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。     

谷朊粉对糙米粉面团性质影响研究

研究了谷朊粉添加量对糙米粉面团性质的影响,主要包括粉质特性、热机械性质、流变学性质、微观结构等。结果表明:随着谷朊粉添加量增大,面团的吸水率、形成时间、稳定时间、淀粉衰减值和回生程度均在逐渐增长,蛋白弱化度在逐渐降低。糙米粉面团的弹性模量和粘性模量均在增大,且弹性模量大于粘性模量。扫描电镜结果显示:随着谷朊粉添加量增大,面团的网络结构越来越明显,淀粉颗粒镶嵌在蛋白形成的网络结构中,增加了面团的弹性及变形的阻力。     

发芽糙米和羟丙基甲基纤维素对面包品质的影响

本文研究了在面粉中添加发芽糙米粉(GBR)和羟丙基甲基纤维素(HPMC)对面包品质的影响。结果表明,添加80目、100目发芽糙米粉制作的面包的比容、硬度、弹性要明显优于60目,而添加80目发芽糙米制作的面包与100目制作的面包之间无显著性差异(p>0.05)。随着发芽糙米粉添加量的增大,发芽糙米面包比容、弹性、内聚性减小,硬度增大;发芽糙米添加量为40%时,其口感已达到不可接受的程度。通过添加HPMC可以有效提高高含量发芽糙米面包的品质,且随着HPMC添加量增大,面包的感官品质逐渐提高。当HPMC浓度为2%时,面包的比容显著性提高,硬度降低,面包的弹性和内聚性增加,提高了面包的整体接受度,改善面包的感官特性。另外,通过考察混合面团的微观结构发现,添加HPMC可以有效改善面团的面筋网络结构。因此,在高含量发芽糙米面包中添加HPMC可以有效改善面包的品质。      

亲水胶体对发芽糙米面包品质特性的影响

研究添加不同浓度的胶体(羟丙基甲基纤维素、海藻酸钠、黄原胶)对发芽糙米面包品质的影响。结果表明,不同胶体对面包的改善作用不同,且不同食品胶适宜添加浓度不同。与未添加胶体的发芽糙米面包相比,添加2%的羟丙基甲基纤维素,面包比容增大25%,硬度降低35%,弹性增加9.5%,内聚性增加9.8%;添加0.1%的海藻酸钠,面包比容增大19%,硬度降低31%,弹性增加10%;而添加黄原胶,对高含量发芽糙米面包的品质无明显改善作用。     

发芽糙米粉理化性质研究

对发芽粳糙米粉和发芽籼糙米粉基本成分、微观结构、热焓特性及糊化性质(RVA)等进行了研究。结果表明:与糙米粉相比,发芽糙米粉中粗脂肪含量降低,蛋白质含量增加,总淀粉含量降低,粗纤维、灰分等含量变化不明显;随着发芽时间的增长,糙米粉峰值粘度、最低粘度、崩解值、最终粘度和回升值都降低;发芽糙米粉峰值温度、起始温度、终止温度及焓值均比糙米粉低,且籼糙米高于粳糙米。扫描电镜结果显示:发芽后糙米粉颗粒结构变得较疏松,棱角不太明显,发芽籼糙米粉颗粒结构较发芽粳糙米粉颗粒结构更加疏松,淀粉颗粒体积更小。      

膨化黑米粉对面包品质影响研究

以膨化黑米粉为主要原料,通过探讨添加膨化黑米粉对面粉粉质、面包焙烤品质及面包贮存过程中老化程度影响,以期制作高质量黑米面包。试验结果表明,添加膨化黑米粉对面团流变性有一定副作用,在不超过8%添加量时影响很小,若超过8%添加量,则性质急剧下降,不适于生产,通过焙烤实验,添加膨化黑米粉可大大改善面包风味,结合储藏实验,在添加量不超过8%情况下面包各理化指标变化不大。     

黑米粉对面团热机械学特性及面包烘焙品质的影响

将黑米粉添加到小麦粉中,研究了不同比例黑米粉对面团热机械学特性、面包品质和贮藏特性的影响。结果表明,随着黑米粉添加量的增加,面团的C1形成时间、稳定时间呈下降趋势,而蛋白质弱化度呈上升趋势;此外黑米粉的添加降低了淀粉的回生值C5-C4,黑米粉添加量为15%时,C5-C4值降低了34.0%。焙烤制得的面包比容下降,感官品质下降,硬度增大,面包的弹性先增加后降低,在添加量为7.5%时弹性最大,添加量在5%~10%均大于对照样品。综合面包比容、色泽、质构与营养而言,黑米粉添加量7.5%时制作的面包品质良好。黑米粉的添加对面包的老化有一定的抑制作用。     

