2.4. colour measurement
The surface colour of slices was determined with a Minolta CR-400 colourimeter. The L∗(lightness), a∗ (reddish–greenish) and b∗ (yellowish–bluish) indexes of the CIELAB colourimetric system were used to evaluate the colour change of the potato samples. Each slice was measured twice (each side), 8 individual slices from each replicate were measured. (16 measurements were carried out for each replication and three replications for each treatment at each time point.)