Impact of pulsed electric field treatment on drying kinetics, mass transfer, colour parameters and microstructure of plum.

Abstract

The aim of the present study was to scrutiny the impact of pulsed electric field (PEF) as a pre-treatment method on the convective drying kinetics, cell disintegration, colours and microstructural changes of fresh plums. In this study, the PEF intensities of 1-3kV/cm, pulses number 30 and 70°C drying temperature was applied to detect the drying kinetics. The specific energy consumption generated by PEF treatment was 10-90kJ/kg. It was explored that the cell disintegration index increased from 0.147 to 0.572 with increased electric field intensity from 1 to 3kV/cm. Further, we found that high cell disintegration leads to increase in drying rate and shorten drying time. The rates of water diffusion coefficient also increase with increasing PEF intensity from 0.27 to 16.47 × 10-9m2/s. PEF pre-treatment followed by convective drying results in enhanced lightness and chroma as compared to untreated plum. Furthermore, the microscopic analysis by scanning electron microscopy at 200 × revealed that the PEF treatment at 3kV/cm had caused shrinkage in the plum tissues which might be responsible for higher diffusion rate of water in the plum. In this work was investigated that drying kinetics and mass transfer after PEF treatment to improve quality of dried plum.