The terms active packaging, intelligent packaging, and smart packaging refer to amplified packaging systems used with foods, pharmaceuticals, and several other types of products. They help extend shelf life, monitor freshness, display information on quality, improve safety, and improve convenience.
The terms are often related and can overlap. Active packaging usually means having active functions beyond the inert passive containment and protection of the product. Intelligent and smart packaging usually involve the ability to sense or measure an attribute of the product, the inner atmosphere of the package, or the shipping environment. This information can be communicated to users or can trigger active packaging functions. Programmable matter, smart materials, etc. can be employed in packages. Yam, Tashitov, and Miltz have defined intelligent or smart packaging as:
Depending on the working definitions, some traditional types of packaging might be considered as "active" or "intelligent". More often, the terms are used with new technologically advanced systems: microelectronics, computer applications, nanotechnology, etc.
Moisture control
For many years, desiccants have been used to control the water vapor in a closed package. A desiccant is a hygroscopic substance usually in a porous pouch or sachet which is placed inside a sealed package. They have been used to reduce corrosion of machinery and electronics and to extend the shelf life of moisture-sensitive foods. With pharmaceutical packages, a common method is to include a small packet of desiccant in a bottle. Other methods of including desiccants attached to the inner surface or in the material have recently been developed.
Corrosion
Corrosion inhibitors can be applied to items to help prevent rust and corrosion. Volatile corrosion inhibitors (VCI) or vapor phase corrosion inhibitors can be provided inside a package in a pouch or can be incorporated in a saturated overwrap of special paper or plastic film. Many of these are organic salts that condense on the metal to resist corrosion. Some films also have VCI emitting capability.
Films are available with copper ions in the polymer structure, These neutralize the corrosive gas in a package and deter rust.
VCIs create a neutral environment in the packaging. It works on the principle of difference in vapour pressure and causes reaction with metals and non-metals, and with moisture to prevent corrosion. There are different forms of VCIs available, such as papers, plastics, HDPE papers, oils, foams, chips, aluminum barrier foils, bubble, and emitters that can prevent corrosion at many stages.
Metal chelation
Trace transition metals in foods, especially iron, can induce oxidative degradation of many food components, especially lipids, and cause quality changes of the products. Metal-chelating active packaging materials are made by immobilizing metal-chelating active compounds onto traditional active packaging material. The surface immobilized metal-chelating compounds can scavenge the transition metals from the product and enhance the oxidative stability of the product. The metal-chelating active packaging technology is also antioxidant active packaging that will extend the shelf-life of consumer products by controlling the oxidation. The metal-chelating active packaging technology is known to be able to remove synthetic food preservatives (e.g. EDTA) from the food product. This technology can be used to address the increasing consumer demand for additive free and 'clean' label food products.
Oxygen control
Oxygen scavengers or oxygen absorbers help remove oxygen from a closed package. Some are small packets or sachets containing powdered iron: as the iron rusts, oxygen is removed from the surrounding atmosphere. Newer systems are on cards or can be built into package films or molded structures. In addition, the physical characteristics of the packaging itself (oxygen transmission rate - OTR) can dictate how effective an oxygen absorber can be, and how long it will stay effective. Packaging with a low OTR will let less oxygen in the closed package through the polymer barrier itself.
Atmosphere
With some products, such as cheese, it has long been common to flush the package with nitrogen prior to sealing: the inert nitrogen is absorbed into the cheese, allowing a tight shrink film package. The nitrogen removes oxygen and interacts with the cheese to make the package functional.