Modelling Modified Atmosphere Storage of Fresh Cauliflower Using Diffusion Channels

Abstract

Abstract The storage of cauliflower under modified atmosphere (MA) was studied experimentally. The composition of oxygen in the storage chambers was regulated through the diffusion of oxygen in narrow channels. Fresh cauliflower was stored at 2·5°C in laboratory chambers equipped with channels of internal diameter 2mm and of different lengths. This technique was shown to be capable of maintaining different steady-state MA compositions (O 2 from 1·5 to 18·0%, depending on the length of the diffusion channels and the mass of the product; CO 2 ≈0%, with the help of a chemical adsorbent) for long periods of time. The steady-state compositions were stable under fluctuations in the cold room temperature. A model based on the molecular diffusion theory was developed to represent the observed phenomena. This model includes the effect of the mass of the produce and of the length and cross-sectional area of the diffusion channel, on the final gas composition in the chamber. Predictions of the diffusion model greatly underestimated the results obtained by experiment (i.e. 90% difference on the estimated channel length for an oxygen molar fraction of 0·03). Another model which takes into account convection in addition to pure diffusion, was found to be more appropriate to represent the experimental data (i.e. 10% difference on estimated length for the same conditions as above).