Ohmic heating behaviour and electrical conductivity of two-phase food systems

2003 ◽  
Vol 4 (1) ◽  
pp. 45-55 ◽  
Author(s):  
M.R Zareifard ◽  
H.S Ramaswamy ◽  
M Trigui ◽  
M Marcotte
Keyword(s):  
Electrical Conductivity ◽  
Food Systems ◽  
Ohmic Heating ◽  
Two Phase

Effective Parameters Consideration in Ohmic Heating Process in Two Phase Static System of Bio-Particle-Liquid

2011 ◽  
Vol 7 (1) ◽  
Author(s):  
Mostafa Keshavarz Moraveji ◽  
Reza Davarnejad ◽  
Emad Ghaderi
Keyword(s):  
Electrical Conductivity ◽  
Ohmic Heating ◽  
Three Dimensional ◽  
Liquid System ◽  
Heat Diffusion ◽  
Heating Process ◽  
Static System ◽  
Effective Parameters ◽  
Distribution Profile ◽  
Two Phase

In this research, the effective parameters on Ohmic heating in aseptic and heating applications were studied. For this purpose, two- and three-dimensional Ohmic heating models in a two phase bio-solid-liquid system were developed. In these models, effects of particles distribution, particles size, effect of electrical conductivity on heating, overall heating of mixture and effect of salt concentration on heating rate were investigated. Temperature distribution profile, effects of intensity and distribution of electrical field on total temperature, and type of salt on phase electrical conductivity was also investigated. The modeling equation was solved with Finite Elements Method. The results showed that in Ohmic heating, heat diffusion in entire products was faster than the conventional methods, and it was accomplished with almost an equal rate in both phases.

Development of Conductive Packaging for Beverage Processing by Ohmic Heating

2020 ◽  
Vol 861 ◽  
pp. 213-217
Author(s):  
Sumuncharee Suyraksa ◽  
Pitiya Kamonpatana ◽  
Noppadon Kerddonfag ◽  
Amporn Sane ◽  
Vanee Chonhenchob
Keyword(s):  
Electrical Conductivity ◽  
Orange Juice ◽  
Sodium Sulfate ◽  
Ohmic Heating ◽  
Uniform Heating ◽  
Molding Process ◽  
Conductive Material ◽  
Blow Molding ◽  
Extrusion Blow Molding

This study was aimed to develop conductive packaging for ohmic heating. Polypropylene (PP) was mixed with conductive material (CM) in the ratios of 70:30 (CM30), 75:25 (CM25), and 80:20 (CM20) (w/w), then the conductive bottles were developed using extrusion blow molding process. The bottles were suspended in different sodium sulfate (Na2SO4) solutions (0.2, 0.3, and 0.5% w/w) as a transmitting current medium for ohmic heating and heated for 8 min. The CM30 and CM 25 had the highest electrical conductivity compared to the CM20, however the CM20 exhibited best processability, hence it was selected to be used for ohmic heating of orange juice. Different concentrations of Na2SO4 solutions had the effects on ohmic heating. The CM20 bottle suspended in 0.2% Na2SO4 solution resulted in the most uniform heating and suitable for ohmic processing of orange juice. The new conductive bottles developed could potentially be used for beverage processing by ohmic heating.

Electrical Conductivity of Yellowtail (Seriola quinqueradiata) Fillets During Ohmic Heating

2015 ◽  
Vol 8 (9) ◽  
pp. 1904-1913 ◽  
Author(s):  
Yinzhe Jin ◽  
Yu-dong Cheng ◽  
Mika Fukuoka ◽  
Noboru Sakai
Keyword(s):  
Electrical Conductivity ◽  
Ohmic Heating ◽  
Seriola Quinqueradiata

Correlation of Electrical Conductivity and Thermal Properties of Native Starch during Ohmic Heating

2011 ◽  
Vol 7 (5) ◽  
Author(s):  
Lam-Lam Wong ◽  
Yong-Wei Xu ◽  
Zhan-Hui Lu ◽  
Li-Te Li
Keyword(s):  
Electrical Conductivity ◽  
Room Temperature ◽  
Ohmic Heating ◽  
Heating Process ◽  
Rapid Evaluation ◽  
Scanning Calorimetry ◽  
Heating Method ◽  
Starch Gelatinization ◽  
On Line ◽  
Water Ratio

