The Rheological Properties of Turkish Delight

2009 ◽  
Vol 6 (1) ◽  
Author(s):  
Zurriye Yilmaz ◽  
Mehmet Dogan ◽  
Mahir Alkan ◽  
Serap Dogan
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Food Industry ◽  
Arrhenius Equation ◽  
Flow Behavior ◽  
Effect Of Temperature ◽  
Flow Properties ◽  
Different Temperatures ◽  
Dependent Flow

In the food industry, rheological properties, such as viscosity, shear rate, and shear stress, are the most important parameters required in the design of a technological process. Therefore, in this study, we determined the flow behavior and the time-dependent flow properties of Turkish Delight (TD) in the temperature range of 25-75°C using a capillar rheometer. The structure and thermal properties of TD were investigated by XRD and a simultaneous DTA/TG analysis. The shear rate values ranged from 5 to 300s-1. We found that: (i) TD behaved as non- Newtonian pseudoplastic foodstuff; (ii) while the measurement temperature increased, viscosity decreased; and (iii) TD was a rheopectic material. The effect of temperature on viscosity was described by means of the Arrhenius equation. The activation energies for the flow of pseudoplastic TD varied from 50.1-74.2 kJ/mol, depending on shear rate. Three models were used to predict the flow behavior of TD, namely, the Power law, Bingham and Casson models. The Power law model adequately described well the flow behavior of TD at different temperatures.

scholarly journals Rheological Behavior of Sumac (Rhus coriaria L.) Extract as Affected by Temperature and Concentration and Investigation of Flow Behavior with CFD

2020 ◽  
Vol 10 (6) ◽  
pp. 7120-7134
Keyword(s):  
Arrhenius Equation ◽  
Flow Behavior ◽  
Rheological Behaviour ◽  
Effect Of Temperature ◽  
Sudden Expansion ◽  
Flow Properties ◽  
Rotational Viscometer ◽  
Different Temperatures ◽  
Rhus Coriaria ◽  
Temperature Ranges

The purpose of this study is to investigate the rheological properties of sumac extract in different concentrations at different temperatures as well as its flow behavior in sudden expansion-contraction and at 90o elbow with CFD. The rheological behaviour of sumac extract in different concentrations (45.65%, 50.44%, 55.53%, 60.32%, and 65.13% total solids) were evaluated using a rotational viscometer at different temperatures (10, 20, 30, 40 and 50 C). Sumac extract samples showed Newtonian flow properties in these temperature ranges. Arrhenius equation was used to determine the effect of temperature. Ea value varied in the range of 11.16-34.35 kJ/mol, which diminished with a decrease in concentration. Power and Exponential models were used to characterize the effect of concentration on flow behavior. Time average velocity vector and contours, vorticity contours, kinetic energy contours, and pressure contours are given to show the flow behavior of sumac extract.

Flow Behaviors of Commercial Food Thickeners Used for the Management of Dysphagia: Effect of Temperature

2012 ◽  
Vol 8 (2) ◽  
Author(s):  
Se-Ra Hong ◽  
Dong-Soo Sun ◽  
Whachun Yoo ◽  
Byoungseung Yoo
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Flow Behavior ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
High Shear ◽  
Flow Properties ◽  
Different Temperatures ◽  
Management Of Dysphagia ◽  
Arrhenius Temperature

Gum-based food thickeners are widely used to care for patients with dysphagia in Korea. In this study, the flow properties of commercially available gum-based food thickeners marketed in Korea were determined as a function of temperature. The flow properties of thickeners were determined based on the rheological parameters of the power law and Casson models. Changes in shear stress with the rate of shear (1-100 s-1) at different temperatures (5, 20, 35, and 50 oC) were independent of the type of thickener. All thickeners had high shear-thinning behavior (n=0.08-0.18) with yield stress at the different temperatures tested. In general, apparent viscosity (na,50) values progressively decreased with an increase in temperature. In addition, the consistency index (K) and Casson yield stress (σoc) values did not change much upon an increase in temperature from 5 to 35 oC, except for sample B. In the temperature range of 5-50 oC, the thickeners followed an Arrhenius temperature relationship with a high determination coefficient (R2=0.93-0.97): activation energies (Ea) for the flow of thickeners were in the range of 2.44 - 10.7 kJ/mol. Rheological parameters demonstrated considerable differences in flow behavior between the different gum-based food thickeners, indicating that their flow properties are related to the type of thickener and the flow properties of gum.

