Analysis of bread loss factor using modified Debye equations

A modified Debye equation method was developed to analyze the frequency dependent behavior of bread loss factor over the moisture content range of 34.0-38.6% and temperature range of 25-85 degrees C. Moisture sorption isotherm of the bread was used to estimate monolayer and multilayer bound water contents. The overall contribution of bound water to loss factor was small. The calculated free water contribution to the dipole loss decreased with increasing temperature, while it increased with increasing moisture content. Over the studied frequency range, ionic conduction played the dominant role, while the importance of dipole relaxation of free water was very small at low frequencies and moderate at high frequencies. The effective ionic conductivity in breads increased with moisture content and temperature which explains the effect of these two parameters on changes to the ionic component of loss factor. (C) 2009 Elsevier Ltd. All rights reserved.