2.3. Shrinkage of carrot
The ratio (V/V0) of the carrot volume after drying to the initial
volume (before drying) was used as a parameter to assess the
shrinkage. The carrot volume after drying was measured using
pycnometry (i.e., the dried carrot was coated with silicon oil and
put into the pycnometer with water).
2.4. Mathematical models
The moisture ratio (MR) is used as a parameter to evaluate the
drying characteristics of food and agricultural products:
MR ¼ w we
w0 we
(1)
where w0 and we are the initial and equilibrium moisture contents,
respectively. Thewater activity was also measured as an expression
of the moisture content of the material, and was determined from
the moisture content of free water. In other words, the moisture
ratio is related to the water activity. The moisture ratio is a
convenient parameter for analysis of the drying characteristics and
has previously been used by many researchers. In the present study,
the moisture ratio is used to express the moisture content of the
carrot sample.