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.     

Effects of enzymatic treatment conditions on dietary fibre content of wheat bran and use of cellulase-treated bran in cookie

A commercial cellulase preparation (Viscozyme Cassava C) was employed to process wheat bran to improve the ratio of insoluble to soluble dietary fibre. The effects of initial moisture content, enzyme dosage, and incubation time on the content of soluble and insoluble fibre during the enzymatic treatment were investigated. The appropriate conditions for the cellulase treatment were initial moisture content of 0.75 g water g⁻¹ dry matter, enzyme dosage of 9 U g⁻¹ dry matter and incubation time of 120 min under which the ratio of insoluble to soluble fibre of wheat bran was lowered by 42%. Untreated and cellulase-treated wheat bran was incorporated into cookies at levels of 0%, 20%, 30%, 40% and 50%. Cookie with 50% cellulase-treated bran showed 21% lower ratio of insoluble to soluble fibre as well as 14% lower hardness and 13% higher overall acceptability than sample with the same amount of untreated bran.     

Bran-induced changes in water structure and gluten conformation in model gluten dough studied by Fourier transform infrared spectroscopy

The impact of bran addition on the state of water and gluten secondary structure in gluten dough was studied using Fourier transform infrared spectroscopy to understand the underlying physical mechanism by which bran impacts dough properties. Comparison of the OH stretch band of water in gluten dough with that of H₂O–D₂O mixture having the same water content revealed formation of two distinct water populations in gluten dough corresponding to IR absorption frequencies at 3580 cm⁻¹ and 3180 cm⁻¹. The band intensity at 3180 cm⁻¹, which is related to water bound to gluten matrix, decreased with increase of moisture content of the dough. Addition of bran to gluten dough caused redistribution of the bound water in the gluten-bran dough system. This water redistribution affected the secondary structure of gluten in the dough as evidenced from changes in the second-derivative spectrum in the amide I region. In the hydrated state, β-turn (in the form of β-spiral) was the major secondary structure (∼60%) in gluten. Addition of bran to gluten dough caused conversion of β-spirals into β-sheet and random structures. However, the extent of this conversion in the presence of bran was inversely related to the moisture content of the dough. This study revealed that when bran is added to gluten dough, water redistribution promotes partial dehydration of gluten and collapse of β-spirals into intermolecular β-sheet structures; this trans-conformation might be physical reasons for the poor quality of bread containing added bran.     

小麦麸皮膳食纤维在食品中的应用

介绍了小麦麸皮作为食品添加剂在食品中的应用，并对其制成品的生产工艺进行了简要介绍。     

小麦麸皮膳食纤维挤压加工工艺研究

以小麦麸皮膳食纤维为原料,采用双螺杆挤压机对其进行挤压加工,以提高小麦麸皮膳食纤维中可溶性膳食纤维的含量。研究了挤压温度、物料含水量和螺杆转速对原料中可溶性膳食纤维含量的影响,研究结果表明:麸皮含水量20%,挤压温度170℃,主机转速185 r/min时,麸皮原料中可溶性膳食纤维含量由3.22%提高到10.14%。通过高效液相色谱、扫描电镜检测及持水力与膨胀力试验显示,加压处理可以有效地增加可溶性膳食纤维的含量,以及改变麸皮的表面结构。     

麦麸膳食纤维提取条件的优化

本实验以麦麸为原料,采用酶-化学结合法制备膳食纤维,通过正交实验得出其最佳提取条件：α-淀粉酶用量为2.33%,酶解时间20min,碱浓度1mol/L,处理时间45min, 此条件下制备的膳食纤维得率为30.42%,纯度可达86%以上,其中可溶性膳食纤维含量为23.28%。     

麦麸膳食纤维的提取及在食品中的应用

膳食纤维作为“第七大营养素”对维护人体健康起着必不可少的作用,麦麸作为丰富且理想的谷物膳食纤维来源,已受到普遍关注与广泛研究利用。本文综述了麦麸膳食纤维的提取方法及食品应用研究进展,并对未来的研究与发展方向进行了展望,旨在为麦麸膳食纤维有针对性的开发利用提供借鉴与帮助。     

