The tests of temperature dependence of electrical conductivity were performed in the temperature range 290–510 K. The tests were performed in two stages. In the first one, the samples were heated in the temperature range 290–380 K. The aim of this test was to investigate the free and bound water release processes, which occur in this temperature range. In the second stage, the samples were cooled down and reheated to 510 K. The aim of the heating was to determine the denaturation temperature TD.