Effects of rice flour size fractions on gluten free rice bread

Fractionation (F-1, F-2, and F-3) of semi-dry milled rice flour (SDMRF) was performed using air-classification wheel speeds (ACWS, 1,000, 2,000, and 3,000 rpm) to identify suitable size fractions for preparation of gluten-free rice bread (GFRB). Characteristics and effects of fractions on GFRB were investigated. Fractions had higher water absorption indices than unfractionated flour (control). Fractions were smaller in size, and the amount of damaged starch was larger for higher ACWS values. The F-1 fraction had higher peak viscosities and specific volumes than other fractions. The F-3 fraction had lower values. GFRB prepared using the F-1 fraction had a lighter air-cell structure and lower hardness than control bread. From sensory evaluations, the particle size of SDMRF affected the appearance of GFRB. GFRB prepared using the F-1 fraction had more uniform and smaller air-cells. The quality of GFRB can be improved by controlling the particle size of flour.     

Effect of black rice flour with different particle sizes on frozen dough and steamed bread quality

This article presents a novel idea for the preparation of frozen dough and steamed bread by which black rice flour (BRF) with different particle sizes (0.18–0.25 mm, 0.15–0.18 mm and 0.125–0.15 mm) was added into wheat flour (WF), considering the nutritional values of BRF. The characteristic of the composite flour (CF), frozen dough and steamed bread was studied. CF had higher contents of dietary fibres (2.01–2.16%) but lower content of protein (11.57–11.92%) compared with WF (1.6% and 12.60%, respectively). Correlation analysis showed that the addition of BRF could alleviate the damage to dough caused by freezing, which may be due to that water in CF dough was more stable. The content of freezable water in WF dough increased by 23.48%, while that in CF dough increased by 6.09–12.11% after frozen storage. With decreasing particle size, the hardness of CF dough decreased and the resistance to extension and gas retention coefficient increased, whereas the specific volume and the soft crumb texture of CF steamed bread increased. In short, small-sized BRF is more suitable for use in the preparation of steamed bread.     

Effects of size of cellulose granules on dough rheology, microscopy, and breadmaking properties

ABSTRACT:  Breadmaking was performed with cellulose-blended wheat flour. Cellulose granules (7 types) of various sizes (diameter) were prepared by kneading. With increase of the blend percent of the cellulose samples from 10% to 20%, breadmaking properties such as bread height and specific volume (SV) gradually decreased in every sample; however, the decreasing levels of the properties in 7 types of various sizes varied. The decrease of bread height and SV was associated with the size of the cellulose granule. It was observed at both 10% and 20% blends that the same bread height and SV as for bread baked with only wheat flour could be obtained when the diameter of cellulose granule was above 154 μm in cellulose/wheat flour breadmaking, while they gradually decreased with granules below 154 μm. When the largest cellulose granules were mechanically ground to make smaller ones, the bread height and SV decreased with increasing grinding time. It was ascertained that the size of the cellulose granule was important for breadmaking properties. Cellulose-blended wheat flour was subjected to mixograph tests. When cellulose granules above 154-μm dia were blended with wheat flour, the profile of the mixogram was almost the same as that for wheat flour; that is, the profile had a short mixing requirement and showed a viscous gluten matrix. However, when cellulose granules below 81-μm dia were blended, a different curve showing a nonviscous dough due to breakdown of the gluten protein was observed, as ascertained by microscopy. Farmograph test showed that the amount of the released gas from cellulose-blended bread dough increased with decrease of the size of the cellulose granule due to breakdown of the gluten protein.     

