The freshness analysis of an apple and a potato using dielectric properties at the microwave frequency region

Dielectric properties of food products have been measured at the microwave frequency region. So that, whether fresh or stale product has been observed. Potato and apple were selected as food products. Second measurements for stale products have been carried out 3 days later from the first measurements. Scattering parameters (S parameters) which are used to obtain the permittivity values have been measured by vector network analyzer (VNA) device. Working frequency has been selected as 4.9-7.05 GHz. Waveguide method has been applied for measurements and permittivity values have been evaluated with Nicholson-Ross-Weir New Non-Iterative Method. Temperature and moisture have been determined for each material. Results showed that whether freshness or staleness of food products affect the electrical properties. Moreover, frequency, temperature and structure are major topics for determination of the permittivity values.