The primary role of packaging in food industry is preservation and protection from external contamination. It includes safety of packaged foods, maintenance of quality, increment in shelf life and delay in retardation. Packaging protects foods from the influences of environment like light, heat, absence or presence of oxygen, moisture, enzymes, microorganisms, insects, dust, gaseous emission, pressure, etc. These factors lead to the deterioration of foods & beverages. Shelf life of foods is enhanced by decreasing microbial, biochemical, and enzymatic reactions through different strategies like moisture control, temperature control, removal of oxygen, addition of chemical additives/preservatives, or a combination of these. In order to avoid recontamination, proper integration of the product, process, package, and distribution is important. The perfect packaging material should not allow molecular transfer to or from packaging materials, should be inert and resistant to hazards.

Apart from the above mentioned roles, there are other important functions of packaging, including containment, convenience, marketing, and communication. The involvement of containment ensures that a product is not intentionally spilled. Communication plays a key link between consumer and food processor, displaying certain mandatory information like weight, source, ingredients, etc. Nutritional value and cautions for use are also required now by law.

Active and Intelligent Food Packaging
Traditional food packages are designed to delay the unfavorable effects of the environment on the food. Active packaging plays a dynamic role in food preservation and allows packages to interact with food and the environment. Many areas of packaging have advanced with the developments in active packaging, including  controlled respiration rate, delayed oxidation, moisture migration, and microbial growth. Many other improvements in packaging technologies include odor absorbers, ethylene removers, carbon dioxide absorbers/emitters, and aroma emitters. Oxygen removal, purge and moisture control have been noticeable in active packaging, of which purge control is commercially the most successful.

Smart or intelligent packaging has enabled to monitor and communicate information about food quality, with the help of the likes of time-temperature indicators, radio frequency identification, ripeness indicators, and biosensors. These devices may be incorporated either in package materials or attached to the inside or outside of a package. As of now, the commercial application of these technologies has been limited but they are likely to gain prominence as a mechanism for tracking and tracing produce and others perishable commodities.
 
Oxygen Scavengers
Presence of oxygen in packaged food might accelerate oxidative reactions resulting in food deterioration. Oxygen helps the growth aerobic microbes and molds. Oxidative reactions produce off-odors, off-flavors, undesirable color changes, and reduced nutritional quality of the food. Oxygen scavengers are those agents that remove oxygen, diminishing oxidative reactions. They come in different forms such as sachets, labels, or may be directly incorporated into package material and/or closures. Oxygen scavenging compounds are mostly agents that react with oxygen to reduce its concentration. Some most common oxygen scavengers are ferrous oxide, ascorbic acid, sulfites, catechol, photosensitive dyes.

Carbon dioxide Absorbers & Emitters
Carbon dioxide is added in certain products like baked goods, fresh meat, poultry, cheese, etc. for beneficial effects, as for suppressing microbial growth. It is also used to decrease the respiration rate of fresh produce, to overcome package collapse or partial vacuum caused by oxygen scavengers. Carbon dioxide is found in different forms, like moisture-activated bicarbonate chemicals in sachets and absorbent pads.

Moisture Control Agents
Excess moisture in moisture-sensitive foods can have adverse results, for example, softening of crispy products, caking in powdered products, and moistening of hygroscopic products. Vice-versa is also true. Too much moisture loss from food may result in product desiccation. Adding moisture control agents help control water activity, removing melting water from frozen products, reducing microbial growth, prevent condensation from fresh produce, and keep the rate of lipid oxidation in check.