In order to investigate the applicability of ohmic heating in the blanching and heat sterilization process of vegetable foods, various electrical properties and heating characteristics were studied using intact potato. The electrical conductivity of potato with cell structure was 0.025 S/m, which was lower than that of starch and protein gel, and was increased linearly with increasing temperature. The temperature of ohmic heating was sharply increased from 8 min at 60 V, reaching 90°C after 10 min. The temperature rise was rapid at 60°C which was due to the increase of current flow by structural change related to the gelatinization of starch. The increase of temperature was faster when the frequency was increased, such as from 500 Hz to 1000 Hz. When potato was heated by ohmic heating at 60- 90 V and 40-120 Hz, rapid and uniform heat generation was possible. Thus, commercial utilization of ohmic heating can be applied for various types of vegetable foodstuff with ohmic heating was observed.

Abstract
Introduction
Materials and Methods
    Vegetable materials
    Experimental apparatus
    Experimental procedure
    Electrical conductivity measurement
    Statistical analysis
Results and Discussion
    Electrical conductivity of plant tissue
    Temperature dependence of electrical conductivity
    Effect of voltage on plant tissue
    Effect of frequency on plant tissue
    Electrical model of plant tissue
    Ohmic heating effect compared to conventional heating
References

• Won-Il Cho(CJ Foods R&D, CJ Cheiljedang Corp.)
• Sang-Hoon Song(Division of Applied Food System, Major of Food Science & Technology, Seoul Women's University) Corresponding author