Packaging protects food from external environmental influences, such as bacteria, dust or moisture, but so-called passive packaging has only limited functionality. Active packaging also provides additional protection and ensures that the quality of the food is maintained under more favorable conditions, thus preventing its rapid deterioration and the proliferation of pathogens, and as a result, the shelf life of the packaged food will be longer.
1.) What is active packaging and what is the “essence” of its use?
Active packaging is characterized by the fact that it contains actively acting elements and thus consciously improves the environmental conditions surrounding the packaged food.
Active packaging contains components that extract certain substances from the food (e.g. by extracting oxygen from the air in the packaging) or release desired substances (e.g. preservatives). But they can also regulate e.g. humidity of food packaging, or they can also stop the growth of pathogens.
Active packaging can thus contribute to reducing the use of additives (e.g. preservatives) or even avoiding them altogether.
2.) What products are they used for packaging?
The following products are the specific areas of application of active packaging:
- beverages
- cold cuts, meat products, ready meals
- vegetables and fruit
- medicines, dietary supplement tablets
2.) How does active packaging increase the shelf life of food?
In order to improve the quality of food, active packaging contains special “active” components that are integrated into the packaging – or added as a separate insert.
As a result, different mechanisms of action and combinations of different active systems are possible.
Active packaging:
- regulates the humidity,
- binds oxygen;
- prevents changes caused by light,
- stops ripening processes,
- protects against loss of flavour,
- reduces the growth of bacteria and pathogens.
The authorisation of active packaging is regulated by an EU regulation.
The types of active packaging are as follows:
2.1. Humidity control
Active packaging keeps food dry in the packaging by using moisture-regulating substances such as silica gel or starch polymers.
The moisture-regulating components are either in the packaging material itself or in inserts such as small bags or the like placed under/next to the product. A common example of its application is the use of absorbent pads for meat products packaged under fresh protective gas. The meat juice that leaks out over time is absorbed by polyacrylates (plastics), which can hold up to 500 times their own weight. However, if meat juice collects in such active packaging, it indicates that the capacity of the absorbent pad has been exhausted and in this case there is an increased risk of rotting.
Absorbent pads are also often used as pads for plastic fruit trays.
2.2. Oxygen binding
Oxygen causes oxidation of food and accelerates the growth of aerobic (oxygen-loving) microorganisms. This in turn leads to food spoilage. Lower oxygen concentrations in food packaging can delay these processes.
Oxygen binding materials, such as iron, can actively reduce oxygen levels in food packaging. Depending on the type of material, they can be used as a separate layer in packaging materials such as foils, menu trays or PET bottles, or as a sealing insert in beverage caps.
For example, active films bind oxygen in shrink-wrapped meat products, making them more durable. Foods such as mashed potatoes or sauerkraut retain their color longer on a menu tray with an oxygen-absorbing layer. Packaging materials with these properties are already used for PET-bottled beers.
Another form of packaging could be the use of so-called sachets (single-dose pillow bags) in the packaging, which also serve to bind oxygen.
2.3. Whey coating instead of plastic packaging
Scientists at the Fraunhofer Institute have developed a natural alternative from whey to replace synthetic coatings. Whey accumulates in large quantities as a by-product of food production, i.e. it is a largely unusable by-product.
Modified whey proteins are used to produce a coating that has very good moisture and oxygen barrier properties. Additionally, proteins have natural antimicrobial properties that further improve the shelf life of the food. The carbon dioxide emissions during production are also lower than with traditional packaging.