Water activity (a_w) of osmotically dehydrated and CaCl2 infused purple sweet potatoes are shown in Figure 2. The results showed that a_w was continuously decreased in the samples during storage at both temperature (RT & 4˚C). Water activity in the potatoes was ranged from 0.9500 to 0.9343. The different temperature storage was no significantly influenced the a_w in osmotically dehydrated potatoes. The samples stored at room temperature was losing a_wmore quickly than 4˚C. Water activity was decreased gradually throughout the storage under low temperature. However, the low-temperature storage was controlled of moisture loss better than room temperature.