Mass transfer of sugar from beets enhanced by pulsed electric field

Extraction by solvent is the process used to extract the sugar from sugar beets. In sugar beet processing, the sliced beets are subjected to a thermal treatment by hot water at 70-74degreesC. This leads to alteration of the cell tissue and loss of pectin into the juice, which consequently needs complicated purification. The application of pulsed electric field (PEF) ensures a non-thermal permeabilization of cellular membrane which ameliorates the juice purity. This study concerns the extraction of sugar from sugar beets, combined with the PEE Discs of fresh sugar beet were pre-treated by PEF at different intensities and different numbers of pulses. Then they were immersed in water at ambient temperature with liquid-to-solid ratio equal to 1. The extraction kinetics were modelled using a simplified two-exponential kinetic model, which corresponds to mass transfer in two stages. The optimal parameters of PEE giving the maximal juice yield under the minimal energy consumption, were determined. The influence of energy input on the yield of solute and the effect of agitation speed on the mass transfer rate were studied. The optimal speed of stirring was 250 rpm.