Thin-layer infrared radiation drying of red pepper slices

Abstract

Drying characteristics and changing of quality parameters of red pepper were determined experimentally as a function of infrared power (IP) and air velocity during infrared drying. Drying experiments of red pepper slices were carried out at three levels of IP (300, 400 and 500 W) and at three air velocities (1.0, 1.5 and 2.0 m/s). The drying time at air velocity from 1.0 to 2.0 m/s ranged between 314 and 455 min, 213 and 297 min and 196 and 230 min at IP of 300, 400 and 500 W, respectively. Drying rate increased with increasing IP and decreasing air velocity. All drying experiments had a falling rate of drying period. The specific energy consumption was varied between 4.62 and 7.59 kW·h/kg for all the drying conditions. Thickness change/shrinkage was found to be in the range of 0.162 and 0.263. The color parameters and the rehydration ratio were significantly influenced by IP and air velocity. © 2008 Wiley Periodicals, Inc.