Rice cooking using ohmic heating: Determination of electrical conductivity, water diffusion and cooking energy

In this research, ohmic heating was proposed as an alternative method to cook rice. Jasmine rice grain's swelling behavior and electrical conductivity, water diffusion, and cooking energy were investigated. Results showed that rice grains expanded faster when the temperature was higher than 80 degrees C. A triphased linear relationship between electrical conductivity and temperature was observed with two transition temperatures at around 60 and 80 degrees C. Water diffused into rice grains faster when the temperature was higher than 80 degrees C and even faster during steeping in boiling water. A higher electric field strength increased the diffusion rate. The energy consumption by the ohmic cooking process was about 1/4 of the total energy consumed by an electric rice cooker while the cooking time was slightly shorter (18 and 17 min). Differences from a rice cooker included no fouling was observed of the rice-layer on the cooking container after ohmic cooking. (C) 2016 Elsevier Ltd. All rights reserved.