EFFECTS of PULSED ELECTRIC FIELD ON QUALITY FACTORS and MASS TRANSFER DURING OSMOTIC DEHYDRATION of APPLES

High intensity electric field pulses using varying field strengths (0.5, 1.0 and 2.0 kV/cm corresponding to 12, 48 and 192 J/kg, per pulse, respectively, with a pulse duration of 400μs) and pulse numbers (2 to 50) were applied to apple slices as a pretreatment to study their influence on mass transfer during osmotic dehydration (OD). Cell membrane permeabilzation increased with increasing field strength and higher pulse number. Higher water loss and solids gain were obtained at 1.0 kV/cm. Pretreated apples turned brown but sample brightness improved with OD time but L values decreased with increasing pulse number. Maximum deformative force and amount of strain experienced by dried samples were influenced by both the field strength and OD time. Vitamin C content of dried samples reduced at higher field strengths and longer immersion times.