Prospects of sustainable and renewable source-based carbon quantum dots for food packaging applications

CQDs are relatively new nanomaterials discovered accidentally during the purification process of carbon nanotubes. Since then, several attempts have been made to synthesize CQDs from various sources, particularly economically and sustainably. Carbon is one of the most important life support elements and is widely distrib-uted as a major component in all living and non-living organisms. The recent discovery that CQD is produced during the normal cooking process has provided an innovative dimension in the sustainable production of CQD from waste food or food by-products. CQDs produced during the cooking process or from food processing wastes are similar to those produced chemically and have been successfully used for sensing and bio-imaging due to their characteristic photoluminescence. However, other functional properties of CQDs, such as antibacterial and antioxidant activity, have been reported recently and have not yet been widely utilized. Moreover, the low toxicity of CQDs has not been sufficiently discussed. This review focuses on the prospect of CQDs as functional materials for active food packaging applications by manufacturing CQDs with various functionalities from food waste or food processing by-products. The concept of incorporating CQDs into active films could be an emerging active food packaging revolution. Therefore, it is worthwhile to study new information on the proficiency of CQD-based films in emerging inexpensive and sustainable active packaging materials. The present review briefly describes the synthetic methods, various functionalizations, and current CQD applications. Additionally, their potential use as sustainable, low-cost, value-added multifunctional fillers in food packaging films and their mechanisms were discussed along with suggested and supported research data. The prospects of CQD will guide researchers to develop new materials for active food packaging applications.