Predicting Gas Concentrations of Welsh Onion in Polymeric Film Packaging and Shipping Containers

Abstract

A theoretical model of the atmosphere within polymeric film and shipping containers was developed and validated by experiments with or without Welsh onion (Allium fistulosum L.). There were three processes in the model: respiration of fresh vegetables, permeability of gas in polymeric film and permeability of gas in the shipping container. The respiration rate of Welsh onion was expressed in a multiple regression equation. When empty packages were used, changes in carbon dioxide (CO2) and oxygen (O2) concentrations inside the unperforated polypropylene (OPP) film packaging and expanded polystyrene (EPS) containers agreed very well with the simulated data. These results indicate the suitability of the proposed model. Changes in CO2 and O2 concentrations in the EPS container were approximated when Welsh onion was placed in the film package. The predicted CO2 and O2 concentrations in the OPP film differed slightly from the experimental data obtained with a maximum of 1.5% and 1.2%, respectively, but gas correlated significantly with the model. Therefore, the simulation model may be useful for fresh vegetables wrapped with polymeric film and then encased in shipping containers.