The purpose of this study was to examine the influence of ultrasound-assisted osmotic dehydration (OD) on the appearance characteristics (colour indexes) of kiwifruit slices. As the sonication power (40 kHz) increased from 0W to 150W, the lightness (L*) index values of kiwifruit slices reduced from 64.8 to 60.6 (30°Brix). Also, with increasing sucrose solution concentration from 20°Brix to 40°Brix the lightness index values of kiwifruit slices decreased from 61.8 to 59.3 (power=150W). The results showed that the mean of ∆E(total colour difference) index values of dehydrated kiwifruit slices increased during OD period. The highest ∆E index (8.03) and lowest surface area (8.64 cm2) values were for the kiwifruit slices treated by the lowest ultrasound power (0W) and the highest sucrose solution (40°Brix). The average surface area of fresh kiwifruit slices, dehydrated samples, hot-air drying samples, and rehydrated samples were 9.50 cm2, 9.05 cm2, 6.44 cm2, and 7.82 cm2, respectively.
