Effect of rice variety,rice flour concentration and enzyme levels on composite bread quality

A study was conducted to determine the suitability of substituting portions of wheat flours with rice flours for breadmaking. The levels of substitution were 50, 100, 150 and 200 g kg^?1. Two kinds of enzymes, barley malt and fungal amylase, were added to composite flours, and their effects on the volume and quality of the rice-based bread were determined. The results showed that the enzymes, levels of replacement and the varieties of rice had significant effects on weight, specific volume and overall acceptability of the bread samples. However, the enzymes did not have significant effects on the volume, protein and fat contents or on the character and color of the crust in the sensory analysis. Comparisons were made of the nutritional and sensory qualities of the bread made entirely from wheat flour, and the sample which performed best, the bread with 50 g kg^?1 of flour from low amylose variety (183.3 g kg^?1) with barley malt, showed non-significant differences. The overall acceptability of the products showed that it is acceptable to substitute wheat flour with flours generated from rice up to the 150 g kg^?1 replacement level only.     

乙腈沉淀-离子色谱法测定婴幼儿米粉中硝酸盐和亚硝酸盐

目的 建立一种婴幼儿米粉中硝酸盐和亚硝酸的乙腈沉淀-离子色谱分离检测方法。方法 样品经乙腈/水(体积比5/5)溶液沉淀蛋白后, 在提取温度35℃,超声提取30 min的条件下, 过0.22 μm滤膜净化。采用KOH水溶液作为流动相进行梯度洗脱, 离子色谱检测硝酸盐与亚硝酸盐。结果 本实验比较了乙腈沉淀、亚铁氰化钾-乙酸锌沉淀法和淀粉酶酶解法对婴幼儿米粉中亚硝酸盐和硝酸盐分离的影响, 结果显示, 乙腈沉淀法比较适合婴幼儿米粉中硝酸盐和亚硝酸的提取净化。实验还优化了提取试剂乙腈/水(体积比)的比例、提取时间和提取温度对硝酸盐和亚硝酸盐的影响。在提取试剂乙腈/水(体积比)为5/5, 提取温度35℃, 提取时间30 min条件下, 米粉中硝酸盐和亚硝酸盐的提取效果最好, 回收率均在90~110%之间。结论 该方法操作简便、提取速度快、检出限低,适用于婴幼儿米粉中硝酸盐和亚硝酸盐的检测。     

Utilization of chestnut flour in gluten-free bread formulations

In this study, gluten-free bread formulations using chestnut and rice flours at different ratios (0/100, 10/90, 20/80, 30/70, 40/60, 50/50 and 100/0) were tested. In addition, the influence of hydrocolloid blend (xanthan-locustbean gum (LBG), xanthan-guar gum blend) and emulsifier DATEM on the rheological properties of dough formulations and quality parameters of breads were also investigated for the samples having chestnut/rice flour ratio of 10/90, 20/80, 30/70 and 40/60. Herschel-Bulkley model was found to explain the flow behavior of all dough formulations. The power-law index (n) of dough samples at 25 °C ranged from 0.52 to 0.87, the consistency index (K) of the samples ranged from 3.6 to 79 Pa sⁿ and the yield stress of the samples ranged from 4.8 to 85.9 Pa. The breads prepared with chestnut/rice flour ratio of 30/70 and containing xanthan-guar blend and emulsifier, had higher quality in terms of hardness, specific volume, color and sensory values. However, elevated levels of chestnut flour led to some deterioration in quality parameters (low volume, harder texture and darker color) regardless of gum blend and emulsifier addition.     

