GG was selected for mass transfer studies, as it had shown least
oil uptake during puri frying (17.22%). The frying time period was
extended upto 35 s (beyond its optimum frying time (25 s)) for the
purpose of getting pseudo-equilibrium points for moisture content
(mN) and oil content (oN). There will not be any real equilibrium
existing in the present case of deep fat frying unlike in drying
operation. However, the system behaves as if there exists an
equilibrium (dm/dt and do/dt¼ 0) mainly due to the physical
changes that occur in the product during frying, that restrict the
mass transfer of moisture and oil. Since mN and oN do not represent
the physical driving potential for water and oil transfer, they
are considered as pseudo-co-efficients. But these co-efficients have