Smart monitoring of gas/temperature changes within food packaging based on natural colorants

Abstract

The development of smart packaging and innovation in common food packaging technology will greatly help to meet market needs, including consumer preference for "safe" foods, high-quality products and mitigate the negative environmental impacts of food packaging. In addition, consumers' tendency to use natural ingredients such as pigments and biopolymers has provided the basis for their application in the food industry, including smart food packaging. Hence, smart packaging in addition to protecting food products against environmental damage can also reveal a sign (colorimetric, chemical, electric, etc.) in real time in response to any changes in the packaging conditions and food quality. This comprehensive review emphasizes on the gas/temperature-sensitive smart films based on natural colorants and their key applications in the food packaging systems. Technological considerations associated with the natural colorantresponsive films, smart packaging, biopolymers, and importance of natural colorants versus synthetic dyes are investigated. In practice, the most common designed colorimetric indicators for monitoring gas and temperature changes and application of relevant smart films in real food models have also been discussed. Gas and time-temperature indicators provide a rapid, reliable, and online assessment and a visual indication of the food product quality level, usually through a color change, which is directly related to gas and temperature conditions during distribution and storage of relevant food products. However, future studies need to consider main points such as cost, consumers' acceptance, and confidence, regulatory aspects (i.e., labeling) and multifunctionality of smart packaging to be commercially sustainable.

Recent Advances in the Development of Smart and Active Biodegradable Packaging Materials

“…This type of colorimetric pH-sensor, which is also referred to as a halochromic sensor, is typically based on an exchange of protons (H + ) between the pigments and their environment [180]. Some colorimetric indicators can also give a color change in response to the presence of specific volatile compounds, which can also provide an indication of alterations in food quality [17,[181][182][183].…”

“…Active packaging materials contain additives, such as antioxidants or antimicrobials, that can improve the quality, shelf-life or safety of foods by inhibiting chemical reactions or microbial growth [ 15 ]. Smart packaging materials are designed to respond to a specific trigger, such as a change in pH, temperature, moisture content, gas levels, light exposure, chemical composition, or enzyme activity [ 16 , 17 ]. For instance, they may contain a natural pigment that undergoes a color change in response to one of these triggers, which can then be used to report alterations in the ripeness, quality, or safety of a food [ 11 ].…”

Smart and Active Food Packaging: Insights in Novel Food Packaging

“…During the storage time, some metabolites including CO 2 , H 2 S, O 2 , ethylene, and volatile compounds like ammonia, amines, and ethanol appear in the headspace of the packaging (Mills, 2009;Lang and Hübert, 2011;Koskela et al, 2015;Saliu and Pergola, 2017). These metabolites can be employed as a quality-indicating index for spoilage monitoring by employing an indicator within the packaging system (Mohammadian et al, 2020). Not only do majority of these indicators identify the carbon dioxide and oxygen concentrations (Meng et al, 2014), but water vapor, ethanol, hydrogen sulfide, and other gases are also checked (Fang et al, 2017).…”

Bio-Based Sensors for Smart Food Packaging—Current Applications and Future Trends

“…In this sense, the use of packaging is a strategic choice for the protection and conservation of food [3] as it acts as a barrier to gases (oxygen, carbon dioxide), water vapor, and dust [4][5][6]. Therefore, packaging must be able to provide four main functions: protection, containment (small items can be grouped together in one package), information transmission (how to use, transport, recycle, or dispose of the package or product), and marketing (encourage potential buyers to purchase the product) [7,8]. It contributes to assuring the safety and quality of the food products for both suppliers and consumers, resulting in a reduction in food waste and more safety for the consumers [9,10].…”