Abstract
In the cheese industry, the longest phase in the manufacture of
cheese is ripening, during which a considerable loss of water occurs.
An understanding of the mass transfer mechanisms of drying would
thus contribute to improving engineering design and the quality of the
final product. In this work, a mathematical model for a cubic shape
was proposed to predict the drying kinetics and moisture distribution
during cheese drying. The model was developed taking into consideration
both the external and internal resistances to mass transfer and
an effective diffusion dependent on local moisture and temperature.
Furthermore, a specific model for sorption isotherms was established
from experimental results and used to complete the overall model
formulation. The drying experiments were carried out at 6.3, 12.2,
and 18.2C and 1.0ms1 until a moisture content of approximately
0.30 kg kg1 (db) was reached. Moisture distribution was experimentally
measured from the center of the cheese cube to the center
of the surfaces and to the vertexes using a time-domain nuclear
magnetic resonance (TD-NMR) method. The proposed model was
solved using a finite element method and validated by comparing
the experimental moisture profiles with those simulated by the model.
A satisfactory simulation was obtained for both the drying curves
and the moisture profiles. For both groups of data, a mean relative
error lower than 6% and a percentage of explained variation higher
than 97% was achieved.
