2.6. Colour measurement
The colour of samples was measured in the reflectance using
Konica-Minolta CR-5 (Osaka, Japan) Chroma Meter according to
CIE L⁄
a⁄
b⁄ system. Measurement was performed on the sample
surface using CIE Standard Illuminate D65, di:8 (diffuse
illumination/8 C viewing angle) and CIE: 2 Standard Observer.
Before analysis the Chroma Meter was calibrated with a white
and black ceramic standards plates. The analysis were conducted
in tree repetitions for 10 randomly selected slices.
L⁄ parameter is lightness, a⁄ parameter indicates red (+) or green
() parameters of colour measurement and b⁄ parameter represents
chromaticity yellow (+) or blue (). On the basis of these
parameters were calculated a chroma (C⁄
), which indicates saturation
of the colour [35] and total colour difference (DE) according to
Eqs. (3) and (4), respectively.