Effect of Pulsed Electric Fields on the Drying Process of Orange Peel Waste

The objective of this work was to evaluate the potential of PEF application on the decrease in orange peel air-drying time and temperature, resulting in energy savings. Orange peel waste (by-product of squeezable orange juice typical production, with a moisture content of 70%) was PEF pretreated (1.0–5.0 kV/cm electric field strength, frequency of 20 Hz, pulse width 15 μs, >1000 pulses), achieving a cell disintegration index Z ranging from 0.1 to 0.8. Drying experiments of PEF-treated orange peels were carried out at mild temperatures (40–70 °C). The moisture diffusion coefficients Deff and the air-drying energy consumed of all samples were estimated and compared. At low drying temperatures (<55 °C), PEF treatment led to increased effective moisture diffusivity Deff by up to 25%, resulting in reduced drying time and energy savings up to 15 MJ/kg, compared to untreated samples. More intense PEF conditions resulted in higher drying rates, while, for temperatures > 60 °C, there was no significant effect on the moisture diffusion coefficient for PEF pretreated samples. PEF treatment did not lead to changes in the antioxidant activity of dried samples. The results showed the potential of PEF pretreatment to accelerate the drying process of orange peel waste minimizing energy consumption.