论浆液粘度测量规范化

本文主要讨论了浆液的流变特性及粘度对切变速率依赖性理论,并在大量实验的基础上提出了常用化学浆粘度测定的具体条件和方法。     

草浆高浓黑液的流变性与粘流温度效应

利用Rheometrics RFSII流体粘弹仪测量了蔗渣浆黑液多聚物体系的剪切应力，表现粘度与剪切速率的关系，由实验得出了蔗渣浆高浓黑液在工程剪切速率范围（10^-1～10^3s^-1)内属剪切稀化流体，浓度和温度越高，黑液的剪切稀化现象越显著。此外，利用Brookfield粘度仪测定了黑液的剪切粘度与温度的关系，得出蔗渣浆黑液的粘度与温度的关系符合指数递规律。粘度越大，黑液粘度对温度的依赖性越强。     

剪切速率对表面活性剂／水体系的作用研究

本文研究了剪切速率对表面活性剂／水体系粘度的影响，结果表明在低剪力速率下，该体系的粘度随其浓度和温度的变化有两个特征，在粘度突跃区，该体系呈现假塑性流体，遵循时渐等效定律，非粘度突跃区，该体系呈现牛顿流体的特点，此时温度成为粘度的主要影响因素。     

水溶性高分子聚合物对喹吖啶酮颜料分散体系流变性质的研究

研究了不同类型水溶性高分子聚合物对喹吖啶酮颜料(颜料红122)分散体系流变性能的影响。实验结果表明：加入不同类型高分子聚合物后，颜料红122分散体系的粘度随剪切速率增大而下降，即剪切变稀，采用Herschel—Bulkley模型描述加入不同类型高分子聚合物后颜料红122分散体系的剪切速率—剪切应力变化曲线，并使用稠度系数、流动特性指数和屈服值表征了不同类型高分子聚合物对分散体系流变性能的影响。     

应用果胶甲基酯酶改善番茄酱的粘度

研究了添加果胶甲基酯酶对不同类型番茄酱粘度的影响。结果表明,果胶甲基酯酶对于热破番茄酱具有明显增强粘度的作用,而对于冷破番茄酱作用较弱。热破番茄酱中的果胶在果胶甲基酯酶的作用下成为低酯果胶,并在钙离子的作用下进一步形成交联,从而使粘度提高;而冷破番茄酱中没有果胶(或含量很低),所以果胶甲基酯酶对其粘度没有明显作用。     

冰淇淋稳定剂的分类和作用机理

１　冰淇淋稳定剂的主要功能１）提高冰淇淋浆料的粘度，降低流度。根据物理化学、胶体化学的基本原理，冰淇淋浆料是一种热力学不稳定的微多相体系。在足量冰淇淋稳定剂存在的前提下，冰淇淋浆料中的分散相经过均质机或超微胶体磨切变力而均质、分散。冰淇淋浆料进入老化罐后的搅拌降温以及达到老化温度后继续搅拌的恒温过程中，由于冰淇淋浆料粘度的提高远远超过搅拌切变稀化粘度的降低，各分散相微粒难于聚结，避免了分散相与分散介质的分离，而使冰淇淋浆料保持稳定。２）降低冰淇淋浆料中“空气／水”、“油／水”界面的界面张力，使冰…     

应用生物酶开发高粘度番茄酱产品初步研究

探讨了在番茄酱生产过程中,在不同条件下,应用生物酶制剂改变番茄酱产品中的粘度指标可行性。结果表明,运用生物酶可以有效地改变番茄酱产品的粘度指标,生产高粘度番茄酱产品。     

海藻酸钠原液流变性能的研究

采用TR-1型毛细管流变仪对海藻酸钠原液的流变性能进行了研究。通过实验得出在不同浓度、不同温度的条件下,原液表观粘度相剪切速率之间的关系,通过数据处理,求得了不同浓度原液的非牛顿指数n、结构粘度△η、粘流活化能△E等流变参数;讨论了温度和浓度对原液流变性能的影响。结果表明:通过调节原液的浓度、温度和切变速率,可以改善原液的流变性能和可纺性。从而为纺制海藻酸盐纤维提供了理论依据。     

变性淀粉与膳食纤维在番茄酱中的应用

研究变性淀粉和膳食纤维在番茄酱里的应用性能，测定添加变性淀粉与膳食纤维后的粘度和色差，进行比较。试验证明添加变性淀粉和膳食纤维可有效地提高番茄酱的粘度，且随着添加量的增加（1％～2％）番茄酱的粘性增强。     