Image Analysis of Representative Food Structures: Application of the Bootstrap Method

ABSTRACT:  Images (for example, photomicrographs) are routinely used as qualitative evidence of the microstructure of foods. In quantitative image analysis it is important to estimate the area (or volume) to be sampled, the field of view, and the resolution. The bootstrap method is proposed to estimate the size of the sampling area as a function of the coefficient of variation (CV _Bn ) and standard error (SE _Bn ) of the bootstrap taking sub-areas of different sizes. The bootstrap method was applied to simulated and real structures (apple tissue). For simulated structures, 10 computer-generated images were constructed containing 225 black circles (elements) and different coefficient of variation (CV _image ). For apple tissue, 8 images of apple tissue containing cellular cavities with different CV _image  were analyzed. Results confirmed that for simulated and real structures, increasing the size of the sampling area decreased the CV _Bn  and SE _Bn . Furthermore, there was a linear relationship between the CV _image  and CV _{Bn .} For example, to obtain a CV _Bn  = 0.10 in an image with CV _image  = 0.60, a sampling area of 400 × 400 pixels (11% of whole image) was required, whereas if CV _image  = 1.46, a sampling area of 1000 × 100 pixels (69% of whole image) became necessary. This suggests that a large-size dispersion of element sizes in an image requires increasingly larger sampling areas or a larger number of images.     

Determination of a representative area element (RAE) based on nonparametric statistics in bread

The concept of representative area element (RAE) was applied to quantify the air cell present in pre-sliced bread. Ten slices from bread were selected and each divided into nine subareas where 60 air cells were measured. To determine the RAE, one to nine sampling areas were considered and five positions in the image were randomly selected and compared by nonparametric statistic and the fluctuation of mean air cell area method. The RAE was attained when the air cell area size distribution curves for each sampling area did not present significant differences. Hence, the RAE size was 67% of the image using the nonparametric method (equivalent to six subareas of the nine subareas that form the image), whereas the RAE could not be estimated using the fluctuation of mean air cell area method. Therefore, nonparametric statistics are a useful tool to determine the RAE in structures with size distributions that do not fit a normal distribution.     

Physico-chemical changes in breads from bake off technologies during storage

Quality of several bread specialties from frozen partially baked breads was assessed to define main quality features. Loss of crust freshness shortly after baking was also determined. Quality parameters that characterize bread crust and crumb were determined by instrumental methods in nine different (regarding to formulation and bake off duration) bread types obtained from frozen partially baked breads. Principal component analysis (PCA) allowed discriminating among bread specialties. Quality parameters that enable the differentiation of wheat bread types were crust mechanical properties together with specific volume, crumb hardness and structure. Crust flaking barely represented a problem in the studied types of bread. Crust mechanical properties were rapidly lost during the first 4 h after baking and the rate of the process was greatly dependent on the bread type. The force to promote crust fracture underwent increase up to 6 h after baking and those changes occurred in the Aw range of 0.50-0.74 or moisture content 9-15 g/100 g.     

Particle Size of Whole Meal Rye Bread does not Affect the Digestibility of Macro-Nutrients and Non-Starch Polysaccharides and the Energy Value of Dietary Fibre in Humans

The effect of particle size of whole meal rye bread on the apparent digestibility of macro-nutrients, non-starch polysaccharides (NSP) and energy, the energy value of rye NSP and on faecal weight was studied in balance experiments in seven young women. The whole meal breads were prepared from one single batch of rye milled to two different particle sizes (coarse bread: 50% of particles >2 mm, 90% >1 mm; fine bread: 86% of particles <0·5 mm, 58% <0·2 mm). Two diets containing either coarse (350 g day⁻¹) or fine (377 g day⁻¹) whole meal bread and a low fibre control diet were consumed for 3 weeks each in a 3×3 cross-over design. Relative to the low fibre control diet, digestibility of protein, NSP and energy was significantly lower for the diets containing the whole meal breads. Digestibility of fat was the same for all diets. Partial digestible energy value for each g of NSP from coarse and fine whole meal rye bread was calculated to be −3±7 and 1±5 kJ, respectively. There were no differences between coarse and fine whole meal rye bread in the effects on the parameters measured with the exception on faecal wet weight, which was higher for the coarse bread diet.     

