scholarly journals Physicochemical, Microstructural, and Rheological Characterization of Tigernut (Cyperus esculentus) Starch

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
P. T. Akonor ◽  
C. Tortoe ◽  
C. Oduro-Yeboah ◽  
E. A. Saka ◽  
J. Ewool
Keyword(s):  
Physicochemical Properties ◽  
Amylose Content ◽  
Flow Behavior ◽  
Pasting Properties ◽  
Cyperus Esculentus ◽  
Rheological Characterization ◽  
Freeze Thaw ◽  
Starch Gels

The aim of this study was to characterize the physicochemical properties of starch isolated from two varieties of tigernuts. The results showed wide variations between the two types of tigernuts. Mean granule sizes were 11.1 and 6.1 μm, respectively, for starch from the yellow and black while amylose content ranged from 19 to 21%. Starch gels from the yellow variety were more stable to freeze-thaw and recorded 37.1% syneresis, compared to 56.5% after the first storage cycle. Pasting properties were significantly different (p < 0.05) among starch from the two tigernut varieties, with black recording higher peak viscosity, lower breakdown, and higher setback viscosity. Gels made from the yellow variety were clearer, softer, more adhesive, and more cohesive. Both gels showed a pseudoplastic flow behavior without thixotropy.

scholarly journals Rheological Characterization of a Concentrated Phosphate Slurry

Fluids ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 178
Author(s):  
Souhail Maazioui ◽  
Abderrahim Maazouz ◽  
Fayssal Benkhaldoun ◽  
Driss Ouazar ◽  
Khalid Lamnawar
Keyword(s):  
Flow Behavior ◽  
Continuous Phase ◽  
Raw Material ◽  
Rheological Characterization ◽  
Phosphate Ore ◽  
Insoluble Particles ◽  
Experimental Protocols ◽  
Solid Liquid

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

scholarly journals Influence of growth locations on physicochemical properties of starch and flour from amadumbe (Colocasia esculenta) genotypes

2017 ◽  
Author(s):  
◽  
Bruce Mawoyo
Keyword(s):  
Physicochemical Properties ◽  
Water Absorption ◽  
Functional Properties ◽  
Amylose Content ◽  
Starch Synthesis ◽  
Major Effect ◽  
Pasting Properties ◽  
Mineral Contents ◽  
Soluble Fibre ◽  
Swelling Power

Amadumbe commonly, known as taro is a traditionally underutilised tuber crop in Southern Africa. Nutritionally, amadumbe corms contain appreciable levels of carbohydrate mainly in the form of starch which is resistant to digestion. It also contains mucilage, a soluble fibre, which is good for the human digestive health. Thus, amadumbe starch and mucilage can be used as functional ingredients in food formulations. The aim of this research was to investigate the effects of genotypes and growth location on the physicochemical properties of amadumbe flour and starch. Eighteen (18) amadumbe genotypes grown in Roodeplaat, Gauteng and Umbumbulu, Kwazulu-Natal, South Africa, were studied. Roodeplaat received a lower annual average rainfall (514 mm) and high environmental temperature (24oC) compared to Umbumbulu (828 mm, 19oC) during the cropping season. Specifically, the influence of growth location and genotypes on the chemical composition (proximate composition and mineral contents) as well as the functional properties of amadumbe flours were investigated. Furthermore, starch was extracted and its physicochemical and functional properties were also studied. The carbohydrate contents (73-81%) of amadumbe flours were substantially high and varied with growth location. Mucilage contents (6-9%) were very low across genotypes in both locations. Water absorption and oil absorption capacities positively correlated to carbohydrates and mucilage in the flour irrespective of growth locations. Swelling power and solubility index was influenced by the amylose content of the flour. Genotype and growth location significantly affected the pasting properties of amadumbe flour. The pasting temperature was very high (approx. 90oC) across genotypes in both locations, while peak viscosity differed significantly (54-242 RVU) for genotypes grown in different environments. The amylose contents (0-14.4%) of amadumbe starches were low and varied significantly with growth location and among genotypes. Three genotypes, G2, G20, and G21 grown in Roodeplaat lacked amylose. Amadumbe starches showed reflective peaks at 2θ=15o and doublet at 17o, 18o and 24o typical of A-type starches. Amadumbe genotypes had small sized (1-5 µm) and polygonal starch granules. Functional properties including water absorption, swelling power, gelatinisation temperature and peak viscosity significantly positively correlated with amylose content. These findings further suggest that water availability could have a major effect on starch synthesis as the two locations received a different amount of rainfall during the growing season. Findings from this study are important for future improvement programmes and selection of appropriate genotypes for industrial production or food application of amadumbe flour and starch.

