The rapid non-enzymic determination of damaged starch in flour

A rapid non-enzymic method for the measurement of damaged starch in wheat flour is described. The method is based on the iodometric determination of extractable amylose. A comparison with damaged starch values obtained using an enzymic method showed that the correlation between the non-enzymic and enzymic methods was better for flours milled from soft wheats than for flours milled from hard wheats. The relationship between starch damage values obtained by the two methods and flour particle size is examined, the results suggesting that the two methods differ in their sensitivity to the type of damage suffered by hard wheats during milling.     

Suitability of various australian wheats for chinese-style steamed bread

Three methods of preparation of steamed bread on a laboratory scale were evaluated to determine the one most suitable for discriminating between flour samples. The preferred method was then applied to a number of wheat varieties at different protein levels to select the most suitable ones for this product, and to determine the key analytical parameters of the most suitable flour. Flour colour and protein content appeared to be more important than other physical and chemical properties. Flour samples with high protein content (greater than 12%) and strong doughs gave bread with a wrinkled surface and dark colour, whereas low protein (less than 10%) soft wheat flours gave poor texture and eating quality, although the surface was smooth. It is suggested that flours of medium protein content (10–12%) and medium dough strength are the most suitable for steamed bread. Processing conditions affected steamed bread quality. Blending of high protein hard strong wheats with soft weak wheat could be practical for preparing flour for steamed bread.     

脱皮对不同筋力小麦粉及其馒头品质的影响

对小麦进行适度脱皮,既能去除粗纤维和表面污染物,还能较好的保留微量营养素.以高筋、中筋和低筋小麦为原料,研究4％脱皮率对不同筋力小麦粉及其馒头品质的影响.结果表明,高筋和低筋小麦脱皮后糊化参数均有所提高,而中筋小麦有所下降;脱皮后,高筋、中筋和低筋小麦粉破损淀粉质量分数分别增加了6.0％、2.6％和4.2％;高筋和低筋...     

不同粒径小米粉对面团流变特性及馒头质构特性的影响

为研究小米粉添加对面团流变特性和馒头制品质构特性的影响,分别选取不同粒径的粳性和糯性小米粉,利用损伤淀粉测定仪、快速黏度分析仪等对不同小米粉的损伤淀粉含量和糊化特性进行分析,通过流变仪测定小米面团的流变学特性,结合扫描电镜观察小米面团微观结构变化,并利用质构仪测定小米馒头的质构特性。结果表明：随着小米粉粒径的减小,多数品种小米粉（除冀谷39和汇华金米）损伤淀粉的碘吸收率增加;受直支比的影响,相同目数下,粳性小米粉的峰值黏度、谷值黏度、最终黏度和回生值较糯性小米粉大。流变学研究表明,除汇华金米和冀谷39,储能模量与损耗模量随角频率增加总体上升。扫描电镜观察发现小米粉的添加使面团结构更加松散。小米粉的添加会对馒头质构性质中硬度、咀嚼性和弹性等有一定程度的负面影响。主成分分析表明馒头咀嚼性、损伤淀粉、峰值黏度、谷值黏度、最终黏度、崩解值和回生值可作为区分粳糯品种和馒头品质特征的指标。     

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.     

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

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

Nutritional and functional performance of high β-glucan barley flours in breadmaking: mixed breads versus wheat breads

The ability of high β-glucan barley (HBGB) flour versus regular commercial barley (CB) to make highly nutritious wheat (WT) blended breads meeting functional and sensory standards has been investigated. Mixed breads obtained by 40 % replacement of WT flour by HBGB flours are more nutritious than those replaced by CB flours and much more than regular WT flour breads in terms of elevated levels of dietary fibre fractions (soluble, insoluble, resistant starch and β-glucans), slowly digestible starch subfraction and bioaccessible polyphenols providing higher antiradical activity. WT/CB and WT/HBGB breads can be, respectively, labelled as source of fibre (3 g DF/100 g food) and high-fibre breads (6 g DF/100 g food), according to Nutritional Claims for dietary fibre foods. The consumption of 100 g of WT/HBGB can meet up to almost 50 % the required dietary fibre, providing a β-glucan intake high enough to meet the requirements of the EFSA health claim (3 g/day), contributing a reduced blood cholesterol level. The techno-functional performance of fresh blended breads and the sensory appreciation were in general preserved or even improved.     

