Impact of different pretreatments on drying kinetics and quality of button mushroom slices dried by hot-air or electrohydrodynamic drying

Abstract

The effects of three pretreatments (pulsed electric field (PEF), ultrasound (US), and conventional blanching (CB) pretreatments) prior to drying were evaluated on drying kinetics and quality of button mushroom slices that were dehydrated in either electrohydrodynamic (EHD) drying or by hot-air (HA) drying. Results showed that the US and PEF pretreatments prior to the drying process significantly reduced the drying time and energy consumption of button mushroom slices and also improved drying rate and effective moisture diffusivity. However, the antioxidant activity of dried mushroom slices pretreated by US or PEF was significantly lower than that of the CB pretreated samples. In general, US pretreatment was more effective on drying kinetics and had a greater effect on the reduction of specific energy consumption than PEF pretreatment. Results also showed that hot air drying was much faster than EHD drying and EHD had detrimental effects on the total phenolic compounds and antioxidant activity of button mushrooms than HA drying. These data demonstrated that selecting the appropriate set of control variables in US and PEF pretreatments and EHD drying techniques are necessary to ensure high-quality dried foods as well as low energy consumption.