糙米粉添加量对面包品质的影响

研究了糙米粉添加量(10%~70%)对糙米面包品质的影响。结果表明:随着糙米粉添加量增大,糙米面包体积逐渐减小,弹性、内聚性、回复性逐渐降低;面包的硬度、胶黏性、耐咀性逐渐升高,孔壁厚度、气孔直径及粗糙气孔体积都随之增大,气孔壁加厚,结构粗糙、紧实,面包芯颜色逐渐加深,外观有褶皱出现,当添加量为40%时,其外观及口感可以接受。     

Composite wheat–germinated brown rice flours: selected physicochemical properties and bread application

Selected physicochemical properties of composite [wheat/germinated brown rice (GBRF)/germinated glutinous brown rice (GGNBRF)] flours at 100:0:0 (control), 70:30:0, 60:30:10, 60:40:0 and 50:40:10 (%) were evaluated. Germination (steeping at pH 3 for 24 h at 35 °C) increased free gamma‐aminobutyric acid from 2.11 to 32.7 and 2.41 to 30.69 mg per 100 g flour for GBRF and GGNBRF, respectively. The 60:30:10 and 50:40:10 composite flours exhibited the lower peak viscosity (70.42 and 68.54 RVU, respectively). The setback viscosity of composite flours containing GGNBR was significantly lower than other flours. The presence of GBRF and GGNBRF significantly lowered specific volume and expansion ratio of breads. However, all sensory liking scores, except for appearance, were not significantly different among composite flour breads. Overall liking scores of all breads ranged from 6.8 to 7.2 (like moderately). This study demonstrated feasibility of incorporating GBRF and GGNBRF up to 50% by weight in bread formulations without compromising sensory liking.     

Physicochemical and sensory properties of soy bread made with germinated,steamed, and roasted soy flour

For the development of healthful gluten-free soy bread acceptable to consumers, we evaluated the effects of various processing procedures for soy flour on bread quality, in terms of beany flavour and texture. We pretreated soy flour by both non-heating (raw:NS and germinated:GS) and heating (steamed:SS and roasted:RS) methods. In addition, to improve the loaf volume, we added 1% hydroxypropyl-methylcellulose (HPMC) to RS flour. Lipoxygenase activity was retained in the non-heat-treated flours (279 U/g for NS and 255 U/g for GS), but was significantly reduced in the heat-treated flours (106 U/g for SS and 69 U/g for RS). Moreover, heat-treated flour had higher isoflavone and ferric reducing antioxidant power than had non-heat-treated flour. However, RS flour had the lowest moisture content and lowest L^∗ value. The GS bread had the highest specific loaf volume (3.53 cm³/g), followed by NS (2.96 cm³/g), RS (2.25 cm³/g), and SS (1.81 cm³/g) bread. GS bread had the lowest hardness (1.53 N), followed by NS (1.65 N), RS (2.00 N), and SS (3.75 N) bread. The addition of 1% HPMC to RS increased the loaf volume (2.44 cm³/g), but decreased the bread’s hardness (1.80 N). As to the sensory properties, the bread with heat-treated flour was perceived to have a less beany odour and taste than was the bread with non-heat-treated flour. However, the latter had a better appearance than the former. These results indicated that soy flour pretreatment could enhance the loaf volume and reduce the beany flavour of whole soy bread.     

Bread quality and dough rheology of enzyme-supplemented wheat flour

The enzymatic treatment of wheat flours is an interesting alternative for improving their functional properties. Since enzymes with different biochemical activities could induce synergistic effects on dough behaviour or product quality, the individual and combined use of a wide range of enzymes (transglutaminase, glucose oxidase, laccase, α-amylase, pentosanase and protease) applied nowadays in bread-making processes were investigated. The blend of enzymes resulted in an improvement in the rheological behaviour of doughs and the quality of the final product. The simultaneous presence of transglutaminase (TG) and glucose oxidase (GO), as well as TG and protease (PROT) led to a synergistic effect on alveograph parameters. Polysaccharide-degrading enzymes exercised a significant effect on rheology only when used in combination with other enzymes, mainly affecting consistograph parameters. Analysis of bread-making data revealed significant interactions between TG and all the other enzymes except laccase (LAC). Significant synergistic effect on bread quality was observed by the combined use of GO and LAC, GO and pentosanase (PP), amylase (AMYL) and LAC, AMYL and PROT, and PP and PROT. Bread quality parameters showed greater correlations with alveograph parameters than with consistograph properties of dough. Tenacity (P) and extensibility (L) proved to be acceptable predictors of the height/width ratio of loaves. The duration of the alveograph test enhanced the prediction of bread quality parameters. Conversely, none of the rheological properties studied showed a high correlation with the specific volume of loaves.     

