Broadband Dielectric Properties of Honey: Effect of Water Content

Influence of water on the dielectric properties of jujube, yellow-locust, and vitex honey was investigated by dielectric spectroscopy in broadband from 40 Hz-40 GHz. At lower frequencies, two relaxations which were from interface polarization and dipole orientation polarization of macromolecules in honey were observed. Other relaxations contributed by free and bound water were observed at microwave frequencies. The analysis of the observed relaxations revealed that the honey/water interface and bound water molecules that interact with the macromolecules in honey are responsible for the changed dielectric properties of honey solutions. Besides, the linear correlations between the permittivity (around 2.45 GHz) and water content of honey solutions were developed, which indicates that water content in honey solutions can be measured by dielectric spectroscopy. In addition, we also compared the dielectric properties of different pure honey types and found that the pure yellow-locust honey, which contains the maximum water content, has the highest permittivity. This suggests that different honey types with different water content can be roughly identified by dielectric spectroscopy. This study shows that the water content influences the dielectric properties of honey and dielectric spectroscopy is feasible for detecting honey adulteration with water.