Electrical conductivity of starch suspension during ohmic heating was applied to analyze the starch gelatinization process. Native starches from wheat, corn, rice, potato, sweet potato, and pea were prepared on a starch to water ratio of 1:3 (w/w) with adding 0.05 M potassium chloride. A laboratory scale ohmic heating setup was designed to heat the starch suspension from room temperature to 90°C at a controlled heating rate of 10°C/min operating at 50 Hz and 110 V. The results show that starch gelatinization temperatures could be precisely calculated from electrical conductivity of starch suspension during ohmic heating process. The starch gelatinization temperatures based on ohmic heating were comparable to those measured by differential scanning calorimetry (DSC). Highly significant correlation of onset temperature (R=0.9972) and peak temperature (R=0.9950) were observed. The ohmic heating method could provide an alternative way to DSC with a promising potential for on-line and rapid evaluation of starch gelatinization temperatures.

Influence of Hydrocolloid Concentration, Salinity and Citric Acid Addition on Heat Transfer in the Ohmic Heating Process

2011 ◽  
Vol 7 (5) ◽  
Author(s):  
Mostafa Keshavarz Moraveji ◽  
Emad Ghaderi ◽  
Reza Davarnejad
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Citric Acid ◽  
Ohmic Heating ◽  
Solid Particles ◽  
Heating Process ◽  
Process Conditions ◽  
Heating Rates ◽  
Acid Addition ◽  
Ph Level

In this article, the effects of Ohmic heating process conditions on electrical conductivity and heat transfer were investigated. In order to study the Ohmic heating process, various hydrocolloid solutions containing starch in water with concentrations of 4–8% in the static cells were used. Temperature increments increased electrical conductivity of the solution, linearly. The concentration of dispersed solid particles in the solution caused a progressive trend in time-temperature curve for hydrocolloid solutions (with concentrations of 4, 5.5 and 8%) without electrolytes. The electrical conductivity was raised by increasing temperatures. In order to consider the salinity impact on electrical conductivity and the heating rate, sodium chloride (with concentrations of 1–0.25%) was added to the solution. It was observed that the salt addition to the system had a major effect on electrical conductivity and time-temperature curves. The pH level was modified with Citric acid addition, and the influence of pH level on the time-temperature curves and heating rates were investigated. The Citric acid addition had no on significant effect on the time-temperature curves.

scholarly journals Effect of Frequency and Waveform on Inactivation of Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium in Salsa by Ohmic Heating

2012 ◽  
Vol 79 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Su-Yeon Lee ◽  
Sangryeol Ryu ◽  
Dong-Hyun Kang
Keyword(s):  
Escherichia Coli ◽  
Electrical Conductivity ◽  
Heating Rate ◽  
Salmonella Enterica ◽  
Treatment Time ◽  
Ohmic Heating ◽  
Content Type ◽  
Significant Difference ◽  
Serovar Typhimurium ◽  
The Impact

ABSTRACT The effect of frequency of alternating current during ohmic heating on electrode corrosion, heating rate, inactivation of food-borne pathogens, and quality of salsa was investigated. The impact of waveform on heating rate was also investigated. Salsa was treated with various frequencies (60 Hz to 20 kHz) and waveforms (sine, square, and sawtooth) at a constant electric field strength of 12.5 V/cm. Electrode corrosion did not occur when the frequency exceeded 1 kHz. The heating rate of the sample was dependent on frequency up to 500 Hz, but there was no significant difference ( P > 0.05) in the heating rate when the frequency was increased above 1 kHz. The electrical conductivity of the sample increased with a rise in the frequency. At a frequency of 60 Hz, the square wave produced a lower heating rate than that of sine and sawtooth waves. The heating rate between waveforms was not significantly ( P > 0.05) different when the frequency was >500 Hz. As the frequency increased, the treatment time required to reduce Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium to below the detection limit (1 log CFU/g) decreased without affecting product quality. These results suggest that ohmic heating can be effectively used to pasteurize salsa and that the effect of inactivation is dependent on frequency and electrical conductivity rather than waveform.

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