microwave-absorbing properties of rice starch

In the food industry, research into the characteristics of microwave-heated materials has focused on dielectric properties. However, the lack of studies on microwave-absorbing properties has hindered the application of microwave technology. The aim of the present study was to investigate the microwave-absorbing properties of rice starch. It should be noted that this was the first time that the improved arch method was used to measure the microwave reflection loss (RL) of the starch dispersion. The results showed that the microwave absorption of the liquid system corresponded to the classical quarter-wavelength resonator model. When the concentration of the native starch was increased from 1% to 30%, the RL decreased from −5.1 dB to −1.2 dB at 2.45 GHz. Therefore, the absorption rate of microwave, γab, decreased from 69.1% to 24.1%. At 1.7 to 2.6 GHz, the interference effect of pregelatinization rice starch in an aqueous system on the microwave absorption properties became weak compared to native starch.