The L value of fresh seaweed changed from 23.01 to 15.69, 15.99, 16.27 and 15.86 for untreated, 7.00, 35.61 and 75.78 W cm2 ultrasound power levels, respectively. After rehydration, all the ultrasound pre-treated samples showed a small increase in L value compared to the control. Samples treated with the lowest ultrasound power (7.00 W cm2) had the highest increase in L value from15.99to37.46 which represents increasing lightness of samples. Moreover, samples with lowest ultrasound treatment had lower a and higher b values representing increased greenness and yellowness. This phenomena can be explained by the fact that ultrasound causes degassing effects [24], physical damage and membrane destruction of the cells, which contributes to easier elution of pigment substance from biological materials [10]. However no consistent trend was observed in the color of rehydrated samples. These results are in agreement with those reported by Deng and Zhao [25] for apple drying. Different values of color measurement and corresponding confidence interval obtained are listed in Table 3.