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 fiber addition on antioxidant capacity and nutritional quality of wheat bread

Wholegrain and high fiber foods are recognized as nutritious and healthful products due to their content of dietary fiber, antioxidants and bioactive compounds. In this study, wheat, rye, barley, oat wholegrain flours and two fibers namely cellulose (insoluble fiber) and xanthan gum (soluble fiber) were used to replace a portion of wheat flour in pan bread to study effects of fibers on phenolic compounds, antioxidant capacity, dietary fiber fractions, and starch digestibility in vitro. Incorporation of wholegrain flours increased free and bound phenolics and antioxidant capacity of all the breads examined to various extent depending on the source of fiber. Additionally, soluble, insoluble and total dietary fiber fractions and total minerals increased with the addition of wholegrain flours or fibers. Rapidly and slowly digestible and resistant starches were not significantly influenced by adding wholegrain flours or fibers to breads. The study demonstrates the importance of enriching wheat bread with wholegrain flours to boost antioxidants and dietary fibers. On the other hand, more research is required to better understand impact of wholegrain flours or fiber on starch digestibility in vitro and glycemic response.     

小麦入磨水分和硬度对研磨特性的影响

在间歇式实验制粉系统上研究了硬度和水分调节对小麦研磨特性的影响。皮磨系统对入磨水分的变化敏感，随着水分的增加，小粒度麦渣心的提取率基本保持不变，而大粒度麦渣心的提取率显著降低；皮磨系统面粉出率增加，面粉灰分也降低；细麸皮的出率基本保持不变，而粗麸皮的出率显著增加。用硬麦获得的麦渣、麦心的数量显著高于软麦的，特别是大粒度麦渣心的数量，小粒度麦渣心的数量基本一样；硬麦在皮磨系统面粉的出率低于软麦，而总出粉率高于软麦；硬麦的细麸皮和次粉的出率和软麦基本一致，而粗麸皮的出率显著低干软麦。水分调节和硬度对小麦研磨特性的影响相似。     

The Effect of Pin and Attrition Milling on Starch Damage in Hard Wheat Flours

Starch damage of 10.9 and 15.7%, respectively, in break and reduction flours of commercial hard wheats was increased to 16.0 and 28.6%, respectively, by pin milling. Attrition milling and cryofreezing prior to pin milling resulted in less pronounced starch damage, apparently due to reduced heat evolution and mechanical stresses as evidenced by the intensities of the X-ray diffraction patterns. Pin-milled flours exhibited chipping and splitting of starch granules as compared to surface abrasions and deep pitting on the granules from attrition-milled flours. It appeared that the latter flours would be more suitable for air classification of hard wheat flours into protein concentrates and starch fractions.     

A comparison of equilibrated lipid water systems and the effect of added lecithin on dough rheology of flour milling-streams

The lipid part of four wheat flour milling streams was extracted by ethanol. The flours were two spring wheats and two winter wheats, where one of each spring and winter wheats were obtained from the reduction-roll system and the other one from the break-roll system. Equilibrated lipid water mixtures were prepared and centrifuged to distinguish between non-polar and polar lipids. The lipids interacting with water were investigated in the microscope under polarised light to establish the presence of the lamellar liquid-crystalline phase. The stress relaxation behaviour of flour water doughs and doughs made with lamellar lecithin added were also studied. The largest amount of lipids able to form the lamellar liquid-crystalline phase was recovered for the winter wheat from the reduction milling-stream. The corresponding spring wheat also formed the lamellar phase, while the break flours did not. A large amount of oil phase was obtained from the two break flours. The rheological parameters increased to the same value for the two break flours and the two reduction flours when lecithin was added. This suggests that a flour containing protein and lipids of approximately the same quality will be improved to the same extent when lamellar lecithin is added. © SCI 1998.     

