The colour of the mashed potato samples in the pots was measured using a HunterLab model D25
(Reston, Virginia, USA) colour difference meter fitted with a 5 cm diameter aperture fitted with a
5 cm diameter aperture. Measurements were performed in triplicate and the results averaged.
9
Results were expressed in L*a*b* scale, where L* indicates the lightness, a* represents the
green-red colour axis and b* the blue-yellow axis, recommended by the International
Commission on Illumination (CIE, 1978). Colour was also expressed as L*/b*, i.e. the
white/yellow ratio