谷氨酰胺转氨酶对挤压糙米粉面团蛋白特性和面条品质的影响

将挤压糙米粉(EBR)与小麦粉以1∶1(m/m)的比例混合制成面条,研究了谷氨酰胺转氨酶(TG)添加量(0.5%、1.0%和1.5%)对面条性质的影响。结果表明,TG添加后,面条中游离巯基含量减少,SDS-PAGE条带显示面条中形成了大分子质量的聚集体。随着TG的添加,面条最佳蒸煮时间增加,干物质损失率降低,吸水率升高。添加量为1.0%时,面条最佳蒸煮时间和吸水率达到最大值,蒸煮损失率达到最小值。TG添加量为0.5%时,面条的硬度、耐咀性、回复性和剪切力最大。扫描电镜结果显示,TG的添加明显增强了面条内部结构的连接与聚合,面条内部变得更加紧实,连续性增强。TG添加量为0.5%~1.0%时,挤压糙米粉面条质构品质和蒸煮品质较好。     

Influence of phosphorylated rice flour on the quality of gluten‐free bread

The chemical modification of rice flour by phosphorylation is an alternative to improve the technological quality of bakery products. The aim of this study was to investigate the effect of phosphorylation process of rice flour on technological properties (specific volume, crumb and crust colour) of gluten‐free breads and the hardening of these breads during two storage temperatures (21 °C and ?24 °C). Breads were made with native rice flour, with phosphorylated rice flour and with wheat flour, used as control. The phosphorylation causes significant reduction in the synaeresis of pastes and in retrogradation tendency of rice flours, varying from 258.7 cP (native rice flour) to 122 cP (phosphorylated rice flour). The breads prepared with phosphorylated rice flour showed reduction in the hardness in both storage temperatures studied and effect on rice bread volume, crumb appearance and colour, demonstrating the possibility of use of the phosphorylated rice flour in gluten‐free breads.     

Effect of the shape of rice starch granules on flour characteristics and gluten‐free bread quality

The effect of three different rice varieties with different starch shapes (Seolgaeng (SG), round starch structure; Samkwang (SK), polygonal starch structure and Boramchan (BRC), polygonal starch structure) on rice flour characteristics and gluten‐free bread baking quality was investigated. Rice flours were produced by dry milling and passed through a 200 mesh sieve. Electron microscopy revealed that the structure of SG grains, with round starch granules, possessed larger void spaces than SK and BRC, composed of polygonal starch granules. For this reason, SG grain had low grain hardness and consequently, it was milled to a fine flour with low damaged starch content. The thermo‐mechanical properties were determined by Mixolab, which revealed that SG was gelatinised rapidly and maintained high viscosity after gelatinisation. These characteristics gave SG flour the ability to build up bread structure without gluten. Specific volume and crumb hardness of gluten‐free rice breads made of SG, SK and BRC flours were 3.37, 3.11 and 2.12 mL g^?1 and 2.61, 2.76 and 6.46 N, respectively. The SG flour with round starch structure is appropriate for making gluten‐free rice breads.     

燕麦全粉对面团特性及馒头品质的影响

以不同比例(0%~50%)的燕麦全粉替代小麦面粉,通过粉质、拉伸、快速黏度分析、旋转流变、F3-发酵流变、面团p H值的测定及质构分析等手段研究了混合面团的流变学特性、发酵特性及馒头的质构品质。结果表明:随着燕麦全粉替代比例的增加,混合粉的湿面筋含量显著降低,面团的吸水率增大,形成时间和稳定时间先增大后减小,弱化度逐渐增大,最大拉伸阻力和拉伸比例先降低后升高,延伸度逐渐降低;混合粉的峰值黏度、回生值、糊化温度及面团的弹性、黏性模量都随燕麦全粉的加入而逐渐增大;面团的持气性逐渐降低,漏气时间提前;燕麦全粉的加入使面团的p H值增大,使酵母及乳酸菌等的代谢受到了影响;燕麦全粉的替代比例小于20%时,混合粉仍具有较好的加工特性,更高含量燕麦全粉的加入将会导致馒头的比容和弹性显著降低,硬度明显增大。     

