Kinetic parameters of surface color degradation of canned fresh green peas sterilized in a rotary retort

The kinetic parameters of surface color degradation of canned fresh green peas sterilized in a rotary retort, using the a* value from a spectrophotometer as the physical parameter and the concept of fractional conversion in conditions of unsteady state were determined in the range of retort temperatures of 120 and 131 °C. Experimental initial a* values fluctuated between −14.4 and −15.7, while final a* values ranged between −0.165 and −4.75. After five iterations performed, solving simultaneously the energy balance of the system, the differential equation of unsteady conduction for spheres and the first-order degradation reaction of surface color by numerical methods, the best values of k100 °C and Ea determined were 5.48×10−4 s−1 and 89.37 kJ/mol respectively, being 5.68% the deviation between experimental and predicted fractional retentions of a* with the determined parameters.