷脂对馒头品质的影响。结果表明,加水量、和面时间以及大豆蛋白、小麦胚芽、卵磷脂的添加量对馒头回复性、内聚性和咀嚼性影响显著或极显著。随加水量增加,馒头的内聚性和回复性先增后减,咀嚼性呈减小趋势;随和面时间与大豆蛋白添加量的增加,馒头内聚性和回复性均减小,咀嚼性均先减后增;随小麦胚芽添加量的增加,馒头的内聚性与回复性先减后增,咀嚼性先减后增;随卵磷脂添加量的增加,内聚性先增后减,咀嚼性先减后增,回复性减小。优质馒头制作的适宜加水量、和面时间以及大豆蛋白、卵磷脂和小麦胚芽添加量分别为粉质吸水率的80％、4min、2%、0．4％、8％。     

Predicting hot-press wheat tortilla quality using flour,dough and gluten properties

A cost-effective, faster and efficient way of screening wheat samples suitable for tortilla production is needed. This research aimed to develop prediction models for tortilla quality (diameter, specific volume, color and texture parameters) using grain, flour and dough properties of 16 wheat flours. Another set of 18 samples was used to validate the models. The prediction models were developed using stepwise multiple regression. Dough rheological tests had higher correlations with tortilla quality than grain and flour chemical tests. Mixograph mixing time and dough resistance to extension (from extensibility test using a texture analyzer) were correlated best with tortilla quality, particularly tortilla diameter (r = −0.87 and −0.86 respectively, P < 0.01). Insoluble polymeric proteins (IPP) and gluten index were significantly correlated with tortilla diameter (r = −0.70 and −0.67 respectively, P < 0.01) and specific volume (r = −0.73, P < 0.01). Tortilla diameter was the quality parameter best explained (R² = 0.86) by the prediction models using mixing time and dough resistance to extension. Rheological parameters such as rupture distance and maximum force were also successfully predicted. These prediction models, developed from linear equations, will be an easy and fast tool for breeders to advance or eliminate wheat lines specifically bred for tortilla production.     

Relationship of Protein Quantity,Quality and Dough Properties with Chinese Steamed Bread Quality

Using selected Chinese and Australian wheats, flour protein content and composition of high-molecular-weight (HMW) glutenin subunits were studied in relation to northern style Chinese steamed bread quality. Flour protein content had a significant impact on Chinese steamed bread quality. The Chinese wheats were characterised by shorter Farinograph dough development time and stability in comparison with the Australian wheats. Dough stickiness in the Chinese wheat cultivars was a significant factor deteriorating Chinese steamed bread quality. A significant negative correlation was found between Farinograph stability time and steamed bread quality in Australian wheats while a significant and positive correlation existed in Chinese wheats. It would be necessary to increase the dough strength of Chinese wheat cultivars in order to improve their steamed bread making quality.     

Effects of glycerol on water properties and steaming performance of prefermented frozen dough

The amount of ice in both unfrozen steamed bread dough (UFD) and prefermented frozen steamed bread dough (PFD) with and without glycerol was investigated by differential scanning calorimetry (DSC). The quality of unfrozen steamed bread (UFB)/prefermented frozen dough steamed bread (PFB) was also evaluated. Frozen stability and steaming performance of prefermented frozen dough were negatively correlated with ice crystal growth. Glycerol effectively prevented the formation of ice crystals during freezing and frozen storage, maintaining the quality of steamed bread from prefermented frozen dough even over a period of 30 days. The best steamed bread performance was observed with the dough containing 2% of glycerol (flour weight basis) addition. Prefermenting conditions significantly affected the quality of UFB/PFB. The highest quality scores of steamed bread from prefermented frozen dough were obtained from 32 °C and 85% rh for 40 min.     

Properties of whole grain wheat flour and performance in bakery products as a function of particle size

The aim of this study was to evaluate the effect of particle size distribution on composition, properties rheological, pasting, microstructural and baking properties of whole grain wheat flour (WGWF) of three different particles sizes (194.9 μm, 609.4 μm and 830.0 μm). The quantification of free sulfhydryl groups (-SH) of WGWF samples, together with the effects observed in the behavior of the dough and bread showed that particle size influences the functionality of the gluten network in a differentiated way. Firmer and lower breads volume compared to refined wheat flour (RF) were correlated with the quality of the gluten network. In the sample of finer particles, more pronounced adverse effects in quality (dough rheology, bread volume and texture) compared to the medium and coarse particle size sample suggests that the larger contact surface and the increased release of reactive compounds due to cell rupture interact with the gluten-forming proteins changing their functionality.     

