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Properties of Starches from Several Low-Amylose Rice Cultivars

¹National Agricultural Research Center for Kyushu Okinawa Region, National Agricultural Research Organization, Nishigoshi, Kumamoto, 861-1192, Japan. ²Present address: Department of Upland Agriculture, National Agricultural Research Center for Hokkaido Region, National Agricultural Research Organization, Memuro, Hokkaido, 082-0071, Japan. ³Corresponding author. Phone: +81-155-62-9278. Fax: +81-155-62-2926. Email: noda@affrc.go.jp.

The starch properties of five low-amylose rice cultivars, Yawarakomachi, Soft 158, Hanabusa, Aya, and Snow Pearl, were compared with those of two normal amylose rice cultivars, Nipponbare and Hinohikari. There were no large differences in the distributions of the amylopectin chain length determined by high-performance anion-exchange chromatography, and the starch gelatinization properties determined by differential scanning calorimetry, between normal and low-amylose rice cultivars. Results obtained using rapid viscosity analysis indicated that low-amylose rice starches had lower peak viscosity, breakdown, and setback values than normal amylose rice starches. Starch granules from low-amylose rice cultivars had a higher susceptibility to glucoamylase than those from normal amylose rice cultivars. The results of this study showed some differences between normal and low-amylose rice starches in pasting properties and enzymatic digestibility.