Microwave dielectric properties of sugarcane juice

Authors: Trabelsi, Samir; White, Paul

Submitted to: Microwave Power Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/23/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Sugarcane is the main material for sugar production because of its high sugar content. Current methods for the characterization of sugarcane juice are labor intensive and time consuming. They involve the use of near infrared polarimetry to measure sucrose content, refractometry to measure soluble solid content (Brix), and measurements of fiber content. In the food and agricultural industries, dielectric properties were successfully used to determine instantaneously and nondestructively important quality attributes including, moisture content, water activity, and bulk density. Dielectric properties of sugarcane solutions were measured at microwave frequencies and different temperatures. In this paper, dielectric properties of sugarcane juice of different quality indexes were measured with an open-ended coaxial-line probe and a vector network analyzer over a broad radiofrequency range (200 MHz to 20 GHz) and at a room temperature of 25 oC. The main objective of this paper is to analyze the obtained dielectric spectra and identify correlations between the dielectric properties and sugarcane indexes. The spectra obtained for these samples showed that the dielectric loss was sensitive to changes in the sugarcane indexes at the lower region of the frequency range between 200 Megahertz and 1 Gigahertz. This allowed the establishment of direct correlations between the dielectric loss factor and each quality index at a single microwave frequency. Here these equations are given at 500 Megahertz. The resulting equations can be programmed in a microwave sensor for rapid and simultaneous determination of quality indexes of sugarcane juice from measurement of the dielectric loss factor at a single microwave frequency.