Effect of zinc chloride concentration
Fig. 2 shows the effect of adding ZnCl2 up to 600 ppm on the formation
of Zn–chlorophyll derivatives. Increasing Zn2+ concentrations
improved the greenness (a⁄ value) of the spinach pulp.
There was a significant color change in the spinach pulp
between the negative control sample and 100 ppm ZnCl2 addition.
The a⁄ value reached the maximum level at 300 ppm. No signifi-
cant color value differences were observed in Zn–chlorophyll
derivatives between 300 and 600 ppm (P > 0.05). Senklang and
Anprung (2009) reported an identical ZnCI2 concentration optimum
in pandan leaf extracts in their study. It was previously
reported that the formation of complexes depends on the Zn2+ concentration,
pigment concentration, and pH value of the material
(Laborde & Von Elbe, 1990).