Antioxidant Properties and UV-blocking of Carbon Quantum Dots in Food Packaging Applications

Each year, a substantial quantity of food is lost within the supply chain. The reports indicate that approximately 60% of this loss could be avoided. The primary factors contributing to food spoilage are oxidation, microbial contamination, exposure to light, undesirable moisture levels, excessive ethylene presence, and inadequate temperature control (Riahi, Hong, Rhim, Shin, & Kim, 2023a). Effective food packaging is crucial for reducing food wastage throughout storage and distribution processes (Jung et al., 2020). Active packaging involves the deliberate incorporation of active constituents with the capacity to absorb or release substances within the packaged food or its surrounding environment. This process aims to uphold the quality, sensory properties, and safety of the food product (Ahmed et al., 2022). For example, the active component may serve as a scavenger to absorb residual oxygen, water vapor, and ethylene or alternatively act as an emitter to release carbon dioxide/ethanol or provide UV-shielding and gas barrier capabilities. Hence, active packaging systems significantly contribute to mitigating food wastage (Roopa et al., 2023). Various active compounds, encompassing natural plant extracts, food-derived sources, essential oils, and nanomaterials, are utilized in the fabrication of such active packaging systems (Riahi, Khan, Rhim, Shin, & Kim, 2023b). At present, nanocomposite food packaging technology utilizing nanomaterials stands as one of the forefront areas within the food industry (Garcia, Shin, & Kim, 2018). In the last few years, carbon dots (CDs) have emerged as active additives for packaging films, addressing the requirements of food safety applications (Khan, Riahi, Tae Kim, & Rhim, 2024). These particles exhibit distinctive characteristics, including photoinduced electron transfer, pronounced absorption within the blue and UV spectra, adjustable photoluminescence, fluorescence sensing capabilities, photocatalytic activity, biocompatibility, notable chemical stability, straightforward functionalization, and antioxidant as well as antimicrobial attributes (Khan, Ezati, Kim, & Rhim, 2023a). CDs have demonstrated the ability to scavenge reactive oxygen species (ROS), including hydroxyl radicals, superoxide anions, nitric oxide, and peroxynitrite, in both extracellular and intracellular environments through mechanisms involving adduct formation, hydrogen donation, and electron transfer (Moradi, Molaei, Kousheh, T. Guimarães, & McClements, 2023). Furthermore, CDs have garnered significant interest as ultraviolet (UV) absorbers due to their exceptional UV absorption capabilities and high visible transmittance rates, stemming from their particle sizes being less than 10 nm. These characteristics are anticipated to revolutionize traditional UV absorbers (Hu et al., 2019). The antioxidative and UV-blocking efficacy of carbon dots in packaging materials has been documented in several investigations (Ezati, Priyadarshi, & Rhim, 2022; Kousheh, Moradi, Tajik, & Molaei, 2020; Linlin Zhao, Zhang, Mujumdar, & Wang, 2023). This chapter presents insights into the antioxidative and UV-blocking characteristics of carbon dots, elucidating their mechanisms of action, followed by an overview of their application in food packaging technology. In the end, the challenges and future recommendations of carbon dots as an active filler of packaging materials are briefly discussed.