How to extend shelf life of food

August 16, 2023

        With the development of packaging technology, packaging bags can effectively extend the shelf life of food. But what types of packaging bags can effectively delay the shelf life of food as well as ensuring the freshness of food? At present, vacuum bags, vacuum bags with air valves and bags with air valves can all have the function. Because they effectively extend the shelf life, this type of packaging bag is widely used for some food, such as fresh vegetables and fruits, meat, coffee beans etc.

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        Our company specializes in different kinds of vacuum bags with air valves and coffee bags with air valves. based well utilized, they are approved by our customers.

        Today, let's learn about the working principle of vacuum bags with air valves and coffee bags with air valves in order to know about how they can effectively extend the shelf life of food and ensure the freshness and safety of food.

        First of all, let's figure out what is a vacuum bag. 

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       As we all know, the cause of food spoilage is due to oxidation, which produces a large number of microorganisms and bacteria. Then, the principle of the vacuum bags is that by isolating oxygen. Once there is no oxygen, the food will not oxidize and the microorganisms cannot survive. Therefore, the vacuum mainly removes oxygen, and some use nitrogen to preserve the quality of food. The principle is also to remove oxygen with protecting the food from being crushed meanwhile. 

The vacuum bag with air valve



        This kind of bags is with an air valve on the basis of the original bag. Do you know what the function of the air valve is? The air valve on the bag makes the air in the bag flow out through the difference of pressure between inside and outside of the bag and then the bag is completely sealed through the sealing valve to achieve the purpose of keeping fresh and moisture-proof. The specific principles are as follows:

1. Exhaust:

        Exhaust the air in the bag through the vacuum valve to form a pressure difference between the inside and outside of the bag. When exhausting, lock the sealing valve at the bag mouth, and if open the vacuum valve, the outside air enters the bag through the valve, and the air in the bag is discharged at the same time.

2. Sealing:

        When the pressure difference between the inside and outside of the bag reaches a certain level, the sealing valve will automatically close and the bag will be completely sealed. When sealing, the vacuum valve will be closed to maintain the pressure at the mouth of the bag, then the sealing valve can be turned outward to lock the mouth of the bag. At last the handle next to the valve is pressed up and down in order to close the valve and seal itself.

Coffee bags with air valve

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        Nowadays we find that there is always an air valve on the coffee bags. The general air valve is composed of five parts: polyethylene cap, rubber gasket, silicone oil viscous layer, polyethylene plate and paper filter.

        So why should the coffee bag be equipped with an air valve? 

        Because of the many chemical reactions when coffee is roasted and volatile gases such as carbon dioxide form inside the beans. These gases add flavor to the coffee, but they continue to be released for a while. After roasting, the carbon dioxide starts to escape, but it takes several weeks for it to disappear completely.

        Thus, the valve allows carbon dioxide to escape and prevents oxygen from entering. This process prevents oxidation and increases shelf life. The release of carbon dioxide causes pressure to build up inside the package, causing the flexible rubber gasket to deform and release the gas. After the release phase is complete, the internal and external pressures are balanced, and the rubber gasket returns to its original flat configuration, sealing the package again. Moreover, the valve helps you pick your coffee. Because the coffee aroma will be released through the valve with carbon dioxide as the time goes, and the smell will become less strong as the coffee ages. If you want to check that the beans are fresh before buying, you can squeeze the bag slightly to release the gas through the valve.

        In addition, the vent valve allows gases to escape, helping the coffee pack retain its shape. If gas is trapped inside the package, it can cause the bag to swell. Not only is this unsightly, but it can end up causing the package to burst or leak.

The function of the air valve on the coffee bags:

Maximize freshness

        The vent valve prevents other gases from entering the package, mainly oxygen. When coffee beans are exposed to oxygen for extended periods of time, they can easily spoil, shortening their shelf life and negatively affecting flavor.

Improve packaging efficiency

Using a vent valve allows the factory to pack the coffee quickly rather than waiting for all the gas to be released, increasing the efficiency of the product line.

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