Modelling O₂ and CO₂ exchange for development of perforation-mediated modified atmosphere packaging

Perforation-mediated modified atmosphere packaging relies on the use of macro perforations or tubes to control the O₂ and CO₂ exchange and create the desired atmosphere inside an otherwise gas-tight package. In this work, the O₂ and CO₂ exchange through a single tube was studied. Different temperatures (5-20 °C) and tube dimensions (length from 9 to 17 mm and diameter from 6 to 30 mm) were tested. O₂ and CO₂ mass transfer coefficients were determined according to a lumped mass transfer capacitance model that yielded a good description of the gas transfer. Temperature in the range tested did not show a significant effect on the mass transfer coefficients. A multiplicative non-linear equation was found to yield a good prediction of the dependence of the O₂ mass transfer coefficient on tube diameter and length. The ratio between the CO₂ and O₂ mass transfer coefficients, an important parameter in the design of MAP, was 0.81 and none of the factors tested influenced its value.