Rheological Properties of Butia Pulp

Author(s):  
Charles Windson Isidoro Haminiuk ◽  
Maria-Rita Sierakowski ◽  
Giselle Maria Maciel ◽  
José Raniere Mazile Bezerra Vidal ◽  
Ivanise Guilherme Branco ◽  
...  

Rheological parameters of Butia pulp were determined at different temperatures using a concentric cylinder Haake Rotovisco rheometer, model RV-20, with measurement system ZA-30. Butia pulp was found to exhibit non-Newtonian, pseudoplastic behavior at all temperatures and the rheological parameters were adequately described by the Herschel-Bulkley model. Yield stress, flow behavior index, and consistency coefficient were significantly affected by temperature. The yield stress decreased exponentially with process temperature and ranged between 36.60 and 21.70 Pa. Apparent viscosity calculated through the Herschel-Bulkley model decreased with an increase in temperature. The Arrhenius model gave a good description of temperature effect on apparent viscosity of the pulp.

2008 ◽  
Vol 18 (3) ◽  
pp. 34482-1-34482-11 ◽  
Author(s):  
Vassilios C. Kelessidis ◽  
Roberto Maglione

AbstractA methodology is presented to invert the flow equation of a Herschel-Bulkley fluid in Couette concentric cylinder geometry, thus enabling simultaneous computation of the true shear rates, γ̇HB, and of the three Herschel-Bulkley rheological parameters. The errors made when these rheological parameters are computed using Newtonian shear rates, γ̇N, as it is normal practice by research and industry personnel, can then be estimated. Quantification of these errors has been performed using narrow gap viscometer data from literature, with most of them taken with oil-field rheometers. The results indicate that significant differences exist between the yield stress and the flow behavior index computed using γ̇HB versus the parameters obtained using γ̇N and this is an outcome of the higher γ̇HB values. Predicted true shear rates and rheological parameters are in very good agreement with results reported by other investigators, who have followed different approaches to invert the flow equation, both for yield-pseudoplastic and power-law fluids.


Author(s):  
Eliza Guadalupe Arcos-Estrada ◽  
Mayra Díaz-Ramírez ◽  
Judith Jiménez-Guzmán ◽  
Erika Berenice León-Espinosa ◽  
Mariano García-Garibay ◽  
...  

Objective: Analyze the effect of grasshopper (Sphenarium purpurascens Charpentier) paste addition on the rheological behavior of Mole Poblano (MP) and its relation with the technological properties of the grasshopper paste. Design/methodology/approach: The addition of grasshopper paste was done at different proportions as follows: T0= 0% of grasshopper paste (GP) and 100% of mole Poblano (MP); T10=10% GP and 90% MP; T15=15% GP and 85% MP, T20=20% GP and 80% MP, T25=25% GP and 75 % MP, T30=30% GP and 70% MP. Water retention and emulsifying capacity of grasshopper paste were evaluated. Density, kinematic and apparent viscosity, and rheological behavior were analyzed at 25ºC; rheological parameters (consistency index (k) and flow behavior index (n)) were calculated by performing a regression analysis to adjust the graphs to a power-law model. Findings/conclusion: Grasshopper paste had higher emulsifying capability than water retention capability.  Apparent viscosity of all formulations decreased as shear rate increased, so all mixtures of GP and MP demonstrated No-Newtonian behavior and pseudoplastic performance. Index consistency increased as GP content increased, these results are related with protein content because GP had a good emulsifying capability. Limitations on study/implications: More studies about the characterization of the proteins of GP and their interaction with other components are required.


Author(s):  
Se-Ra Hong ◽  
Dong-Soo Sun ◽  
Whachun Yoo ◽  
Byoungseung Yoo

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.


