Electrochemical impedance spectroscopy for detecting honey adulteration by sugar syrup

In this study, Electrochemical Impedance Spectroscopy (EIS) is investigated as a rapid, non-destructive, and cost-effective technique for assessing the impact of sugar adulteration in honeys from six different botanical origins: Tilia europea L, Robinia pseudoacacia L, Thymus vulgaris, Castana sativa Mill, Lavandula angustifolia Mill., Citrus×limon. A series of adulterated honey samples was prepared by adding increasing concentrations of beet sugar (99.9% saccharose) syrup (10 w/w%, 20 w/w%, 50 w/w%, and 80 w/w% ), and their impedance responses were measured over a frequency range of 20 Hz to 500 kHz. After fitting with a Randles equivalent electrical circuit, the increase of the bulk resistance was shown to be linear in the 0 w/w% to 50 w/w% range. The determined detection limit is 3.3% of saccharose syrup. These results confirm that EIS is a sensitive and reliable analytical tool for the rapid screening and authentication of honey, with a strong potential for routine application in food safety and regulation.