Dough rheology and baking performance of wheat flour–lupin protein isolate blends

The impact of addition of two lupin protein isolates (LPI), enriched either in proteins belonging to globulin (LPI G) or to albumin (LPI A) fraction, on wheat flour dough and bread characteristics was investigated. LPI addition increased the dough development time and stability plus the resistance to deformation and the extensibility of the dough. The presence of LPI proteins in dough affected bread quality in terms of volume, internal structure and texture, while extra gluten addition to the blends to compensate for wheat gluten dilution, resulting from LPI addition, led to an improvement of bread quality characteristics. Generally, the incorporation of LP isolates to wheat flour delayed bread firming. The results obtained are discussed in terms of a possible action of LPI particles as a filler of the gluten network and partly in terms of possible interactions that take place between the gluten protein constituents and those of lupin.     

青麦粉添加对馒头面团及面筋蛋白结构的影响

以馒头专用粉及青麦粉制作青麦馒头,利用激光共聚焦显微镜、黏度仪、红外光谱仪等分析仪器进行测定,探究不同青麦粉添加量(0%、5%、10%、15%、20%)对面团粉质特性、糊化特性、微观结构及面筋蛋白二级结构的影响。结果表明,随着青麦粉添加量的增加,混合粉湿面筋含量、面筋指数减少;糊化温度、峰值黏度降低,面团糊化时间缩短,面团稳定时间从6.18 min降至4.92 min、粉质质量指数减小了18,面筋强度变弱,承受力变差;面团拉伸面积、延伸度和最大拉伸阻力在135 min时显著减小;面筋网络结构逐渐出现孔洞,分布不均匀;面团面筋蛋白各吸收峰都发生了偏移,β-折叠和α-螺旋结构含量增加;综上所述,青麦粉的加入改变了面团特性和面筋蛋白结构,这些变化可能是导致青麦馒头品质下降的主要原因。     

Combined effects of wheat gluten and carboxymethylcellulose on dough rheological behaviours and gluten network of potato–wheat flour-based bread

Incorporating high level of potato flour into wheat flour enhances nutritional values of bread but induces a series of problems that lead to the decline of the bread quality. To overcome the barrier, wheat gluten and carboxymethylcellulose (CMC) were added into potato–wheat composite flour to improve dough machinability and bread quality. The rheological properties, thermo-mechanical properties and microstructures of dough were investigated. The results showed that the interaction between gluten and CMC mitigated the discontinuity of gluten matrix and gluten protein aggregation caused by the addition of potato flour, which yielded a more branched and compact gluten network. The compact three-dimensional viscoelastic structure induced improvements of gas retention capacity and dough stability, making it mimic the machinability properties of wheat flour dough. Bread qualities were apparently improved with the combined use of 4% gluten and 6% CMC, of which specific volume increased by 42.86%, and simultaneously, hardness reduced by 75.93%.     

Rheological and Microstructure Characterization of Composite Dough with Wheat and Mesquite (Prosopis spp) Flours

Rheological behavior and microstructural characteristics of composite dough with wheat and mesquite flours (from Prosopis alba) were analyzed by response surface methodology. A central composite design was applied varying proportions of water (50 to 80 g each 100 g wheat flour) and mesquite flour (0 to 70 each 100 g wheat flour). Texture profile analysis showed that increasing the amount of mesquite flour and decreasing the amount of water led to less cohesive and more resilient doughs. Stress relaxation curves were fitted with a Maxwell model and relaxation times were obtained. These parameters resulted higher for those formulations low in mesquite content and high water levels. Composite dough showed a typical viscoelastic behavior with higher elastic moduli (G’) when mesquite flour ratio in the mixture was increased. ¹H-RMN T2 relaxation assays revealed higher mobility in samples with high amounts of water and minimum level of mesquite. A farinograph was adequate to obtain optimum water amounts and showed that addition of mesquite led to less stable dough respect to control wheat dough. By using confocal laser scanning microscopy with fluorescent probes rhodamine B and fluoresceine isothiocyanate, a poor gluten network development or protein aggregation was observed when water contents were far from optimum.     

Enzymes Action on Wheat–Soy Dough Properties and Bread Quality

High levels of soy flour added to wheat bread produce negative effects on gluten network formation, dough properties, and on bread final quality. The objective of this study was to assess the influence of three enzymes, transglutaminase (TG), glucose oxidase (GOX), and endoxylanase (XYL), on dough properties and final quality of high-protein breads. The addition of TG and GOX increased the mixing stability and maximum resistance of dough, decreased its extensibility, and produced stronger and more consistent dough samples. XYL incorporation produced opposite results. XYL addition and the lowest GOX dose increased bread volume significantly and decreased initial crumb firmness, while high doses of TG (0.3%) produced detrimental effects on bread volume and crumb firmness. In conclusion, XYL and GOX 0.001% addition improved the final quality of soy-fortified breads, but XYL was the best additive to improve dough properties, bread volume, and quality.     

