Starch granules of sweet potatoes, the Suwon 147 and the Chunmi were observed by photomicroscope and scanning electron microscope were round and polygonal. Granule sizes of the Suwon 147 and the Chunmi were 14∼30㎛, 16∼34㎛, respectively.
X-ray diffraction pattern of starch granules resulted weak crystallinity at 2θ 14.8, 17.2, 22.5. Starch granules were of the Ca crystalline type.
The blue values of the Suwon 147 and the Chasnmi were determined to be 0.342 and 0.279, amylose contents 27.6% and 23.6%, and water binding capacity 178.7% and 185.5%.
Swelling of the starches negligible until 50℃ thereafter it increased rapidly. Swelling power of the Suwon 147 was more slightly than that of the Chunmi. Optical transmittance of 0.2% starch suspensions was increased rapidly from 65% and the gelatinization at 65∼80℃ was of single stage. Amylogram patterns of 4% starch solutions were similar to no peak viscosity. Viscosity of the Suwon 147 was increased, but that of the Chunmi was decreased at 92.5℃.
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