The distribution of starches in sweet potato (Ipomoea batatas L. ) tuber was studied. A fresh sweet potato tuber was cut into six equivalent parts, and then the extraction contents and viscosity properties of starches from different parts were determined. The results showed that the extraction content of starch from the middle section of sweet potato was lower than that from the head and the end section, and the extraction content from the inner layer was higher than that from the outer layer. The extraction contents of starch from the inner-end part and the outer-middle part of sweet potato were 16. 2% and 10. 3%, respectively. The amylose content was relatively higher in the middle section and outer layer of sweet potato tubers. The amylose contents in the outer-middle part and the inner-end part of sweet potato tubers were 29. 5% and 26. 7% respectively. The viscosity properties of starches from different parts of sweet potato tubers were different from each other. The peak viscosity and final viscosity of the starch from the head and the end sections were similar and obviously higher than the middle section, and those from the inner layer were higher than the outer layer. The composition and viscosity characteristics of starch were significantly different among different parts of sweet potato, and sweet potato starch with different characteristics and use could be produced by taking sub-site precision machining method.%为了研究甘薯块根中淀粉的分布规律,将鲜甘薯切分成质量相近的6个部位,测定了不同部位的淀粉含量、淀粉中直链淀粉含量以及淀粉黏度特性.结果显示:鲜甘薯中淀粉含量的分布特点是:尾段＞头段＞中段,内层＞外层,尾内部位的淀粉提取量达到16.2％,中外部位的淀粉提取量为10.3％;直链淀粉含量的分布特点是:中段＞头段＞尾段,外层＞内层,中外部位淀粉中,直链淀粉含量达到29.5％,尾内为26.7％;头尾两段中淀粉的峰值黏度、最终黏度相近,均明显高于中段,内层淀粉的峰值黏度、最终黏度略高于该段的外层.甘薯不同部位间淀粉的组成和黏度特性差异显著,采取分部位精细加工的方法,可以制取不同特性、用途的甘薯淀粉.
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