Rheological Characterization of a New Alloy for Thixoforming

2008 ◽  
Vol 141-143 ◽  
pp. 301-306 ◽  
Author(s):  
Annalisa Pola ◽  
Roberto Roberti ◽  
Michael Modigell ◽  
Lars Pape
Keyword(s):  
Flow Behavior ◽  
Thermodynamic Simulation ◽  
Semisolid State ◽  
Rheological Characterization ◽  
Scanning Calorimetry ◽  
Globule Size ◽  
Semisolid Alloy ◽  
Dependent Flow ◽  
Mechanical Performances

A new aluminum alloy (AlSi5Mg0.5Cu0.3Ag) for semisolid die-casting applications was designed, starting from computational thermodynamics calculations by Computherm Database. The goal was to obtain a combination of good castability and proper concentration of hardening elements for strengthening precipitation treatment. The predicted thixotropic properties were verified by measuring the microstructural conventional parameters, such as globule size and shape factor, and the solidification range, by means of differential scanning calorimetry. To complete the characterization of this new alloy and to evaluate its applicability in industrial production, the shear rate and time-dependent flow behavior of the alloy in the semisolid state was studied in a Searle-type rheometer. A future aim of the present research is to try to use rheology testing as the tool to optimize the chemical composition, in order to design an alloy characterized by good mechanical performances and easy processability. Considering the strong influence of the solid fraction content on semisolid alloy viscosity, the rheology tests were interrupted after a certain time and the alloy was deeply freezed using vaporized liquid nitrogen, in order to fix the microstructure and verify the correctness of the thermodynamic simulation.

scholarly journals Comparative Analysis Reveals Changes in Some Seed Properties in Amaranth Mutant Variety ‘Zobor’ (A. hypochondriacus × A. hybridus)

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2565
Author(s):  
Andrea Hricová ◽  
Veronika Mistríková ◽  
Alena Gajdošová ◽  
Jozef Fejér ◽  
Jana Nôžková ◽  
...  
Keyword(s):  
Seed Weight ◽  
Amylose Content ◽  
Mutation Breeding ◽  
Pasting Properties ◽  
Phenotypic Characterization ◽  
New Variety ◽  
Yield Trait ◽  
Radiation Induced ◽  
Induced Mutagenesis

The aim of our long-term research program is to improve the quality and quantity of amaranth production through mutation breeding using γ-radiation. In this paper, we present the characterization of the new variety ‘Zobor’ of A. hypochondriacus × A. hybridus developed by radiation-induced mutagenesis of hybrid K-433. Multiyear phenotypic characterization of an important yield parameter (1000-seed weight) showed that the studied mutant variety ‘Zobor’ has an advantage in seed weight over the nonirradiated control seeds of K-433 with predictable performance of this yield trait. ‘Zobor’ exhibited changes in seed morphometric parameters, starch particle size, and pasting properties with no change in amylose content and swelling power. Moreover, the seeds of ‘Zobor’ showed the significantly highest folate content among selected amaranth varieties. The mutant variety could, therefore, be interesting for the development of functional foods and as a low-management crop, attractive for cultivation in Europe.