Grain of high digestible,high lysine (HDHL) sorghum contains kafirins which enhance the protein network of composite dough and bread

The aim of this study was to determine whether protein body-free kafirins in high digestibility, high-lysine (HDHL) sorghum flour can participate as viscoelastic proteins in sorghum-wheat composite dough and bread. Dough extensibility tests revealed that maximum resistance to extension (g) and time to dough breakage (sec) at 35 °C for HDHL sorghum-wheat composite doughs were substantially greater (p < 0.01) than for normal sorghum-wheat composite doughs at 30 and 60% substitution levels. Functional changes in HDHL kafirin occurred upon exceeding its T_g. Normal sorghum showed a clear decrease in strain hardening at 60% substitution, whereas HDHL sorghum maintained a level similar to wheat dough. Significantly higher loaf volumes resulted for HDHL sorghum-wheat composites compared to normal sorghum-wheat composites at substitution levels above 30% and up to 56%, with the largest difference at 42%. HDHL sorghum-wheat composite bread exhibited lower hardness values, lower compressibility and higher springiness than normal sorghum-wheat composite bread. Finally, HDHL sorghum flour mixed with 18% vital wheat gluten produced viscoelastic dough while normal sorghum did not. These results clearly show that kafirin in HDHL sorghum flour contributes to the formation of an improved protein network with viscoelastic properties that leads to better quality composite doughs and breads.     

The final established physicochemical properties of steamed bread made from frozen dough: Study of the combined effects of gluten polymerization,water content and starch crystallinity on bread firmness

The gluten polymerization behavior, water content, starch crystallinity and firmness of Chinese steamed bread made from frozen dough were investigated and their correlations were also established in this study. The decreased degree of gluten polymerization in steamed bread was observed by the enhanced SDS-extractable proteins (SDSEPs) upon frozen storage. Less incorporation of glutenin in the glutenin–gliadin crosslinking of steamed bread mainly contributed to the decreased degree of gluten polymerization. The decreased moisture of steamed bread had a significant negative correlation with the sublimated water in frozen dough (r = −0.8850, P < 0.01). Frozen storage also induced an increase in starch crystallinity and bread firmness. A multiple linear regression model with SDS-extractable proteins, water content and melting enthalpy of starch crystals of steamed bread accounted for 86% of the variance in the natural logarithm of firmness and further revealed that starch crystallinity mainly contributed to bread firmness.     

Dough rheology and bread quality of wheat-chickpea flour blends

In this study, partial substitution of wheat flour with chickpea flour at the levels of 10, 20 and 30% was carried out to study their rheological and baking performance. Chickpea flour addition increased the water absorption and dough development time (p < 0.05), while, the extensibility of dough and the resistance to deformation were reduced. Regarding dough stability, it appears that 10% chickpea exhibited higher stability and resistance to mechanical mixing values than the control, while it decreased as the substitute level increases from 20% to 30%. The dough surface of the wheat dough and the blend with 10% was classified as “normal”, however the blend with 20% and 30% produced “sticky” dough surface. The presence of chickpea flour in dough affected bread quality in terms of volume, internal structure and texture. The color of crust and crumb got progressively darker as the level of chickpea flour substitution increased. While the substitution of wheat flour with 10% chickpea flour gave loaves as similar as control.     

Soy ingredients stabilize bread dough during frozen storage

Bread with 48.5% soy ingredients was assessed for quality during frozen storage of the dough. Soy protein was hypothesized to prevent water migration during frozen storage, thereby producing dough that would exhibit fewer structural changes than traditional wheat bread. Wheat and soy bread were baked from dough that was fresh or frozen (−20 °C, 2 or 4 wks). Dough and bread were assessed for physical properties including moisture content, percent “freezable” and “unfreezable” water, dough extensibility, and bread texture. The bread was subjected to an untrained sensory panel. The soy bread was denser, chewier, and had a higher moisture content than wheat bread. When baked from fresh or frozen dough, soy bread was rated “moderately acceptable” or higher by 70% of panelists. Soy minimized changes in dough extensibility and resistive force to extension, leading to minimal changes in bread hardness. Although consumers could distinguish between bread baked from soy dough that was fresh or frozen for 4 wks, sensorial and textural data suggested that the rate at which the quality of the soy dough deteriorated was slower than that of wheat dough. In conclusion, the dough of consumer-acceptable soy bread retained quality characteristics during frozen storage slightly better than wheat dough.     

