To study the effects of pH on the
process conditions, the spinach pulp was adjusted to various pH
values from 3 to 9 by addition of either 1 N citric acid or 1 M NaOH
solution. In these experiments the ZnCl2 (300 ppm) concentration
and heating parameters (121 C for 15 min) were kept constant.
The optimum pH level was determined according to the highest
greenness (a⁄ value) gain using a Hunterlab Colorflex CFLX 45-
2. Investigation of the optimum ZnCl2 concentration was carried