Gas exchange dynamics in modified atmosphere packaging of soft cheese

摘要

Modified Atmosphere Packaging (MAP) is a shelf-life extension technique that has been widely applied to horticultural, meat and dairy products. It relies on the interaction between product, packaging material and environment, which determines the gas composition inside the package at steady state. Therefore, MAP design needs to take into consideration O_2 consumption and CO_2 production rates of the product and the mass transfer coefficients for the gas exchange through the packaging material and how they are affected by environmental factors such as storage temperature. In this work, a mathematical model was developed for designing MAP systems for a soft cheese (camembert-type). The model was used to evaluate the effect of perforations on O_2 and CO_2 concentrations of package containing cheese, at constant and varying storage temperatures. The predicted gas composition was compared with those obtained experimentally at 293 and 285 K with packages having different numbers of perforations (1)-(3). Experimental values of gas composition observed at steady state with one perforation were 0.050 and 0.148 (v/ v) at 285 K for O_2 and CO_2 respectively, and 0.003 and 0.207 (v/v) at 293 K. Gas composition was found to take values between 0.009-0.058 for O_2 and 0.154-0.200 for CO_2, when the packages with a single perforation were exposed to storage temperature varying between 285 and 293 K during 14 days of storage. The model developed was able to accurately predict the gas exchange dynamics of the package throughout the storage period whether the temperature of storage was constant or not.