谷朊粉对高含量荞麦面团的影响及其作用机理

本文全面研究了不同添加量谷朊粉(5%、10%和15%)对高含量(50%小麦粉替代率)荞麦面团流变学特性及馒头品质的影响,并以添加10%谷朊粉的混合面团和参照组(纯小麦粉)面团为基础,通过扫描电镜,红外光谱及分析面团中的化学作用力等分析手段,进一步探讨了谷朊粉对改善混合面团流变学性质及馒头品质方面的作用机理。结果表明,添加10%的谷朊粉能够增加荞麦-小麦混合面团中二硫键的含量,改变面团中的化学作用力(离子键、氢键含量和疏水作用力),进而改变面团中面筋蛋白的构象,改善面团的微观结构,从而改善混合粉的糊化特性及面团的粉质和拉伸特性,提高馒头的比容和弹性,改善馒头芯的孔隙结构,但仍达不到参照组馒头的品质,表明添加高含量荞麦全粉不仅仅是稀释面筋蛋白。     

品质改良剂对复合杂粮面包粉流变学特性的影响

以营养优化后的复配杂粮面包粉为原料,选择谷朊粉、硬脂酰乳酸钠（sodium stearoyl lactylate,SSL）、黄原胶及瓜尔豆胶为品质改良剂,通过单因素试验研究4 种品质改良剂对杂粮面包粉流变学特性的影响,在此基础上通过响应面分析试验,以面团综合得分为响应值,得出复合改良剂的最佳配方为：1 000 g杂粮面包粉（杂粮粉占比34%）为基重,谷朊粉3.77%、SSL 0.35%、黄原胶1.08%、瓜尔豆胶0.35%。各因素对杂粮面包粉综合评分的影响大小为：黄原胶添加量＞谷朊粉添加量＞瓜尔豆胶添加量＞SSL添加量。添加复合改良剂后杂粮面包粉的稳定时间由4.7 min上升到14.2 min,形成时间由3.9 min上升到了13.3 min,粉质指数从56上升到192。复配杂粮面包粉流变学特性有很大程度改善,达到制作杂粮面包的粉质要求。     

Incorporation of several additives into gluten free breads: Effect on dough properties and bread quality

The objective of this work was to assess the effect of emulsifiers, hydrocolloids and enzymes on gluten-free dough rheology and thermal properties and bread quality, while relating dough properties parameters to bread technological quality. Breads were based on rice flour, cassava starch and full-fat active soy flour, with 65% or 75% (flour-starch basis) of water incorporation. Additives used were emulsifiers (diacetyl tartaric acid ester of monoglycerides – DATEM and sodium stearoyl lactylate – SSL), enzymes (glucose oxidase and α-amylase) and hydrocolloids (xanthan gum, carboxymethylcellulose, alginate and carrageenan). Results showed that additive incorporation modified dough behavior, evidenced by different calorimetric and rheological properties. Besides, the electrophoretic pattern of dough extracted proteins changed with glucose oxidase addition. These modifications resulted in breads with different characteristics, such as specific volume, firmness and firming rate, and crumb structure. Nonetheless, they did not necessarily show better quality parameters than the control bread. The control dough displayed good performance for obtaining gluten-free breads of acceptable volume, crumb structure and, principally, with lower hardening rate during storage. Contrary to widespread opinion, this work shows that the presence of additives is not essential for gluten-free bread production. This fact provides new perspectives to the gluten free market at the moment of selecting raw materials and technological parameters, reducing production costs and facilitating gluten free products development.     

Enrichment of Bread with Nutraceutical‐Rich Mushrooms: Impact of Auricularia auricula (Mushroom) Flour Upon Quality Attributes of Wheat Dough and Bread

Edible mushrooms contain a variety of bioactive molecules that may enhance human health and wellbeing. Consequently, there is increasing interest in fortifying functional foods with these nutraceutical‐rich substances. However, incorporation of mushroom‐based ingredients into foods should not adversely affect the quality attributes of the final product. In this study, the impact of incorporating powdered Auricularia auricula, a widely consumed edible mushroom, into bread products was examined. The rheological and structural properties of wheat dough and bread supplemented with 0% to 10% (w/w) A. auricula flour were measured. Supplementation of wheat doughs with A. auricula flour increased the peak viscosity and enhanced their water holding capacity. Rapid viscosity analysis showed that peak and final viscosities of the blended flour (wheat flour with A. auricula flour) were higher than wheat flour alone. However, dough stability and elastic modulus were reduced by blending wheat flour with A. auricula flour. SEM observation showed that doughs with up to 5% (w/w) A. auricula flour had acceptable gluten network microstructure. Characterization of the quality attributes of bread indicated that incorporation of A. auricula flour at levels >5% negatively impacted bread volume, height, texture, and appearance.     

