Mass transport analysis in perforation-mediated modified atmosphere packaging of strawberries

A space-and-time dependent mathematical model was developed to predict O₂, CO₂, N₂ and H₂O concentration in perforation-mediated polymeric packages during cold-storage of strawberries. The numerical solution of the corresponding mathematical model was obtained by applying the finite element method (FEM). The problem was solved in a domain corresponding to the headspace of a package augmented by the total void spaces of the contained bulk produce and for realistic boundary conditions. Transport of O₂, CO₂, N₂ and H₂O was modelled based on Maxwell–Stefan equations for gas transport through packaging’s headspace and on Fick’s law for diffusion through the micro-perforated packaging. The model predictions were tested against published experimental data of O₂ and CO₂ concentrations in modified atmosphere packaging storage of strawberries and the agreement is satisfactory. As for reaching the recommended in the literature gases concentrations for strawberry storage, the model predictions revealed that the tested micro-perforated polypropylene packaging combined with the adopted storage conditions are marginally adequate. To this end, the theoretical findings are suggestive of improvements, in terms of material properties, especially with regard to the permeability of the polymeric packaging film.