Drying is a process of heat and mass transfer
simultaneously. Where, the heat energy applied to the
fish is utilised to increase the temperature of fish and to
vaporise the moisture present in the fish through
provision of latent heat of vaporisation. The removal
of moisture from the interior of the fish takes place due
to induced vapour pressure difference between the fish
and surrounding medium. The desired difference of
vapour pressure may be obtained either by increasing
the vapour pressure of the fish surface or by decreasing
the vapour pressure of the surrounding or by both. The
above parameters may be employed for controlling
drying rate under the controlled conditions of drying.
However, this is not true with the open solar drying,
since it is weather-dependent process