热水预抽提对南方松碱法制浆过程影响的研究

本文研究了热水预抽提对南方松碱法制浆过程的影响。结果表明:热水预抽提可使蒸煮过程中黑液固形物含量和木素的溶出量增加,提高后续蒸煮过程中有效碱的作用效率。合适时间的热水预处理可使木片具有更好的制浆性能,但预处理时间过长会导致蒸煮后成浆强度下降。     

Effects of freezing and frozen storage conditions on the rheological properties of different formulations of non-yeasted wheat and gluten-free bread dough

Empirical and fundamental rheological measurements were made on fresh and frozen dough to study the effects of freezing and frozen storage conditions. Frozen dough was stored at two different temperatures, −18 °C and −30 °C, and for 1, 7 and 28 days. Four dough formulations were tested: a standard wheat dough, a fibre-enriched wheat dough, a standard gluten-free dough and a gluten-free dough containing amaranth flour. No yeast was used in any formulation. The wheat dough is more affected by freezing and by the first days of storage whereas the gluten-free dough is more affected by a longer storage time. A storage temperature of −30 °C alters dough rheological properties more than a storage temperature of −18 °C. The addition of dietary fibres to the wheat dough increases its resistance to freezing and frozen storage. The addition of amaranth flour to gluten-free dough also increases its resistance to freezing but decreases its resistance to storage conditions.     

脱脂活性豆粉对面粉品质的影响

通过在面粉中添加一定比例的脱脂活性豆粉,研究了其对面粉流变学性质、快速粘度性质及馒头品质影响。粉质试验表明,脱脂活性豆粉可使面团的校正吸水率提高,稳定时间提高(除1.0%略低于空白外),形成时间缩短,粉质指数提高,弱化度降低;快速粘度特性结果表明,脱脂活性豆粉可使面粉峰值粘度、低谷粘度、崩解值和最终粘度降低,糊化温度(除2.5%)提高;馒头实验表明,脱脂活性豆粉可以提高馒头表面白度,增加成品质量和体积。     

添加荞麦多肽粉对面团流变学特性的影响

将不同水解条件下得到的荞麦多肽粉按不同浓度梯度分别添加到强筋和弱筋面粉中,探讨荞麦多肽粉对面团流变学特性的影响。结果表明:添加不同量荞麦多肽粉的面团,吸水率均随荞麦多肽粉添加量的增加而不断降低,当超过8%添加量后,吸水率受到的影响较小;面筋的含量随着荞麦多肽粉添加量的增加呈现先增加后减小的趋势;面团形成时间和稳定时间随荞麦多肽粉添加量的增加均呈先减小后增加的趋势,弱化度呈上升趋势,评价值也呈现一直增加的趋势。从拉伸特性来看,随着荞麦多肽粉添加量的增加,面团的延伸性变好,拉伸阻力在高浓度添加量的情况下比原面粉大,拉伸能量则呈现一直增加的趋势。总体而言,添加荞麦蛋白粉及其多肽粉对面团粉质及拉伸特性均具有促进作用。     

The effect of different mixing processes on dough extensional rheology and baked attributes

BACKGROUND: Mixing is a significant part of the breadmaking process and is responsible for the development of the essential structure that will facilitate gas retention during proofing and the early stages of baking. The main objective of this study was to examine whether the dough extensional rheological and baking properties were affected from different mixers and energy inputs during mixing. RESULTS: It was found that extensional properties in uniaxial and biaxial extension were affected by the mixing equipment used and by the energy input used. Doughs mixed using a Farinograph had higher maximum resistance to uniaxial extension, higher P value and lower biaxial extensibility (Alveograph) and higher biaxial extensional viscosity than doughs mixed in a Stephan mixer (P < 0.01). The energy input was specific to each type mixing equipment and affected the biaxial extensional viscosity. Also, higher loaf volumes were achieved when higher energy inputs were used, whereas other baking properties were not affected. CONCLUSION: Altering the mixing equipment and the mixing speed affected the rheological properties of dough. Dough development during proofing as well as loaf volume was affected by the energy input levels and was increased by increasing the energy input and therefore the mixing time. Copyright © 2010 Society of Chemical Industry     

热水直埋管道设计要点

结合CJJ 34-2002城镇热力网设计规范和CJJ 104-2005城镇供热直埋蒸汽管道技术规程等相关规范,介绍了热水直埋管道设计要点,分别对管道布置,补偿方式的选择,保温层的选择计算等进行了具体阐述,提出了相应的理论基础和设计思路,以期指导实践。     

超声波辅助热水浸提茶树菇多糖工艺

茶树菇多糖具有抑制肿瘤细胞生长,调节机体免疫功能,它是由10个以上的单糖残基通过糖苷键连接而成的高分子多聚物.本研究通过L9(34)正交试验设计优化茶树菇多糖提取过程4个对多糖提取率影响程度较高的条件因素(浸提时间、水浴温度、超声波破碎时间和功率),并对提取的多糖进行了必要的性质鉴定.结果表明:茶树菇菌柄和菌盖中多糖的提取条件中水浴温度为75℃,超声波破碎时间为190 s,超声波破碎功率为80W;但菌柄多糖浸提时间较菌盖长,分别为85 min和80 min.     

硬脂酰乳酸钠对冻融循环发酵面团及其油炸甜甜圈品质的影响

作者研究了硬脂酰乳酸钠(Sodium stearyl lactate,SSL)对预醒发冷冻面团及其油炸甜甜圈品质的影响.将SSL加入自制发酵面团中,通过测定4次冻融循环后发酵面团的拉伸特性、流变学特性、可冻结水含量,以及冻融循环发酵面团油炸甜甜圈的比容、质构特性、表皮色泽、内部纹理结构、吸油率和水分损失率及感官评分,研...     

拉面改良剂对拉面面团的影响研究

主要研究拉面改良剂对拉面面团的流变学特性、二硫键含量和蛋白二级结构的影响。采用质构仪、揉辊仪、二硫键和傅里叶变换红外色谱的测定方法,对不同添加量的拉面剂对面团的影响进行测定分析。试验结果表明:当拉面剂添加量在0.8%~1.2%时,质构特性显示面团延伸性最佳(68.43mm),最大拉伸力适中(73.09g);揉辊特性显示和面时间和8min带宽适中,此时面团筋力和耐揉性较好;二硫键结果显示此时面团内部二硫键含量为21.62%,游离巯基含量为6.92%;红外结果显示面筋蛋白二级结构中的β-折叠含量最高,此时面筋蛋白中有序结构(β-折叠+α-螺旋)整体含量最高。实验结果证实拉面改良剂具有还原和弱化面筋增加面团延伸性的作用。     

质构仪在面团和面包品质评定中的应用研究(英文)

以八种品牌面粉为试验材料,采用英国 CNS-FARNELL 公司制造的质构仪测试了面团的硬度、弹性、粘力、粘着性、断裂力、断裂能量、断裂回复形变程度、回复能量、回复形变程度等九种指标,并通过相关分析研究了这些指标与面包品质(面包体积和弹性变化率)以及与小麦面粉的品质性状的相互关系。研究结果表明:面团的硬度、粘力与面包的体积呈正相关,相关系数分别为 0.546、0.568,弹性与面包的体积呈负相关,相关系数为-0.606;粘力与24h后室温下弹性变化率呈显著的正相关,相关系数为0.707。面团的质构特性与面粉的品质指标的相关性也非常明显。