Development of a dual cylindrical microwave and ohmic combination heater for minimization of thermal lags in the processing of particulate foods

Abstract

a b s t r a c tDual cylindrical microwave chambers equipped with ohmic heating tubes were designed to maximize the electric field strength for thermal treatment of particulate foods. Temperature profiles of particleliquid mixtures containing sodium chloride solution (C s , 5e20 g/L), chicken, and potato particulates at different mass fractions (M f, 10e15 g/100 g) were collected and compared for individual and combination heating modes. Results indicated that particle size (S p , 0.5 and 1 cm cubes) and salt concentration affected temperature variations between solution and particulates in ohmic heating. For microwave heating, the solution temperature lagged behind the particle temperature up to 12.5 g/L salt concentrations, regardless of particle size and mass fraction; however, an opposite tendency was observed in the food mixtures including 20 g/L salt concentration. The maximum temperature differences between particles and solution obtained by individual microwave and ohmic heating were 7.1 ± 1.7 and 11.9 ± 2.9 C, respectively, while the combination heating exhibited little significant temperature gaps (maximum difference < 3.08 C) at 12.5 g/L salt concentrations. 3D block diagrams constructed using the controllable ranges of C s , S p , and M f estimated by empirical equations could be used to describe temperature similarities between particles and solution when the combination heating was applied.Published by Elsevier Ltd.

Design and Fabrication of a Dual Cylindrical Microwave and Ohmic Combination Heater for Processing of Particulate Foods

“…In addition, the effect of microwave and ohmic combination heater on uniform heating of multiphase foods was validated by using particle and liquid mixture foods that consisted of two fixed-size chicken breasts and potato cubes as well as base solutions mixed with sodium chloride and carboxymethyl cellulose (CMC) solutions, and NaCl solution with different salt concentration (Lee et al, 2015). When the particle and liquid mixture foods were treated by individual microwave and ohmic heating, the temperature difference between the particles and liquid foods was significant; however, uniform heating of particles and liquid mixture foods was obtained in the combination heating, finally resulting in a quite acceptable temperature difference between particles and liquid foods for commercial production of multiphase foods (Lee et al, 2015).…”

“…When the particle and liquid mixture foods were treated by individual microwave and ohmic heating, the temperature difference between the particles and liquid foods was significant; however, uniform heating of particles and liquid mixture foods was obtained in the combination heating, finally resulting in a quite acceptable temperature difference between particles and liquid foods for commercial production of multiphase foods (Lee et al, 2015).…”

Evaluation of structural changes and intracellular substance leakage of Escherichia coli O157:H7 induced by ohmic heating

“…There has been an increasing interest in alternative food processing methods because of the increasing consumer demand for safe, nutritious and high‐quality products. Therefore, some alternative heating techniques have been widely studied by researchers and food industries, such as infrared heating, microwave heating and ohmic heating (OH) (Lee et al ; Sengun et al ). Ohmic heating, one of the most promising techniques, is carried out via electric current flowing through the food (Kim et al ), and the main advantages of this technique are short processing time, uniform temperature distribution and high energy efficiency (Somavat et al ; Kaur and Singh ).…”