Effect of Gamma Irradiation on Physicochemical Properties of Brown Rice

2015 ◽  
Vol 11 (4) ◽  
pp. 563-571 ◽  
Author(s):  
Shabir Ahmad Mir ◽  
Sowriappan John Don Bosco ◽  
Manzoor Ahmad Shah ◽  
Mohammad Maqbool Mir ◽  
Kappat Valiyapeediyekkal Sunooj
Keyword(s):  
Physicochemical Properties ◽  
Gamma Irradiation ◽  
Irradiation Dose ◽  
Amylose Content ◽  
Raman Band ◽  
Brown Rice ◽  
Pasting Properties ◽  
Raman Spectrometry ◽  
Irradiation Treatment ◽  
Rice Samples

Abstract Brown rice was exposed to 60Co source at 0, 2, 4, 6, 8 or 10 kGy doses and the effect of gamma irradiation treatment on physicochemical properties were investigated. L* value of brown rice was decreased with increase of irradiation dose, whereas a* and b* values increased. The results showed the decrease of kernel hardness, amylose content and pasting properties considerably with irradiation treatment. A-type diffraction pattern was observed in non-irradiated and irradiated rice samples and crystallinity was decreased with irradiation dose. Raman spectrometry showed the decrease of Raman band intensity at higher irradiation doses. Thermal properties of rice samples were decreased slightly after irradiation treatment. Pearson’s correlation studies revealed that irradiation dose was positively correlated with b* value and negatively correlated with amylose content and pasting properties.

scholarly journals Development of a Rheology Die and Flow Characterization of Gas-Containing Polymer Melts

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3305
Author(s):  
Clemens Kastner ◽  
Dominik Altmann ◽  
Eva Kobler ◽  
Georg Steinbichler
Keyword(s):  
Polymer Melts ◽  
Flow Behavior ◽  
Volumetric Flow Rate ◽  
Thermal Characterization ◽  
Polymer Processing ◽  
Rheological Characterization ◽  
Process Measurement ◽  
Flow Characterization ◽  
Chemical Blowing Agents

We present a novel measurement die for characterizing the flow behavior of gas-containing polymer melts. The die is mounted directly on the injection-molding cylinder in place of the mold cavity and thus enables near-process measurement of viscosity (i.e., under the conditions that would be present were a mold attached). This integration also resolves the issue of keeping gas-containing polymer melts under pressure during measurement to prevent desorption. After thermal characterization of the die, various correction approaches were compared against each other to identify the most suitable one for our case. We conducted measurements using polypropylene in combination with two different chemical blowing agents. Increasing the blowing-agent content to up to 6% revealed an interestingly low influence of gases on melt viscosity, which was confirmed by elongational viscosity measurements. For verification, we compared our results to corresponding measurements taken on a high-pressure capillary rheometer and found that they were in excellent agreement. Our die cannot only be used for rheological characterization. Combined with ultrasound sensors, it provides an innovative way of measuring the volumetric flow rate. This development represents an important step in improving the sustainability of gas-containing polymer processing.

scholarly journals Printing of Zirconia Parts via Fused Filament Fabrication

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5467
Author(s):  
Dorit Nötzel ◽  
Ralf Eickhoff ◽  
Christoph Pfeifer ◽  
Thomas Hanemann
Keyword(s):  
Flow Behavior ◽  
Special Focus ◽  
Fused Filament Fabrication ◽  
Rheological Characterization ◽  
Structural Details ◽  
Low Shear Stress ◽  
Flow Situation ◽  
The Individual ◽  
Low Shear

In this work, a process chain for the fabrication of dense zirconia parts will be presented covering the individual steps feedstock compounding, 3D printing via Fused Filament Fabrication (FFF) and thermal postprocessing including debinding and sintering. A special focus was set on the comprehensive rheological characterization of the feedstock systems applying high-pressure capillary and oscillation rheometry. The latter allowed the representation of the flow situation especially in the nozzle of the print head with the occurring low-shear stress. Oscillation rheometry enabled the clarification of the surfactant’s concentration, here stearic acid, or more general, the feedstocks composition influence on the resulting feedstock flow behavior. Finally, dense ceramic parts (best values around 99 % of theory) were realized with structural details smaller than 100 µm.

