The a* and b* values of carrots dried in microwave at high powers and halogen lamp–microwave combination oven were found to be significantly the same (Figs 5 and 6). Air dried carrot slices were found to be darker with less yellow and red hues as compared to microwave dried ones (Lin et al., 1998). The yellow and red colour of carrot slices is attributed to the presence of carotenes (Wagner & Warthesen, 1995). Due to the short period of drying in microwave and halogen lamp–microwave combination oven carotenes might be less destroyed and colour is more preserved.