Color measurement of the samples was done in the range of
380–780 nm with 10 nm intervals using a GretagMacbeth Color Eye
7000A spectrophotometer (USA), an instrument with 8/d geometry in a specular component included (SCI) mode, and then trans- formed into CIELAB colorimetric coordinates (L*, a*, b*) using CIE standard illuminant D65 and a CIE 1964 standard colorimetric observer. An increase in L* indicates lightening of the sample. A
positive �a* signifies a color shift toward red; a negative