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

The sun, oven (50 and 70 °C) and microwave oven (210 and 700 W) 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 Küük" model exhibited high coefficient of determination (R2) 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 °C. The calculated effective diffusivity (Deff) values (m2/s) of pepper slices for the drying processes ranged between 0.31 and 87.39 × 10-9. Sun dried and followed by microwave oven (700 W) dried samples revealed the highest L*, a* and b * colour values than the other dried samples. Microwave oven dried (210 W) and oven dried (50 °C) samples exhibited the lowest TEAC and DPPH radical scavenging activities among the dried samples. © 2010 The Institution of Chemical Engineers.