A Comparison of Rheological Models and Experimental Data of Metallocene Linear Low Density Polyethylene Solutions as a Function of Temperature and Concentration

2016 ◽  
Vol 12 (3) ◽  
pp. 4322-4339
Author(s):  
Salah Hamza
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Low Density Polyethylene ◽  
Effect Of Temperature ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Shear Rates ◽  
Wide Range

Knowledge of rheological properties of polymer and their variation with temperature and concentration have been globally important for processing and fabrication of polymers in order to make useful products. Basheer et al. [1] investigated, experimentally, the changes in rheological properties of metallocene linear low density polyethylene (mLLDPE) solutions by using a rotational rheometer model AR-G2 with parallel plate geometry. Their work covered the temperature range from  to  and  concentration from  to . In this paper, we reconsider Basheer work to describe the rheological behavior of mLLDPE solutions and its dependence on concentration and temperature.Until now, several models have been built to describe the complex behavior of polymer fluids with varying degrees of success. In this article, Oldroyd 4-constant, Giesekus and Power law models were tested for investigating the viscosity of mLLDPE solution as a function of shear rate. Results showed that Giesekus and power law models provide the best prediction of viscosity for a wide range of shear rates at constant temperature and concentration. Therefore, Giesekus and power law models were suitable for all mLLDPE solutions while Oldroyd 4-constant model doesn't.A new proposed correlation for the viscosity of mLLDPE solutions as a function of shear rate, temperature and concentration has been suggested. The effect of temperature and concentration can be adequately described by an Arrhenius-type and exponential function respectively. The proposed correlation form was found to fit the experimental data adequately.

Rheological investigations of water-soluble polysaccharides extracted from Moroccan seaweed Cystoseira myriophylloides algae

2020 ◽  
Vol 11 (3-4) ◽  
pp. 49-63
Author(s):  
Soumia Zaim ◽  
Omar Cherkaoui ◽  
Halima Rchid ◽  
Rachid Nmila ◽  
Reddad El Moznine
Keyword(s):  
Rheological Properties ◽  
Power Law ◽  
Flow Behavior ◽  
Viscoelastic Behavior ◽  
Shear Thinning ◽  
Water Soluble ◽  
Flow Behavior Index ◽  
Dynamic Rheological Properties ◽  
Different Temperatures ◽  
Tan Δ

The rheological properties and spectrum infrared of polysaccharides extracted from Cystoseira myriophylloides algae were investigated in the concentrations range from 3 to 9% (w/v) and at different temperatures. Results of rheological characteristics in a steady shear rate showed pseudoplastic properties and the dynamic rheological properties showed a fluid-like viscoelastic behavior. The flow and viscoelastic characteristics of polysaccharides were described using the power-law (the Ostwald model). The values of flow behavior index of the sample were close to unity (0.91) for 3% and it decreased up to 0.71 for 9% revealing the shear-thinning (pseudoplastic) nature of these polysaccharides. Moreover, the consistency coefficient increased non-linearly with concentration and it was described by a power law. The flow behavior as a function of temperature was satisfactorily described using the Arrhenius law and the activation energy values were extracted. It decreased from 15.68 and 17.21 kJ/mol when the concentration increased from 5 to 9% (w/v). Additionally, in dynamic rheological measurements, tan δ > 1 and G″ > G′ reveling a shear-thinning behavior. Finally, the analysis of the FTIR spectra of these polysaccharides showed the presence of uronic acid groups. This behavior would suggest that polysaccharides extracted from Cystoseira myriophylloides could be an interesting additive as thickeners.

