Dehydration of red bell-pepper (Capsicum annuum L.): Change in drying behavior, colour and antioxidant content

The sun, oven (50 and 70 degrees C) and microwave oven (210 and 700W) drying behaviors of red bell-pepper slices were investigated. Effects of these drying methods in terms of colour indices and antioxidant activity of pepper slices were also studied. Midilli and Kucuk model exhibited high coefficient of determination (R-2) values for all the drying methods used in the assay, ranging between 0.994-0.999, while Page and Modified Page models fit better for oven drying at 70 degrees C. The calculated effective diffusivity (D-eff) values (m(2)/s) of pepper slices for the drying processes ranged between 0.31 and 87.39 x 10(-9). Sun dried and followed by microwave oven (700W) dried samples revealed the highest L*, a* and b* colour values than the other dried samples. Microwave oven dried (210W) and oven dried (50 degrees C) samples exhibited the lowest TEAC and DPPH radical scavenging activities among the dried samples. Crown Copyright (C) 2010 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.