Effect of waxy flour blends on dough rheology and bread quality

Although much research has been conducted on wheat flour dough rheology, the principal focus has been the role of the protein fraction. Starch is the main component of flour and plays a key role in dough dynamic properties, particularly during heating. This study assesses the effect of two different waxy flours, a durum and a bread wheat, and their blends with commercial bakers' flour on dough rheology during heating with a concurrent investigation into baking performance. Both waxy flour blends produced similar effects on dough rheological behaviour despite differences in protein content, acting to delay gelatinisation and reduce storage modulus. The main effects in bread were to increase loaf expansion during baking and reduce loaf firmness. It is postulated these effects are largely water mediated, with the higher swelling ability of the waxy starch granules reducing overall water availability and driving complete gelatinisation to higher temperatures.     

Effect of xylitol on wheat dough properties and bread characteristics

The aim of the experiment was to evaluate the effect of xylitol on wheat dough properties and bread qualities. The results showed that peak viscosity of bread flour containing 20% xylitol was about 12.59% higher than that of the control. The development time and stability time of dough containing 5% xylitol were 2.55 and 1.62 min longer than those of the control, and the drop value decreased from 454 FU to 359 FU. The extensibility of dough containing 10% xylitol was 21 mm longer than that of the control. The maximum resistance and energy area showed an increasing trend. Scanning electron microscopy images showed a discontinuous gluten matrix in which starch granules were not covered completely with gluten when containing xylitol. The springiness of bread with 10% xylitol was increased by 10.6% compared with that of the control, while the hardness was decreased by 21.5%. The bread added 10% and 15% xylitol had higher scores than the control.     

百合粉添加量对面团特性及面包品质的影响

为拓宽百合的应用渠道,提高面包的营养价值,研究了百合粉添加量(0%,5%,10%,15%,20%)对面团的微观结构、糊化特性、流变学特性以及面包品质的影响。结果表明:随着百合粉添加量增大,混合粉的持油性先降低后增加,持水性显著增加(P<0.05)。添加了百合粉后,面团的糊化温度升高,回生值和峰值黏度下降,面团的弹性模量和黏性模量均呈上升趋势。百合粉的添加,破坏了面筋蛋白原本均匀致密的微观结构;使面包的硬度显著增大(P<0.05),弹性、内聚性、胶黏性、咀嚼性、回复性、比容和感官评分显著降低(P<0.05);改变了小麦面团的特性和面包的品质,在小麦粉中添加5%～10%的百合粉,能保证面包较高的感官品质。     

Dough and crumb grain changes during mixing and fermentation and their relation with extension properties and bread quality of yeasted sweet dough

Dough and crumb grain evolution of yeasted sweet dough, as affected by the combined effect of mixing (dough development) and fermentation times, and their relation to rheological properties and bread quality was studied. Structural changes of under or optimum developed dough, without fermentation, were related mainly to increments in extensibility (P > 95%), without a noticeable change in pH. At all mixing stages, fermentation duration increased R_m, whereas extensibility and pH decreased. When plotting R_m with bread specific volume, cell area, total cell area fraction or yellow crumb colour parameter (b*) simple mathematical models, with determination coefficients larger than 0.85 were obtained. Bread crumb image analysis showed that crumb cell size was not affected by mixing time, while fermentation duration had a direct influence on this parameter, increasing the proportion of the smallest and the largest crumb cells, without changing cell density, possibly as a result of Ostwald ripening, coalescence and separation‐redistribution mechanisms.     

Effects of freezing and frozen storage conditions on the rheological properties of different formulations of non-yeasted wheat and gluten-free bread dough

Empirical and fundamental rheological measurements were made on fresh and frozen dough to study the effects of freezing and frozen storage conditions. Frozen dough was stored at two different temperatures, −18 °C and −30 °C, and for 1, 7 and 28 days. Four dough formulations were tested: a standard wheat dough, a fibre-enriched wheat dough, a standard gluten-free dough and a gluten-free dough containing amaranth flour. No yeast was used in any formulation. The wheat dough is more affected by freezing and by the first days of storage whereas the gluten-free dough is more affected by a longer storage time. A storage temperature of −30 °C alters dough rheological properties more than a storage temperature of −18 °C. The addition of dietary fibres to the wheat dough increases its resistance to freezing and frozen storage. The addition of amaranth flour to gluten-free dough also increases its resistance to freezing but decreases its resistance to storage conditions.     