Physical and Rheological Properties of Animal Manure: A Review

2018 ◽  
Vol 61 (3) ◽  
pp. 1113-1120
Author(s):  
Ibrahim Denka Kariyama ◽  
Xiaodong Zhai ◽  
Binxin Wu
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Pressure Head ◽  
Animal Manure ◽  
Anaerobic Treatment ◽  
Pseudoplastic Fluid ◽  
Power Law Equation

Abstract. This literature review was conducted on the physical and rheological properties of animal manure slurries and their applications. The review revealed the importance of these properties in the design of anaerobic treatment plants, pipe systems to transport slurries to treatment and storage units, and other applications and management of raw and treated slurries. The selection of pumping and mixing equipment and their power requirements, the flow behavior, mass, and heat transfer, the quality of mixing, pressure head loss, and other applications of manure slurries are affected by the physical and rheological properties. The review shows that manure slurries generally exhibit non-Newtonian pseudoplastic fluid behavior with a decreasing apparent viscosity as the shear rate increases and that the power law equation can successfully be used to describe the relationship between shear stress and shear rate, especially for low total solids concentrations. Keywords: Animal manure slurries, Apparent viscosity, Non-Newtonian pseudoplastic fluids, Power law equation, Rheological properties.

Characterization of Cellulose Nanocrystal Suspension Rheological Properties Using a Rotational Viscometer

2021 ◽  
Vol 71 (3) ◽  
pp. 290-297
Author(s):  
Yucheng Peng ◽  
Changlei Xia ◽  
Brian Via
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Cellulose Nanocrystal ◽  
Rotational Viscometer ◽  
Spindle Rotation ◽  
Quality Control Tool ◽  
Calculation Results

Abstract Interest in cellulose nanocrystal (CNC) recently has been growing significantly. Many applications have been developed for CNC and appropriate procedures to handle the CNC suspensions are critical for these applications. In this study, we explored a method evaluating CNC suspensions based on rheological property characterization. We used a rotational viscometer to characterize CNC suspensions at concentrations of 3, 4, 5, and 6 wt.%. We collected primary readings from the rotational viscometer, including spindle rotation speed and torque, to generate apparent viscosity and shear rate for CNC suspensions. We applied three different methods summarized from the literature to calculate apparent viscosity and real shear rate. We critically analyzed differences among calculation results from the three methods. Shearing thinning behaviors obeyed the power law flow model for all CNC suspensions in the shear rate tested. At different concentrations, consistency and flow behavior indices in the model differed in the measured shear rate range. With the same shear rate, higher concentration CNC suspension had a higher apparent viscosity. The apparent viscosity of the CNC suspension was associated with its weight concentration in a power law relationship. This study indicated that a rotational viscometer can be used as a quality control tool for characterizing the rheological properties of the CNC suspensions. We made recommendations for using appropriate calculation methods to obtain shear rate and apparent viscosity of CNC suspensions from the primary readings of a rotational viscometer under different situations.

Application of Modified Power Law and Arrhenius Relationship in Studying Rheological Behavior of Bio-Oils

2006 ◽  
Vol 517 ◽  
pp. 147-152 ◽  
Author(s):  
W.S. Wan Nik ◽  
S.G. Eng Giap ◽  
H.H. Masjuki ◽  
H.B. Senin
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Power Law ◽  
Corn Oil ◽  
Flow Behavior ◽  
Type Equation ◽  
Power Law Model ◽  
Flow Behavior Index ◽  
Different Temperatures ◽  
Modified Power Law

Tribological aspects of bio-oils have to be investigated before they are used as industrial fluids. In this paper rheological (fluid deformation under shear) properties of four bio-oils are presented. A Couette type viscometer was used to evaluate flow behavior of the oils at seven discrete temperatures. Commercial coconut, canola, sunflower and corn oil were used in this study. For all the oil samples, viscosities were affected by the change of shear rate and temperature. Two rheological models, temperature dependence and shear rate dependence, were used in the study. The original power law gives contradict picture of flow curves and flow parameters. Thus, modified power law model was proposed. The modified model was fitted to experimental data to obtain the flow behavior index. Arrhenius type equation was fitted to experimental data to obtain the activation energy due to different temperatures and shear rates. Evaluation of rheological properties by modified power law model indicates that these bio-oils belong to the pseudo-plastic group.

