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1.
Physical modification of soy flour was shown to greatly improve the dough and baking qualities of soy–wheat (1:1) composite doughs, compared to raw soy flour, giving better stability and Rmax, although extensibility was still below that of the wheat dough.Reasons for improvements caused by the physical-modification process were sought by determining the relative size distribution of proteins in the soy–wheat composite doughs by size-exclusion high-performance liquid chromatography (SE-HPLC). Results were expressed as the proportion of ‘unextractable polymeric protein’ (%UPP)—the proportion of the protein that is over 100,000 Da and only extractable after sonication. Protein extracts from the soy–wheat dough were sampled at different stages of dough mixing and fermentation, and their molecular-size distributions evaluated.Unextractable soy proteins were lower in raw soy flour (only 8% UPP) than in two physically-modified soy flours (19 and 34% UPP, respectively). Unextractable polymeric protein was much greater for wheat flour (57% UPP). After mixing a 1:1 soy–wheat composite dough, the %UPP was 36 and 22 (for the two types) when made from physically modified soy flours, compared to 8 for a composite dough using raw soy flour, and 43 for a wheat-only dough. The higher proportion of UPP for the wheat-modified soy doughs was taken as a reason for this composite dough providing better dough and baking qualities. Prolonged fermentation time caused a decrease in UPP percentages for all composite doughs and for the wheat-only dough.  相似文献   

2.
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.  相似文献   

3.
Acrylamide (AcA) contents of different rice flour- and wheat flour-based butter cookies baked at 130 °C for 20, 55, or 90 min were investigated. AcA contents of different flour-based cookies increased with baking time. Color parameters in terms of CIE L*, b*, C*, and ΔE values showed significant opposite correlation to the AcA formation in each of the raw flour cookie. The cookies based on white rice flour had the lowest AcA contents ranging from not detectable (ND) to 204 μg/kg, followed by cookies based on brown rice flour (ND to 450 μg/kg), white wheat flour (155 μg/kg to 661 μg/kg), and whole wheat flour (306 μg/kg to 982 μg/kg). Considerably lower AcA levels were found in the rice flour-based cookies than in the wheat flour-based cookies, as well as in the milled flour-based cookies than in the whole-grain cookies. Although the flour source was considered to play a primary role in determining the AcA content, AcA content was apparently not dependent on the quantities of reducing sugars and free asparagine in the starting raw flour and cookies during baking. In summary, given its reducing potential for AcA formation, rice flour could be used in the production of cookies safe from heat-induced contaminants.  相似文献   

4.
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.  相似文献   

5.
Samh seeds obtained from Al-Jouf area were ground into flour analyzed and used as a replacement for wheat in the ratio of 10, 20 and 30% for bread and 30, 60 100% for cookies. The rheological effect of the Samh flour on Saudi wheat flour was also studied. The bread and cookies obtained were evaluated physically and by sensory evaluation. The results obtained indicated that samh flour has high protein content and could be used as a replacement for wheat flour upto 30% without adversely affecting the bread specific volume much. Samh flour has improved the cookies appearance specially the colour (chocolate colour) and spreading ratio. The results also revealed that it is possible to make cookies from 100% samh flour. Due to the high protein content of the samh seeds the nutritional value of the bread and cookies made with samh flour will be improved. The results of the sensory evaluation of the bread and cookies indicated that the bread made with samh flour upto 30% has similar characters except for the crumb color and the overall acceptability which were rated as significantly inferior. The sensory evaluation of the cookies showed that the cookies made with samh flour upto 100% were significantly superior (p<0.05) to the cookies made with 100% wheat flour (control).  相似文献   

