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We have developed a range of MAPAX® solutions to overcome the challenges facing fruit and vegetable specialists.
Because fruit and vegetables transpire, permeability is the key success factor in packaging. If fruit and vegetables are sealed in an insufficiently permeable film, undesirable anaerobic conditions (<1% oxygen and >20% carbon dioxide) result in lower quality. Conversely, excessive permeability prevents retention of the modified atmosphere. The resulting moisture loss also leads to accelerated deterioration in quality. Microporous film and LDPE/OPP are examples of MAP films suitable for fruit and vegetables.
When fruit and vegetables transpire, the modified atmosphere develops into an equilibrium modified atmosphere (EMA). With an EMA, the rate of oxygen (O2) and carbon dioxide (CO2) transmission through the film equals the product’s respiration rate. Numerous factors, such as respiration rate, temperature, packaging film, pack volume, fill weight and light affect the EMA. In turn, the respiration rate is affected by the variety, size, maturity and preparation of the product. This makes calculation of the optimal EMA for a particular item is complex.
At AGA, to create the optimum EMA for your produce, we can help you to select a gas mixture accommodating different respiration rates. In typical situations, the shelf lives of fruit and vegetables are dramatically increased by optimal EMAs of 3–10% O2 and 3–10% CO2.
As previously explained, modified atmospheres evolve within an air-sealed pack due to respiration. However, in certain cases it may be desirable to gas-flush the package – this accelerates the creation of a beneficial EMA. For example, enzymatic browning of salad vegetables can be delayed by gas flushing instead of air packing.
Our engineers will run a series of tests to establish the optimum solution for your fruit or vegetables. Different conditions may apply, for example, to peeled potatoes and apples (to avoid enzymatic reactions that result in browning, these should not be packed using oxygen). For instance, pre-peeled potatoes can be packed in 20% CO2 + 80% N2. At +4 to +5°C (+39.2 to +41ºF), this extends the shelf life from 0.5 hours to 7–8 days.