High electric field pulse pretreatment: potential for sugar beet processing

The application of high intensity electric field pulses (HELPs) on the cell disintegration of sugar beet cells was investigated. HELP treatment (20 pulses, similar to2.5 kV/cm, 5 muF, 1-6 Hz) rapidly performed disintegration of sugar beet cell membranes in 20 s or less. In particular, field strength (1.2-21.5 kV/cm) and pulse number (1-200) had a key influence on the disintegration. Apart from the conventional thermal cell disintegration (at 75-80degreesC) followed by extraction, it is possible to extract sugar beet after HELP-pretreatment at ambient temperatures. HELP permeabilized sugar beet can be completely depleted of sucrose after one or two pressing steps (at 2 or 5 MPa, respectively) by adding water (less than 40% of the raw material weight) between the pressings. The HELP-treated and subsequently pressed pulp showed higher dry matter (similar to30% dry matter) than the conventionally heat extracted and pressed pulp (similar to15% dry matter) which provides a significant reduction in process time and energy requirement during dehydration of the extracted cossets. (C) 2002 Elsevier Science Ltd. All rights reserved.