面粉灰分含量对面制品的影响

对影响面粉灰分的各因素进行了分析,并探讨了面粉灰分含量对面制品的影响。     

杂粮粉与小麦粉粘度特性比较研究

对几种杂粮粉与小麦粉的粘度特性进行了比较研究,结果显示:杂粮粉糊化温度和开始糊化的时间、热粘度及其稳定性、冷粘度及其稳定性等粘度特性都存在着明显的不同。为进一步了解小麦与杂粮淀粉的特性及应用开发提供了一定的理论依据。     

Fatty acids composition and rheology properties of wheat and wheat and white or brown rice flour mixture

Manufacturing of bread from rice flour only presents technological difficulty because the rice is gluten-free and gluten is the most important structure forming protein. By using wheat and rice flour mixture, this problem can be avoided, and end product is enriched by rice-oil constituents. In this paper fatty acids composition, with an emphasis on total saturated, and total unsaturated fatty acids, rheological and baking properties of wheat–rice flour mixture (70:30 w/w) were investigated. The results show that wheat–rice flour mixture has better fatty acids composition with higher content of stearic, arachidic, lignoceric, oleic, and phthalic acids compared to wheat flour. Also, wheat flour did not include myristic, arachidic, lignoceric and linolenic acids, so rice flour addition made fatty acids profile richer as number of constituents is higher, nine instead six. The content of total unsaturated fatty acids content was higher in wheat–brown rice flour mixture than in wheat flour and in wheat–white rice flour mixture. When rice flour was added to wheat flour the rheological properties were changed: flour mixture had less water absorption, less degree of softening, longer development time, higher gelatinization temperature, but better stability and finally, better quality number and group than wheat flour. So, the wheat and rice flour mixture can be considered as a good quality flour and can be used for making good quality wheat-rice bread and cake.     

Expansion of rice flour treated with lactic acid and sodium bisulphite

This study aimed to develop the expansion property of rice flour using a 2² complete factorial experimental design, investigating the effects of sodium bisulphite concentration and pH on the expansion capacity, carbonyl and carboxyl contents and viscoamylographic behaviour. The sodium bisulphite concentration and pH influenced the development of the expansion property of the lactic acid treated rice flour, presenting the best volumes at pH 4 with 2.18 and 7.82 g/100 g sodium bisulphite. In order to express the highest specific volume, the proportion between the carbonyl and carboxyl groups was more important than the sum of the two, the best proportion being between 0.3 and 0.4 carbonyl and between 0.6 and 0.7 carboxyl. The chemical modification using lactic acid and sodium bisulphite affected the maximum viscosity of the rice flour, but did not influence the minimum or final viscosities.     

The effects of freeze, dry, and wet grinding processes on rice flour properties and their energy consumption

This study attempted to replace the wet grinding process of rice with a freeze grinding process. The freeze grinding process involved soaking the rice samples in liquid nitrogen before grinding in a dry grinding machine. Three different types of grinders (hammer mill, roller mill, and pin mill) were used in both the freeze and the dry grinding processes. Wet grinding resulted in significantly (P < 0.05) smaller average particle size and a lower percentage of damaged starch than the alternative methods of grinding. Freeze grinding, especially using the hammer mill significantly reduced both the average particle size and the damaged starch content. Moreover, freeze grinding produced a higher yield after sieving in comparison with dry grinding using an identical grinder. In particular, freeze grinding with the hammer mill gave a significantly higher yield after sieving than dry grinding with the hammer mill. The wet grinding process had the significantly highest specific energy consumption (13,868 kJ/kg) due to the large consumption of electrical energy by the many machines in the process. The energy consumption of freeze grinding was similar to dry grinding. Consequently, the freeze grinding process was a viable alternative to the traditional wet grinding process.     

