scholarly journals Improving Microwave Heating using Polysaccharides as Thickeners

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S342-S345
Author(s):  
L. M Guardeño ◽  
M. Hernández-Carrión ◽  
J. M Catala-Civera ◽  
P. Plaza ◽  
I. Pérez-Munuera ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Electric Field ◽  
Microwave Heating ◽  
Penetration Depth ◽  
Loss Factor ◽  
The Other ◽  
Model Systems ◽  
Starch Concentration ◽  
Modified Starches ◽  
Kappa Carrageenan

The aim of this work was to improve microwave heating in white sauces using different polysaccharides in their formulation; &iota;-, &lambda;- and &kappa-carrageenan and native and modified starches were used as thickeners. Five model systems were prepared, each one with a different polysaccharide, salt, and water. Dielectric loss factor (&epsilon;'') was measured and penetration depth of the electric field was calculated at 20 and 40°C at 2450 GHz. The results showed that &epsilon;'' increased significantly (<I>P</I> < 0.05) when temperature rose in all the model systems. Moreover, &epsilon;'' decreased significantly (<I>P</I> < 0.05) when the polysaccharide concentration rose in the systems elaborated with starch (both native and modified). The penetration depth increased significantly at 40°C when native starch concentration rose. Not significant differences due to the thickener concentration were found in the depth penetration values in the other model systems, both at 20 and 40°C.

Molekülinterne Dipolorientierung und dielektrische Absorption in verdünnter Lösung bei Mikro-und Submillimeterwellen. V.Acetyl-Verbindungen

1989 ◽  
Vol 44 (9) ◽  
pp. 853-865
Author(s):  
Gerhard Klages
Keyword(s):  
Fourier Transform ◽  
Dielectric Loss ◽  
Steric Hindrance ◽  
Loss Factor ◽  
The Other ◽  
Fourier Transform Spectrometer ◽  
Aromatic Rings ◽  
Molecular Laser ◽  
Aliphatic Compounds ◽  
Fast Relaxation

Abstract The dielectric loss of sixteen molecules, eleven with the acetyle group in aromatic bonds and five in aliphatic bonds, has been measured in very dilute solutions of cyclohexene at 20 °C. Five of these molecules are investigated in decalene solutions, too. The measurements have been made at wavenumbers in the range 0.08 to 140 cm -1 above 8 cm -1 making use of a pumped molecular laser. They are supplemented by the data of a Fourier transform spectrometer up to 300 cm -1. All microwave spectra of loss factor ε″ are analysed in terms of three absorption areas using the two variable Mori formalism. On the other hand, Lorentz curves are fitted to the FIR absorption spectra of α(v̄).The fast relaxation process of the aliphatic compounds is suggested to be due to intramolecular reorientation of the acetyle group itself, since in acetyle cyclohexene the remaining part of the molecule is rigid. To the contrary, the acetyle group is not able to reorientate swiftly, if bounded to aromatic rings. Presumably, it is fixed by mesomeric interaction with the dipole in the plain of the ring. However, 2-methyl acetophenone and 1-acetyle naphthone show some quick dipole reorientation, which coincides with a steric hindrance of the group in entering the plain of the ring.

Numerical Simulation of Microwave Heating for Soot Oxidation

2014 ◽  
Vol 564 ◽  
pp. 256-262 ◽  
Author(s):  
Haitham B. Al-Wakeel ◽  
Z.A. Abdul Karim ◽  
Hussain Hamoud Al-Kayiem
Keyword(s):  
Electric Field ◽  
Microwave Heating ◽  
Penetration Depth ◽  
Soot Oxidation ◽  
Small Samples ◽  
Front Face ◽  
Maximum Temperature ◽  
Ignition Point ◽  
Transient Thermal ◽  
The Mathematical Model

This paper presents the simulation of microwave heating by coupling high frequency electromagnetic with transient heat transfer using finite element method edge base of ANSYS software. Helmholtz equation of electric field has been formulated from Maxwell equations to predict electric field and the mathematical model of transient thermal analysis was included. Three cases have been examined numerically to investigate electric field, dissipated heat, temperature distribution and weight loss of soot at operation frequency 2.45 GHz. The simulation results showed that heat is generated from inside to outside of soot. The temperature at penetration depth increased till ignition point and after further heating, maximum temperature was attained, followed by temperature decreases due to mass transport. Maximum electric field was found to be located on the front face for the small samples with dimensions less than penetration depth. The predicted results have been compared with experimental results which show the validity of the simulation.

Morphology Control of Phosphors Synthesized by Microwave Heating Method

2010 ◽  
Vol 445 ◽  
pp. 233-236
Author(s):  
Ayano Toda ◽  
Kazuyoshi Uematu ◽  
Tadashi Ishigaki ◽  
Kenji Toda ◽  
Mineo Sato
Keyword(s):  
Dielectric Loss ◽  
Microwave Irradiation ◽  
Microwave Heating ◽  
Loss Factor ◽  
Raw Materials ◽  
Single Mode ◽  
Microwave Energy ◽  
Microwave Oven ◽  
Sharp Drop ◽  
Heating Method

Ba2Gd3Li3Mo8O32:Eu3+ phosphor was prepared using a single mode microwave oven operated at a frequency of 2.45 GHz and a power of 500 W. The temperature of raw materials, mixtures of BaCO3, Gd2O3, Li2CO3, MoO3 and Eu2O3 subjected to microwave irradiation increased to about 1073 K in 120 s, followed by a sharp drop despite irradiating the raw materials continuously. By measuring the dielectric loss factor of the raw materials at 2.45 GHz, the temperature increased could be attributed to the fact that MoO3 absorbs a high proportion of microwave energy. In the case of the microwave heating method, the phosphor particles were highly non-aggregated.

