pH of the osmotically dehydrated with CaCl_2 of purple sweet potatoes is shown in Figure 3. pH of purple sweet potatoes were decreased continuously during storage under room temperature and a low temperature (4˚C). The initial level of pH in the potatoes that were prior to storage was 6.72. However, during the storage if tend to decreased to 4.31 under room temperature storage and 6.15 under a low temperature storage. The pH of potatoes that were stored under low temperature was fluctuated throughout the storage (p≥0.05). pH of osmotically dehydrated purple sweet potatoes during storage was significantly differed among the different temperature storage. The samples stored under room temperature was losing pH more quickly than at 4˚C.