Processing Characteristics and Correlation to Phosphorus of Different Varieties of Sweet Potato Starch

The starch content, dry matter content, soluble sugar content, viscosity profile and phosphorus content of 24 sweet potato varieties were compared. The results showed that the average starch content was 22.14%, in which Yushu 1 was the highest, reaching 31.45%. The average rate of dry matter was 31.38%, and the difference between varieties was not significant. The average soluble sugar content was 2.32%, Qinshu 5 was the lowest (0.42%). The browning index was 7.00~20.01, the lowest was Yushu 27.The gelatinization temperature of starches ranged from 66.8 to 77.1℃, and gelatinization temperatures of starches of Qinshu 9, Sushu 24, Yanshu 26 and Jishu 25 were lower than 70℃. Starch of Yunshu 271 had the highest peak viscosity, which reached 1207 BU. Starch of Guifen 3 had the lowest breakdown value, which was 381 BU. Starch of Qinshu 5 had the lowest setback value, which was 241 BU. The phosphorus contents of starches were 82~231 mg/kg, which was significantly positively correlated with peak viscosity (p<0.01). It was suggested that when processing starch products, appropriate varieties should be selected according to the characteristic parameters. In this way, the best use of starches could be achieved. Among the tested sweet potatoes, Yushu 1, Yushu 27, Jishu 25 and Sushu 24 had better comprehensive processing characteristics and were recommended as breeding parents.