Electrical conductivity is the most important parameter for applying ohmic heating in food
processing. In this study, 10 kinds of juices were heated in a static ohmic cell to the temperature
of 80 °C applying voltage gradients in the range between 10 and 32 V cm-1. Furthermore, the
concentrated orange and pineapple juices and the purees were heated at various concentration
levels. The data of sample temperature, electrical current, and voltage gradient were recorded at
each time step in order to determine the ohmic heating characteristics and calculate the electrical
conductivities of samples. It appeared that the electrical conductivities of 10 juices were in the
range from 0.08 to 1.75 S m-1 while those of concentrated juices and purees were between 0.34
and 1.51 S m-1. The electrical conductivities of samples were significantly affected by their
concentrations and temperatures. As a result, a number of empirical models were created for
estimating the electrical conductivities as a function of these factors with the good fitting result
(R2 ≥ 0.954 and RMSE ≤ 0.048 S m-1 for 10 juice samples and R2 ≥ 0.969 and RMSE ≤ 0.069 S
m-1 for concentrated juices and purees). In addition to electrical conductivity, pH, total soluble
solid, density and specific heat of juices and purees were investigated in order to be background
information for the researchers and food industry that intent to apply ohmic heating technology
for these products.