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天冬多糖理化性质和流变学特性研究 总被引:1,自引:0,他引:1
以野生天冬块根为原料,通过水提醇沉法得到天冬多糖(asparagi radix polysaccharide,ARP),研究其理化性质和流变学特性。结果表明,ARP中总糖含量为(93.75±1.68)%,总糖醛酸含量为(26.99±0.97)%,酯化度为(38.2±0.14)%,重均分子量为730 kDa。ARP由鼠李糖(Rha)、阿拉伯糖(Ara)、半乳糖(Gal)、葡萄糖(Glc)、木糖(Xyl)、甘露糖(Man)6种单糖和半乳糖醛酸(GalA)、葡萄糖醛酸(GlcA)2种糖醛酸组成,物质的量比是0.27∶1.39∶4.42∶12.66∶1∶0.50∶4.83∶0.29。扫描电镜和原子力显微镜观察发现ARP构象为球形聚集状,表面结构紧致平滑。X-衍射结果表明ARP结晶度低。热学特性结果显示ARP具有较高的热稳定性。流变学结果表明,温度、质量浓度、盐离子(Na+和Ca2+)的种类和浓度对ARP的黏度和剪切应力均有影响,且作用方式不同。ARP溶液的黏度随着剪切速率的增加呈现下降趋势,出现剪切稀化现象,表明ARP溶液属于非牛顿流体。研究结果为天冬多糖在食品和医药等领域的开发利用提供理论依据。 相似文献
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为了定量描述织物中水分传输过程中的两个关键因素——芯吸与蒸发的机制,确定影响织物吸湿快干性能的控制因素,采用精密电子天平组装了等液位分段快速响应毛细液体测试装置;并对3种织物的孔径分布与垂直于织物平面方向的芯吸速率进行了测量,对织物的蒸发速率进行了测试,分别比较了3种不同材质与结构织物的芯吸速率与蒸发速率,定量分析水分在织物表面蒸发的机制,分析了织物的孔隙率、平均半径、毛细管大小及孔径分布与织物蒸发速率的关系。试验表明织物的蒸发速率比芯吸速率慢,所以蒸发速率成为织物吸湿快干的速度控制因素。织物的结构应是粗毛细管比例多,外层的材质应疏水。疏水材质织物的芯吸与蒸发速率均快。 相似文献
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目的探究小麦面粉蛋白质理化特性与面团流变学特性之间的关系。方法以19份抗旱节水鉴定品种小麦籽粒为试验材料,测定了蛋白质、湿面筋、谷蛋白大聚体含量、沉降指数等面粉蛋白质理化特性,以及粉质参数和拉伸参数等面团流变学特性,采用通径分析研究了面粉蛋白质理化特性与面团流变学特性的关系。结果面粉蛋白质含量对面团吸水率直接增强效应较大,但对稳定时间、拉伸长度的抑制效应较大;谷蛋白大聚体含量对形成时间、最大拉伸阻力、拉伸面积的直接增强效应和综合增强效应均较大;沉降指数对稳定时间和最大拉伸阻力、拉伸面积的直接增强和综合增强效应较大;所测蛋白质理化特性中未发现对拉伸长度有增强效应的指标。结论面粉中谷蛋白大聚体含量和沉降指数是对面团形成时间、稳定时间、拉伸阻力影响较大的因素,影响为正效应,可为专用面粉生产质量控制提供参考。 相似文献
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大豆分离蛋白起泡性和乳化性影响因素的研究 总被引:4,自引:0,他引:4
大豆分离蛋白的乳化性和起泡性与蛋白质、NaCl、卡拉胶、蔗糖和山梨酸钾含量、pH值、加热温度等密切相关。蛋白质质量浓度分别为2.0g/100mL和2.5g/100mL时,大豆分离蛋白乳化性和起泡性分别达到最大值;远离pH4.5,大豆分离蛋白起泡性和乳化性增加;加热温度45℃时起泡性最好,而乳化性最差;氯化钠、卡拉胶、山梨酸钾添加量分别为1.00g/100mL、0.20g/100mL、0.08g/100mL时,起泡性和乳化性好;添加蔗糖会使蛋白质的起泡性下降,而蔗糖添加量6.0g/100mL时乳化性好。 相似文献
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《Food Hydrocolloids》2006,20(2-3):184-195
Small- and large-strain rheological methods were used to develop rheological profiles of agarose gels, including linear, non-linear, and fracture properties. Gel properties were examined under conditions of varying agarose concentration (0.5–2.5% w/w), glycerol concentration (0–60% w/w), and strain rate (0.0017–0.17 s−1). Small-strain behaviors were primarily elastic with only slight frequency dependence. Large-strain behaviors and fracture properties were dependent upon strain rate, agarose and glycerol concentration. Increasing concentrations of agarose produced an increasingly stronger, more brittle network, while increasing concentrations of glycerol produced an increasingly stronger, more deformable network. All fracture properties and non-linear behaviors increased with increasing strain rate in a similar manner, suggesting a general mechanism responsible for strain rate effects that is similar for non-linear and fracture behavior. Increasing concentrations of agarose and glycerol, respectively, increased and decreased the strain rate dependence of non-linear behavior. Phenomenological models were evaluated for describing non-linear behavior. A second-order polynomial equation was determined to describe the data more accurately than the commonly used BST equation [Blatz, P. J., Sharda, S. C., & Tschoegl, N. W. (1974). Strain energy function for rubberlike materials based on a generalized measure of strain. Transactions of the Society of Rheology, 18 (1) 145–161.], providing an estimated parameter that allowed relative non-linear behavior to be reliably quantified. 相似文献