发芽糙米粉面团性质及面包品质研究

将未发芽和发芽12、24、36、48 h的糙米磨粉,分别与20%的谷朊粉混合制作面团和面包,研究了发芽糙米-谷朊粉面团流变性质及面包品质。结果表明,随着发芽时间的增加,糙米面团弹性模量和粘性模量均降低。扫描电镜结果显示,发芽12 h和24 h糙米面团形成均匀致密的网络结构,发芽24 h后,网络结构部分破裂。随着发芽时间的延长,糙米面包比容、弹性、回复性降低,硬度先降低后升高。发芽12 h和24 h,糙米面包硬度较低,比容、弹性和回复性较大。发芽12 h的糙米面包感官评分最高。因此,发芽12 h时的糙米面包品质最好。     

油脂对面团特性及面制品品质影响研究进展

文章综述了油脂类别、添加量及油脂饱和度对面团特性及面制品品质的影响,指出后续可对有关油脂的内在组分与结构对面团的作用机理,以及油脂、淀粉与蛋白质体系的作用机制进行探究。     

小麦粉改良剂对面团流变学特性的影响

采用粉质仪和拉伸仪研究不同面团改良剂单体(酶制剂、氧化剂、磷酸盐)对小麦粉面团流变学特性的影响。结果表明:α-淀粉酶、木聚糖酶和ADA对面团粉质特性有显著影响;木聚糖酶、ADA和Vc对面团拉伸特性有显著影响,且ADA的影响程度较大。随着α-淀粉酶、木聚糖酶和ADA添加量的增加,面团的稳定时间和评价值呈下降趋势,弱化度呈上升趋势。随着木聚糖酶添加量的增加,延伸性呈增大趋势,拉伸比值和最大抗拉伸阻力均呈下降趋势,且变化幅度较大;随着ADA和Vc添加量的增加,延伸性、拉伸比值和最大抗拉伸阻力与添加木聚糖酶时变化趋势相反。焦磷酸钠和三聚磷酸钠对拉伸特性无明显作用,在一定添加量时对面团粉质特性有明显影响。脂肪酶对粉质和拉伸特性影响不明显。     

豆渣对面团特性及馒头品质的影响

利用粉质仪、拉伸仪、快速黏度仪、物性测试仪研究了豆渣对面团特性及馒头品质的影响。结果表明,随着豆渣添加量的增加,面团吸水率和粉质指数增大、形成时间和稳定时间延长、弱化度减小;面团的最低黏度、衰减值、最终黏度、回生值和峰值时间不断减少,糊化温度先升后降,峰值黏度先降后升,在7.5%出现峰值。随着发酵程度的增大,各面团中淀粉的峰值黏度、最低黏度、最终黏度、回升值、糊化温度都增大,衰减值减小。添加7.5%豆渣可使相同发酵程度下淀粉的峰值黏度、最低黏度、衰减值、最终黏度、回生值、糊化温度都有所降低。添加豆渣后,馒头比容变小,含水量呈增大趋势;馒头硬度、感官评分随着豆渣添加量的增加先降低后增加,在添加量为7.5%时出现峰值。添加豆渣可延长馒头货架期。     

香菇粉对小麦面团热机械学和动态流变学特性的影响研究

本试验通过测定不同比例的香菇粉和小麦粉混合粉的热机械学和动态流变学特性,研究香菇粉对小麦面团特性的影响。结果表明,香菇粉的添加使小麦面团的吸水率增大,面团的形成时间和稳定时间先下降后上升,相应的蛋白质弱化度先升高后降低。香菇粉的添加使小麦面团的峰值黏度和回生值均显著降低。动态流变学试验显示:香菇粉的添加使得小麦面团的黏弹特性发生了显著的变化,储能模量(G')与损失模量(G")均呈现先降低后升高的趋势。而tanδ随香菇粉比例的增大呈现了先略微升高后明显降低的趋势,表明了混合体系中分子交联的程度有所增加,弹性比例增大。     