6.
The high and low Mr glutenin subunit compositions (controlled by the Glu-1 loci and the Glu-B3 locus, respectively) and the bread-making quality characteristics of 26 durum wheat (Triticum turgidum) genotypes were determined. The relationships between quality parameters and Glu-B1 and Glu-B3 controlled glutenin subunit composition were also investigated. The Glu-A1-controlled null allele was present in all the genotypes. High Mr subunits 20, 6 + 8 and 7 + 8 occurred in similar proportions in the cultivars analysed. The Glu-B3 low Mr allelic variants, LMW-1 and LMW-2, were both represented, with LMW-1 being present in lower proportion. Flour protein, SDS-sedimentation volume, dough strength (Alveograph W value), dough mixing time and bread loaf volume varied among the genotypes. Most samples had high Alveograph tenacity/extensibility (P/G) ratios, typical of tenacious gluten character. SDS-sedimentation volume, dough strength, dough mixing time and bread loaf volume were all interrelated. An association with flour protein content was observed only for mixing time, while the Alveograph tenacity/extensibility ratio was not correlated with the other parameters. Comparisons within the Glu-B1 and Glu-B3 loci indicated that the high Mr subunit 7 + 8 and the low Mr subunit LMW-2 had significantly greater beneficial effects on gluten strength and bread-making quality than the high Mr subunits 6 + 8 or 20 and the low Mr subunit LMW-1, respectively. High Mr subunit 6 + 8 had greater beneficial effects on quality than subunit 20.  相似文献   

7.
Wheat (Triticum aestivum L.) flour is able to form dough with unique rheological properties that allow bread making. It is well known that wheat protein content affects dough rheological properties, but there is not enough evidence about the role of other minor flour constituents. One such minor constituent is non-starch flour polysaccharides, which are mainly pentosans formed by a xylopyranosyl linear chain branched with arabinofuranosyl residues. Their spatial distribution and branching pattern can affect their relationship with gluten forming proteins and thus influence their functional properties, the dough rheological properties, and thereby the flour baking quality. In this study the content and structural characteristics of non-starch polysaccharides were investigated, as well as their influence on some dough physicochemical parameters. Five different wheat flours samples milled from Uruguayan wheat varieties with diverse rheological and breadmaking properties were used in this study. Water soluble flour polysaccharides were extracted and the amount of pentosans was determined by the orcinol-HCl method. The pentoses composition was determined before and after acidic hydrolysis of the water soluble polysaccharide fractions by GC. No free pentoses were detected in any of the assayed flour samples, so the pentoses composition found in the hydrolyzed samples was attributed to the non-starch water soluble polysaccharides. Water unextractable non-starch polysaccharides were determined by difference between the total and the soluble non-starch polysaccharides flour content.An improved method for the quantification of water extractable and non-extractable non-starch polysaccharides, using baker's yeast, was developed. Using this method, total and soluble non-starch polysaccharides content could reliably be determined both in whole flour and in pentosans enriched fractions. Free monosaccharide content was in the range from 0.03% to 0.06% (w/w), while the arabinose/xylose (Ara/Xyl) ratios varied from 0.8 to 1.4 in soluble non-starch polysaccharides and from 0.7 to 0.9 in total non-starch polysaccharides. The different Ara/Xyl ratios found for water extractable and unextractable arabinoxylans clearly indicates different substitution degrees in the polymers. Analysis of the dough rheological parameters in relation to the water soluble and non-soluble non-starch polysaccharides and the Ara/Xyl ratios from different wheat varieties was performed. A clear relation between some of these parameters could be inferred, since a direct relationship between total unextractable (AXi) content and resistance of dough to extension (P), as well an inverse relationship between the same parameter and dough extensibility (L) were observed. These results suggest that the flour non-starch polysaccharide content, as well the Ara/Xyl ratios may be used as additional parameters to estimate some of the wheat flours dough properties.  相似文献   

