Diffusion of carbon dioxide in tomato fruits during cold storage in modified atmosphere

Summary Treatments with 20% CO2 of tomato fruit produced a beneficial extension of storage life. The diffusion of CO2 in tomato (Lycopersicon esculentum Mill) cv. Platense was measured chromatographically and the concentration profiles in the internal gaseous atmosphere of the fruit were determined for non‐steady state conditions to establish minimum treatment times that can ensure adequate penetration of the gas. The effective diffusivity of CO2 in the tissue was determined by fitting concentration data, obtained from experiments with whole fruit without skin, to the non‐steady state solution of the diffusion equation, assuming negligible external mass transfer resistance. The diffusivity was modelled using Maxwell‐Eucken expressions, taking account of the heterogeneous structure of the tissue. The resistance of the fruit skin was evaluated using whole fruits with the stem scar covered with paraffin and fitting experimental data to the solution in terms of mass Biot number; the specific resistance of the peel was some 200 times greater than that of the stem scar.