To evaluate the effect of the rate of starch retrogradation on the process of sake mash and on its chemical components, small-scale sake brewing was examined. The rate of starch retrogradation was determined beforehand for the rice of a
Yamadanishiki cultivar by dynamic oscillation rheometry in combination with a repeated freeze-thaw cycles(DORFT)method. Multiple mashes(total of 10g rice)were prepared and one of the mashes was randomly selected and pressed to measure Baumé, concentrations of total sugars, and ethanol. Physical properties of the mash were measured by a Rapid Visco-Analyzer. Results showed that the CO
2 evolution of the mash of the rice with a slow starch retrogradation rate was higher than that of the fast rate after the middle period, which was almost the same pattern as for ethanol production. Regarding the maximum total sugars equivalent to maximum Baumé, the mash with the rice with the fast starch retrogradation rate was higher than that with the slow rate. At the early period of the mash, the viscosity of the mash of the rice with the fast starch retrogradation rate was lower than that for the low rate one. After the middle period of the mash, the concentrations of total sugars and ethanol of the rice with the low starch retrogradation rate was higher than that with the fast rate one. These results showed that the retrogradation rate significantly influenced the process of mash of the sake and its chemical components.
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