Dough mixing and breadmaking properties of quinoa-wheat flour blends

Flour blends of quinoa-wheat containing 0, 5, 10, 15, and 20% of manually dehulled quinoa meal or flour were evaluated for dough mixing and breadmaking properties and liking of the bread by a small panel. Increasing amounts of quinoa meal or flour increased farinograph absorption and dislike of bread for most of the panel. Dough development time increased with increase in meal but decreased with increase in quinoa flour. At 10% inclusion levels differences in liking from control 100% wheat flour bread were smaller for flour or water extracted meal to most of the panel, than with 10% non-extracted meal. This suggests that 10% inclusion of flour or water extracted meal may have potential for further investigation.     

D-Erythroascorbic Acid in Bakers'Yeast and Effects on Wheat Dough

Extraction of hydrated and freeze-dried bakers’yeast yielded ～ 50 μg erythroascorbic acid (EAA) and 5 μg ascorbic acid (AA)/g dry yeast as determined by HPLC with electrochemical detection. D-EAA (82 ppm based on flour) slightly increased the flow of dough as rest time increased. Gluten isolated from a flour-water dough containing 82 ppm D-EAA or 100 ppm Lcysteine stretched at a faster rate than control gluten. EAA like AA did not change dough development time. Unlike AA, EAA showed neither oxidizing effect on dough and gluten nor improving effects on bread.     

Permeability Measurements of Porous Food Materials

Permeability of air through porous pre-gelatinized flour dough was measured as a function of porosity (0.10–0.60), moisture content (15–50%, wet basis), and fat content (0–6%). At free stream velocities <2 cm/sec, flow rate and pressure drop followed Darcy's law for flow through porous media. Permeability values ranged from 0.02 darcies at 0.10 porosity to about 23 darcies at 0.60 porosity. Permeability of dough does not follow the Kozeny model for granular materials, possibly due to differences in tortuosity between dough and granular materials. Moisture content <50% and fat content to 6% did not directly affect permeability.     

Effects of water on the rheological characteristics of biscuit dough and quality of biscuits

 The influence of water on the rheological characteristics of biscuit dough and quality of biscuits was studied. A variation of even 1% in water content considerably changed the various rheological characteristics of biscuit dough. Increasing water content by 3% significantly increased the compliance from 32.6% to 45.6%, and decreased the extrusion time from 100 s to 34 s, the apparent biaxial extensional viscosity from 3.06×10⁵ Pas to 1.5×10⁵ Pas, and the consistency from 943 Ns to 620 Ns for dough based on weak wheat flour. The elastic recovery of biscuit dough increased significantly from 0.425 mm to 0.535 mm. Dough became more cohesive and adhesive with increasing water content, whilst biscuits became harder, as indicated by increases in density, breaking strength and compression strength. Received: 14 September 1998     

添加剂及储藏温度对糯性粉团抗老化的研究

研究了在不同储藏温度(-18、4、25和37℃)下的糯性粉团,通过分析储藏0-5 d中的水分含量、水分活度、质构特性和热力学特性的变化来研究老化性质,并对食品添加剂对其抗老化作用作了研究。研究表明:(1)在各个储藏温度条件下,食品添加剂的加入可以有效地抑制糯性粉团的老化回生,可使糯性粉团的硬度较小、水分含量较高、水分活度较低、DSC测定的ΔH较小。(2)在-18℃条件下储藏的糯性粉团的老化速率最慢,经过自然解冻后其品质接近于新鲜糯性粉团。当储藏温度位于冰点温度(0℃)以上时,在4℃储藏的糯性粉团的老化速率相比25℃和37℃要快很多,且37℃条件下储藏的糯性粉团的老化速率低于在25℃条件下储藏的糯性粉团。表明糯性粉团最适宜的储藏温度应是-18℃。而当储藏温度位于冰点温度(0℃)以上时,温度越低,糯性粉团的老化回生愈加显著。     

THERMAL AND DYNAMIC-MECHANICAL PROPERTIES OF FROZEN WHEAT DOUGHS WITH ADDED SUCROSE,NaCl, ASCORBIC ACID,AND THEIR MIXTURES

The effects of sucrose, NaCl, and ascorbic acid on the physical state of wheat dough at sub-zero temperatures were investigated using Differential Scanning Calorimetry (DSC) and Dynamic-Mechanical Analysis (DMA). The DSC thermograms were obtained for annealed samples by scanning from ?80 to 10°C at 5°C/min. Added sucrose and NaCl decreased the onset of ice melting of doughs, and they were found at ?26°C. Added sucrose and NaCl increased the relative amount of unfrozen water in doughs, while added ascorbic acid had not noticeable effects. DMA measurements were made for annealed samples at a heating rate of 1°C/min from ?150 to 10°C. The loss modulus, G″, of DMA showed an α-relaxation (glass transition), two low temperature relaxations (β and γ), and melting of ice in all doughs with added ingredients.     

