Abstract
A non-destructive and continuous method to measure gelatinization of rice samples in a rice-water system during rice cooking process was examined. An aluminum pot and a lid of a rice cooker were used as two electrode plates, and changes in dielectric properties (capacitance: C, and dielectric dissipation factor: tan δ) of the samples in the rice cooking process were measured by a capacitance meter. Differential scanning calorimetry (DSC) was used to measure gelatinization enthalpy and to determine the degree of gelatinization. Dielectric loss was calculated from the dielectric properties, which changed as the rice cooking process proceeded. Thus, we defined the degree of gelatinization as the value obtained by integrating the dielectric loss with respect to time. The degree of gelatinization based on the dielectric properties was consistent with that based on the DSC. We concluded that the degree of gelatinization in the rice cooking process can be non-destructively and continuously determined by measuring the dielectric properties.