Effect of isomaltodextrin on dough rheology and bread quality

Isomaltodextrin (IMD) is a novel highly branched α-glucan ingredient that has potential applications in foods as a promising source of dietary fibre. In this study, we assessed the incorporation of IMD in baked products and its effect on dough rheology and physico-textural characteristics of wheat breads. IMD was added to wheat flour to reach the US FDA level of ‘good’ source of fibre (10% IMD). Use of the straight-dough method with IMD and regular dough mixing time (8 min) resulted in less elastic doughs and resulting breads displayed lower cohesiveness, springiness and chewiness compared to the control bread. A modified straight-dough method, with longer mixing time (36 min) and adjusted water level (70%), and a sponge-and-dough method were used to allow gluten structure to more fully hydrate and develop. With IMD addition, the modified straight-dough (36 min dough mixing time) and sponge-and-dough methods yielded enhanced dough elasticity compared to the original straight-dough method. Breadmaking methods were identified (improved straight-dough and sponge-and-dough) whereby IMD could be added at a 'good source' of fibre level with loaf appearance and texture similar to breads without IMD.     

Effect of flaxseed and wheat flour blends on dough rheology and bread quality

The rheological and baking properties of flaxseed/wheat composite flours were studied. Flaxseed flour was used to replace 50, 100, 150 and 200 g kg^?1 of wheat flour in bread. Farinographic studies showed that water absorption, dough development time and mixing tolerance index increased as the amount of flaxseed flour increased, while dough stability decreased at 100, 150 and 200 g kg^?1 of flaxseed flour substitution. The extensographic energy of dough also decreased at 150 and 200 g kg^?1 flaxseed levels. The addition of increasing amounts of flaxseed flour caused a decrease in extensibility. Doughs containing 100, 150 and 200 g kg^?1 flaxseed flour showed resistance to extension comparable to that of control dough. The specific volume of flaxseed flour breads was similar to that of control bread. Crust L, a, b values of breads with flaxseed flour were lower than those of control bread. Breads with flaxseed flour gave lower crumb L and b values and higher a values than control bread. The sensory properties showed that an acceptable bread could be produced using flaxseed flour up to a level of 200 g kg^?1. Copyright © 2007 Society of Chemical Industry     

谷朊粉对面包基础粉品质特性的影响

探讨不同添加量的谷朊粉对面包基础粉蛋白质的品质、流变特性及面包烘焙品质的影响。结果表明:谷朊粉可以明显增加面包基础粉的湿面筋含量、沉淀值和蛋白质含量,强化其流变学特性,有效改善面包烘焙品质,增大面包比容和高径比并改善其弹性和硬度。当谷朊粉添加量为10%时,面包烘焙品质最好。     

米粉对面团流变特性及酥性饼干品质的影响

目的 探究了米粉的添加对面团流变学特性以及酥性饼干品质的影响。方法 选取了3种米粉(粳糯米粉、籼糯米粉、普通粳米粉)分别以0%、10%、20%、30%的比例替代中筋小麦粉，研究分析了米粉-中筋小麦粉混合粉的糊化特性，面团的粉质拉伸特性，动态流变以及酥性饼干的理化性质，质构特性及感官品质。结果 随着两种糯米粉添加量增加，混合粉的糊化特征值均呈下降趋势，而添加普通粳米粉后则趋势相反；添加米粉后混合面团的吸水率和弱化度随着三种米粉的添加量的增加显著升高，分别可达65.7%和160.50，而面团形成时间和稳定时间则显著降低(P<0.05)；混合面团的弹性模量（G''），黏性模量（G"）和损耗角正切值（tanδ）随着米粉添加量的增加而逐渐减小，表明米粉的添加减弱了面筋网络的形成；与低筋粉酥性饼干相比，混合粉酥性饼干的延展比较低，且三种米粉的添加可显著提升酥性饼干的脆性，经感官评价及综合比较后得出添加20% 籼糯米粉的混合粉饼干整体品质较佳。结论 通过在中筋面粉中加入米粉后可以有效改变面团的特性，以替代低筋面粉应用于酥性饼干的加工 ，本研究也为米粉在酥性饼干专用粉的制备奠定了理论基础。