涡流喷气纱成纱结构与捻度测试方法探讨

分析了MVS涡流喷气纱微观结构形态,探讨了涡流喷气纱捻度概念及其测试方法.对外包纤维含量测试方法进行了探索,提出了可能影响外包纤维含量的一些因素.     

不同Waxy蛋白亚基缺失小麦材料的籽粒性状和面团流变学特性的比较

普通六倍体小麦中存在为数不多的自然突变的Waxy蛋白亚基缺失小麦材料。选用自然突变形成的4种缺失1个或2个Waxy蛋白亚基的部分糯小麦材料,2种Waxy蛋白亚基全缺失的糯小麦品系,以普通中筋小麦济麦19作为对照,研究其籽粒性状和面团的粉质特性、揉混特性、拉伸和黏度特性。结果表明,糯小麦的籽粒硬度、直链淀粉含量与其他小麦相比明显偏低;部分糯小麦的直链淀粉含量比对照有不同程度的降低。面团的粉质特性、揉混特性和拉伸特性测定表明,糯小麦面团的吸水率极显著高于其他小麦,其稳定时间、断裂时间,揉混特性的中线峰值时间、峰值面积、8min尾高,拉伸特性的最大拉伸阻力、拉伸曲线面积、最大拉伸比显著低于对照,而部分糯小麦（江苏白火麦除外）的粉质参数（吸水率除外）、揉混参数、最大拉伸阻力、最大拉伸比均高于对照,达显著或极显著水平。黏度特性上,糯小麦的面团黏度、附着功、黏聚性较大,部分糯小麦（江苏白火麦除外）的面团黏度较小,均呈显著或极显著性差异。综合面团的流变学特性测定表明,糯小麦面粉的吸水率高,但面团的结构差,筋力弱;Sturdy、Satanata和IKE3个部分糯小麦的面团的耐揉性、耐搅性、面团筋力优于济麦19,也优于糯小麦;缺失Wx—D1亚基的江苏白火麦的大多数面团流变学参数与糯小麦无显著性或极显著性差异。     

复合添加剂改善面包冷冻面团质量的试验研究

冷冻面团的出现为面食制品和主食的工业化、标准化、连锁化生产创造了条件，但是冷冻面团在应用过程中会出现各种各样的问题。本文全面分析了影响冷冻面团流变学特性的主要因素，研究了酶制剂、硬酯酰乳酸钙钠、谷朊粉、维生素C、磷酸盐时冷冻面团流变学特性的影响，通过正交试验确定了复合冷冻面团品质改良剂的最佳配比，大大改善了冷冻面团的流变学特性，使其烘焙的面包品质大大提高。     

Effects of flour from different barley varieties on barley sour dough bread

Twenty flours from 16 different barley varieties cultivated in 1990 and 1992, and a Swedish reference flour, were fermented by Lactobacillus plantarum A1 to sour doughs. Barley breads (40% barley/60% wheat flour) from each flour type were baked with and without an admixture of barley sour dough in order to investigate how the sour dough admixture would affect the baking properties. A trained panel carried out sensory evaluation by conventional profiling on breads made from three of the barley varieties and the Swedish reference flour, made with and without sour dough admixture.

The barley varieties influenced both the sour dough properties and the properties of the barley bread. The pH of bread with sour dough ranged from 4.6 to 4.8 as compared to 5.4 to 5.6 in bread without sour dough. The acidity of the breads with sour dough ranged from 4.1 to 5.0 ml NaOH/ 10 g bread crumb as compared to 2.4 to 3.6 in breads without sour dough. In 14 of the twenty bread types an addition of sour dough lowered the bread volume. Breads with a sour dough admixture scored higher for total taste and acidulous taste than breads without sour dough. The β-glucan content of the flours had no significant influence on the sour dough or the sensory characteristics of the bread, except for the breadcrumb colour.