Cantilever beam bending as a potential method to determine the elasticity of cooked Udon noodles

Elasticity is a critical measure of the eating quality of Udon noodles. To characterize the elasticity of Udon noodles, an instrumental method based on the cantilever beam bending test was established. Firstly, the optimum test parameters were determined. Then, texture profile analysis, compression, tension, and cantilever beam bending methods were used to measure the elasticity of 25 commercial Udon noodles with different shapes and sizes, and the correlations between elasticity obtained by the above instrumental methods and sensory evaluation were analyzed. Finally, how the shape and size of Udon noodles influenced their elasticity was discussed in detail. Within the deflection of 2.0 mm, the force increased approximately linearly with increasing deflection, and moderate loading speed (0.5–1.0 mm/s) should be used in the cantilever beam bending experiments to improve the accuracy of results. The bending stiffness obtained by the cantilever beam bending method exhibited a higher coefficient of variation and stronger correlation with the elasticity of sensory evaluation than other instrumental methods. Furthermore, the Udon noodle sample with a higher size, especially the thickness, had higher elasticity, and the Udon noodle sample with a rectangular cross-section showed higher elasticity than that with a circular cross-section. In conclusion, the bending stiffness determined by the cantilever beam bending method could be used to characterize the elasticity of cooked Udon noodles.     

Influence of maize flour particle size on gluten‐free breadmaking

BACKGROUND: Maize, one of the suitable grains for coeliac consumption, is, together with rice, the most cultivated cereal in the world. However, the inclusion of maize flour in gluten‐free bread is a minority and studies are scarce. This paper analyses the influence of different maize flour types and their particle sizes on the quality of two types of bread without gluten (80% and 110% water in the formulation) obtained from them. We also analysed the microstructure of the dough and its behaviour during the fermentation. RESULTS: Finer flours had a lower dough development during fermentation in all cases. Among the different types of flour, those whose microstructure revealed compact particles were those which had higher specific bread volume, especially when the particle size was greater. Among the formulations, the dough with more water gave breads with higher specific volume, an effect that was more important in more compact flours. The higher volume breads had lower values of hardness and resilience. CONCLUSION: The type of corn flour and mainly its particle size influence significantly the dough development of gluten‐free bread during fermentation and therefore the final volume and texture of the breads obtained. The flours having coarser particle size are the most suitable for making gluten‐free maize bread. © 2012 Society of Chemical Industry     

Discrimination of Volatiles of Refined and Whole Wheat Bread Containing Red and White Wheat Bran Using an Electronic Nose

Abstract: The principal objective of this study was to evaluate the capability of electronic (E) nose technology to discriminate refined and whole wheat bread made with white or red wheat bran according to their headspace volatiles. Whole wheat flour was formulated with a common refined flour from hard red spring wheat, blended at the 15% replacement level with bran milled from representative samples of one hard red and 2 hard white wheats. A commercial formula was used for breadmaking. Results varied according to the nature of the sample, that is, crust, crumb, or whole slices. Bread crust and crumb were completely discriminated. Crumb of whole wheat bread made with red bran was distinct from other bread types. When misclassified, whole wheat bread crumb with white bran was almost invariably identified as refined flour bread crumb. Using crust as the basis for comparisons, the largest difference in volatiles was between refined flour bread and whole wheat bread as a group. When refined flour bread crust was misclassified, samples tended to be confused with whole white wheat crust. Samples prepared from whole bread slices were poorly discriminated in general. E‐nose results indicated that whole wheat bread formulated with white bran was more similar in volatile makeup to refined flour bread compared to whole wheat bread made with red bran. The E‐nose appears to be very capable to accommodate differentiation of bread volatiles whose composition varies due to differences in flour or bran type. Practical Application: Consumer preference of bread made using refined flour in contrast to whole wheat flour is partly due to the different aroma of whole wheat bread. This study used an electronic nose to analyze bread volatiles, and showed that whole wheat bread incorporating white bran was different from counterpart bread made using red bran, and was closer in volatile makeup to “white” bread made without bran. Commercial millers and bakers can take advantage of these results to formulate whole wheat flour with brans of preferred type in order to foster increased consumption of whole wheat products which confer many favorable health benefits.     

