Toma, Leung, Augustin, and Iritani (1986) studied the ect of
surface freezing pre-treatment on colour changes during
deep fat frying. They reported that surface freezing
treatment is an eective means of decreasing oil adsorption
and improving the colour of french fries. Smith
(1975) treated potato slices in a solution of glucoseoxidase,
an enzyme that changes glucose, one of the reducing sugars responsible for colour development in
chips, to gluconic acid, which does not enter into the
browning reactions. The results indicated that it may be
possible to use this treatment in order to reduce the
production of dark colour chips. Economically, however,
this method would not be justi®ed. Jiang and
Ooraikul (1989) examined the reduction of non-enzymatic
browning in potato chips and french fries with
glucose oxidase. They reported that enzyme treatment
results in a lighter and more uniform colour of french
fries.
Paul and Mittal (1996) examined how the degradation
of oil during frying of canola aected the colour of
the fried product. They noted high correlations between
the colour parameters and oil degradation during frying.
Kozempel, Tomasula, and Craig (1995) developed a
simulator for food processes such as blanching, drying
and frying of potatoes. The model was also used to
control the colour of fried potatoes. Khalil (1999), examined
the quality of french fried potatoes as in¯uenced
by the coating with hydrocolloids. They noted that
coated french fries exhibited higher red and yellow colours.
The objective of this study is to examine the colour
changes during deep fat frying of french fries. The eect
of the main process variables, i.e. frying oil temperature,
size of potato strips, and concentration of hydrogenated
oil in the frying medium on colour kinetics
is examined.