Effects of wheat sourdough process on the quality of mixed oat-wheat bread

The aim of this work was to study the effects of sourdough fermentation of wheat flour with Lactobacillus plantarum, on the quality attributes of mixed oat-wheat bread (51 g whole grain oat flour and 49 g/100 g white wheat flour). Emphasis was laid both on β-glucan stability as well as bread structure and sensory quality. The variables of the sourdough process were: dough yield (DY), fermentation time, fermentation temperature, and amount of sourdough added to the bread dough. The sourdough process was shown to be a feasible method for mixed oat-wheat bread, and, when optimized, provided bread quality equal to straight dough baking. A small amount (10g/100 g dough) of slack sourdough fermented at high temperature for a long time resulted in the most optimal sourdough bread with the highest specific volume (3.5 cm³/g), the lowest firmness after 3 days storage (0.31 kg), and low sensory sourness with high intensity of the crumb flavour. Wheat sourdough parameters did not affect the content of oat β-glucan in the bread. Additionally, both straight dough and sourdough bread contained 1.4-1.6 g β-glucan/100 g fresh bread. The average molecular weight of β-glucan was 5.5 × 10⁵ in both types of bread, while that of oat flour was 10 × 10⁵. This indicates that a slight degradation of β-glucan occurred during proofing and baking, and it was not affected by variation in the acidity of the bread between pH 4.9-5.8.     

酚基木聚糖对面团特性及馒头品质的影响

以小麦粉为原料,采用0.5%、1.0%、1.5%、2.0%四个添加量添加酚基木聚糖,研究酚基木聚糖对面团特性及馒头品质的影响。结果表明:随着酚基木聚糖添加量的增加,面团的吸水量、弱化度增大,形成时间、稳定时间和粉质指数先增大后减小,酚基木聚糖显著地改善了面团的粉质特性;面团的弹性模量G'呈下降趋势,黏性模量G"呈先升后降趋势,损耗角正切tanδ呈上升趋势;馒头的色泽、比容、硬度、黏附性、胶黏性和咀嚼性下降,凝聚性和回复性无显著差异。在酚基木聚糖添加量为0.5%时,馒头的综合评价最高。随着馒头储藏时间的延长,馒头的硬度呈上升趋势,弹性和回复性呈下降趋势,酚基木聚糖能减缓馒头硬度上升幅度和回复性下降幅度。馒头的老化主要集中在储藏前24 h内,酚基木聚糖的添加能减缓馒头的老化程度。     

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.     

Effect of high hydrostatic pressure to sweet potato flour on dough properties and characteristics of sweet potato‐wheat bread

The effect of high hydrostatic pressure (HHP, 100–400 MPa) for 20 min at 25 °C to sweet potato flour (SPF) on dough properties and characteristics of sweet potato‐wheat bread was investigated. The particle size of SPF after HHP was decreased significantly. The obvious rupture was observed in granules of SPF after HHP at 300 and 400 MPa by scanning electron microscopy (SEM). After HHP, significant differences on endothermic peak temperatures (T_P) of SPF were observed by differential scanning calorimetric (DSC), of which the enthalpy change (ΔH) had a slight increase, expect that at 200 MPa. Gas retention of dough with SPF after HHP increased markedly from 1199 (0.1 MPa) to 1246 ml (100 MPa). Specific loaf volume of bread with SPF at 400 MPa was increased significantly, while the hardness and chewiness were reduced. Thus, SPF treated with HHP at 400 MPa could be potentially used in wheat bread production.     

Evaluation of antioxidant, rheological and sensorial properties of wheat flour dough and bread containing ginger powder

The effects of addition of ginger powder (0, 3, 4.5 and 6%) in formulation were examined in order to obtain an antioxidant-enriched bread with good physico chemical and sensorial properties. The rheological properties of doughs were evaluated using dynamic rheological measurements. Physical properties, total phenolics content (TPC- Folin-Ciocalteau method), radical scavenging activity (RSA- DPPH assay) and sensory analysis (hedonic test) of the supplemented bread were determined.The highest TPC (0.48 and 0.71 mg GAE/g DW on crumb and crust respectively) and RSA activity (0.15 and 0.24 μmol DPPH/mg DW ml⁻¹ on crumb and crust respectively) were achieved in the bread having the highest percentage of ginger powder (6%). But this sample showed the worst results regarding the rheological properties indicating that the dough and the bread had a tough structure. Moreover, by sensory evaluation this bread sample was not acceptable.Among the studied samples, bread with 3% of ginger powder showed good rheological characteristics and doubled anti-oxidant content compared to the control bread and the highest sensorial acceptability.     

