Active and intelligent packaging helps reduce food waste and the environmental impact of packaging. The trend is toward combining intelligent and active packaging capable of integrating multiple functions.

Given the huge food losses throughout the supply chain, it is increasingly important to develop new active packaging solutions that can release functional elements on demand and in a controlled manner to effectively reduce food waste. It is also worth exploring how different packaging responds to different environmental factors, including pH, temperature, light, and humidity.

These reactive behaviors can be synergistic, while still being consistent with actual storage requirements. The role of new functional elements is not limited to antimicrobials but can also regulate other storage factors such as humidity. Thanks to the integration of certain antimicrobial components, such as anthocyanins, metal nanoparticles, and carbon dots, new packaging can have multiple functions, such as freshness indication and light-responsive antimicrobial capacity.

Researchers are studying the concept of multiple responses and the sequential release of functional elements to achieve secondary functionalities in packaging. The development of new multifunctional food packaging could help reduce dependence on petrochemical materials.

Limiting waste

According to a report published by the Food and Agriculture Organization of the United Nations (FAO) in 2021, global losses of fruit and vegetables reached up to 45% of total production. The development of biodegradable food packaging could be essential for reducing food waste. The concept of active food packaging systems is broad and always involves the absorption and release of specific substances, including hygroscopic and oxygen-absorbing packaging, ethylene-absorbing packaging, antimicrobial packaging, and antioxidants.

Numerous compounds derived from natural or renewab​​ s have been used to make active packaging. Polysaccharide-based materials contain many free hydroxyl groups, which can form hydrogen bonds with other substances to make a film. However, their high hydrophilicity can weaken their resistance in high humidity conditions, making it necessary to incorporate hydrophobic substances. Starch, pectin, sodium alginate, and cellulose (commonly derived in forms such as methylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, etc.) are the most common sources.

Chitosan, found in the shells of arthropods and marine insects, is produced by partially removing the acetyl group from the natural polysaccharide chitin. It is known for its excellent film-forming properties, antimicrobial effects, and low toxicity, acting as both a carrier and an antimicrobial agent. Protein-based materials are mainly whey proteins, alcohol-soluble proteins, soybean isolate proteins, etc. These materials have good cross-linking ability and can provide a source of nitrogen during degradation, despite their poor water barrier capacity.

The excellent moisture resistance is attributed to the high hydrophobicity of lipid materials. Materials such as oils, fats, and waxes are available from plants and animals, but they can present problems of surface cracking and greasiness. The above-mentioned materials form the main basis of the preservation system through mixing and layering, while their activity and intelligence are mainly determined by the functional elements incorporated. The controlled release of functional elements is fundamental to active packaging, as it is influenced by the microenvironment in which the food is stored, such as temperature, humidity, pH, microorganisms, light, and specific chemicals.

This process requires precise release on demand at specific points and times. Premature release results in the waste of functional elements and can alter the organoleptic properties of the food, while delayed release fails to achieve the purpose for which the system was designed. In recent years, emerging functional elements have offered several possibilities for active packaging. Not only do they combat potentially harmful microorganisms, but they also help regulate the storage microenvironment.

Active and intelligent cellulose-based packaging

Traditional petroleum-based plastics are widely used in packaging materials due to their ease of processing, low cost, and good barrier and mechanical properties. However, the extensive use of petroleum-based plastics has led to environmental pollution, increased environmental pressure, and a heavy dependence on petroleum resources. In recent years, the food packaging industry has increasingly focused on the development of active packaging systems, particularly through the valorization of food waste.

This innovative approach not only addresses the environmental issues of plastic packaging but also promotes the reduction of food waste by reusing food by-products as valuable bioactive ingredients. Active packaging involves the integration of bioactive compounds extracted from food waste into packaging materials, allowing them to actively influence the internal environment of the package. This can improve food freshness by preventing microbial growth and preserving sensory and nutritional quality. With the development of biomass-based materials, it has become possible to replace petroleum-based plastics with environmentally friendly and sustainable biomass-based materials.

Biomass-based materials are increasingly being developed as substrates for packaging due to their renewable nature, non-toxic properties, excellent biocompatibility, and degradability. Cellulose is the most abundant biomass polymer on Earth, with an annual production of up to 1.5 × 10¹² tons. It boasts diverse sources and superior performance characteristics, including mechanical strength, thermal stability, barrier properties, and biocompatibility. By using cellulose as the base material for the development of food packaging films, it is possible to avoid the problems of migration of plasticizers and stabilizers commonly found in traditional packaging films, thereby improving food safety during transportation and storage.

Cellulose has become a widely used eco-friendly packaging material due to its excellent mechanical properties, film-forming properties, low cost, and renewability. Some studies have shown that irradiation can be used to induce cross-linking in biopolymer films and to graft natural antimicrobial compounds, improving the multifunctional properties of cellulose-based films. In particular, trans-cinnamaldehyde (TCA) has been shown to act as both a cross-linking agent and an antimicrobial agent during irradiation treatment.

These results suggest that combining irradiation with active compounds such as TCA offers an environmentally friendly and effective strategy for developing water-insoluble antimicrobial films. Furthermore, several studies hypothesize that integrating active packaging with irradiation could reduce the required decontamination dose while extending the shelf life of food products and reducing food waste.

Challenges and future prospects

Currently, active and smart packaging is mainly food packaging that responds to moisture, pH, microbial contamination, and other indicators. The future of smart packaging lies in the development of systems that integrate active packaging with smart packaging to create a single material capable of responding appropriately to changes in the internal environment through environmental feedback.

Currently, although smart packaging has potential advantages over traditional packaging, there are still some issues with its large-scale application. The main obstacle to active packaging is undoubtedly the loading of active ingredients, which requires both the maintenance of the mechanical and barrier properties of the base material and the guarantee of the activity of the loaded active ingredients during food storage and transport. In the future, it will be necessary to use large-scale production machinery to simplify the packaging production process, thereby reducing costs and making its application to food packaging more feasible.

The development of active packaging is receiving increasing attention, and numerous new functional elements are being developed. Some of these are expected to integrate multiple functions, and indeed, active packaging should not be limited to antimicrobials; the regulation of other microenvironmental factors, such as pH, humidity, atmosphere, and light, is also crucial. The existence of future smart packaging systems will allow the internal environment of the packaging to be monitored and regulated in real time, information such as food sources, processing techniques, and status to be read, and consumers to understand product information more easily, thereby promoting consumption.

At the same time, active and smart packaging should be reusable, easy to recycle, environmentally friendly, and sustainable. By applying smart packaging systems to food packaging in a practical and sustainable way, the transparency, healthiness, and safety of the food supply chain will be improved, and the value of products will be increased.

Conclusion​

Active and intelligent packaging responds to trends in the food industry and consumer demands; existing research shows that the increase in biodegradable and edible materials with natural active agents helps reduce food waste and the environmental impact of packaging, while improving food safety and consumer health.

Active packaging can delay or prevent the growth and reproduction of various microorganisms in food. The trend for the future is the combination of smart and active packaging. Research is not focused exclusively on the antibacterial, antioxidant, indicator, and reactive properties of packaging materials, but also on cost reduction, a key factor for the improved application of active and smart packaging systems in food packaging.