scholarly journals Effects of pectin and carrageenan on thermophysical and rheological properties of tapioca starch

2011 ◽  
Vol 24 (No. 6) ◽  
pp. 275-282 ◽  
Author(s):  
J. Babić ◽  
D. Šubarić ◽  
Đ. Ačkar ◽  
V. Piližota ◽  
M. Kopjar ◽  
...  

The effects of hydrocolloids pectin, carrageenan, as well as of pectin/carrageenan mixtures on gelatinisation, retrogradation, rheological characteristics, and swelling power of tapioca starch were studied with Brookfield rotational viscometer and differential scanning calorimeter (DSC). The results showed that hydrocolloids retarded the retrogradation of tapioca starch. Enthalpy and temperatures of gelatinisation, as well as solubility, did not vary significantly in starch-hydrocolloid systems. Viscosity of tapioca starch increased on the addition of hydrocolloids: the effect of carrageenan on viscosity was more remarkable than that of pectin.    

Author(s):  
ANIDA MARIA MORAES GOMES ◽  
CLÁUDIO ERNANI MENDES DA SILVA ◽  
PALOMA LIMA DA SILVA ◽  
NÁGILA MARIA PONTES SILVA RICARDO ◽  
MARIA ISABEL GALLÃO

The effects of annealing on the properties of unfermented (polvilho doce-PD) and fermented (polvilho azedo-PAD) cassava starches were studied. The samples were submitted to annealing treatment for 24, 72, 96, 144, 192 and 240 hours. The annealing treatment changed the main physicochemical (gelatinization, enthalpy and temperature) and rheological properties (swelling power, peak viscosity and pasting temperature) of the both samples. The increase in the gelatinization temperatures and the narrowing of the gelatinization range was attributed to an reinforcement in the packing of the double helices of the amylopectin. The PAD samples seemed to be more affected by this treatment than PD ones. The PAD samples presented some characteristics of a waxy starch, such as increased crystallinity and increased stability of the pastes, which from a technological point of view is very important to diversify further its use in the food industry.


Author(s):  
Manish Dak ◽  
Radha Charan Verma ◽  
S N A Jaaffrey

Rheological properties of tomato concentrate were evaluated using a wide-gap rotational viscometer (Brookfield Engineering Laboratories: Model LVDV-II) at different temperatures of 20, 30, 40, 50, and 60oC, at concentration of 18, 12.18 and 8.04 % total solids, and at appropriate shear rate(1-100 RPM). The power law model was fitted to the experimental results. The values of flow behaviour index (n) were found less than unity (0.23 to 0.82) at all the temperature and the concentration indicating shear-thinning (pseudoplasticity) behaviour of the concentrate. The correlation between the observed consistency coefficient ranging from 0.09 to 65.87 Pa.sn and the inverse absolute temperature has been exhibited by Arrhenius model. Consistency coefficient increased exponentially with increase in the concentration. Statistical model was used for prediction of the consistency coefficient as a function of temperature and concentration which showed a good agreement (r2=0.99) between experimental and theoretical values. The magnitude of activation energy were found to be in the range of 8.6 to 14.08 kJ/mol.K.


2013 ◽  
Vol 16 (3) ◽  
pp. 63-66
Author(s):  
Peter Hlaváč ◽  
Monika Božiková

Abstract This paper presents the selected rheological properties of pancake dough such as dynamic and kinematic viscosity and fluidity. The effect of used ingredients and temperature on rheological properties is investigated. Measurements were performed on three pancake dough samples. In two samples, there was used milk with a different fat content, and in the third sample, all ingredients were in a powder state. A digital rotational viscometer Anton Paar DV-3P was used for measuring the rheological properties. The principle of viscometer measurement is based on the dependence of sample resistance to probe rotation. Results of measurements are shown as graphical dependencies of rheological parameters on temperature. Exponential functions were used to express the dependencies of all rheological parameters on temperature. Dynamic and kinematic viscosity decreased, and fluidity increased with temperature. The highest values of dynamic viscosity were obtained for pancake dough from powder ingredients. A higher fat content of used milk caused higher values of dynamic viscosity.


2019 ◽  
Vol 4 (1) ◽  
pp. 1-6
Author(s):  
Yovial Mahyoedin ◽  
Kurnia Harlina Dewi ◽  
Wenny Marthiana ◽  
Rizky Arman ◽  
Ridho Azhari

