Dielectric properties of starch slurries as influenced by starch concentration and gelatinization

• Published in: Carbohydrate polymers Vol. 67; no. 1; pp. 73 - 79
• Main Authors: Motwani, Tanuj, Seetharaman, Koushik, Anantheswaran, Ramaswamy C.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 02-01-2007; Elsevier Science
• Subjects: Applied sciences; Dielectric constant; Dielectric loss factor; Exact sciences and technology; Frequency; Gelatinization; Natural polymers; Physicochemistry of polymers; Starch and polysaccharides; Frequency; Dielectric constant; Dielectric loss factor; Gelatinization; Concentration effect; Oside polymer; Experimental study; Corn starch; Aqueous dispersion; Dielectric relaxation
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2006.04.017

Dielectric properties of corn starch slurries of 10–50% (w/w) starch concentration were measured at temperatures between 40 and 90
°C and in the frequency range from 15
MHz to 3
GHz. Dielectric constant decreased and the loss factor increased with increasing starch concentrations. The dielectric loss factor of the starch slurries decreased at frequencies 15–450
MHz and increased at frequencies 450
MHz to 3
GHz. A significant effect of frequency on the dielectric constant was evident only at higher starch concentrations (>40%). Dielectric constant of starch slurries decreased with increasing temperature throughout the frequency range while the dielectric loss increased with temperature between 15
MHz and 450
MHz and then decreased with increase in temperature between 450
MHz and 3
GHz. During gelatinization, the dielectric constant for 20% starch slurry decreased in a linear fashion. A significant correlation (
R
2
=
0.87611;
P
<
0.05) was observed between the dielectric constant and the percentage gelatinization for the 20% starch slurry in the temperature range from 60 to 72
°C.