Dielectric traces of food materials in the terahertz region

We investigated the feasibility of identifying food products using the complex dielectric constant of food materials, and insects as a foreign substance, in the terahertz (THz) frequency range from 0.3 to 1.2 THz. Although the food and insect materials have unique dielectric properties, several materials could not be distinguished by the dielectric constant. To discriminate all food materials completely, we obtained the dielectric traces, in which the real and imaginary parts of the values are plotted. Consequently, food materials and insects can be separated effectively using this analysis. Our results indicate that food materials and foreign substances can be unambiguously distinguished and detected according to the dielectric traces and independent parameters extracted from the complex dielectric constants, using THz time-domain spectroscopy.