Investigation of Dielectric Properties of Potato, Tomato and Onion Juices at Microwave Frequencies

The dielectric properties of fresh juices of Solanum tuberosum (potato), Solanum lycopersicum (tomato) and Allium cepa (onion) were measured in terms of the dielectric constant and dielectric loss factor, over a frequency range from 1 to 50 GHz and at temperatures ranging from 30 to 60 °C, by using the PNA network analyzer model E8364C and open-ended coaxial probe 85070E. A prediction of relaxation frequencies of molecules for the three different juices was done and their molecular behavior was then studied by plotting dielectric constant vs. frequency and dielectric loss factor vs. frequency curves in the frequency range from 1 to 50 GHz at four different temperatures from 30 to 60 °C. The dielectric properties of food products play a crucial role in determining their heating behavior when subjected to an electromagnetic field. Understanding these properties is essential for the development of microwave pasteurization and sterilization processes tailored to various food products.