低浓度阿拉伯树胶溶液的流变特性及影响因素研究

以低浓度阿拉伯树胶溶液为研究对象,考察了其流变特性及浓度、剪切速率、温度、pH、搅拌时间对溶液粘度的影响。结果表明,低浓度阿拉伯树胶溶液的粘度随溶液浓度的增加呈下降趋势,表现为牛顿流体的特性;在一定浓度下表现出剪切稀化的特性;其粘度对温度有一定的依赖性,粘度随温度的升高呈波动性变化;在pH低于5时,其粘度随pH的下降而显著升高,在pH为5.79~11.17的范围,粘度不受pH变化的影响;低浓度阿拉伯树胶溶液在不同的搅拌时间作用下具有不同的粘度。     

Preparation of High‐Grade Powders from Tomato Paste Using a Vacuum Foam Drying Method

We present a rapid and gentle drying method for the production of high‐grade tomato powders from double concentrated tomato paste, comparing results with powders obtained by foam mat air drying and freeze dried powders. The principle of this method consists of drying tomato paste in foamed state at low temperatures in vacuum. The formulations were dried at temperatures of 50, 60, and 70 °C and vacuum of 200 mbar. Foam stability was affected by low serum viscosity and the presence of solid particles in tomato paste. Consequently, serum viscosity was increased by maltodextrin addition, yielding optimum stability at tomato paste:maltodextrin ratio of 2.4:1 (w/w) in dry matter. Material foamability was improved by addition of 0.5% (w/w, fresh weight) egg white. Because of solid particles in tomato paste, foam air filling had to be limited to critical air volume fraction of Φ = 0.7. The paste was first pre‐foamed to Φ = 0.2 and subsequently expanded in vacuo. After drying to a moisture content of 5.6% to 7.5% wet base (w.b.), the materials obtained were in glassy state. Qualities of the resulting powders were compared with those produced by freeze and air drying. Total color changes were the least after vacuum drying, whereas air drying resulted in noticeable color changes. Vacuum foam drying at 50 °C led to insignificant carotenoid losses, being equivalent to the time‐consuming freeze drying method. In contrast, air drying caused lycopene and β‐carotene losses of 18% to 33% and 14% to 19% respectively. Thus, vacuum foam drying enables production of high‐grade tomato powders being qualitatively similar to powders obtained by freeze drying.     

Effect of Tomato Paste on Rheological Properties and Particle Size Distribution of Model Oil-in-Water Emulsions

The role of tomato paste in stabilizing model o/w salad dressing formulations pre-stabilized with xanthan and propylene glycol alginate was studied at levels of tomato paste ranging from 3 to 12% using creep measurements, steady shear measurements and particle size measurements. The addition of tomato paste shifted the particle size distribution to lower values; this distribution was a function of aging time. Creep and steady shear measurements showed an increase in rheological parameters and an increase in viscosity, respectively, suggesting that at higher or equal levels of 6% tomato paste the stability of the o/w emulsion was enhanced significantly.     

番茄汁加工工艺的研究

在番茄汁加工中分别给予85℃、65℃冷榨及100℃热烫的预热处理,并对不同预热处理的番茄汁进行了均质和不均质对比,结果发现:预热对出汁率、粘稠度及清液粘度均有显著影响,而均质主要影响番茄汁的维生素C(Vc)含量;预热和均质对粘稠度的交互作用显著;番茄汁的浆液分离和粘稠度呈高度负相关,而和清液粘度无任何相关;不同的预热温度与不同的均质处理相结合均有可能生产出品质良好的番茄汁。     

梨膏的流变学特性及其影响因素

目的 考察人为加糖、加胶后梨膏触变性及黏度的变化。方法 以鸭梨为实验材料,通过真空浓缩方式制备鸭梨膏,采用HR-10型流变仪对其流体类型、黏度、触变性进行测定。结果 鸭梨膏属于非牛顿流体,具体细分为无限接近牛顿流体的假塑性流体,具有剪切稀化特性和正触变特性;损耗模量G″总是大于储能模量G’,表现出液体黏性性质;剪切速率与剪切力变化关系符合PowerLaw方程,拟合效果良好(r2>0.99);温度显著影响梨膏黏度,黏度随温度升高而降低,二者关系符合Arrhenius方程,拟合效果良好(r2>0.99);可溶性固形物含量(solublesolidscontent,SSC)对黏度的影响符合指数函数关系,模型拟合效果良好(r2>0.99);SSC以及人为加糖、加胶处理对梨膏触变性、黏度影响显著(P<0.05),黏度随SSC的升高而增强,人为加胶、加糖加胶会导致梨膏黏度显著升高(P<0.05);触变性随SSC的升高而增强,同时人为加糖、加胶、加糖加胶处理会导致梨膏触变性显著减弱(P<0.05)。结论 人为添加糖、胶会导致梨膏的流变学特性发生改变。本研究可为工业...     

