Quality assessment of mushroom slices dried by hot air combined with an electrohydrodynamic (EHD) drying system

In this study, hot air combined with an electrohydrodynamic (EHD) drying system was designed and examined for drying button mushroom (Agaricus bisporus) slices. The effects of three levels of voltage (17, 19 and 21 kV) and electrode gap (5, 6 and 7 cm) on solid and bulk density, porosity, shear strength, water absorption capacity (WAG) and total color difference (triangle E) of dried mushroom slices in comparison to oven dried mushroom slices were investigated. ANOVA showed that the hot air combined with EHD drying method had significant effects on bulk density and shear strength (p <= 0.01) reduction as well as on porosity (p <= 0.001) and WAC increase (p <= 0.01), but this system had no significant effects (p >= 0.05) on the solid density and triangle E parameters in comparison to the oven drying system. In addition, results indicated that increasing the voltage or decreasing the electrode gap resulted in some advantages such as bulk density and shear strength reduction or porosity and WAG increase that introduced this combined drying method as an improved method for drying mushroom slices. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.