Effect of box materials on the distribution of 1-MCP gas during cold storage: A CFD study

1-Methylcyclopropene (1-MCP) is a synthetic plant growth regulator used commercially to delay ripening of fruits. The substance is applied in gas form (as a fumigant) in the storage room. In long term postharvest cold storage, fruit are placed in boxes (usually plastic or wooden bins) and stacked in a specific pattern. The top of the boxes are frequently covered with a thin plastic sheet for the purpose of reducing fruit moisture loss. Wooden boxes, card linings and other plant based porous materials used in bins have 1-MCP adsorption capacity. Plastic covers affect the airflow and with that the 1-MCP transport. In this paper, the influence of box materials and plastic cover on the distribution of 1-MCP in cold storage was studied using validated CFD models. Reynolds Average Navier-Stokes equations with the SST k-ω turbulence model were used to calculate the airflow. Diffusion, convection and adsorption of 1MCP were modeled to obtain 3D spatial and temporal distributions of 1-MCP inside a storage container, boxes and fruit. Time dependent profiles of calculated 1-MCP concentrations in the air in the container agreed well with measurement data. The plastic cover imposed no effect on the adsorption of 1-MCP. Wooden boxes notably adsorbed 1-MCP from the treatment atmosphere and may reduce the efficacy and uniformity of the treatment.