Dielectric Properties of Milk Powder at 2.45 GHz

Abstract

Milk powder is an important nutritional source for the human body. Like other food powders, it can be contaminated by pathogens, leading to major health concerns. Hence, dielectric properties relevant to dielectric heating were investigated at 2.45 GHz, which is a common ISM frequency. These properties (dielectric constant and dielectric loss factor) were determined using the cavity perturbation method with the help of a vector network analyzer (VNA) in a moisture and temperature range of 3–17% (w.b) and 15–65 °C, respectively. Present studies showed that the dielectric constant and loss factor increased with temperature and moisture content. The calculated penetration depth based on these properties decreased with increasing moisture and temperature. A  2nd regression equation was generated to know  dielectric property values at 2.45 GHz for desired moisture content and temperature, for which the R² value is 0.9947.