Abstract:

An analytical method for detecting sugar content in alcoholic beverages by dielectric spectroscopy was
presented. Dielectric measurements of binary ethanol/water system and ternary glucose/ethanol/water system were carried
out over the frequency band of 1－20 GHz at 20 ℃. The dielectric parameters characterizing the dielectric behaviors of
the ternary system were obtained by fitting the dielectric spectral data with the Cole-Cole equation. A standard curve was
established with gradient glucose concentrations and validated for prediction of sugar content in alcoholic beverages. The
method allowed estimation of sugar content in samples based on known alcohol content and dielectric constant and alcohol
content could be inversely estimated from known sugar content and dielectric constant. Moreover, the reliability of this
method in detecting nine commercially available alcoholic beverages was validated. Therefore the method proposed in this
work is promising for the detection of sugar or alcohol content in alcoholic beverages and other liquid foods.

Key words: microwave measurement, dielectric parameters, wine, alcohol, glucose