What kind of gas do you know for inflatable packaging?

[China Packaging Network News] According to experts from China Packaging Network, modified atmosphere packaging (MAP), also known as gas-flushing or inflatable packaging, is a widely used technique in food preservation. This method involves replacing the air inside the package with a specific mixture of gases such as nitrogen (Nâ‚‚), oxygen (Oâ‚‚), and carbon dioxide (COâ‚‚), or combinations like Oâ‚‚ + Nâ‚‚ or COâ‚‚ + Nâ‚‚ + Oâ‚‚. The primary goal of this technology is to extend the shelf life of various food products and enhance their overall value. In this article, we will take a closer look at the common gases used in food packaging and their specific applications.

First, the use of carbon dioxide (COâ‚‚) in food packaging

One notable example comes from Sweden, where a company has developed packaging solutions that utilize 100% COâ‚‚ to store meat. The high concentration of COâ‚‚ helps prevent the growth of aerobic bacteria and mold by extending the lag and exponential phases of microbial development, thus acting as an effective preservative. With this method, pork can be stored for up to 120 days without freezing, and with re-pressurization, even longer storage periods are possible.

Recently, U.S. researchers have introduced new technologies using CO₂ in plastic packaging materials. By mixing equal amounts of CO₂ with ethylene oxide or propylene oxide and using special catalysts, they created a transparent, gas-impermeable plastic similar to polycarbonate and polyamides. This material does not fully decompose at 240°C and is biodegradable, making it an environmentally friendly option that reduces pollution and soil contamination.

In China, scientists have successfully applied nanotechnology to efficiently produce biodegradable plastics from COâ‚‚. By reducing the catalyst to nano-scale, they enable efficient polymerization of COâ‚‚ into new packaging materials. This process allows for the synthesis of approximately 42% COâ‚‚ into packaging materials per gram of catalyst, offering a sustainable and eco-friendly alternative with great potential in the market.

Second, the role of nitrogen (Nâ‚‚) in food packaging

Nitrogen is considered an ideal inert gas for food packaging due to its non-reactive nature. It helps reduce oxygen levels inside the package, which significantly inhibits the growth of bacteria and molds, slows down oxidation, and keeps food fresh for longer. Nitrogen-filled packaging also prevents food from crumbling, sticking, or shrinking, maintaining its shape, texture, color, and flavor. This type of packaging is increasingly replacing traditional vacuum packaging and is commonly used for snacks like potato chips and fried foods. Due to its popularity among younger consumers, nitrogen packaging is expected to expand to more food types in the future.

In the United States, nitrogen is used to strengthen thin aluminum beverage cans. Before filling, nitrogen is dissolved in the beverage, and once sealed, it is released, creating internal pressure that makes the can more durable—similar to an inflatable container. This technique improves the structural integrity of the can, preventing damage during transport and storage, while preserving the quality of the drink. It can also be applied to plastic bottles made of polyester.

When using nitrogen in food packaging, it's essential to ensure high purity. Nitrogen obtained through membrane separation or pressure swing adsorption can reach over 99.9% purity, meeting the safety standards required for food-grade applications.

Third, the application of composite gases in packaged foods

Composite modified atmosphere packaging (MAP) is a global standard for food preservation. The gas mixtures typically include COâ‚‚, Nâ‚‚, Oâ‚‚, and sometimes small amounts of other gases. COâ‚‚ suppresses the growth of aerobic spoilage bacteria and molds, while Oâ‚‚ inhibits anaerobic bacteria and maintains the color and freshness of fruits and vegetables. Nâ‚‚ acts as a filler gas, helping to maintain package structure and prevent compression. The right combination of gases depends on the food type, preservation needs, and packaging material, ensuring optimal freshness, nutrient retention, and extended shelf life.

Experts from China Packaging Network note that MAP is also highly effective for preserving fresh-cut produce. Products like cut fruits and vegetables, often referred to as "net vegetables," are popular due to their convenience, nutrition, and freshness. However, they tend to brown quickly after cutting. Using MAP to reduce oxygen levels helps maximize shelf life. For example, in the U.S., cut lettuce is preserved with a gas mixture containing 1–3% O₂, 5–6% CO₂, and 90% N₂. This technique is also suitable for sliced apples, potatoes, and leafy greens. Developing packaging films tailored for MAP is key to improving the freshness and longevity of fruits and vegetables.