Extensive shrinkage affects product quality negatively.
Changes in shape, loss of volume, and an increased hardness
in many cases result in a decrease of rehydration
and a negative impression to customers.[12] Degree of
shrinkage and destruction of the cellular structure depend
on the method of drying, air temperature, and air velocity.[
13,14] Air drying usually leads to the most significant
shrinkage compared to other methods. Ratti[15] found that
at high air velocities the inner resistances control the transport
mechanisms in the product. From the very beginning
the surface moisture content is very low, which leads to a
stiffening of the surface that in turn reduces shrinkage.
According to Ratti,[15] air velocity is the only factor influencing
shrinkage significantly, whilst air temperature
in the range investigated had no influence. Bai et al.[