Effect of soil moisture stress from flowering to grain maturity on functional properties of Sri Lankan rice flour

Functional properties of flour from rice variety BG 250 (short‐season) and BG 359 (long‐season) exposed to soil water stress from flowering to grain maturity were investigated. Protein content was reduced in both varieties but lipid was reduced only in BG 359 in response to soil moisture stress. AAM content decreased in BG 250 but unaffected in BG 359. Water stress increased swelling power, onset of pasting, peak viscosity, granular breakdown, gel hardness, and cohesiveness in both varieties. Gelatinization temperatures in both varieties were unaffected by water stress, while gelatinization enthalpy was increased in BG 359 but unchanged in BG 250. A double endotherm (type I and type II) appeared in AM–lipid complex in all the flour samples. Type I AM–lipid complex was reduced in BG 359 in response to water stress. Only a single endotherm appeared in the re‐formed AM–lipid complex in gelatinized starch. The magnitude of the ΔH of re‐formed AM–lipid complex was reduced in BG 359 in response to soil moisture stress, but unaffected in BG 250. Water stress decreased AP retrogradation in BG 359 while it was unaffected in BG 250.     

利用清粉机提高面粉质量及出粉率的技术措施

面粉质量及出粉率与小麦加工企业经济效益密切相关,清粉机对提高面粉质量及出粉率起到至关重要的作用,制粉工艺的复杂性及清粉机本身操作的复杂性对利用好清粉机具有一定的难度。基于此,从清粉系统的合理配置、研磨和筛理的配合、清粉机的操作与清粉效果的控制三个方面介绍了利用清粉机提高面粉质量及出粉率的技术措施。     

不同出粉率小麦粉的品质特性及营养组分研究

小麦制粉过程不同出粉率的小麦粉粉质特性、营养组分含量都有明显差异。根据在线生产的各系统粉管的出粉率和流量比,按流量比例取不同粉管的小麦粉配成出粉率分别为35%,40%,50%,60%,70%,80%,90%、97%的小麦粉。对不同出粉率的小麦粉进行粉质特性和营养组分测定,研究出粉率对小麦粉品质和营养组分含量的影响,以期为生产中生产出加工品质、食用品质、营养品质均佳的小麦粉提出理论上的参考。试验结果表明微量营养素和粉质特性在出粉率80%左右达到最佳状态,但是灰分含量偏高。     

石磨面粉与钢磨面粉特性比较研究

目前石磨小麦粉在市场上日趋增多,石磨以其转速低而与钢磨有所区别,因此造成两种加工方式的小麦粉特性差异。通过测定两个品种石磨小麦粉和钢磨小麦粉的水分、含砂量、湿面筋质量分数、面团形成时间、稳定时间、拉伸比等理化指标进行比较,得出烟农21和济麦22(邹城)石磨小麦粉的湿面筋质量分数分别为34.2%、39.1%,稳定时间分别为2.7、1.6 min,面团形成时间分别为4.6、2.3 min。以上指标石磨小麦粉优于钢磨小麦粉,但在含砂量方面,若不严格控制小麦的清洗和除磁去石,石磨小麦粉的含砂量将偏高。     

Production of acidic extruded rice flour and its influence on the qualities of gluten-free bread

One of the greatest technological challenges in the production of gluten-free bread (GFB) is to find a low-cost ingredient capable of retaining gas during fermentation and the baking process. The use of gelatinized starch appears to show promise for this purpose. In this study, GFB was made using raw rice flour (100 g) with the addition of 10 g acidic extruded rice flour (AERF). The AERF was produced in a single-screw extruder, varying the extrusion temperature and lactic acid concentration. Response surface methodology (RSM) and the principle components analysis (PCA) were used to analyze the results. The results of RSM showed no significant difference, but the mean volume obtained with the AERF (1.95 mL g⁻¹) was still low when compared with that of wheat bread (6 mL g⁻¹). The crust and crumb colors and the texture (hardness = 173 g; chewiness = 90.5 and fracturability = 178) presented results similar to those of wheat bread and better than other GFB found in the literature. When analyzed by PCA the AERF obtained at 150 °C-0.5 mol L⁻¹ lactic acid, showed the best results for the GFB obtained. IR spectroscopy showed that no bands were found for esters (1740 cm⁻¹) in the AERFs, which could indicate that no new bonds were formed between the rice flour and the lactic acid.     

