Permeable Gas Cavity at Elevated Pressure Enhances Modified Atmosphere Packaging of Fresh Produce.

Modified atmosphere packaging (MAP) of fresh produce involves exploiting package properties to satisfy respiration activity of produce. While effective, package material properties are not infinitely adjustable to match needs of all products. Additional ways of providing favorable in-package gaseous environments are needed. This work explores the use of permeable inserts filled with gas at elevated pressures as a means to achieve in-package gaseous atmospheres that may not be possible by the package alone. Mathematical models were developed to predict transient package atmospheres for packages containing respiring produce and pressurized permeable inserts. The model was validated for semirigid tray packages containing grape tomatoes and Granny Smith apples. With inserts initially pressurized with oxygen at approximately 200 to 300 kPa (about 30 to 45 psi), about 2 weeks additional shelf life was observed relative to controls for both tomatoes and apples in test packages. Additionally, simulations provide design guidance for pressurized inserts for the case of very high respiration rate produce such as spinach.

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This work promises to expand application of modified atmosphere packaging (MAP). Currently, applications are limited by gas transfer material properties of existing packaging films. However, packaging offers other important functions that may not be well served by materials that satisfy critical gas permeation requirements. This work demonstrates an approach that disconnects packaging material specifications from MAP design.