Sugar and water contents of honey with dielectrc property sensing

Authors: GUO, WENCHUAN - Northwest Agriculture And Forestry University; ZHU, XINHUA - Northwest Agriculture And Forestry University; LIU, YI - Northwest Agriculture And Forestry University; Zhuang, Hong

Submitted to: Journal of Food Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2009
Publication Date: 3/1/2010
Citation: Guo, W., Zhu, X., Liu, Y., Zhuang, H. 2010. Sugar and water contents of honey with dielectrc property sensing. Journal of Food Engineering. 97:275-281.

Interpretive Summary: Honey is an important ingredient for many popular food products and provides human being with nutritional benefits. However, honey adulteration is a common phenomenon, especially in certain areas of the world, and can result in health problems to the consumers who rely on nutrients from honey products. Water is the most common ingredient for honey adulterations. Dielectric property measurements have been successfully used to predict moisture/water contents in food and grains rapidly and nondestructively. The objective of our study was to investigate dielectric property sensing for sugar and water contents in honey. Our results show that the critical frequency and the maximum loss factor increased with increasing water content. There were strong linear correlations between the dielectric constant and the total soluble solids (an estimation of sugar content) and water contents. The linear coefficients of determination were higher than 0.995 from 650 to 960 MHz. suggesting that microwave dielectric properties could be used in developing sensors to determine sugar and water contents of honey rapidly and non-destructively.

Technical Abstract: The dielectric properties of pure yellow locust, jujube and rape flower honey and their water-adulterated products with water content from 18% to 42.6% were measured with open-ended coaxial-line probe technology and a network analyzer from 10 to 4500 MHz at 25oC. Dielectric constants of pure honeys and water-added honey samples decreased monotonically with increasing frequency, and increased with increasing water content. Dielectric relaxation was evident in the dielectric loss factors. The critical frequency and the maximum loss factor increased with increasing water content. There were strong linear correlations between the dielectric constant and the total soluble solids and water contents. The linear coefficients of determination were higher than 0.995 from 650 to 960 MHz. The good linear correlations and the sufficient penetration depth >20 mm below 960 MHz, suggest that microwave dielectric properties could be used in developing sensors to determine sugar and water contents of honey.