Résumé
Assessing gas permeation of the whole food packaging in industrial conditions (RH, temperature including stretching and sealing effect) is fundamental for predicting the quality changes of packed food during processing and shelf life. Permeability coefficients are usually assessed on a small flat, piece of packaging material which is not representative of the whole pack (usually assembly of tray + lid film or pouches of flexible films sealed on at least 2 or 3 sides) used in the industry. Moreover, conditions used are standardised (temperature of 23 degrees C, 0% RH) which are not representative of conditions that prevail in real use. This simplified approach may lead to erroneous mass transfer predictions when simplified permeability values are used in calculation. To face this problem, we propose a simple methodology for the assessment of the gas permeability coefficients (N-2, CO2, O-2) in sealed intact large scale (industrial) packaging (whole packaging) in conditions of temp and RH mimicking the real conditions of use (encountered by the material in contact with the food product). The CO2 permeability assessed in the industrial-like conditions was significantly higher compared to the one assessed with standard method. The higher gas permeation measured was ascribed to the impact of industrial operations such as shrinking and hot sealing. Our results highlight the necessity to better characterize impacts of industrial conditions such as hot sealing and shrinking on the permeability of the whole pack when prediction of gas permeation through packaging during food processing is needed.