8.
Whole wheat and maize (corn) flours were supplemented with 10, 20 and 30% levels of a 1:1 mixture of peanut and chickpea flours (PCF). Supplementation increased the protein content of the wheat and maize blends by 20–61%. Significant increases in other proximate constituents as well as K, Ca, P, Fe, Zn and Cu levels and lysine were observed. The chemical score (FAO/WHO, 1973) of wheat flour increased from 53 to 72 and that of maize flour from 49 to 71 with 30% PCF. Biological evaluation of wheat breads (baking time = 7 min at 220°C) at 10% protein level and maize breads (baking time = 15 min at 250°C) at 8% protein level in the diet showed significant (P<0.05) improvement in the protein quality of PCF-supplemented breads as judged by gain in body weight, protein efficiency ratio, net protein ratio, net protein utilization, biological value and utilizable protein (NPU% × protein% ÷ 100) content. A supplementation level of 20% was considered adequate to achieve the desired nutritive benefits.  相似文献   

9.
为明确安徽大田生产环境下软质小麦籽粒和终端产品品质表现,评价优质软麦品种的加工适用性,本研究选取该区当前推广种植的24个软质小麦品种,对其籽粒和面粉的主要品质性状及其制品南方馒头和曲奇饼干的品质进行差异性、相关性分析,并以美国软白麦近五年的主要品质性状平均值为理想指标进行灰色关联度比较。结果表明,供试材料的硬度、面粉色泽b*、湿面筋含量、面团形成时间、稳定时间等籽粒品质性状变异系数较大,而容重、面粉L*值和吸水率变异系数较小。南方馒头品质性状中,白度差异最小,比容差异最大;曲奇饼干品质性状中,感官评分变异系数较大,饼干直径均值和变异系数都较小。蛋白质含量、湿面筋含量、稳定时间均符合弱筋标准(GB/T 17320-2013)的样品数为0。相关分析表明,容重、降落值、面粉L*、b*、白度与大部分性状间相关性不显著;籽粒硬度与水SRC和乳酸SRC均呈显著正相关,与湿面筋含量和面粉a*值均呈显著负相关。蛋白质含量与面粉a*值等7个指标均呈显著正相关,与面粉b  相似文献   

10.
Fractionation and reconstitution/fortification techniques were utilised to study the role of gluten in Arabic bread. Glutens from two wheat cultivars of contrasting breadmaking quality were fractionated by dilute HCl into gliadin and glutenin. Gluten, gliadin and glutenin doughs from the good quality flour had higher G ′ and lower tan δ values than those from the poor quality flour at all the frequencies examined. Interchanging the gliadin and glutenin fractions between the reconstituted flours showed that the glutenin fraction is largely responsible for differences in the breadmaking performance. Fortification of an average quality flour with the gliadin and glutenin fractions from the poor and good quality flours, at the levels of 1% and 2% (protein to flour mass), induced marked differences in the mechanical properties of bread. The resilience of the loaves was not adversely affected by the addition of gliadins and increased, with a concomitant significant (p<0·05) improvement in quality, at the 2% level of fortification with gliadins from the good quality flour. Addition of glutenin resulted in loaves with leather-like properties that became particularly apparent at the higher level of fortification; the observed deterioration in quality paralleled the increase in the elastic character of the doughs. It is suggested that highly-elastic doughs are not compatible with the rapid expansion of gases at the high-temperature short-time conditions employed in the baking of Arabic bread and that there exists a threshold in dough elasticity beyond which a rapid decline in quality takes place.  相似文献   

11.
The mechanical properties of flour–water doughs and hydrated gluten of different wheat cultivars were determined. Measurements were performed at small deformations (dynamic measurements) as well as at large deformations (biaxial extension measurements). Results of dynamic measurements of flour doughs related poorly to breadmaking quality. For hydrated gluten doughs, all having the same water content, it was found that glutens from wheat cultivars with good baking quality had higher values for the storage modulus,G, and lower values for the loss tangent. The relevant type of deformation around an expanding gas bubble is biaxial extension. Wheats with a good baking performance exhibited greater strain hardening and greater extensibility. The differences in strain hardening observed at 20 °C were also present at 55 °C. No clear effects of NaCl or emulsifiers on the biaxial extension properties of flour dough were found. Extensograms as well as Alveograms from the flour doughs showed that, in general, good baking flours exhibited stronger resistance to extension and a greater extensibility, but differences found were not directly related to the results of the baking tests. The results indicate that the baking performance of dough is related to a combination of at least three different rheological characteristics.  相似文献   

