Physicochemical properties of starch in rice flour with different hardening rates of glutinous rice cake (mochi)

The hardening rate of glutinous rice cake (mochi) made by Kagura-mochi (Kag) was two times higher than that of Hakusanmochi (Hak). Protein in the waxy rice indicated a similar distribution and content; therefore, the textural properties of the rice product were dependent on the physicochemical properties of starch in the rice flour. Urea-induced gelatinization, differential scanning calorimetry, and rapid visco analysis revealed that starch in Kag was less easily gelatinized than that in Hak. The solubility and swelling power at 70 degrees C of starch in Kag rice flour were slightly lower than that in Hak. Relative crystallinities of starch in Kag and Hak rice flour were 55.1% and 49.3%, respectively. The chain length distribution of the short chain of amylopectin in Kag rice flour was lower than that in Hak. The low short-chain content in Kag may be related to the increase in the hardening rate of the mochi made by Kag.

Automated summary

The hardening rate of mochi made by Kagura-mochi was twice as high as that made by Hakusanmochi. The textural properties of the rice product are influenced by the physicochemical properties of starch in the rice flour. Starch in Kagura-mochi is less easily gelatinized compared to Hakusanmochi.