燕麦麸皮添加量对面团流变特性及面筋蛋白结构的影响

将燕麦麸皮以0%、10%、15%、20%、25%(w/w)的比例添加到小麦粉中,研究燕麦麸皮添加量对面团及面筋品质的影响。实验结果表明,随着燕麦麸皮添加量的增加,面团吸水率、形成时间、粘度崩解值显著(p<0.05)增加,稳定时间、回生值显著(p<0.05)降低,面团的热机械学性质下降;面筋蛋白的弹性模量、粘性模量增大,tan δ值降低,面筋蛋白固体特性增强,机械强度增大;面筋蛋白的热降解温度下降、600 ℃时的质量损失率显著(p<0.05)增大,面筋蛋白热稳定性降低;面筋蛋白二硫键含量显著(p<0.05)下降了25.74%~37.59%;扫描电镜的结果表明,添加燕麦麸皮后面筋蛋白原本均匀、致密的网络网络结构遭到破坏,面筋蛋白网络结构变得脆弱、呈蜂窝状。综上所述,添加燕麦麸皮会破坏面筋蛋白均匀致密的网络结构,这可能是导致面团流变性质劣变的原因。     

Wheat bran particle size effects on bread baking performance and quality

Commercial hard red spring, hard red winter, soft white and durum wheat brans were used to evaluate the particle size effect of wheat bran on bread baking performance and bread sensory quality. Three different particle size bran samples were obtained from each bran by grinding, not by sifting, the bran samples. The bran samples were similar in chemical composition, but different in particle sizes. Results of baking experiments showed that breads containing fine bran had lower specific loaf volume and darker crumb colour than breads containing coarse or medium size bran. Sensory test panellists found that fine bran contributed smoother crust appearance and less gritty mouthfeel than the coarse bran. The sensory panel also indicated that breads containing soft white wheat bran had significantly better flavour and mouthfeel than breads containing hard red spring wheat bran. © 1999 Society of Chemical Industry     

Wheat gluten: high molecular weight glutenin subunits--structure, genetics, and relation to dough elasticity

ABSTRACT:  Gluten proteins, representing the major protein fraction of the starchy endosperm, are predominantly responsible for the unique position of wheat amongst cereals. These form a continuous proteinaceous matrix in the cells of the mature dry grain and form a continuous viscoelastic network during the mixing process of dough development. These viscoelastic properties underline the utilization of wheat to prepare bread and other wheat flour based foodstuffs. One group of gluten proteins is glutenin, which consists of high molecular weight (HMW) and low molecular weight (LMW) subunits. The HMW glutenin subunits (HMW-GS) are particularly important for determining dough elasticity. The common wheat possesses 3 to 5 HMW subunits encoded at the Glu-1 loci on the long arms of group 1 chromosomes (1A, 1B, and 1D). The presence of certain HMW subunits is positively correlated with good bread-making quality. Glutamine-rich repetitive sequences that comprise the central part of the HMW subunits are actually responsible for the elastic properties due to extensive arrays of interchain hydrogen bonds. Genetic engineering can be used to manipulate the amount and composition of the HMW subunits, leading to either increased dough strength or more drastic changes in gluten structure and properties.     

麦麸膳食纤维软糖的制备

探讨了麦麸膳食纤维软糖的制备工艺,由实验得知软糖的最佳工艺参数为麦麸膳食纤维为5%、卡拉胶为2.5%、甜味料为85%(蔗糖与淀粉糖浆比为1.51∶)。     

小麦麸皮微波处理对全麦粉面筋品质和流变学特性的影响

目的 探讨小麦麸皮微波处理灭酶对全麦粉面筋品质特性和流变学特性的影响.方法 以中高筋小麦为原料,对麸皮微波处理后再回添到小麦粉中制得全麦粉,设置麸皮水分含量、微波处理时间和麸皮厚度3个变量因素,固定其中2个变量因素,探讨另1个变量因素对全麦粉中面筋特性和流变学特性的影响.结果 麸皮水分含量对湿面筋含量、面筋吸水率、面团...     