汉中面皮水磨米粉的加工技术优化研究

目的为简化传统汉中面皮的生产工艺,对汉中面皮水磨米粉的生产加工技术进行优化。方法在保持汉中面皮传统风味口感的前提下,以出品率作为评价标准,选择大米的浸泡时间、水温、米水比例、搅拌速度4个因素进行单因素实验。在此基础上,通过正交实验对汉中面皮水磨米粉生产工艺条件进行优化,得出最佳工艺参数。结果通过正交实验获得的最佳工艺参数为:浸米时间4.5 h,水温20℃,浸泡米水比1:2.5(g:mL),搅拌速度30 r/min(搅拌1次/h,每次搅拌15 min)。使用此工艺参数生产水磨米粉的出品率为93.6%。结论优化了汉中面皮水磨米粉加工工艺,将汉中面皮的加工原料由大米改为水磨米粉,省去了大米浸泡和磨浆工序,省时省力,为消费者提供方便实用的产品。     

比萨专用粉制备研究

该文报道以加麦、国优小麦为原料制备比萨专用粉工艺,通过以必胜客比萨、棒约翰比萨为对照的应用效果比较,运用感官评定和质构分析等方法加以分析,结果表明,所制备比萨专用粉既适于作为薄底比萨、又适于作为厚底比萨原料,更具适用性。     

燕麦粉及其与小麦粉混合后白度的探讨

探讨了16个品种燕麦粉的白度,并将燕麦粉按不同比例与小麦粉混合,对混合粉的白度进行测定分析。结果表明,燕麦粉的白度值为60.00~69.90;不同品种、不同地区的燕麦粉白度有所差异;燕麦粉的白度整体上明显小于小麦粉的白度。分析发现混合粉白度与燕麦粉和小麦粉的比值成显著线性关系,且燕麦粉白度越小,随着小麦粉比例的增大,混合粉的白度上升幅度增大。     

Effects of particle size distributions of rice flour on the quality of gluten-free rice cupcakes

The particle size distributions (PSD) of rice flour and milling processes are important in making gluten-free products. The dry rice flour was prepared by grinding dried rice grains after soaking. Effects of PSD on the quality of rice cupcakes were investigated using the newly-developed rice flour. The flour properties passed through 80, 120, 160, and 200 (<180, <125, <95, and <75 μm) meshsieves, and batters and cupcakes prepared from their flours were analyzed. The PSD patterns showed two peaks containing cells and free starch fractions, in which the starch fraction peak intensity increased as a particle size decreased. While damaged starch, water binding capacity, solubility and lightness increased, crude protein and yellowness decreased as a particle size decreased. The final and setback viscosities increased as a particle size decreased. The specific volume of cupcakes was the highest in the cupcakes made with rice flour passed through under 95 μm. Hardness and springiness decreased as a particle size decreased. The air cell sizes decreased as a particle size decreased with homogeneity. Air cell homogeneity, volume, hardness, and softness of cakes determined by the different test, and appearance, texture, and overall quality determined by the preference test were all significantly different (p < 0.05).     

玉米粉配比对玉米-小麦混合粉及其馒头品质的影响

采用不同的配比将玉米粉与小麦粉搭配,通过测定玉米-小麦混合粉指标和馒头指标,以研究玉米粉对混合粉及其馒头品质的影响。结果表明:随着玉米粉比例的增加,混合粉的吸水率、稳定时间、粉质指数呈逐渐减小的趋势;最大抗延伸性、拉伸面积、沉降值、湿面筋、面筋指数也逐渐降低;峰值黏度、稀懈值、回升值、降落数值等都有所下降,而糊化温度和弱化度有所上升。玉米粉的使用在一定程度上影响了面团的流变学性能,降低了面筋的品质,但是在比例不超过15%时影响并不十分明显,辅以一定的改良技术,不但可以生产出食用品质优良的馒头,而且可以改善馒头的营养特性。