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.     

苦荞粉添加量对面团性质及馒头品质的影响

通过添加不同量的苦荞粉配成苦荞-小麦混粉,研究混粉揉混特性、面团微观结构的变化以及苦荞馒头的感官品质。结果表明,当添加量在5%~15%时,揉混结果中的和面时间和峰值面积变化不大,微观结构中蛋白质面筋网络结构略微减弱,但当添加量达到20%后,和面时间和峰值面积都有大幅度降低,微观面筋网络结构也出现明显的下降。同时,苦荞粉添加量为15%时馒头感官品质较好。综合分析可知,添加量为15%时苦荞馒头仍具有较好的品质。     

Effects of microencapsulated glucose oxidase on wheat flour dough properties and Chinese steamed bread quality

This study was to investigate the effects of microencapsulated glucose oxidase (MGO), in comparison with free glucose oxidase (GO), on wheat flour dough properties and Chinese steamed bread (CSB) quality. Effects on wet gluten (WG) content, farinograms and extensograms properties, dynamic rheological properties, microscopic structure, texture profile and sensory evaluation scores were studied. The results demonstrated that MGO catalysed the oxidation of dough at a much slower speed and exerted relatively great advantages in many aspects such as WG content, extensibility, G′ (Elastic modulus), G″ (viscous modulus), tan δ (equal to G′/G″), microstructure and texture properties and sensory evaluation scores of CSB, compared with free GO. The results suggested that slow oxidation of MGO was superior to free GO based on the improvements of wheat flour dough properties and subsequent CSB quality.     

Optimization of Additive Combination for Improved Soy–Wheat Bread Quality

The protein content of ordinary white bread ranges from 8% to 9%. Specialty breads can be made with 13–16% protein by including soy protein. However, incorporating high levels of soy protein depresses loaf volume, gives poor crumb characteristics, and decreases acceptability. The objective of this study was to determine the influence of sodium stearoyl-2-lactylate (SSL), transglutaminase (TG), and xylanase (HE) on high-protein dough properties and bread quality and to improve dough handling and bread quality of soy–wheat bread by using an optimized additive combination. The influence of SSL, TG, and HE on soy–wheat dough and bread properties was modeled by response surface methodology. The negative effect of soy products on gluten network was confirmed. With regards to the additives tested and their combination, TG showed a major improving effect on dough rheological properties and crumb uniformity, whereas SSL and HE enhanced both dough and bread quality. The best formulation tested produced an increment of approximately 65% soy–wheat bread volume and a decrease of 79% and 71% crumb hardness and chewiness, respectively, compared with the standard formulation.     

Effect of hydroxypropyl methylcellulose,whey protein concentrate and soy protein isolate enrichment on characteristics of gluten‐free rice dough and bread

Due to a lack of gluten, rice dough needed some additives to improve its properties. This study aimed to investigate effect of hydroxypropyl methylcellulose (HPMC), whey protein concentrate (WPC) and soy protein isolate (SPI) on rice dough and bread. HPMC increased water absorption of the rice dough (P ≤ 0.05). Adding SPI (2–4 g per 100 g flour) together with HPMC tended to increase stability time and reduce tolerance index. During fermentation, HPMC increased maximum dough height, while SPI increased final dough height (P ≤ 0.05). All addition improved tan δ (G″/G′) to be comparable to the wheat dough, but it could not improve gas production and retention. Therefore, specific volume, springiness, cohesiveness and chewiness of rice bread were lower than those of wheat bread (P ≤ 0.05). Percentage of small pores in rice bread was reduced to be comparable to wheat bread, by adding WPC. All addition could improve porosity of the rice bread.     

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     

Evaluation of baking procedures for incorporation of barley roller milling fractions containing high levels of dietary fibre into bread