Organoleptic and nutritional evaluation of wheat breads supplemented with soybean and barley flour

Supplementations of soy (full fat and defatted) and barley flours to wheat flours at 5, 10, 15 and 20% levels were carried out to test the effects on organoleptic and nutritional evaluation of the supplemented bread. Additions of 15% barley flour, 10% soy flour (full fat and defatted), 15% barley plus full fat soy flour and 15% barley plus defatted soy flour to wheat flour produced acceptable breads. However, substitution of soy (full fat and defatted) and barley flours to wheat flour separately and in combinations at 20% levels did not produce organoleptically acceptable bread. Various nutritional parameters, such as protein, fat, total lysine, protein digestibility (in vitro), sugars, starch digestibility (in vitro), total and available minerals, antinutrients, dietary fibre and β-glucan were determined in supplemented and control bread. Increasing the level of substitution from 5 to 10% of full fat and defatted soy flour to wheat flour significantly (P<0.05) increased protein (from 12.1 to 13.7 and 12.4 to 13.8%), lysine (from 2.74 to 3.02 and 2.76–3.05 mg/100 g protein) and total calcium (from 70.2 to 81.4 and 71.9–81.8 mg/100 g) contents. However, there was also an increase in phytic acid (238–260 and 233–253 mg/100 g), polyphenol (324–331 and 321–329 mg/100 g) and trypsin inhibitor activity (193–204 and 193–198 TIU/g). When barley flour was substituted separately, and in combinations, with full fat and defatted soy flour up to 15%, this significantly increased the contents of protein, total lysine, dietary fibre and β-glucan. It may be concluded that breads supplemented with barley and defatted soy flour, up to a 15% level, are organoleptically and nutritionally acceptable.     

Hard Winter Wheat and Flour Properties in Relation to Breadmaking Quality of Straight-dough Bread： Flour Particle Size and Bread Crumb Grain

Samples of 12 hard winter wheats and their flours that produced breads varying in crumb grain scores were studied for 38 quality parameters including： wheat physical and chemical characteristics; flour ash and protein contents, starch damage, swelling power, pasting characteristics, and flour particle size distribution; dough properties determined by a mixograph; and breadmaking properties for pup loaves （100g flour）. Only two parameters, the protein content of wheat and the granulation of flour, showed significant correlations with bread crumb grain scores. Protein content of wheat ranging 12.9%- 14.5% determined by an NIR method showed a weak inverse relationship （r =-0.61, p〈0.05） with bread crumb grain score. Flour particle size distribution measured by both Alpine Air Jet Sieve and NIR methods revealed that the weight wt % of particles less than 38 μ m in size and representing 9.6% - 19.3 % of the flour weights was correlated positively （r =0.78, p 〈 0.01） with crumb grain score, whereas wt % of flour particles larger than 125μm had an inverse relationship （r =-0.60, p〈0.05） with crumb grain score.     

Incorporation of pulse flours of different particle size in relation to pita bread quality

BACKGROUND: To increase pulse consumption, pita bread was fortified with pulse flours milled from green lentils, navy beans and pinto beans, which were ground to produce fine and coarse flours. Pita breads were prepared using composite flours containing pulse flours (25, 50, 75%) and wheat flour or 100% pulse flours and adjusting the amount of water required for mixing based on farinograph water absorption. Pita bread quality was evaluated according to diameter, pocket height, specific loaf volume, texture and crust colour. RESULTS: Blends made from pulse flours with coarse particle size showed higher rates of water absorption. All composite flours and 100% pulse flours produced pitas with pockets, confirming their suitability for this product. Crust colour of pitas was affected less by navy bean flour than by lentil flour. Pita breads made with pinto bean flour were superior in texture. Overall, navy and pinto bean flours appeared more suitable for pita bread. Flours with coarse particle sizes produced pitas with better colour and texture. Sensory parameters of pitas containing 25% coarse pinto or navy bean flour were as good as or better than those from the wheat control. CONCLUSION: Acceptable pita breads can be made using pulse flours, although the substitution level is limited to 25%. Copyright © 2012 Society of Chemical Industry     

不同品种马铃薯对马铃薯-小麦复合馒头品质特性的影响

本文以22个品种的新鲜马铃薯为原料制备马铃薯全粉,并对马铃薯全粉的基本成分进行了分析和比较;然后以22个不同品种的马铃薯全粉为原料制作马铃薯-小麦复合馒头(马铃薯全粉:小麦粉=3:7),并对其比体积、高径比、气孔结构和质构特性进行了分析和比较。结果表明,不同品种马铃薯-小麦复合馒头的比体积、高径比、气孔特性和质构特性存在显著差异性(p0.05)。高径比和比体积均较高的品种是紫花白、夏波蒂、陇薯6号、陇薯7号、中薯2号;气孔密度和气孔表面积分率都较高的品种是一点红、青薯9号、大西洋;硬度和咀嚼性都较好的品种是一点红、费乌瑞它、青薯6号、青薯9号、大西洋。综合考虑馒头的感官和物理特性,一点红、青薯9号和大西洋3个品种比较适合替代小麦粉,制得体积较为理想、硬度较低、气孔结构较好的馒头。     