Time Dependent Rheological Characteristics of Pineapple Jam

2007 ◽  
Vol 3 (3) ◽  
Author(s):  
Santanu Basu ◽  
US Shivhare ◽  
GSV Raghavan
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Time Dependent ◽  
Rheological Characteristics ◽  
Fruit Pulp ◽  
Flow Properties ◽  
Thixotropic Behavior ◽  
Dependent Flow

Jam is an intermediate moisture food containing fruit pulp, pectin, sugar and acid. The effect of sugar and pectin concentration, pH, shear rate and temperature on the time dependent rheological properties of pineapple jam was studied using a rheometer. Pineapple jam exhibited thixotropic behavior. Shear stress of the pineapple jam at a particular time of shearing depended on the shear rate, temperature and composition. Weltman, Hahn, and Figoni and Shoemaker, models were applied to describe the time dependent flow properties of pineapple jam. Hahn model described adequately the rheological characteristics of pineapple jam.

scholarly journals Rheological Properties of Cassava Starch Film Forming Solution with Kaffir Lime Oil

2019 ◽  
Vol 8 (4) ◽  
pp. 6781-6786
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Flow Behavior ◽  
Cassava Starch ◽  
Food Preservation ◽  
Effect Of Temperature ◽  
Flow Behavior Index ◽  
Film Forming ◽  
Biopolymer Film

Biopolymer film has attracted interest in food preservation and packaging. In order to obtain biopolymer film of good characteristics, rheological properties of film forming solution is important. In this study, the rheological properties of cassava starch film forming solution incorporated with kaffir lime oil were determined. The flow behavior measurement was made at shear rate of 0.1 to 100 s -1 and 25 C, whereas the effect of temperature on viscosity was measured at 25 to 70 C and shear rate of 10 s-1 . The flow behavior was well described by power law or Ostwald de Waele model. The film forming solution showed flow behavior index (n) in the range of 0.20 to 0.72 which belonged to a non-Newtonian or pseudoplastic behavior. The shear stress increased with increasing shear rate and temperature. The dependency of temperature on viscosity was described by Arrhenius model which allowed the determination of activation energy (Ea ). The Ea of the film forming solutions range between 4.92 to 13.23 kJ mol-1 . The rheological properties obtained in this study provide a basis to correlate the film forming solution properties to the characteristics of the produced biopolymer film.

Rheological properties of cholesteric liquid crystals as lubricant additives

2019 ◽  
Vol 33 (05) ◽  
pp. 1950014 ◽  
Author(s):  
A. Bindu Madhavi ◽  
S. Sreehari Sastry
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Loss Modulus ◽  
Flow Behavior ◽  
Lubricant Additives ◽  
Rheological Parameters ◽  
Practical Applications ◽  
Phase Transition Temperatures ◽  
Frequency Independent ◽  
Temperature Shear

Rheological properties of Cholesteryl n-valerate, Cholesteryl decanoate and Cholesteryl myristate which are esters of cholesterol have been studied. Phase transition temperatures and rheological parameters such as viscosity, elastic modulus G[Formula: see text], loss modulus G[Formula: see text] as functions of temperature, shear rate and time are investigated. In frequency sweep test, a higher transition crossover region has occurred for Cholesteryl myristate, whereas for Cholesteryl n-valerate a frequency-independent plateau prevailed for both the moduli. The occurrence of blue phase in Cholesteryl decanoate during temperature sweep measurements is an indication for the rheological support. The results for steady state have informed that cholesteric esters are having non-Newtonian flow behavior in their respective cholesteric phases. The power-law model has explained well the shear rate dependence of shear stress. A few practical applications of these esters as lubricant additives are discussed, too.

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