麦麸粒径对全麦面团流变学特性的影响

麦麸经不同强度超微粉碎后得到4种不同平均粒径(分别为327、209、144、45μm),将麦麸按照出粉率进行回添得到全麦面粉,以探讨不同粒度组成的麦麸对全麦面团流变学特性的影响。糊化特性分析结果显示随着麦麸粒径的逐渐减小,全麦面粉的峰值黏度、最低黏度、最终黏度和回生值等显著增大。粉质特征显示全麦面粉的吸水率随麦麸粒径的减小逐渐增大,但稳定时间减小、弱化度增大。拉伸仪结果表明醒发时间会影响麦麸粒径对面团面筋网络结构的作用,在面筋网络的逐步扩展和形成阶段(45~90、90~135 min),较小粒径的麦麸会促进面筋网络结构变得密实但降低了其延展性。动态流变学特征显示全麦面团的弹性模量和黏性模量随麦麸粒径的减小而减小,但在扫描范围内高于普通面团。由本研究结果可推测,麦麸粒径的减小会促进淀粉颗粒与麦麸层细胞的分离及麦麸纤维在面团中的分布,但增加了面团形成过程中的物理空间阻碍,干扰了蛋白质分子间的交联和面筋网络结构与淀粉颗粒的结合。      

Effect of frozen storage time on the bread crumb and aging of par-baked bread

The effect of frozen storage time of par-baked bread on the bread crumb and staling of bread obtained after thawing and full baking is described. The moisture content, hardness and retrogradation enthalpy of the amylopectin were determined in the par-baked bread and in the full baked bread after 7, 14, 28 and 42 days of frozen storage at −25 °C. In addition, the effect of frozen storage on the crumb microstructure was analyzed by cryo scanning electron microscopy (Cryo-SEM). The moisture content of both partially and full baked bread decreased with the time of frozen storage. The crumb hardness of the par-baked bread after different periods of frozen storage was kept constant, while that of their full baked counterpart increased with the time of frozen storage. In both types of breads, the enthalpy of amylopectin retrogradation did not vary with the period of frozen storage. The staling, measured as hardness increase and amylopectin retrogradation, increased along the frozen storage. The changes observed on the frozen par-baked bread after thawing were attributed to the damage of bread structures produced by the ice crystallization, and the microstructure study support that conclusion.     

Effect of wheat bran dietary fibre on the rheological properties of dough during fermentation and Chinese steamed bread quality

The effects of wheat bran dietary fibre (WBDF) on the rheological properties of dough during fermentation and quality of Chinese steamed bun (CSB) were investigated. The study revealed that with the increase of the content of WBDF, the dough extensibility and time at which gas starts to escape from the dough significantly decreased but the dough firmness significantly increased (P < 0.05). The elastic modulus and viscous modulus showed an upward trend, probably due to the increased molecular weight of the viscoelastic body resulting from the presence of WBDF. Additionally, by changing the quality of the gluten network, the specific volume and L^* value significantly decreased from 2.52 to 1.31 mL g⁻¹, and from 87 to 51, respectively, these adverse effects on CSBs could be moderated by the fermentation process.     

海藻酸钠对冷冻面团面包烘焙特性的影响

研究添加不同比例(0.1%、0.3%、0.5%和0.7%)海藻酸钠对冷冻面团面包烘焙特性的影响。结果表明,添加海藻酸钠能提高冷冻面团的持水率,减少冷冻面团醒发时间;增大面包的比容,降低面包的硬度和咀嚼性,提高弹性,改善冷冻面团面包的品质。感官评定显示,冻藏不同天数后,添加0.3%的海藻酸钠面包感官评分值最高。     

马铃薯泥对面团及面包品质的影响

为提高马铃薯的利用率,丰富主食面包的种类,选取5个不同品种的马铃薯样品,蒸熟后制成马铃薯泥,按30%的比例添加到面包粉中制作面包。通过分析混合面团的粉质、拉伸特性及发酵性能,研究添加马铃薯泥对混合面团流变学特性的影响;通过对马铃薯泥面包进行感官评价和仪器分析,探索添加马铃薯泥对面包品质的影响。结果表明,添加马铃薯泥后,混合面团筋力减弱,加工性能略有下降,但具有良好的持气能力和产气能力,发酵性能良好;添加马铃薯泥后所制面包体积变大,且不易老化,其中加入5号马铃薯样品的面包感官评价总分最高,面包切片亮度高于对照样品,且粗气孔体积得到改善。综合考虑面包的感官和物理特性,添加5号马铃薯样品做出的面包品质最好。