The eect of frying conditions on the colour changes during deep fat frying of french fries has been investigated. The Hunter
colour scale parameters redness, yellowness and lightness were used to estimate colour changes during frying as a function of the
main process variables (oil temperature, oil type and sample thickness). A ®rst-order kinetic equation was used for each one of the
three colour parameters, in which the rate constant is a function of the main process variables. The results showed that oil temperature
and thickness of potato strips have a signi®cant eect on the colour parameters, which are not aected by the use of
hydrogenated oil in the frying medium.