Non-linear viscoelasticity modeling of tomato paste products

This paper deals with the characterization and modeling of the non-linear rheological properties of tomato paste samples manufactured under different conditions (sieve pore size and breaking temperature). With this aim, flow measurements, dynamic linear viscoelastic and linear and non-linear stress relaxation tests have been carried out on the above-mentioned tomato paste samples. Different geometries with smooth and serrated surfaces have been used to optimize the viscous flow measurements and avoid wall-depletion phenomena. The viscous flow properties of tomato paste samples depend on water insoluble solids (WIS) content and particle size, which may be highly influenced by processing conditions. In general, viscosity follows a power-law relationship with tomato paste water insoluble content and particle diameter. A factorable non-linear viscoelasticity model, the Wagner integral equation, predicts the non-linear rheological response of these products under shear fairly well. The time-dependent part of this model is described by a continuous linear relaxation spectrum, calculated from regularization techniques. The use of the Soskey–Winter damping function provides the best predictions of the viscous flow curves.     

均质压力对番茄浆料粘度的影响

采用流变仪对番茄浆料的流变性质进行测定,研究均质压力对番茄浆料粘度的影响。结果表明:番茄浆料为假塑体系,其粘度随剪切速率的增加而迅速下降。番茄浆料的粘度随均质压力的增加而增加。均质处理会影响番茄浆颗粒的大小和分布、纤维物质的性状以及番茄固形物中果胶物质的释放量,影响由番茄浆颗粒(纤维物质)聚集所形成的网状结构。     

小麦羧甲基淀粉糊性质研究

本文对小麦羧甲基淀粉糊性质进行了详细的研究,包括糊的冻融稳定性、抗生物降解能力、抗老化能力、糊透明度及温度、pH值、剪切力及介质(蔗糖和NaCl)对糊粘度的影响。结果表明,小麦羧甲基淀粉冻融稳定性好,抗生物降解及抗老化能力强,透明度高。糊的热粘度稳定性降低,冷粘度稳定性增加。氯化钠强电解质对小麦羧甲基淀粉糊粘度影响较大。     

In-Line Measurement of Rheological Parameters and Modeling of Apparent Wall Slip in Diced Tomato Suspensions Using Ultrasonics

ABSTRACT: Rheological behavior of a slurry consisting of 1- to 3-mm diced tomatoes suspended in tomato juice was evaluated by an in-line measurement method based upon ultrasonics. This technique permitted the measurements of yield stress, consistency index, and apparent wall slip. The suspension exhibited a yield stress at every flow rate studied, and its value was found to be 0.79 ±0.11 Pa. The shear viscosity at different shear rates was obtained in-line without assuming a specific constitutive equation. A comparison of Herschel-Bulkley, Power Law, Bingham Plastic, and Casson models showed that this suspension was best characterized with the Herschel-Bulkley model. The apparent wall slip region was successfully modeled as a Bingham fluid. This study shows the usefulness of this method for in-line characterization of particulate tomato products.     

A modified model for non-newtonian viscosity behavior of Aureobasidium pullulans culture fluid

The culture fluid of the fungus Aureobasidium pullulans and the exopolysaccharide solution obtained by removal of the microbial cells exhibit a marked shear dependence of viscosity. The viscosity in a high shear rate region was a little higher than that predicted by a non-Newtonian viscosity equation derived previously on the basis of the concept of traveling force. In a sample exhibiting such high shear rate dependence, a hydrodynamic effect based on the fluid structure of the binding of contacting polymers and suspended microbial cells on viscosity becomes comparatively significant. A model for the shear rate dependence of the viscosity is needed to elucidate the mechanism of the viscosity behavior. A term concerning the increase in viscosity caused by the binding of polymers and the microbial cells suspended in a medium was added to the previous viscosity equation. The experimental shear dependence of the viscosity was well simulated by the modified viscosity equation.     

番茄汁液流变性质的关联

对经45、32、24和16目筛网过筛所得番茄汁液的流变性质进行了研究。采用旋转式粘度计测定了番茄汁的剪切速率-剪应力数据。通过剪切速率-剪应力实验数据的关联发现,番茄汁液的流变行为可用Bingham模型表征。确定了不同温度和不同网目下番茄汁液的稠度指数和屈服应力。同时也建立了不同网目下番茄汁液的表观粘度与温度函数关系的关联式。