苦荞馒头抗氧化品质、体外消化特性及感官评价的研究

研究比较不同梯度苦荞粉添加量(4%、8%和12%)的苦荞馒头和小麦馒头之间功能品质、体外消化特性以及感官评价的差异,确定苦荞适宜的添加比例。结果表明：苦荞馒头的黄酮、多酚、抗性淀粉含量和抗氧化能力均显著高于小麦馒头,苦荞馒头的血糖生成指数（estimated glycemic index,EGI）明显低于小麦馒头,并且随着苦荞粉添加量的增加,样品表现出抗氧化活性增强、EGI值下降的趋势。然而,苦荞粉添加比例的增大会降低消费者对产品的接受程度。综合考虑馒头的营养价值和感官品质,适宜的苦荞粉添加量为8%。     

Biscuit making properties of flours from hard and soft milling single variety wheats

Bench scale baking tests for two types of biscuits,¹ a hard sweet (HS) and a short sweet (SS), have been used to examine the biscuit making properties of a large number of flour samples from wheats grown in four consecutive years (1980–1983). Multiple regression models for prediction of biscuit properties using a range of standard cereal laboratory tests as independent variables on results from 1980–1981 harvest wheats confirmed earlier observations that such tests are of limited commercial value for biscuit flour specification. However the results of baking tests, with both types of biscuit, from single wheat varieties grown during 1981–1983 showed that flours from soft milling wheats (SMW) required less water to give biscuit doughs of standard consistency (measured instrumentally) than did flours from hard milling wheats (HMW). In addition biscuit doughs made with SMW flours gave greater oven spring, i.e. biscuits of lower bulk density, than doughs made from HMW flours. In each season the difference in the mean values of both parameters for flours milled from SMW and HMW was highly significant (P<0.001). With one exception the variability of the measured parameters within seasons was not significantly different between SMW and HMW. However within both SMW and HMW varieties highly significant differences (P<0.001) were observed between seasons for the mean values of both measured biscuit parameters. The effect of flour particle size on the biscuits was studied by regrinding a number of flours. With flours from both SMW and HMW reduction in particle size resulted in HS biscuits of higher density but SS biscuits of lower density.     

Laboratory Sprout Damage and Effect of Heat Treatment on Milling and Baking Properties of Indian Wheats

Effect of sprouting and heat treatment of wheat on physicochemical, milling, rheological and baking properties of three high yielding Indian wheat varieties were investigated. Flour recovery, diastatic activity and total sugars increased significantly in sprouted samples whereas damaged starch and gluten decreased with concomitant increase in free amino nitrogen. Poor rheological properties were exhibited by sprouted wheats which considerably improved with heat treatment. The bread baked from sprouted wheat flours had smaller loaf volume with poor crumb characteristics but cookies prepared from the same flour exhibited better spread. Heat treatment brought about considerable improvement in baked volume and crumb characteristics of breads.     

Natural fermentation of lentils. Functional properties and potential in breadmaking of fermented lentil flour

The effects of fermentation on functional properties of lentil flour and rheological properties of doughs and breads produced from blends of wheat and fermented lentil flour were studied. Lentil protein solubility was higher at neutral pH than acid pH; the lowest and highest protein solubility values were observed at pH 4.0 and pH 7.0, respectively. Water hydration capacity and fat binding capacity of fermented lentil flour (FLF) were always higher than those of non-fermented lentil flour (NFLF), irrespective of fermentation temperature (28–42°C) and flour concentration (79–221 g/l). Emulsifying properties of NFLF were similar to the properties of other legume flours in the range used in experiment. In contrast, the emulsion capacity and stability of FLF were very low and flours fermented at 42°C did not even form emulsion. Rheological properties of doughs made from wheat-fermented lentil blends were similar to those from wheat flour with the addition of other legume flours such as pea and bean. Good quality breads were produced at 2.5 to 10% NFLF and FLF supplementation (except for bread with 10% FLF addition which was middle quality).