Abstract
Avoiding grain kernel damage (known commonly as cracking in rice kernels) during drying and wetting, is one of the most important observations to be made in grain kernel drying.
In this paper, coefficients of thermal expansion and hygroscopic expansion, which are necessary to calculate tensile stress or shrinkage stress causing grain kernel crack formation induced by heat and moisture, were determined.
In order to determine these parameters, true density and true volume of grains in bulk at various temperatures and moisture contents were measured, and the effect of temperature and moisture content on volume change of the grains was investigated.
Hence, specific volume based on dry material of grain could be written as a function of temperature and moisture content.
From this equation, coefficients of thermal and hygroscopic expansion were determined as a function of temperature and moisture content.