BACKGROUND: Roller milling of hull‐less barley generates fibre‐rich fractions (FRF) enriched in non‐starch polysaccharides from the endosperm cell walls (β‐glucans and arabinoxylans). This investigation was initiated to compare the suitability of different baking processes and to determine the optimal conditions for incorporation of barley FRF into pan bread. RESULTS: Addition of FRF from waxy and high‐amylose starch hull‐less barley genotypes was evaluated in pan bread prepared from Canada Western Red Spring (CWRS) and Canada Western Extra Strong (CWES) wheat flour. Three bread processes were used: Canadian short process (CSP), remix‐to‐peak, and sponge‐and‐dough. Addition of 20% FRF (equivalent to enrichment with 4.0 g of arabinoxylans and β‐glucans per 100 g of flour) disrupted dough properties and depressed loaf volume. CSP was not suitable for making FRF‐enriched bread because dough could not be properly developed. FRF‐enriched remix‐to‐peak bread was better, especially for the stronger CWES flour. The better bread quality compared to CSP was probably due to redistribution of water from non‐starch polysaccharides to gluten during fermentation prior to remixing and final proof. The sponge‐and‐dough process produced the best FRF‐enriched bread because of the positive effect of sponge fermentation on gluten development and hydration. FRF was added at the dough stage to fully developed dough. CONCLUSION: The method of bread production strongly influences bread quality. Pre‐hydration of FRF improved bread quality. CWRS and CWES flour produced comparable FRF‐enriched sponge‐and‐dough bread. Addition of xylanase to the sponge‐and‐dough formula improved the loaf volume, appearance, crumb structure and firmness of FRF‐enriched bread. Copyright © 2007 Society of Chemical Industry     

Partial Replacement of Wheat Flour with Yellow Field Pea Flour in White Pan Bread

Yellow field pea flour replaced 2.5, 5 and 10% of wheat flour in white pan bread prepared by a straight dough, rapid mix home formulation. Incorporation of pea flour did not affect proofing times. No significant differences were found between Gardner L and “a” values for wheat-pea flour blends, but “b” values increased with increasing levels of pea flour; crumb color of breads did not differ significantly. Volumes of the breads were not significantly affected by pea flour addition. Pea flour breads were judged between fair and good for all characteristics by an experienced taste panel; the 10% pea flour breads were scored significantly lower for texture, color and flavor.     

X-ray micro-computed tomography evaluation of bubble structure of freeze-dried dough and foam properties of bread produced from roasted wheat flour

This study evaluated the bubble structure of freeze-dried dough and foam properties of bread produced from the roasted wheat flour by means of X-ray micro-computed tomography (μCT). Wheat was roasted at 90 °C and 86 Hz, of which the conditions was determined by means of a central composite design, and the flour used to produce dough proofed for 20- and 40 min as well as bread. The use of 10 g dough and bread samples enabled scanning at a much higher resolution. Roasting resulted in a decreased strut thickness of the bread, suggesting a finer crumb structure and softer texture, compared to the control. Porosity increases were observed for the roasted wheat samples. This suggested a slightly weaker gluten strength as was observed with the lower mixograph peak height. Roasting wheat, at the conditions determined by the central composite design, did not negatively affect the foam properties of the breads produced from the roasted wheat flour.     

小麦粉吸水速率对面团特性及馒头品质的影响

该文以不同吸水速率的小麦粉为基础,研究在相同的揉混条件下,其面团特性及馒头品质的变化。使用粉质仪将面团稠度达到最高时所用的加水量与消耗的时间的比值定义为吸水速率,测定不同吸水速率小麦粉其粉质特性、湿面筋含量、面筋指数、游离巯基与二硫键含量、面团质构特性、馒头比容与高径比、馒头的质构特性。研究结果表明,当小麦粉吸水速率从0.17 g/s增大到3.87 g/s时,面团的稳定时间及粉质质量指数显著下降。其湿面筋含量从38.81%下降到19.19%,二硫键含量从13.31μmol/g下降到9.05μmol/g。面团的质构特性在发酵0 min时呈先升高后降低趋势、在醒发45 min后整体呈下降趋势。馒头的比容从2.67 mL/g降低到2.27 mL/g、高径比从0.68降低到0.56,其硬度、胶着性、咀嚼性均成下降趋势。整体而言,吸水速率低的小麦粉其面团相对较硬且馒头较为筋道有嚼劲;吸水速率较高的小麦粉其面团硬度稍弱且馒头较为松软。     

The effects of extruded black rice flour on rheological and structural properties of wheat-based dough and bread quality

Addition of raw black rice flour leads to deficient processability on bread making quality. One of the effective methods to modify the functional properties of black rice flour (BRF) composite dough is to extrude black rice flour (EBRF) before incorporation. This study investigated and compared the effect of BRF and EBRF addition level of 10%–50% on the rheology, microstructure of dough and bread quality. The rheological properties of composite dough were recorded by Mixolab, stress relaxation and tensile test. The substitution of EBRF presented higher water absorption but lower development time, protein weakening, starch gelatinization, starch gel stability and starch retrogradation than wheat flour dough. Both the BRF and EBRF dough presented solid-like behaviour, while the EBRF dough showed more viscous, higher resistance and extensibility than BRF dough. The dough microstructure of dough was observed by SEM, and a more compact structure of EBRF dough could be seen than BRF dough. The incorporation of EBRF in bread quality presented higher specific volume, lower bake loss and firmness than BRF bread. These findings indicated the potential utilisation value of extruded black rice flour in bread making.