In drastic drying conditions, food samples are also
found to develop cracks on its surface which is due to disturbance
in mechanical stress and strain equilibrium inside the matrix
structure because of non-uniform shrinkage. The entire process is
governed by various physical and chemical changes taking place
inside the food. Additionally, sample porosity continuously
changes with change in matrix structure during the entire process.
Porosity is a relative term used to express ratio of void volume
within sample to the volume occupied by material in the sample.
As the drying proceeds, intracellular spaces (pores), previously
occupied by water are replaced either by air or is compressed as
result of shrinkage