Effect of Various Pulsed Electric Fields Conditions on Extraction of Sugar from Sugar Beet

The effects of pulsed electric field (PEF) on the cell disintegration of sugar beet were studied. Field strength (0.5kV/cm to 6kV/cm), pulse number (1 to 100 pulses) and capacity of capacitors (0.5 F to 32 F) were evaluated on degree of cell disintegration and consumed energy in PEF treatment. The field conditions of 1 and 2 kV/cm, 8 F with 20 and 10 pulses respectively disintegrated the cell membrane in less than 1 minute. The most important parameters during cell permeabilization were the total energy input followed by field strength. At energy input of 3.2 kJ/kg, the higher the field strength resulted the higher cell permeabilization. Mass transfer with determination of sugar and ion leaching for PEF pretreated sugar beets at room temperature were compared to moderate and high heat treatment (50, 75 and 80C, 15minutes). Comparison between PEF pretreatment and conventional thermal cell disintegration (average 75C) method showed that high values of sugar may extracted after PEF pretreatment (2kV/cm, 8µF) at ambient temperature while 75C or more with long time thermal duration is needed to achieve the same extracted sugar. In addition, the energy consumption for thermal treatment is approximately 20 times more than PEF pretreatment. Optimization of field condition (Field strength, capacity of condensers, and number of pulses) as well as treatment chamber conditions are very important factors to achieve high yield of sugar from sugar beet when using PEF.