The ability to package food has made our lives easier in many ways. Packaging is important to contain foods, protect it from external elements such as adulteration by water, gases, microbes, dust, to name a few, and to disseminate information to customers about the contents inside it. Although traditional packaging covers the basic need of food containment, advances in food packaging are both anticipated and expected to solve modern problems. One such issue is spoilage during transit; It has become a significant area of concern, recently. Even though supply chain and logistics networks has improved rapidly in this decade, innovation in packaging that can detect as well as prevent spoilage of agro-products will further reduce this problem, thereby preventing post-harvest losses. In India itself, post-harvest losses accounts for around 30% of overall agricultural production. This, coupled with erroneous grading while packaging, makes a severe impact on the farmers income. Thus, it is of utmost importance to invest on the research and development of unconventional yet novel packaging materials and technology.
With growing knowledge in polymer and materials sciences, it is now possible to fabricate “intelligent” polymers as food packaging materials with added functionalities that is both useful and necessary. Two such recent advances are Active and Intelligent packaging materials. Active packaging is defined as packaging in which subsidiary constituents have been deliberately included in or either the packaging material or the package headspace to enhance the performance of the package system, whereas in an intelligent packaging, there contains an external or internal indicator to provide information about aspects of the history of the package and/or the quality of the food it contains. In this article, it is attempted to review the current advances in this domain.
- Active Packaging
The active packaging systems are developed with the goal of extending the shelf life of foods and increasing the period where the food remains of high quality. These technologies include some physical, chemical, or biological actions which change interactions between a package, product, and/or headspace of the package to get the desired outcome. Active packaging helps to increase the shelf-life of products by using absorbing and diffusion systems for various systems for various materials like carbon dioxide, oxygen, ethylene, and ethanol. Although the active packaging systems change the environmental conditions of the packaged food during the preservation period, but this is very important for preserving the safety and sensory properties along with maintaining the quality of packaged foods. The present systems are O2 scavengers, ethylene absorbers, CO2 absorbers/ emitters, flavor releasing/ absorbing systems, antioxidants, antimicrobials, and moisture controllers. Apart from the present functionalities, research is also being conducted to add these functionalities in edible films appropriate for packaging by adding GRAS-certified ingredients such as biopolymers like gums, and bio-fillers derived from natural substances in the matrix. The common type of active packaging materials are scavengers and antimicrobial packaging.
Compounds such as oxygen and ethylene affects the freshness of food products. For instance, an increase in the level of oxygen leads to oxidation of the product, thereby making it rancid and stale, and the release of ethylene by climacteric fruits can cause a series of chain-reactions, making the whole lot ripe before it is due. This phenomenon leads to undesired product quality as well as wastage. Therefore, bio-fillers having specific scavenging properties added in the matrix can counter the undesired molecules present in the environment.
2.2 Antimicrobial packaging
Utilization of antimicrobial agents in food packaging is beneficial to prevent the growth of microbes and bacteria that can be found in a packaged food or packaging materials and thus increases the shelf life of the food products. Research carried out in this field show that antimicrobial films are more effective as compared to the direct addition of antimicrobial agents to foods because the antimicrobial agents slowly gets released from the packaging film surface to food products with the required concentration to prevent microbial growth. Some of the common active agents that acts as antimicrobial agents are silver, carbon dots, copper, essential oils extracted from clove, rosemary, basil, fennel, lemongrass, etc.
- Intelligent Packaging
Intelligent packaging is an emerging food packaging technology that is improving the traceability, safety, and quality of food. It is described as the science and technology that introduce the communication tools for a food packaging system to monitor changes in the internal and external environmental conditions of the system as well as the packaged food, to communicate the status of the system to the stakeholders of the supply chains including producer, retailers, and consumer. It helps the consumers to make buying decisions, enhances food safety and quality by providing relevant and useful information, including warning for potential problems, to all the elements in the food value chain. Some of the most common intelligent packaging systems are indicators like time-temperature indicator, biosensors, and RFID. The addition of these components makes it possible to report the conditions of both the inside and outside of the package. Sensors can detect if the food inside is spoiled, or stale, TTI’s can monitor the temperature history of a food product, in the packaging to consumption chain, and RFID tag can enable consumers to trace the history of the entire food chain.
3.1 Time Temperature Indicator
It is a well know fact that, the quality of a food material is severely dependent to its temperature history from production to consumption. These indicators can monitor the accumulative effect of temperature on food quality. They are attached on the surface of food packages and integrate the exposure of the packaged food to temperature by accumulating effects of such exposures along the entire cold chain. The working principle of these indicators is based on different enzymatic/ mechanical/ chemical reactions between two or more materials, and as a result, the irreversible discoloration of indicator as an explicit response takes place. Two types of TTI’s are most widely used in food applications:
3.1.1. Diffusion-based TTI: It consists of a layer, and inside of it contains thin layers from paper, film, or glue. When the stored temperature of the food reaches a threshold value, the appearance of the indicator changes, thereby indicating the content inside is not suitable for consumption. This indicator is generally made up of a wick porous with dyed fatty acid ester.
3.1.2. Microbial TTI: Its response is directly related to food microbial spoilage; a correlation is established between the bacterial growth and the metabolism withing the corresponding TTI. One type of these indicators is formed from a label containing lactic acid bacteria.
3.2 Gas Indicator
It is an adhesive label placed on the surface to show changes in the composition of the gas inside the package. These type of indicators shows the presence or the absence of carbon dioxide, oxygen, or ethylene. This kind of indicators needs to be in permanent contact with the food and the atmosphere inside the package to function properly.
Biosensors are devices that can detect specific biological analyses and converting their presence or concentration into some electrical, thermal, optical or other signals that can be easily analyzed. A typical biosensor consists of three basic components: bioreceptors, transducer, and electronic system. These biosensors can be integrated into the packaging material to detect several components such as ethylene, microbes, etc.
3.4 Radio frequency Identification System
RFID technology presents an advanced data carrier system which has the capability of data storage up to 1 MB, non-contact and non-line-of-sight ability to collect real time data. The advantage of integrating RFID includes traceability and promotion of quality and safety of food. The RFID technology can be applied in the food industry in the fields of supply chain management, monitoring conditions of foods, and ensuring food safety.
Increasing demand for continuous monitoring of the food quality and extending the shelf-life of food products had led to emergence of developed types of packaging methods as Active Packaging and Intelligent Packaging technologies. These packaging technologies complement the present methods and further add values by adding more functionalities required for modern-day living.
- Further Reading
- Firouz, Mahmoud Soltani, Khaled Mohi-Alden, and Mahmoud Omid. “A critical review on intelligent and active packaging in the food industry: Research and development.” Food Research International 141 (2021): 110113. DOI: https://doi.org/10.1016/j.foodres.2021.110113
- Realini, Carolina E., and Begonya Marcos. “Active and intelligent packaging systems for a modern society.” Meat science3 (2014): 404-419.DOI: https://doi.org/10.1016/j.meatsci.2014.06.031
- De Jong, A. R., et al. “Active and intelligent packaging for food: Is it the future?.” Food additives and contaminants10 (2005): 975-979. DOI:https://doi.org/10.1080/02652030500336254
- Kuswandi, Bambang. “Active and intelligent packaging, safety, and quality controls.” Fresh-cut fruits and vegetables (2020): 243-294. DOI:https://doi.org/10.1016/B978-0-12-816184-5.00012-4