不同提取方法对麦麸膳食纤维特性的影响

介绍以麦麸为原料,探讨用不同方法制取麦麸膳食纤维的工艺过程,并着重分析了不同方法制取对麦麸膳食纤维的感官性状及物理特性的影响。     

复合酶处理对麦麸中膳食纤维的影响

以小麦麸为原材料,采用α-淀粉酶结合复合纤维素酶处理,研究了不同酶处理方法对小麦麸膳食纤维中淀粉、蛋白质及植酸的去除作用及其对膳食纤维最终得率的影响。实验结果表明:α-淀粉酶结合复合纤维素酶处理法的效果显著优于单独使用一种酶处理,能显著降低膳食纤维中淀粉、蛋白质以及植酸的含量,且将麦麸可溶性膳食纤维的得率提高至25.3%。     

酶法提取小麦麸皮膳食纤维工艺研究

以小麦麸皮为原料,采用酶法制备膳食纤维,通过正交实验得出最佳提取条件:α-淀粉酶用量0.4%,α-淀粉酶酶解时间50min,蛋白酶用量0.2%,蛋白酶酶解时间50min,此时小麦麸皮膳食纤维得率为81.3%。     

酶法制备小麦麸皮膳食纤维及其功能性质的研究

采用酶法提取麦麸中的膳食纤维。研究发现,基于耐高温α-淀粉酶的去除麦麸附着淀粉的条件为:pH6.5,温度96℃,淀粉酶添加量2%,作用时间2h;筛选得到了1种水解麦麸蛋白质能力较强的商业蛋白酶:Alcalase2.4L,此蛋白酶的去除蛋白质的适宜条件为:pH7.5,温度60℃,蛋白酶添加量1.8%,作用时间3.5h,得到的麦麸膳食纤维纯度>90%,室温下用5%H_2O_2脱色3.5h,最终产品纯度为89.89%。对其功能性质进行进一步研究,结果显示,麦麸膳食纤维的持水力、膨胀力、吸油力随产品粒度的减小而减小,阳离子交换能力随粒度的变化不明显。     

小麦麸皮膳食纤维酸奶初步研制

该研究以小麦麸皮膳食纤维和优质复原乳为主要原料,经乳酸发酵制备一种新型保健酸奶。以产品感官质量和稳定性为评价指标,通过单因素实验,初步确定小麦麸皮膳食纤维保健型酸奶主要原料最佳配比为:奶粉12%,小麦麸皮膳食纤维1%～2%,白砂糖6%,稳定剂淀粉0.5%(或明胶0.5%),草莓香精0.01‰;发酵接种量为3.5%。     

微波辅助Osborne法提取米糠谷蛋白及对其性质的影响北大核心CSCD

米糠中蛋白质含量丰富,蛋白的必需氨基酸组成也比较完整,是一种优良的蛋白资源,因其组成成分复杂,难于提取。为了更加有效地提取米糠谷蛋白,采用微波辅助Osborne法提取米糠谷蛋白,通过单因素试验研究微波功率、微波时间、微波温度对米糠谷蛋白提取率的影响,在此基础上采用正交试验确定最优提取条件,同时研究了微波处理对米糠谷蛋白结构和功能性质的影响。结果表明:在微波功率800 W、微波时间15 min、微波温度40℃的条件下,米糠谷蛋白提取率为73.1%。微波处理后,米糠谷蛋白的α-螺旋和β-转角向β-折叠转移,β-折叠含量明显提高。经过微波处理后,米糠谷蛋白的溶解性提高了8.12百分点,持水性提高了0.89百分点,起泡性增加了20.41百分点,乳化稳定性增加了5.50百分点。随着微波功率的增加,米糠谷蛋白表面疏水性总体增加。适当的微波处理能有效地增加米糠谷蛋白提取率并改善米糠谷蛋白的部分功能性质。研究结果为米糠谷蛋白的工业化制备及在各种食品配方中的应用提供理论支撑。     

Incorporation of gluten and hydrolysed gluten proteins has different effects on dough rheology and cookie characteristics

This study aims to establish how the substitution of wheat flour by high levels (15%, 30% and 45%) of gluten or hydrolysed gluten proteins affects sugar‐snap cookies properties. An increase in water‐binding capacity was observed when proteins were present. An increase in the dough elastic modulus was observed for gluten protein, but it decreased when hydrolysed gluten protein was used. Regarding the physical characteristics of the cookies, for the same protein percentage, the presence of gluten protein decreased spread ratio and increased hardness, while hydrolysed gluten protein increased spread ratio and yielded darker cookies without modifying the hardness. As for sensory characteristics, taste was negatively influenced by hydrolysed protein and visual acceptability was enhanced when gluten protein was present. Overall acceptability was decreased for the highest levels of hydrolysed gluten protein. Nevertheless, the highest levels of gluten protein did not modify the acceptability.