Diffusion and thermal degradation of ascorbic acid during canned fresh green peas sterilisation

Changes of ascorbic acid (AA) during canned fresh green peas sterilisation in a rotary retort were predicted. It was considered that AA is thermally degraded in green peas and simultaneously diffuses to brine, where it is also degraded; heat transfer, mass transfer and kinetics equations were simultaneously solved during heating and cooling of the sterilisation process. Kinetic parameters of AA thermal degradation in brine were experimentally determined, while all other parameters needed were taken from bibliography. Simplified assumptions were made to explore diffusion and thermal degradation mechanisms relevance. Experimental runs were performed at different retort temperatures, end-over-end rotation speeds and headspaces in a pilot plant rotary retort; experimental data obtained on concentrations of AA in green peas and in brine were used to evaluate predictions goodness. Deviations between experimental and predicted results were 8.44% for AA in green peas and 13.79% in brine.