Author(s):  
ROSANE DA SILVA RODRIGUES ◽  
ÂNGELA MARIA GOZZO ◽  
ROBERTO HERMÍNIO MORETTI

Estudou-se o comportamento reológico de extratos elaborados com grãos, farinha integral e isolado protéico de soja. Extratos com 3% de proteína foram obtidos de grãos de soja (em equipamento conhecido como “vaca mecânica”), de farinha integral e de isolado protéico (por dissolução em água) e pasteurizados a 74±2°C por 15 seg. Os parâmetros reológicos estudados foram o coeficiente de consistência, o índice de comportamento do fluxo e a viscosidade aparente. Foram determinados, também, sólidos totais, proteínas, lipídios, cinzas, fibra bruta, carboidratos e índice de sedimentação (AOAC, 1995). Verificou-se que a viscosidade aparente, a 4 e 25°C, do extrato obtido de grãos de soja (fluido nãonewtoniano com comportamento pseudoplástico) foi maior que a do extrato da farinha (fluido não-newtoniano com comportamento pseudoplástico a 4°C e dilatante a 25°C) e do isolado (fluido newtoniano). O maior índice de sedimentação constatado no extrato de farinha integral e o baixo teor de sólidos solúveis no isolado protéico foram determinantes, entre outros fatores, no comportamento reológico verificado. AbstractRHEOLOGICAL BEHAVIOR OF SOYMILK, WHOLE SOY FLOUR AND SOY ISOLATED PROTEIN The rheological properties of extracts elaborated with soybeans, whole soy flour and isolated protein were studied. Extracts with 3% of protein were obtained from soybeans (in a equipment called “mechanic cow”), whole soy flour and isolated soy protein (by dissolution in water) and pasteurized at 74±2°C for 15 seg. The rheological parameters studied were the flow behavior index, consistency coefficient and apparent viscosity. Total solid, proteins, lipids, ashes, brute fiber, carbohydrates and sedimentation index (AOAC, 1995) was also determined. The apparent viscosity, at 4 and 25°C, of the extract obtained from soybeans (non-newtonian fluid with pseudoplastic behavior), was greater than the one of whole soy flour extract (nonnewtonian fluid with pseudoplastic behavior at 4°C and dilatant at 25°C) and of the isolated soy protein extract (Newtonian fluid). The highest sedimentation index verified in the whole soy flour extract and the low content of soluble solids in the extract of isolated soy protein defined, among others factors, the rheological behavior verified.


2012 ◽  
Vol 430-432 ◽  
pp. 301-305
Author(s):  
Li Wen Tan ◽  
Dong Mei Xu ◽  
Quan Ji ◽  
Bing Bing Wang ◽  
Yan Zhi Xia

Rheological properties of blend spinning solution of sodium alginate and TiO2 nanoparticles (SA/nano-TiO2) were investigated. The rheological parameters, structural viscosity index (Δη) and flow activation energy (Eη) of spinning solutions were calculated. The results reported that the blend spinning solutions were non-newtonian fluids. The apparent viscosity, consistency index (k) and Eη increased with increasing nano-TiO2 content in SA spinning solution, but the degradation degree of apparent viscosity decreased, flow behavior index (n) only slightly decreased and the Δη had no significantly change. The apparent viscosity (ηa) of spinning solutions could be regulated by changing temperature under 50oC. Blend spinning solution had good stability and practical applicability.


2020 ◽  
Vol 50 (6) ◽  
Author(s):  
Stella Regina Arcanjo Medeiros ◽  
Victor Alves de Oliveira ◽  
Amanda Mazza Cruz de Oliveira ◽  
Marjory Lima Holanda Araujo ◽  
Judith Pessoa de Andrade Feitosa ◽  
...  

ABSTRACT: Dairy desserts containing Caesalpinia pulcherrima seed galactomannan were evaluated to determine their static and dynamic rheological behaviors. Variations in consistency index (k), flow behavior (n), yield stress and thixotropy of the desserts indicated that the galactomannan caused an increase in the shear stress and apparent viscosity of the system. All samples exhibited shear-thinning behavior with flow behavior index values (n) between 0.06 and 0.37. Dynamic rheological behavior was evaluated for MD (high solid levels) and MD/2 (half the amount of solids) groups, and both G’ and G’’ moduli were depended on the frequency. The MD and MD/2 groups showed variations in the elastic modulus (G’) throughout the temperature range (mainly at 50 °C), showing greater sensitivity at high temperatures. C. pulcherrima galactomannan was able to promote synergism with starch, milk protein and sucrose and to improve the development of stronger and more resistant gels.