Characterization of Amorphophallus paeoniifolius (Dennst.) Nicolson Modified Fermented Flour

2020 ◽  
Vol 16 (4) ◽  
pp. 514-522
Author(s):  
Ikrar T. Syah ◽  
Anto ◽  
Umar H.A. Hasbullah
Keyword(s):  
Physicochemical Properties ◽  
Physicochemical Analysis ◽  
Pasting Properties ◽  
Whiteness Index ◽  
Randomized Design ◽  
Elephant Foot Yam ◽  
Yam Flour ◽  
Foaming Capacity ◽  
Completely Randomized Design

Background: Flour is generally evaluated by physicochemical analysis of its constituents in order to determine its functional properties. The modification of flour is reflected in many of its physicochemical properties. Objective: In the present study, samples of elephant foot yam (Amorphophallus paeoniifolius) modified fermented flour were characterized based on physicochemical properties of starch, amylose, and amylopectin content, and also flour morphology. Methods: Various starters were applied (mocaf, Bimo-cf, and tape yeast) for 12h fermentation before being processed into flour to modify its properties. The physicochemical parameters of flours consist of whiteness index, pasting properties, foaming capacity, flour morphology, and proximate compositions. All data were taken in triplicate using completely randomized design. Result: All the starters were able to improve whiteness index (WI) of flour. There was a correlation between fat and protein content with pasting properties of native flour and modified fermented elephant foot yam (MoEFY) flours. Fermentation processes caused slight changes of flour pasting properties. The granule size of MoEFY flour became smaller than those in native elephant foot yam flour after fermentation, and granules were polyhedral with slightly pointed and protruding edges. Conclusion: The results suggested that fermentation by Bimo-cf starter within 12h could provide a greater extent of flour modification.

The effect of freeze–thaw cycles on microstructure and physicochemical properties of four starch gels

2013 ◽  
Vol 31 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Lan Wang ◽  
Bijun Xie ◽  
Guangquan Xiong ◽  
Wenjing Wu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Freeze Thaw ◽  
Starch Gels

scholarly journals Changes of physicochemical properties and correlation analysis of common buckwheat starch during germination

Fagopyrum ◽  
1970 ◽  
Vol 36 (2) ◽  
pp. 43-50 ◽  
Author(s):  
Licheng Gao ◽  
Meijuan Xia ◽  
Zhonghao Li ◽  
Pengke Wang ◽  
Meng Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Correlation Analysis ◽  
Physicochemical Properties ◽  
Amylose Content ◽  
Pasting Properties ◽  
Fat Content ◽  
Starch Granules ◽  
Common Buckwheat ◽  
Particle Structure ◽  
Starch Composition

In order to clarify the physicochemical properties of starch during germination of common buckwheat, Xinong9976 was selected as the experimental material to study the main nutrients, particle structure, particle size distribution, transparency, aging value, pasting properties and the correlation between pasting properties and starch composition and main nutrients. The results showed that main nutrients were significantly different. The diameter of starch granules ranged from 2.36 to 8.89.m, and the shapes of starch granules were irregular with obvious holes and cracks on the surface. There were significant differences in starch transparency, aging value and pasting properties at different germination stages. Peak viscosity, through viscosity and final viscosity of germinated common buckwheat was significantly positive correlated with amylopectin content (P < 0.05) and breakdown, final viscosity and setback were significantly negatively correlated with amylose content (P < 0.05). The correlation analysis of starch pasting properties and main nutrients showed that breakdown, setback and crude fat content were significantly negatively correlated (P < 0.01), peak viscosity, through viscosity and final viscosity were significantly negatively correlated with crude fat content (P < 0.05), while the starch pasting properties had no significant correlation with other nutrients.Received: April 14, 2019; accepted: June 8, 2019Key words: common buckwheat, germination, physicochemical properties, starch

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