AbstractModified atmosphere packages were designed and used for the packaging of green chili peppers. Respiration of green peppers at 10°C was characterized by the closed‐system method as a function of O2and CO2concentrations, and was incorporated into mass balance equations of O2and CO2gases in order to predict the gas composition inside the package over time. From the prediction of atmospheres inside packages constructed of the available plastic films, three retail packages (110‐g peppers) were designed and studied experimentally for their ability to modify the package atmosphere and to retain quality (moisture, ascorbic acid and chlorophyll). Pepper packages using 25 μm low‐density polyethylene and 30 μm cast polypropylene could attain modified atmosphere close to the optimal gas concentrations (3% O2and 5% CO2), and therefore provided better quality retention compared with unpackaged