Influence of Temperature and Solvent Content on Electrical Properties of Sunflower Seed Cake

Abstract

Here, we compare the impact of solvent content and temperature on dielectric and conductivity properties of sunflower seed cake. Two different experimental conditions were adopted in this study: permittivity-frequency isothermal spectroscopy of sunflower seed cakes at different temperatures ranging from 30 to 45C; and impedance-frequency spectroscopy of sunflower seed cakes with various solvent contents, ranging from 10 to 50 wt%. Experimental results revealed that increasing solvent content or temperature of sunflower seed cake from 10 to 50 wt% and 30 to 45C, the conductivity of samples increase by around eight times (from 3.52 × 10−6 to 2.73 × 10−5 S/m) and six times (from 1.35 × 10−4 to 7.7 × 10−4 S/m), respectively. The maximum conductivity can be reached by addition of 50 wt% of solvent to sunflower seed cake and raising the temperature to about 45C. Desired electrical properties of sunflower seed cake can be obtained by optimizing its solvent content and the processing temperature. Practical Applications With the dependence equations obtained from the measured data at various temperatures and solvent content, it is possible for the optimization of process parameters for food industry-dependent technologies, which rely on electrical properties of process materials, such as pulsed electric field treatment (PEF), ultrasonic and high-voltage electric discharge for assisted oil extraction.