Dielectric Properties of a Pregelatinized Bread System at 2450 MHz as a Function of Temperature, Moisture, Salt and Specific Volume

摘要

Dielectric properties [dielectric constant (ε′) and loss factor (ε″)] were measured using the transmission line technique. Dielectric constant was independent of salt content while ε″ increased when salt was added. Dielectric constant increased when temperature increased from 25 to 60℃ then became virtually constant from 60 to 95℃ for all samples. Loss factor increased linearly from 25 to 95℃ for samples containing 1/100 salt and decreased linearly when no salt was present. Both ε′ and ε″ increased linearly with respect to mass concentration of water (g_water/ cm~3_sample). Ground bread crumb had lower ε′ and ε″ than intact bread when other parameters were kept constant.