Effect of pulsed electric field pretreatment on mass transfer during hot air drying: Drying and rehydration properties of sweet potato

In this study, to investigate the effects of various pulsed electric field (PEF) strengths (0.5-2.5 kV/cm) on drying sweet potato, drying kinetics, mass transfer rate, rehydration kinetics, and microstructure of sweet potato during hot air drying were observed. After pretreatment of PEF, electric conductivity, and Z- index were increased as the strengths of PEF increased. The drying time was approximately 420 min for PEF at 1.5 kV/cm -2.5 kV/cm and was almost 500 min for control group and the maximum values for moisture diffusivity and mass transfer was observed in 2.5 kV/cm. The shrinkage ratio and microstructure of sweet potatoes did not differ among groups; however, parenchyma cell membranes were empty and disrupted by PEF. The rehydration time decreased as the PEF strength increased, similar to the trend in drying times. PEF pretreatment resolves long-term hot air drying side effects such as quality deterioration and time requirements.

Automated summary

In this study, the effects of various pulsed electric field (PEF) strengths on the drying kinetics, mass transfer rate, rehydration kinetics, and microstructure of sweet potato during hot air drying were investigated. The results showed that PEF pretreatment reduced drying and rehydration times, and improved the quality of sweet potatoes.