2012 ◽  
Vol 32 (2) ◽  
pp. 333-341
Author(s):  
Maria E. M. Duarte ◽  
Deyzi S. Gouveia ◽  
Mario E. R. M. C. Mata ◽  
Alexandre J. de M. Queiroz

In this study the rheological behavior in different temperatures (0; 6; 18 e 24 ºC) and physicochemical parameters of integral annona (Annona squamosa) pulp and the annona pulp with milk in different percentages pulp/milk (75g of annona pulp/25g of milk, 50g of annona pulp/50g of milk, 25g of annona pulp/75g of milk) have been availed, in order to verify the effect of temperature and pulp concentration in the rheological behavior of these beverages. To obtain the rheological parameters a concentric cylinder rheometer has been used and the rheograms were analyzed using the Ostwald-de-Wael (power Law) and Herschel-Bulkley models. The physicochemical parameters (sugars, pH, ash, acidity and soluble solids) were determined in order to establish correlations with the rheological behavior. Finally, the best results had been obtained using the Herschel-Bulkley model; the low values for the behavior index (n <1) obtained confirm the pseudoplastic behavior of all samples.


2006 ◽  
Author(s):  
Alexis Dechelette ◽  
Paul E. Sojka ◽  
Carl R. Wassgren

This study discusses the spreading of a non-Newtonian, power-law, film formed after a drop impinges on a flat surface (i.e., a pharmaceutical tablet). Non-Newtonian drop spreading is described by a model based on the one of Roisman et al. [2002]. The effects of variations in non-Newtonian liquid rheological parameters m (the consistency index) and n (the fluid behavior index) are shown to be significant. In either case, changes leading to a reduction in viscous forces result in enhanced spreading of the film, followed by more rapid recession. Both are expected. Of interest is the observation that an increase in consistency index can be compensated for by a reduction in flow behavior index since the sensitivity of film recession to a change in n is larger than that to variations in m.


Author(s):  
Georgia Dimitreli ◽  
Apostolos S Thomareis ◽  
Peter G. Smith

The influence of five different emulsifying salts on casein peptization (dissociation) and apparent viscosity of processed Gouda cheese was studied. Casein peptization was evaluated as peptization coefficient in the final product, while apparent viscosity was determined as flow behavior and consistency indices in the product during processing before cooling. Increasing moisture content and pH of processed cheese samples generally increases peptization coefficient, however the type of emulsifying salt showed to play an important role also. On the contrary, independently of the type of emulsifying salt, predictive regression models were suggested in order to express flow behavior index and consistency index versus chemical composition and pH. Increasing moisture content or reducing pH increases the flow behavior index. Consistency index, and thus the apparent viscosity, of processed cheese samples was increased when the moisture content was reduced, and when pH and the soluble casein content were increased.


2009 ◽  
Vol 83-86 ◽  
pp. 24-30 ◽  
Author(s):  
Norhamidi Muhamad ◽  
Hooman Abolhasani

A new starch-based binder as a natural polymer has been developed for metal injection molding (MIM). In this study tapioca starch which is cheap and readily available in Malaysia has been used as a binder which composed of starch, glycerol, linear low density polyethylene (LLDPE), citric acid and stearic acid. This developed binder system was mixed with 316 L stainless steel powder to prepare the feedstock at three different of powder loadings of 56, 57 and 58% vol. The rheological behavior of the binder and feedstock were evaluated at different temperatures using a capillary rheometer. The rheological behavior of binder shows less than 10 Pa s and the flow behavior index of the feedstocks were determined to less than 1, which indicates the flow characteristic is pseudo-plastic which is suitable for MIM process. Finally, among these three feedstocks, the feedstock of 57% vol. powder loading was selected and its viscosity values within expected shear rate range are less than 1000 Pa s.


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