Storage performance of Taiwanese sweet potato cultivars.

Three sweet potato cultivars (TNG57, TNG66, and TNG73), provided by the Taiwanese Agricultural Research Institute (TARI), were stored at either 15 °C or under ambient conditions (23.8 ~ 28.4 °C and 77.1 ~ 81.0 % of relative humidity). Sweet potato roots were randomly chosen from each replicate and evaluated for measurement of weight loss, sugar content analysis, and sprouting after 0, 14, 24, 48, 56, 70, 84, and 98 days of storage. Fresh sweet potato roots were baked at 200 °C for 60 min then samples were taken for sugar analysis. After 14 days of ambient condition storage, the sprouting percentages for TNG57, TNG66, and TNG73 were 100, 85, and 95 % respectively. When sweet potatoes were stored at 15 °C, the weight loss became less and no sweet potato root sprouted after 14 days of storage. Because manufacturers can store sweet potatoes at 15 °C for almost 2 month without other treatments, the supply capacity shortage in July and September can be reduced. The total sugar content slowly increased along with increasing the storage time. After baking, the total sugar content of sweet potatoes significantly increased due to the formation of maltose. Maltose became the major sugar of baked sweet potatoes. Raw sweet potatoes stored at 15 °C had higher total sugar contents after baking than those stored under ambient conditions. Raw sweet potatoes were recommended to be stored at 15 °C before baking.