2.6.2. Color measurements
Fresh-cut apples surface color was directly measured with a
Minolta chroma meter (Model CR-400, Minolta, Tokyo, Japan). The
equipment was set up for illuminant D65 and 10 observer angle
and calibrated using a standard white reflector plate. Twenty apple
cylinders were analyzed for each pair of trays. Three readings were
made in each replicate by changing the position of the apple pieces.
Color was measured through changes in L and h* values. Numerical
values of a* and b* parameters were employed to calculate the hue
angle (h*) according to Eq. (3):
h ¼
arctan
b
a (3)