scholarly journals Investigation of the physico-chemical parameters of the «Gelamil» series starches in the technology of mashed soups

2021 ◽  
Vol 5 (3(61)) ◽  
pp. 29-32
Author(s):  
Svitlana Andrieieva ◽  
Yevgen Pyvovarov
Keyword(s):  
Raw Materials ◽  
Potato Starch ◽  
Starch Content ◽  
Textural Properties ◽  
Model Systems ◽  
Special Role ◽  
Starch Concentration ◽  
Organoleptic Characteristics ◽  
Modified Starches ◽  
Starch Paste

The object of research is the technologies for the production of puree soups using modified starches of the «Gelamil» series. One of the main requirements for the quality of the technology of puree soups is the creation of a fluid, uniform, finely ground texture, which plays a special role in the organoleptic characteristics of this type of product. The texture of the product can be adjusted by adding liquid boiling modified starches. Starches of the «Gelamil» series are represented by potato starch with a reduced viscosity and are characterized as air-flowing gelling potato starch, that is, starch, the solution of which gives a low viscosity at high temperatures, and when solidified – a dense gel. Hydrodynamic changes in the parameters of starch paste based on starches of the «Gelamil» series, depending on the temperature and type of starch, have been established. It was determined that starch paste based on starches of the «Gelamil» series, in comparison with native potato starch, have a low temperature of maximum viscosity from 47±2 °C to 57±2 °C, and thus form a paste with a viscous-flowing texture. The effective viscosity of starch paste was investigated depending on the starch content. It has been experimentally established that regulation of the starch content makes it possible to create starch paste according to different textural properties. For viscous-thinned dispersions, the starch concentration is from 1.0 to 3.0 %. For viscous-flowing dispersions having a long texture, the starch concentration is 3.5 to 5.0 %. For viscous-flowing dispersions having a short texture, the starch concentration is 5.5 to 7.0 %. For the content of native potato starch in the system of more than 5.0 %, a dense paste with a short texture is formed. It was found that for a starch paste based on starches of the «Gelamil» series, the separation of the liquid phase occurs due to 2:00 in an insignificant amount. A lot of components and model systems based on vegetable, legume purees and starch paste have been investigated. It has been determined that, depending on the type of vegetable and legume raw materials, the use of starches of the «Gelamil» series of different types and concentrations depends.

Usefulness of Foundry Tooling Materials in Microwave Heating Process

2013 ◽  
Vol 58 (3) ◽  
pp. 919-922 ◽  
Author(s):  
K. Granat ◽  
B. Opyd ◽  
D. Nowak ◽  
M. Stachowicz ◽  
G. Jaworski
Keyword(s):  
Electromagnetic Field ◽  
Microwave Heating ◽  
Loss Factor ◽  
Perturbation Technique ◽  
Resonant Cavity ◽  
Precise Determination ◽  
Heating Process ◽  
Basic Criterion ◽  
Measurement Results ◽  
Heating Technology

Abstract The paper describes preliminary examinations on establishing usefulness criteria of foundry tooling materials in the microwave heating technology. Presented are measurement results of permittivity and loss tangent that determine behaviour of the materials in electromagnetic field. The measurements were carried-out in a waveguide resonant cavity that permits precise determination the above-mentioned parameters by perturbation technique. Examined were five different materials designed for use in foundry tooling. Determined was the loss factor that permits evaluating usefulness of materials in microwave heating technology. It was demonstrated that the selected plastics meet the basic criterion that is transparency for electromagnetic radiation.

Study on stability of electric field in multimode microwave heating cavity

2016 ◽  
Vol 50 (2) ◽  
pp. 321-330 ◽  
Author(s):  
Z.-M. Tang ◽  
K.-M. Huang ◽  
Y.-H. Liao ◽  
T. Hong ◽  
H.-C. Zhu
Keyword(s):  
Electric Field ◽  
Microwave Heating

Dielectric properties of wheat flour mixed with oat meal

2013 ◽  
Vol 27 (2) ◽  
pp. 175-180 ◽  
Author(s):  
D. Łuczycka ◽  
A. Czubaszek ◽  
M. Fujarczuk ◽  
K. Pruski
Keyword(s):  
Electromagnetic Field ◽  
Dielectric Loss ◽  
Wheat Flour ◽  
Loss Factor ◽  
Ash Content ◽  
Dielectric Loss Factor ◽  
Field Frequency ◽  
Impedance Analyzer ◽  
Sedimentation Value

Abstract Possibilities of using electric methods for determining admixtures of oat meal to wheat flour, type 650 are presented. In wheat flour, oat meal and mixtures containing 10, 20 and 30% of the oat meal, moisture, protein, starch and ash content, sedimentation value, yield and softening of wet gluten were determined. In samples containing 0, 5, 10, 15, 20, 25, 30 and 100% of oat meal, the dielectric loss factor and conductivity were determined using an impedance analyzer for electromagnetic field frequency ranging from 0.1-20 kHz. It was found that the dielectric loss factor varied for tested material. The best distinguishing between tested mixtures was obtained at the measuring electromagnetic field frequency of 20 kHz. The loss factor was significantly correlated with the yield of wet gluten and the sedimentation value, parameters indicating the amount and quality of gluten proteins in flour.

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