The rate of softening in several canned vegetables during the retort process was studied. The rate of softening is consistent with two simultaneous first order kinetic mechanisms; mechanism 1 acting on substrate “a” and mechanism 2 acting on substrate “b”. The rate constants for mechanism 1 are 20 times or more greater than the rate constantsfor mechanism 2. Approximately 85% to 97% of the firmness of the raw commodity is contributed by substrate “a” and the remaining firmness is contributed by substrate “b”. Mechanism 1 is probably due to pectic changes in the interlamellar layer. The biochemical nature of substrate 2 is a matter of speculation. The apparent Arrhenius activation energies range from 5.1 to 35.0 Kcal/mole. The data indicates that softening kinetics of vegetables is more complex than has been f