Dielectric properties of six different species of starch at 2450 MHz

Dielectric properties at 2450 MHz were determined for tapioca, corn, wheat, rice, waxymaize and amylomaize starches in granular (moisture content 1 and 13%) and in solution forms [starch-water ratio:1:1, 1:1.5, 1:2 (w/w)] at temperatures from 30 to 95 degrees C. Dielectric, properties were shown to be dependent on temperature, moisture content and starch type. The increase in moisture content increased dielectric constant and loss factor of all types of starches. Increasing temperatures decreased the dielectric values for starch solutions (high moisture content) but increased the dielectric values for granular starches (low moisture content). Quadratic equations were developed to show the relationship between the changes in dielectric properties with temperature for starch species. There were significant differences in dielectric properties of different types of starches. (C) 1998 Canadian Institute of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.