AbstrakPenelitian ini bertujuan menentukan karakteristik reologi komposit serbuk cangkang kemiri (SCK) berukuran 45µm<d<75µm dan resin Poliuretan (PU) dengan komposisi bervariasi, yaitu 5%:95%, 10%:90%, 15%:85%. Pencampuran SCK dan PU dilakukan dengan mechanical mixer dengan kecepatan dan lama pengadukan masing-masing 10, 15 dan 20 menit dan 100, 200 dan 250 rpm. Reologi komposit diperoleh dengan pengujian rotational viscometer dan dioptimasi dengan metoda Taguchi. Penelitian menunjukkan viskositas terkecil 218,66 mPa.s, ditemukan pada komposit dengan komposisi 5% 95%, waktu pengadukan 15 menit dan kecepatan pengadukan 100 rpm.  Kata kunci: Serbuk cangkang kemiri, Poliuretan, Viskositas, Reologi.  Abstract This study aimed to determine the composite rheological characteristics of candlenut shells (SCK) with particle size of 45µm <d <75µm and polyurethane (PU) resins with varying compositions, namely 5%: 95%, 10%: 90%, 15%: 85%. Mixing of SCK and PU is carried out using mechanical mixers with a speed and stirring time of 10, 15 and 20 minutes and 100, 200 and 250 rpm, respectively. Composite rheology was obtained by rotational viscometer testing and optimized by the Taguchi method. The results showed the smallest viscosity of 218.66 mPa.s, found in composites with a composition of 5% 95%, stirring time of 15 minutes and stirring speed of 100 rpm. Keywords: candlenut shell, polyurethane, viscosity, rheology


2021 ◽  
pp. 107380
Author(s):  
Kexin Zhang ◽  
Zhihang Zhang ◽  
Ming Zhao ◽  
Vladimir Milosavljević ◽  
P.J. Cullen ◽  
...  

2014 ◽  
Vol 70 (7) ◽  
Author(s):  
Mohamad Yusri Aman ◽  
Zulkurnain Shahadan ◽  
Munzilah Md. Ruhani ◽  
Rosnawati Buhari

This paper focuses on physical and rheological properties of virgin asphalt binder blended with different percentage of Rediset® content. The rheological properties of the Rediset® modified binders were characterized before and after being subjected to short-term aging using rotational viscometer (RV) and dynamic shear rheometer (DSR) according to SuperpaveTM test protocols. The results indicated that the penetration and softening point were consistently decreased and increased, respectively for unaged and short-term aged samples. The penetration index (PI) and viscosity aging index (VAI) were increased as the Rediset® modified binders aged and showed a high significance correlation. The addition of Rediset® in asphalt binder exhibited change in binder rheology after subjected to short-term aged which influenced the rutting parameter. A statistical analysis showed that Rediset® used as warm asphalt additive had significantly increased the G*/Sin δ parameter which indicated greater resistance to rutting.


1992 ◽  
Vol 289 ◽  
Author(s):  
Gebran N. Karam

AbstractThe most important property of cements and concretes after strength is the workability, which is controlled by the rheological characteristics of the mix. Theoretical modeling having proved complicated and in some cases mathematically untractable, cement specialists have concentrated on empirical based models for the last two decades. The major theoretical contributions to date on the properties of colloidal and concentrated suspensions are summarized and a general framework for theoretical modeling of cement viscosity is established. The empirical modeling and the experimental investigation of the rheological properties of fresh cements are reviewed and discussed. A semi-empirical model is proposed and its validity tested in the interpretation of some published experimental results.


Tribologia ◽  
2016 ◽  
Vol 269 (5) ◽  
pp. 41-49 ◽  
Author(s):  
Wojciech HORAK ◽  
Józef SALWIŃSKI ◽  
Marcin SZCZĘCH

Magnetic fluids are substances whose rheological properties can be actively influenced by treatment with a magnetic field. Two main types of magnetic fluids can be distinguished: ferromagnetic fluids, and magnetorheological fluids. Ferrofluids are mostly used in sealing engineering, whereas magnetorheological fluids are usually applied in controlled systems for the dissipation of mechanical energy, like brakes and dampers. The ability to control the rheological properties of magnetic fluids opens new horizons for development in machine design, among others in the areas of bearing engineering. The paper presents a comparative analysis of the rheological characteristics of selected magnetic fluids with a focus on the possible areas of the application of these substances in bearing engineering.


2017 ◽  
Vol 35 (No. 5) ◽  
pp. 440-448 ◽  
Author(s):  
Rasouli-Pirouzian Haniyeh ◽  
Peighardoust Seyed Hadi ◽  
Azadmard-Damirchi Sodeif

The effects of sugar substitutes on rheological characteristics of compound milk chocolate using a simplex-lattice mixture design were evaluated. For this purpose, two bulking agents (maltitol and xylitol) at different levels (0–100%) were used and ten formulations were examined in order to find the optimum levels. All chocolate samples showed shear thinning behaviour. It was found that compound milk chocolate behaved as a Casson fluid. Chocolate formulations containing the highest maltitol substitution resulted in similar flow properties compared to those of the control and hence can be a good alternative. The results demonstrated that chocolate combinations containing 87.8% maltitol and 12.2% xylitol were found as the optimum concentrations producing the most acceptable rheological properties.


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