EFFICACY OF PULSED ELECTRIC FIELD PRETREATMENT ON DRYING PROCESS OF GRAPE

Abstract

The present study investigated the efficacy of pulsed electric field (PEF) pretreatment on the drying characteristics of black and white grapes during hot air tray drying at 50°C and 70°C. Fresh grape samples were subjected to different PEF intensities (0.3, 1.0, and 2.0 kV/cm) prior to drying to evaluate their effects on drying kinetics, moisture removal, drying time, and product quality. The results revealed that, compared with no treatment, PEF pretreatment enhanced moisture diffusion and accelerated drying. At 50°C, black grapes treated at 2.0 kV/cm presented a reduction in sample weight from 0.103 kg to 0.026 kg after 1600 min, whereas the weight of the control sample reached 0.032 kg. Similarly, white grapes treated with 2.0 kV/cm attained a final weight of 0.022 kg compared with 0.028 kg in the control. At 70°C, the drying time was considerably reduced, and substantial moisture removal was observed in all the PEF-treated samples. Improved color retention, texture, and preservation of quality attributes were also observed in treated grapes due to reduced thermal exposure.