Water activity (a_w) of osmotically dehydrated and CaCl_2 infused purple sweet potatoes are shown in Figure 2. a_w was decreased in the samples during storage under room temperature and a low temperature (4˚C). The initial a_w of osmotically dehydrated and CaCl_2 infused purple sweet potatoes heal a level of 0.95 prior to the storage. The lowest level of a_w found at room temperature storage and it was ranged 0.9343 at 〖10〗^th day and whereas, potatoes stored at 4˚C was ranged lowest a_w 0.9400 on 5^th day and then it fluctuated throughout the storage. a_w of osmotically dehydrated purple sweet potatoes during storage was significantly differed among the different storage temperature. The samples stored at room temperature was losing a_w more quickly when compared with 4˚C.