A Novel Approach to the Study of Bread Porous Structure: Phase-contrast X-Ray Microtomography

ABSTRACT: The evaluation of bread quality can be carried out by performing a nondestructive investigation of its microstructure, which in turn can be performed by adapting image analysis techniques that enables one to obtain rapid, objective, and quantitative information. A suitable and reliable experimental methodology to investigate the porous structure of bread by means of the numerical image processing, and without any sample preparation, has been presented in this work. Different types of breads having varying degrees of porosity were studied by X-ray computerized phase-sensitive microtomography for the acquisition of digital high-resolution images. After acquisition, suitable numeric algorithms were applied to slice reconstruction. Finally, 3D images were rendered and analyzed.     

Microstructure,textural and sensorial properties of durum wheat bread as affected by yeast content

In this study, breads varying in yeast content and therefore leading to distinct cellular structures are investigated. Firstly, X-ray microtomography is used to characterize not only the final cellular structure, but also the process of development of microstructure during the fermentation stage. With μCT, image analysis of the full 3-D microstructure, measuring the size, shape, networking/connectivity and distribution of various phases was possible. These measurements represent the full 3-D microstructure, which is not always possible by 2-D image analysis using statistical techniques. Secondly, the textural properties of the baked bread were obtained by compression tests and finally, the sensorial quality of the final product is also evaluated and correlated with the above properties. Results showed that an increase of the yeast content increased the percentage volume of pores and decreased the force required for compression of the bread sample and the tenacity. Moreover, a larger quantity of smaller sized pores led to a firmer bread structure. Regarding the sensorial properties, none of the investigated microstructural parameters were significantly correlated with the overall quality of the bread. In fact, the overall quality was more strongly affected from other parameters such as odor and appearance attributes.     

特色酵子馒头的感官及风味分析

以河南商丘（SQ）、南阳（NY）、新乡（XX）3个地区的特色酵子及其发酵制作的馒头为研究对象,通过对酵子pH值与可滴定酸度、乳酸菌和酵母菌计数、感官评价、质构分析、图像分析和固相微萃取与气相色谱质谱联用法对不同地区特色酵子馒头的感官及风味物质进行定量定性分析比较。结果表明,酵子样品的pH范围是5.59~5.92;TTA范围是2.12~3.40 mL;从菌落计数上看,XX酵子中的酵母菌细胞密度最高为3.93 lg(cfu/g),SQ酵子中的乳酸菌细胞密度最高为3.39 lg(cfu/g);XX酵子馒头的质地性状、压缩张弛性和黏着性都优于其他两种酵子馒头;在图像分析中,XX酵子馒头的切片亮度、气孔对比度、气孔数量最大,壁厚、粗气孔体积、气孔直径最小,表明其内部纹理结构较好,且更被大众所喜爱;GC-MS分析可知,从XX酵子馒头中鉴定出65种挥发性风味物质,NY酵子馒头为58种,SQ酵子馒头为61种。XX酵子馒头中对风味贡献较大的是烯烃类、醇类和羧酸类,占总量的89.06%。NY酵子馒头对风味贡献较大的也是烯烃类、醇类和羧酸类,占总量的79.13%。SQ酵子馒头中对风味贡献较大的是烯烃类、醇类和酮类,占总量的66.05%。同时,这三种馒头都存在各自所特有的风味物质。结果表明:不同酵子制作馒头的感官和风味存在一定的差异,为馒头工业化生产提供理论支持。     

添加麦芽粉和抗坏血酸对面包烘焙品质的影响

研究添加麦芽粉和抗坏血酸对面包烘焙品质的影响。以河南和山东2个小麦主要生产省的29个代表性品种样品为材料,用布勒实验磨制粉后,在面包基础配方上设置添加组和未添加组,研究添加麦芽粉和抗坏血酸后面包感官评分、质构及C-Cell图像分析变化。结果表明,添加麦芽粉和抗坏血酸后,可明显提高面包体积、体积评分、外观评分和最终综合评分,使面包冠变大,颈变明显;对面包芯色泽、质地和纹理的改善作用不明显。质构分析中面包的硬度和韧性均明显减小,衰减比例无明显变化。C-Cell指标中的面包切片面积、切片周长、气孔数量、平均气孔密度值均明显增大,切片亮度和气孔直径明显降低。仪器评价指标与面包感观评价中部分参数存在相关关系。     

