What Is Active Packaging?

Active packaging is the incorporation of particular components and additives into a packaging system that release or absorb substances  from the packaged food into the surrounding environment. The intention is to extend shelf-life and preserve quality, to maintain food safety and ensure the sensory properties of the food remain optimal. It is highly important and has become a key element of many packaging systems. 

I’m sure we are all familiar with packaging. It is the technology for protecting products which are stored, for sale, for distribution and then their eventual use.

Active packaging often involves placing compounds into different formats such as labels, packaging film, labels and coatings. The active compounds move from the package by diffusion, evaporation or remain fixed through chemical immobilization.

A number of actives are incorporated directly into the packaging by either mixing these materials in with the polymer and then extruding the packaging or by coating onto a polymeric base material. Typical synthetic polymers include  low‐density polyethylene [LDPE] or polypropylene because of their superior mechanical performance (Gaikwad et al., 2020).

The Market For Active Packaging

The global market for smart packaging including intelligent and active packaging is believed to be nearing $26.7 billion dollars by 2024 and probably $31.9 billion dollars by 2026. Back in 2019, the marketplace was then $20.4 billion dollars.

The market drivers are a general demand to protect fresh produce and ready-to-eat foods. It’s also being driven by regulations in the European Union which is restricting growth.

The Active Packaging Segments

Quite simply, the technology for active packaging can be split into six:-

• antimicrobials
• carbon dioxide scavengers or promoters
• oxygen scavengers
• thermal insulation
• moisture removal
• ethylene removal or creation

These are all key areas for further examination as we see here. 

Oxygen Scavengers

One of the most common active packaging systems involves oxygen scavengers which are antioxidants. These function using wide range of materials usually iron based powders and chemicals, mixtures of metal with acids, metal catalysts such as palladium and platinum, enzymes and yeasts (usually immobilised), photosensitized dyes and metals with ascorbic acid or ascorbates.

Oxygen scavengers are often used in combination with barrier packaging or other technologies to create a vacuum or low oxygen environment. The foods that benefit most are those with porous structures.

The oxygen scavengers along with oxygen absorbers are built into the packaging structure or added as sachets in the headspace. Reducing oxygen reduces oxidation and stops microbial growth (Suppakul et al., 2003). 

In some instances the oxygen scavenger is incorporated into polyethylene terephthalate (PET) bottles to protect wine, tomato sauce, orange juice and virgin olive oil (Mentana et al., 2009). In some cases foods can use reduced levels of preservatives if an active oxygen scavenger is used.

A couple of manufacturers have developed the following systems:

• Celox™ for beverages, and involves can sealants and closure coatings (www.grace.com)
• The Carlsberg FreshCap which is designed for beer and has liners on the underside of the beer closure.
• ZERO2 – a system for fresh products. This consists of a multilayer film fused to injection-molded containers (www.ipl-plastics.com)
• ATOX – for cereal products. A film coating containing oregano essential oils (www.artibal.com). 

Most foods, especially ready-to-eat foods and bakery products benefit from these types of functional packages. They include bread, pancakes and tortillas (Antunez et al., 2012), cooked rice, pastas, cheese, dried meats especially beef jerky, fish, coffee, snack foods and various beverages.

Ethylene Scavengers

These are used to restrict or delay ripening of mainly fruits, vegetables and horticultural products. These are based mostly on potassium permanganate (KMnO₄) (Álvarez‐Hernández et al., 2019), activated carbon and activated clays and zeolites. Other materials introduce 1‐methyl cyclopropene (1‐MCP)  which disrupts the production of ethylene.

Ethanol Emitters

These are alcohol sprays or encapsulated ethanol. These are also commonly used in cakes, fish and bakery products.

Moisture Regulators

 The intention of the package is to reduce food water activity using hygroscopic substrates and substances. This provides an environment which makes it less suited to yeast, mould and bacterial growth and spoilage (Sand, 2020).

In many cases these take the form of sachets, labels and films which contain moisture scavengers Some good examples include:-

• Aptar CSP’s range of Activ-Film™. These are low-density polyethylene (LDPE) films which are adjusted and configured to meet various packaging needs. Used for moderate humidity applications especially for fruit and vegetable storage.
• DriLoc (Novipax)
• FreshWell rigid trays from Aptar
• MeatPad by McAirlaid
• Tenderpac® by Sealpac – a two compartment PET tray format which separates the meat from drip loss. A unique design which has considerable potential in other applications.
• MoistCatch films from Kyodo Printing

The fresh meat sector sends over 750 million used moisture pads to landfill in Australia and New Zealand. To overcome the use of soaker pads, SealedAir under the Cryovac brand have developed the HydroLoQ barrier tray where purge, which is extraneous liquid from meat is sequestered and retained in purposefully designed cavities within the tray. This removes the need for a soaker pad because purge can often contaminate meat and make it wet and mushy on the surface. The consequence is to effectively extend both product freshness and shelf-life but also provide a relatively better sustainable approach to reducing land fill.

Thermal Insulation

These are phase change materials. Suppliers include phase change materials.

• Pure Temp – for frozen food and cold storage. Storage of palm oil, coconut oil and soybean oil-based (www.puretemp.com)
• Green Box – for perishable products, vegetable oil-based products (www.greenbox.it).

Active Packaging Systems

There are two basic systems. Ones that retain or eliminate food compounds include those that maintain humidity or even reduce it. There are also systems for removing gases such as oxygen and carbon dioxide as well as bad odours.

The other main system will increase the carbon dioxide content as well as various aromas. There are also systems for releasing antioxidants, antimicrobials and various functional compounds.

You might also find other active systems such as self-heating and self-cooling systems. 

 For the food packager, active packaging is a relatively new system with many preservation benefits. 

References

Álvarez‐Hernández, M., Martínez‐Hernández, G., Avalos‐Belmontes, F., Castillo‐Campohermoso, M., Contreras‐Esquivel, J., & Artés‐Hernández, F. (2019). Potassium permanganate‐based ethylene scavengers for fresh horticultural produce as an active packaging. Food Engineering Reviews, 11, pp. 159–183. (Article) 

Gaikwad, K., Singh, S., & Negi, Y. (2020). Ethylene scavengers for active packaging of fresh food produce. Environmental Chemistry Letters, 18, pp. 269–284. (Article)

Mentana, A., Pati, S., La Notte, E., Del Nobile, M.A. (2009). Chemical changes in Apulia table wines as affected by plastic packages. LWT–Food Sci Technol 42: pp. 1360–6

Sand, C.K. (2020) Active and Intelligent packaging = Longer Shelf Life. Food Technol..

Suppakul, P., Miltz, J., Sonneveld, K., Bigger, S.W. (2003). Active packaging technologies with an emphasis on antimicrobial packaging and its applications. J Food Sci 68(2) pp. 408–20.