影响馒头品质的相关指标分析

为给优质馒头专用小麦的培育和馒头品质改良提供参考依据,以来源于北方冬麦区、黄淮冬麦区、西南冬麦区和长江中下游冬麦区的128个小麦品种(系)为材料,利用感官评价与质构仪测试相结合的方法,分析影响馒头品质的相关指标。结果表明,馒头感官品质中,除馒头的比容与色泽、结构、弹韧性、黏牙性和气味的相关性不显著外,其他指标间均为极显著正相关;馒头质构指标中,馒头的硬度与内聚性和咀嚼性分别呈极显著负相关和正相关;馒头质构指标中的黏附性、弹性、硬度和咀嚼性与馒头感官品质的相关指标显著相关,可以在一定程度上补充或矫正相关的感官评价分析。同时,筛选出感官品质较好的材料有中优9507、CMT-3T88和陕182等,质构指标较好的材料有扬00-126、新麦19和新春9号等,这些材料适合制作优质手工馒头;尤其是筛选出的感官品质和质构指标均较好的材料Kn3106、川麦107、新春9号和新麦19,可作为小麦优质资源加以利用。参试材料的面粉白度较低(平均值为73.83)且高白度材料较少;面粉白度高于80的小麦品种(系)仅有T21-6和武汉麦,这些材料可作为高白度小麦优质资源加以利用,有助于改良馒头的色泽品质。     

Improving the quality of nutrient-rich Teff (Eragrostis tef) breads by combination of enzymes in straight dough and sourdough breadmaking

The growing interest in the benefits of wholegrain products has resulted in the development of baked products incorporating less utilised and ancient grains such as, millet, quinoa, sorghum and teff. However, addition of wholegrains can have detrimental effects on textural and sensory bread product qualities.Enzymes can be utilised to improve breadmaking performance of wholegrain flours, which do not possess the same visco-elastic properties as refined wheat flour, in order to produce a healthy and consumer acceptable cereal product.The effects of Teff grain on dough and bread quality, selected nutritional properties and the impact of enzymes on physical, textural and sensory properties of straight dough and sourdough Teff breads were investigated.Teff breads were prepared with the replacement of white wheat flour with Teff flour at various levels (0%, 10%, 20%, and 30%) using straight dough and sourdough breadmaking. Different combinations of enzymes, including xylanase and amylase (X + A), amylase and glucose oxidase (A + GO), glucose oxidase and xylanase (GO + X), lipase and amylase (L + A) were used to improve the quality of the highest level Teff breads. A number of physical, textural and sensory properties of the finished products were studied. The nutritional value of breads was determined by measuring chemical composition for iron, total antioxidant capacity, protein, fibre and fat. The obtained results were used to estimates intakes of nutrients and to compare them with DRIs.The incorporation of Teff significantly (P < 0.05) improved dietary iron levels as 30% Teff breads contained more than double the amount of iron when compared to corresponding wheat bread (6 mg/100 g v 2 mg/100 g). Addition of Teff also significantly (P < 0.05) improved total antioxidant capacity from 1.4 mM TEAC/100 g to 2.4 mM TEAC/100 g. It was estimated that an average daily allowance of 200 g of Teff enriched bread would contribute to DRIs in the range of 42-81% for iron in females, 72-138% for iron in males; 38-39% for protein in males, 46-48% for protein in females; and 47-50% of fibre in adults.The major challenge was encountered in producing the highest level of Teff bread with good textural and sensory attributes. Increasing the level of Teff significantly (P < 0.05) increased dough development time, degree of softening, crumb firmness and bitter flavour whilst decreasing the dough stability, specific loaf volume and overall acceptability of the bread. Teff breads produced with the addition of enzyme combinations showed significant improvements (P < 0.05) in terms of loaf volume, crumb firmness, crumb structure, flavour and overall acceptability in both straight dough and sourdough breadmaking.     

Effects of different milling methods on flour quality and performance in steamed breadmaking

Three types of wheat: 8901 (hard wheat), Nanyang white wheat, NYWW (medium wheat), and Australian white wheat, AWW (soft wheat) were milled after debranning by abrasion and friction, and by conventional milling. The quality of flours produced by the two procedures and their performance in steamed breadmaking were evaluated. The results showed that debranning affected both the quality of flour and the steamed bread, especially for 8901 and NYWW. Debranning lowered the gluten index, maximum resistance and starch damage; whereas, it increased pericarp content, ash content, L* value, falling number and particle size distribution. The pasting properties such as peak viscosity and final viscosity of NYWWDII and 8901DII were higher than those of NYWWCII and 8901CII. Debranning had positive effects on the quality scores, volume, volume/weight, height and structure of steamed bread from second flour, except for those from soft wheat. For the two other samples, the quality scores for steamed bread were lower than that for the conventional flour. The shape and structure of steamed bread from the top flours of AWWCII and 8901CII were better than from debranned flour. The milling methods did not affect the texture of steamed bread, except in the case of second flour of NYWW.