The Use of Ohmic Heating Assistance in the Extraction of Color Compounds from Red Beetroot
Project no. 21153 · Status: Kapanmış · 2019
Summary
In this project, red beet was extracted about 1 hour at 40? process temperature by ohmic heating assisted extraction (OHAE) and conventional extraction (CE) methods. OHAE method was performed at 3 different voltage gradients and 3 different frequencies with 3 different solvent types. The effects of the process conditions on the effective electrical conductivity value, energy and exergy efficiency, total extraction and color matter efficiencies, quality properties were investigated. The ohmic heating treatment time decreased as the voltage gradient increased, (p<0.05, EK 1). In heating region, EEC increased linearly as the temperature increased. In extraction region, it was determined that the change of EEC depending on time was insignificant (p>0.05). The energy and exergy efficiency values of the OHAE method were found to be 40% higher than CE method. It was determined that the betaxanthine yield was obtained better with salt solution-ethanol solvent at all frequencies and voltage gradient of 17 and 23 V/cm (p<0.05). The higher total extraction yield was obtained with OHAE method compared to CE method (p<0.05). The color values of the extract obtained by OHAE method were determined to be higher than CE method (p<0.05). For the extraction process performed by OHAE method, the optimum conditions were determined as 17 V/cm voltage gradient, 400 Hz frequency and salt solution-ethanol solvent. The heating region and the extraction region of OHAE method was numerically modelled by finite differences method. It has been determined that the difference between the predicted and the experimental data were less than 4%.