12.
Twenty-four farinograms and accompanying flour characteristics obtained from a bakery were used to get additional information for baking characteristics of flours. Farinograms were digitized and four novel parameters were included for comparison: a and b were extracted from an equation of the form y = aebt; the height of the upper curve and the width of the farinograph curve at a time value equal to the dough development time. Stepwise multiple regressions were carried out relating bread volume to novel and existing parameters (water absorption, development time, arrival time, departure time, stability and degree of softening). Results indicated that four farinogram parameters, resistance, water absorption, a and b were related to bake height with an overall value of 61%. A relatively weak correlation (R = 0.44, P < 0.05) was detected between specific loaf volume and bake height.  相似文献   

13.
Prolamin is a major class of rice proteins but its influence on the physicochemical properties of rice is not clear. Rapid Visco Analyser (RVA) and TA-XT2 TPA textural analyses were performed on rice starch with the addition of prolamin extracted from three rice cultivars (Hitomebore, M103 and Amaroo), and on rice flour with the prolamin removed by propan-2-ol extraction. Addition of prolamin to rice starch was found to cause a significant (P<0.05) increase in RVA breakdown viscosity but significant (P<0.05) decreases in hardness, adhesiveness and gumminess of the starch gel. Similarly, when prolamin was removed from rice flour, exactly the opposite effect was observed. Addition of prolamin to rice starch also caused it to absorb water faster during cooking but the gelatinised starch absorbed less water compared with control samples without prolamin.  相似文献   

14.
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.  相似文献   

15.
为探究经过不同热处理的小米粉对小麦面团品质的影响,将小米粉分别进行膨化、蒸制和炒制热处理,经蒸制和炒制的小米粉按照0、5%、10%、15%、20%、25%、30%和35%的比例添加到小麦粉中,膨化小米粉按照0、2%、4%、6%和8%的比例添加到小麦粉中,分别对混合粉面团的流变学特性进行研究。结果表明,不同热处理小米粉的灰分、蛋白质、脂肪、总淀粉和总膳食纤维含量均下降,可溶性膳食纤维含量升高(炒制组除外)。不同热处理小米粉的添加量对小麦面团粉质特性和拉伸特性的影响存在显著差异(P0.05);面团的粉质特性随小米粉含量的增加而减弱;添加蒸制和炒制小米粉的面团粉质特性较好。随着小米粉含量的增加,添加膨化小米粉的面团的拉伸特性呈先增强后减弱的趋势,添加蒸制和炒制小米粉的面团的拉伸特性则逐渐减弱,且3个处理的拉伸特性都随醒面时间的延长有所增强,不同处理之间的拉伸特性差别不大。  相似文献   

16.
The aim of this study was to improve the baking quality of whole-wheat saltine cracker (WWSC) using endoxylanases, vital wheat gluten (VWG), and gum Arabic. SRC results showed both water-SRC and sucrose-SRC of soft white whole-wheat flour (SWWW) were significantly reduced by gum Arabic (r = 0.94, P < 0.05). Alveograph results indicated that the tenacity and extensibility of the whole-wheat dough (WWD) were increased by VWG. Rheometer G′ and G″ moduli increased with higher addition levels of endoxylanases, VWG, and gum Arabic. Low-field nuclear magnetic resonance (LF-NMR) detected three CPMG proton populations (T21, T22, and T23) in WWD. T21 peak area ratio (tightly bound water) reduced and T22 peak area ratio (less tightly bound water) increased with the levels of each additive. LF-NMR results revealed increased water mobility from T21 population to T22 population with addition of these additives, which was beneficial for gluten to form a continuous network. Both stack height and specific volume of WWSC were improved by the use of endoxylanases, VWG, and gum Arabic, but the breaking strength varied. The results of Orthogonal experimental design showed that the most-improved quality WWSC could be produced by combining 0.035% endoxylanases, 1.5% VWG, and 1.5% gum Arabic into SWWW flour.  相似文献   

