关键词: 米饭, 热物性, 介电性

Abstract: Thermal and dielectric properties related to temperature of cooked rice were measured between 5 ℃ and 90 ℃ using a programmed temperature control. Thermal conductivity of cooked rice was measured by using a regular circuit with heating wire coupled with a line temperature probe. Meanwhile, nonlinear relationship was estimated by regression. Results indicated that temperature had a significant effect on specific heat and dielectric loss of cooked rice while the thermal conductivity and dielectric constants were unaffected. The specific heat of cooked rice exhibited an exponential increase as the increase of temperature till 15 ℃, and then remained a stable stage (cp = 2.930 kJ/(kg·℃)). Quadratic polynomial of temperature demonstrated the change in dielectric loss of cooked rice (R2 = 0.998). Penetration depth was a function of dielectric property positively correlated with temperature.

Key words: rice, thermal property, dielectric property