Capacitive (Radio Frequency) dielectric heating has great potential for achieving rapid and uniform heating patterns in foods, providing safe, high quality food products. This review describes and discusses the major technology behind capacitive (RF) dielectric heating in food processing and preservation, the current applications of the technology in the industry, the potential use of mathematical modeling for heating system design, and the major challenges facing the use of this technology in food processing. A vast amount of work is still necessary to further understand the dielectric properties of both food and packaging materials in order to refine system design and maximize performance of this technology in the field of packaged food products. Various economic studies will also play an important role in understanding the overall cost and viability of commercial application of this technology in food processing.

Surimi without enzyme inhibitors containing 78% moisture and 2% NaCl was heated conventionally and ohmically to 90°C after holding at 55°C for 0, 1, 3 and 5 min. Gels heated slowly in a water bath exhibited poor gel quality, while the ohmically heated gels without holding at 55°C showed more than a twofold increase in shear stress and shear strain over conventionally heated gels. Degradation of myosin and actin was minimized by ohmic heating, resulting in a continuous network structure. Ohmic heating with a rapid heating rate was an effective method for maximizing gel functionality of Pacific whiting surimi without enzyme inhibitors.

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Electrical conductivities of Pacific whiting surimi paste with various moisture contents (75, 78, 81, and 84%) and added salt (1, 2, 3, and 4%) were measured using ohmic heating at alternating current of 3.3, 6.7, and 13.3 V/cm. Electrical conductivity of surimi increased with temperature and salt content and slightly increased with moisture content. Electrical conductivity correlated linearly with temperature (r2 = 0.99). Generally, voltage gradient did not affect conductivity. However, variations of conductivity with voltage gradient observed in surimi containing 34% salt, were probably caused by electrochemical reactions at electrode surfaces. The empirical model of electrical conductivity predicted values + 16% of independent experimental results.