Evaluation of water content in honey using microwave transmission line technique

The microwave transmission line technique is presented as an effective method for the evaluation of honey for the first time. The electrical permittivity is an intrinsic parameter of a material that can be used as an index of added water content. For the permittivity calculation, it is found that the combination of the characteristic matrix method and Tischer's model can offer the highest accuracy. A genetic algorithm is introduced to provide an initial approximate permittivity value and acquire the Cole-Cole parameters of the honeys examined. The accuracy provided by the methodology used in this study is superior to that offered by a commercially available probe. Operating at room temperature and a frequency range of 6-8 GHz, the measurements demonstrate that the permittivity of honey increases with increased added water. A relationship between the added water content and the permittivity of honey-water mixture is established, which could be a powerful tool for detecting honey adulteration.