Design and performance evaluation of an ohmic heating unit for thermal processing of highly viscous liquids

Ghnimi, Sami; Flach-Malaspina, Nicolas; Dresch, Marlène; Delaplace, Guillaume; Maingonnat, JF

doi:10.1016/j.cherd.2008.02.005

Cited by 44 publications

(21 citation statements)

References 14 publications

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“…It was possible to establish a correlation between the electrical conductivity and rheological parameters of HPH‐treated and control samples. These results corroborates the potential pointed by several other authors (Fryer et al, ; Ghnimi et al, ; Knirsch et al, ; Sakr & Liu, ).…”

Section: Resultssupporting

confidence: 93%

Effect of concentration and consistency on ohmic heating

Leite

Sastry

Cristianini

2018

J Food Process Engineering

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Ohmic heating (OH) is an emerging technology that has shown great potential in the food industry. Product consistency, concentration, and electrical conductivity are critical factors in OH. These variables are interrelated; how they affect each other, however, is not well described in the literature. This study aimed to verify the impact of concentration and consistency on OH, by evaluating the electrical conductivity of several carboxymethyl cellulose (CMC) solutions. CMC solutions of different concentration (0.5–3%) were processed by high‐pressure homogenization (HPH) at 100 and 200 MPa (unprocessed as control), to obtain solutions with different consistencies and same concentration. Electrical conductivity at 25 °C increased as solution concentration increased (ranging from 0.118 Sm−1 at 0.5% to 0.493 Sm−1 at 3%), and HPH treatment increase the electrical conductivity (ranging, at 3%, from 0.493 Sm−1 at 0 MPa to 0.575 Sm−1 at 200 MPa), however no significant difference between 100 and 200 MPa samples. Several correlations were possible to between concentration, consistency, and electrical conductivity. These correlations may be used as an indirect tool to determine consistency from electrical conductivity and may be applied in process and equipment design. The results corroborate the potential of OH in fluids with high consistency. Practical applications Food consistency is a critical factor in many processes, and ohmic heating shows a great potential for the treatment of highly viscous fluids. How rheological parameters impact ohmic processing without altering product composition has never been investigated. Moreover, the models developed in this study can be used as an indirect tool to estimate rheological parameters from electrical conductivity readings.

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Section: Resultssupporting

confidence: 93%

Effect of concentration and consistency on ohmic heating

Leite

Sastry

Cristianini

2018

J Food Process Engineering

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“…7). Pomerantsev number has been used similarly to assess the performance of ohmic heating systems by Icier et al (2006) and Ghnimi et al (2008). As the temperature increased the current passing through the sample increased.…”

Section: Resultsmentioning

confidence: 99%

Ohmic cooking of ground beef: Effects on quality

Bozkurt

İçıer

2010

Journal of Food Engineering

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“…To get further insight in suspension mechanisms, the viscosity of the liquid was also increased by using aqueous solutions of CarboxyMethylCellulose (CMC, Fluka 21902) at a volume fraction of 1% (T ¼37 1C, ρ L ¼ 999 kg m À 3 , μ L ¼ 20 mPa s) and 0.3% (T ¼37 1C, ρ L ¼ 999 kg m À 3 , μ L ¼ 6:5 mPa s). Despite, in most cases, CMC solutions are expected to be non-newtonian (Ghnimi et al, 2008), the newtonian flow behavior of our CMC solutions was confirmed using rheological measurements on a double-Couette rheometer from TA instruments (New Castel, USA) (Fig. 2).…”

Section: Fluids and Liquid Volume Characterizationmentioning

confidence: 57%

Critical agitation for microcarrier suspension in orbital shaken bioreactors: Experimental study and dimensional analysis

Olmos

Loubière

Martin

et al. 2015

Chemical Engineering Science

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Experimental characterization of particle suspension in orbital shakers. New correlation predicting critical agitation conditions for complete particle suspension. Larger orbital diameters promote smaller power dissipations at complete particle suspension. a b s t r a c tOrbital shaken bioreactors are widely used at the laboratory scale for the culture of animal cells in suspension mode. In the case of adherent-dependent cell lines, the choice of agitation conditions at which all particles are just-suspended (or attain complete suspension) has often to be determined. Indeed, with orbital shaken bioreactors, this choice results from the combination of two parameters: the orbital diameter and the agitation rate. That is why, a new experimental protocol for the determination of critical agitation conditions for microcarrier complete suspension has been developed in this paper. It consisted in a side-view visualization of blue-stained particles in shaken Erlenmeyer flasks and cylindrical flasks. 220 experiments representative of animal cell culture conditions have been carried out to study the effect of various operating conditions (bioreactor size and geometry, particle type, density and diameter, liquid viscosity, shaking diameter, filling ratio). Furthermore, a dimensional analysis has been performed, leading to a correlation relating a Froude number (in which the critical agitation N c for complete particle suspension is embedded) to four other dimensionless numbers. Then, the critical agitation conditions determined in this paper were analyzed and discussed with respect to the data available in the literature on the flow structure occurring inside the flask. Our findings revealed that high orbital shaking diameters and large cylindrical vessels should be promoted to get microcarriers into suspension at a minimized power dissipation per unit of volume.

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Design and performance evaluation of an ohmic heating unit for thermal processing of highly viscous liquids

Cited by 44 publications

References 14 publications

Effect of concentration and consistency on ohmic heating

Effect of concentration and consistency on ohmic heating

Ohmic cooking of ground beef: Effects on quality

Critical agitation for microcarrier suspension in orbital shaken bioreactors: Experimental study and dimensional analysis

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