Accurate kinetic parameters, rate constant and activation
energy, are essential to predict quality changes that
occur during thermal processing (Steet & Tong, 1996).
Heat sterilization of green vegetables results in color
change from the natural green to what is described as an
olive brown color, being attributed the color change to the
conversion of the cholrophyll found in the green plants to
pheophytin, through the substitution of the magnesium of
the chlorophyll by hydrogen (Hayakawa & Timbers, 1977).
These authors studied the influence of heat treatment on
changes in visual green color of asparagus, green beans and
green peas using the ratio of stimulus value a/b to
evaluate the color changes; they reported a z-value of
39.4 1C for the discoloration of green peas using the