Prediction of Changes in O₂ and CO₂ Partial Pressures in Modified Atmosphere Packages of Tomatoes

Abstract

A model for predicting changes in O₂and CO₂partial pressures in modified atmosphere packages of tomatoes stored at 10°C was developed by using a respiration model based on enzyme kinetics and a simple mathematical model. The respiration models of tomatoes were determined using a Michaelis-Menten-type equation without inhibition by CO₂by means of a closed system experiment. Mathematical model equations were solved simultaneously by the fourth-order Runge-Kutta method using Microsoft Excel software to predict changes in O₂and CO₂partial pressures inside the package. The validity of the model was verified by results of simulation and an experiment using two types of model package, one containing about 0.24 kg of tomatoes with a film surface area of 0.01 m²and the other containing about 0.55 kg of tomatoes with a film surface area of 0.02 m². The predicted values of gas composition inside the package agreed well with the experimental data. This model enables prediction of changes in O₂and CO₂partial pressures inside a package of tomatoes by using input variables that are used in the design of modified atmosphere packaging to prevent fruit damage caused by anaerobic respiration.