17.
Addition of a gluten-free flour such as sorghum has negative impact on the quality of wheat dough for bread making. One of the methods which can be used to promote the quality of sorghum-wheat composite dough is to extrude the sorghum flour before incorporation. In this regard, to produce a dough with appropriate bakery properties sorghum flour was extruded at 110 °C and 160 °C die temperature with 10%, 14% and 18% feed moisture. The effect of extruded sorghum flour incorporation (10%) on rheological (farinography and stress relaxation behavior), morphological and temperature profile of sorghum-wheat composite dough were evaluated. Extrusion cooking altered the sorghum-wheat composite dough properties through partial gelatinization of starch granules. Addition of extruded sorghum flour increased the water absorption and dough development time but it decreased the dough stability. Native sorghum-wheat composite dough showed viscoelastic liquid-like behavior whereas addition of sorghum flour extrudate changed dough to a more viscoelastic solid-like structure. Maxwell model was more appropriate than Peleg model to describe the viscoelasticity of the sorghum-wheat composite dough. Extrusion cooking decreased composite dough elasticity and viscosity. Sorghum extrudate increased the heating rate of composite dough crumb during baking. Addition of extruded sorghum flour formed a non-uniform and less compact dough structure. As a result, dough containing extruded sorghum flour had a good potential for producing a high-yielding bread in a short time of baking.  相似文献   

18.
Determination of the physico-chemical characteristics of composite soft wheat flours in which 5–25% (w/w) of the wheat flour was replaced with untreated, roasted and germinated black gram (Phaseolus mungo) flours (BGF) showed that when roasted BGF comprised 20% (w/w) of the blend, the increases in the ash and protein contents were 123% and 35%, respectively. The values for the gluten contents and the Zeleny and sodium dodecyl sulphate sedimentation test volumes for the composite flours indicated a weakening effect of BGF on the quality of soft wheat flour proteins, which could be beneficial for the preparation of biscuits (cookies). The alkaline water retention capacity values increased with the increasing addition of differently processed BGFs. Biscuit baking studies indicated that the diameter and spread ratio of biscuits were reduced, while the thickness increased, with increasing addition of all three BGFs, but the maximum reduction in diameter was observed with the addition of germinated BGF. The hardness value for biscuits increased with the addition of BGFs, but the effect was minimal with roasted BGF and maximal with germinated BGF. The surface grain score was reduced with increasing addition of BGF, but, in general, the roasted BGF showed the minimum adverse effect. From the overall biscuit making quality, addition of untreated BGF at the 15% level and of roasted and germinated BGFs at the 20% level were considered optimal for supplementing wheat flour.  相似文献   

19.
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 Tg. 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.  相似文献   

20.
Infrared stabilized rice bran (SRB) substitution to white wheat, wheat bran and whole grain wheat breads at the levels of 2.5, 5.0 and 10.0% was evaluated in terms of proximate composition, crumb color, dietary fiber, texture and sensory attributes. An increasing tendency was observed in crude fat and ash content of the breads. Redness (+a*), yellowness (+b*) chroma and redness (a*/b*) values were increased gradually with the addition of SRB. Crumb color was found to be darker when 10% of SRB was added to the breads. SRB inclusion did not affect the content of soluble dietary fiber while it significantly increased the insoluble and total dietary fiber contents of the breads (p < 0.05). In general, whole grain wheat bread differed from the other bread types in terms of textural behavior. Based on the overall acceptability scores, white wheat and wheat bran breads were sensory accepted up to 10% of flour replacement with rice bran, while substitution levels higher than 2.5% negatively affected the sensory scores of whole grain wheat bread.  相似文献   

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