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淀粉是自然界中仅次于纤维素的第二大生物质, 是碳水化合物在自然界中贮藏的主要形式之一。淀粉既是人类的主要能量来源, 也是一种重要的可再生资源, 被广泛应用在食品、造纸、纺织、精细化工和医药等领域。但是, 原淀粉结构的局限性, 限制了其应用范围和效果。因此, 本文首先综述了淀粉分子结构和颗粒结构对其性能的影响。其次, 阐述了通过淀粉的生物合成、淀粉结构修饰以及纤维素合成淀粉等手段改变淀粉结构, 从而达到调控淀粉性能的目的的方法, 以期为之后的深入研究提供参考。 相似文献
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J M Blanshard 《Journal of the science of food and agriculture》1970,21(8):393-399
The effects in foods of hydrocolloids such as polysaccharides on water-binding capacity, evaporation rate, crystallisation, rheological and other properties are reviewed. 相似文献
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N. CHAMBERLAIN T. H. COLLINS E. E. McDERMOTT 《International Journal of Food Science & Technology》1981,16(2):127-152
Commercial baking trials, designed to investigate the effects of α-amylase activity during baking are described. Increasing α-amylase activity changes both the physical and chemical properties of bread, the physical changes resulting in a loss of crumb mechanical strength, and the chemical changes resulting in an increase in the amount of starch degradation products in the bread, and thus an increase in crumb stickiness. Both types of change can cause problems at the bread slicing stage. A reduction in water added at doughmaking is a successful ameliorative measure, as also is special lubrication of the slicer blades.
Results from the commercial trials have been corroborated and extended in the pilot scale bakery and the laboratory, the more controllable conditions furnishing results that implicate the high molecular weight degradation products of starch as the predominant cause of crumb stickiness. These pilot scale trials also provide evidence for the commercial usefulness of additions of acid calcium phosphate and extra fat as ameliorative measures. 相似文献
Results from the commercial trials have been corroborated and extended in the pilot scale bakery and the laboratory, the more controllable conditions furnishing results that implicate the high molecular weight degradation products of starch as the predominant cause of crumb stickiness. These pilot scale trials also provide evidence for the commercial usefulness of additions of acid calcium phosphate and extra fat as ameliorative measures. 相似文献
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以燕麦籽粒为原料提取燕麦分离蛋白(OPI),研究不同pH及盐离子强度下燕麦分离蛋白溶解性、起泡性、乳化活性及亚基特性。结果表明:①燕麦分离蛋白在pH 5.0~6.0时溶解度最低,起泡性最低,泡沫稳定性最高,在碱性条件下乳化性及乳化稳定性较高;pH 2.0,3.0的酸性条件造成了可溶性燕麦分离蛋白肽链的部分水解,形成了相对分子质量为31.0~43.0kDa的亚基条带,碱性条件下无明显区别。②NaCl浓度为0.05mol/L时溶解度最低,在0.6~0.9mol/L时,起泡性、泡沫稳定性及乳化性均较高;溶解度最低时,可溶性蛋白主要是由相对分子质量为43.0kDa的亚基组成,NaCl的加入,造成了可溶性燕麦分离蛋白肽链的断裂,形成了相对分子质量分别为43.0,66.2kDa的多肽链。 相似文献
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