Composite flour blends: Influence of particle size of water chestnut flour on nutraceutical potential and quality of Indian flat breads

Different sieve particle sizes P1 (Whole), P2 (≤0.212 mm) and P3 (≤0.125 mm) of water chestnut flour (WCF) were studied for proximate composition, mineral content, physico-chemical, functional, pasting and antioxidant properties in comparison to refined wheat flour (WF). WCF had significantly higher levels of fiber, resistant starch, mineral (K, Mg, Zn, and Cu), phenolics and flavonoids than WF in the order (P1?>?P2?>?P3?>?WF). Increase in flour fineness decreased antioxidant activity (P1?>?P2?>?P3) with P1 having highest phenolic (4.72 mg GAE/g), flavonoid (2.46 mg QE/g) content. Pasting properties of P1 were significantly lower than WF but significantly increased with increase in flour fineness. Quality of flat bread produced from WCF-WF blends significantly varied with particle size and blending. Bake loss and baking time significantly decreased while shrinkage increased with decrease in particle size. L* value decreased with blending but showed an irregular trend with variation in particle size. (WF?>?P2?≥?P3?>?P1). Baking decreased DPPH scavenging activity more in WF bread (46.68%) than WCF bread (P1?=?17.71%, P2?=?16.45%, P3?=?19.63%). Baking decreased total phenolic and flavonoid content by 49 and 20% in wheat & 38 and 16% in WCF respectively while significantly increased the resistant starch content in the order (P3?>?P2?>?P1?>?WF). This shows better retention of antioxidant activities and greater stability of WCF phenolics than WF phenolics during baking. Sensory analysis showed WCF breads had fair acceptability due to their characteristic flavor. Thus, gluten free WCF bread is also antioxidant rich with ample resistant starch content than WF breads.     

Interrelationship between image,dough and Barbari bread characteristics; use of image analysis to predict rheology,quality and shelf life

Cellular materials are often anisotropic, i.e. their properties depend on the direction in which they are measured. The aim of this work was to examine the effect of liquid improver components on image features (colour difference, average size, area fraction, cell wall thickness, fractal dimension, solidity, and circularity) of Barbari flat bread in both cross and longitudinal sections. Glycerol, sodium stearoyl‐2‐lactylate and enzyme active soy flour were evaluated as improver constituents. Image characteristics were furthermore correlated with dough rheology, quality, and shelf life in both sections of bread. Results from statistical analysis suggest that the parameters describing anisotropy or the favourite orientation of cell structure are crucial in understanding more than 50% of differences observed in crumb architecture. The coefficients of determination of all the response variables were higher than 0.81. Among image features, colour difference and average size gave the most correlations from ?0.857 to 0.896 and ?0.784 to 0.698 with other properties, respectively.     

斜向分割线在现代旗袍结构中的应用

为拓展旗袍结构设计思路,以分割线为切入点,选择具有代表性的无袖旗袍作为研究对象,对斜向结构线在旗袍中的应用进行研究。设计了2种同尺寸的旗袍结构,设已有的斜裁制版方式为对照组,调整分割线所含省量的结构为实验组;每组结构均以2种不同的丝向(垂直和45°斜向)进行裁剪,并制作4款样衣。通过对比4款样衣的人台着装效果证实:调整后的旗袍腰部贴合度更好,但整体流畅度有待提高;竖直丝向裁剪的服装弹性较好,但衣片宽度较宽,对面料幅宽有较高要求;经进一步分析样本优劣,得出每种制版方式和裁剪方式的适用情况,并总结出斜向分割线应用于旗袍的设计规律。