Combined pressing-diffusion technology for sugar beets pretreated by pulsed electric field

This work presents a new efficient process for sugar beet sucrose extraction by tuning experimental conditions. Sliced beets were first treated by PEF at E = 600 V cm(-1) and t(PEF) = 10 ms. Electroporated slices were then pressed and the obtained press cake was finally introduced in a pilot diffuser (10 kg/h) to extract the residual sucrose. Results showed that cold PEF treatment followed by rapid pressing permitted expression 50% of undiluted juice (Brix approximate to 21.2%). Sucrose extraction from pressed slices with reduced draft (80-100%) allowed substantial water and energy savings for the extraction step. Experiments revealed that slices were better exhausted by the new extraction process which permitted to reduce the sucrose loss in pulp from 1.2% to 0.8%. Moreover, the obtained juice was more concentrated in sucrose, less colored (7000 vs. 10,000 IU) and purer (92.8% vs. 91.8%) than that conventionally extracted by diffusion. (C) 2015 Elsevier Ltd. All rights reserved.