Abstract: Food-borne fluorescent carbon dots (FFCDs) are a new type of endogenous fluorescent nano-particles produced in food processing. The formation of FFCDs involves in the complex physical and chemical conversion process and interaction of nutrients in food processing. FFCDs generally have particle size less than 10 nm and good water solubility with abundant active functional groups on the surface. FFCDs can emit bright fluorescence under the irradiation of excitation light. They were first discovered and extracted from bread in 2012. Recent years have witnessed an upsurge of research interest in preparing FFCDs using natural green substances as a carbon source. In this review paper, the physicochemical properties, such as morphological structure and size, element composition, functional groups, and fluorescence characteristics of FFCDs derived from different food ingredients are summarized. Furthermore, it reveals the in vivo digestion process of FFCDs using an in vitro digestion model based on the unique fluorescence properties of FFCDs, highlights the biological effects of FFCDs with respect to interaction with biological molecules and antioxidant function. Finally, it concludes with a summary of the cytotoxicity and animal toxicity of FFCDs with the aim to provide a reference for risk assessment of FFCDs in food processing and research on possible health problems associated with FFCDs in the future.

Key words: food-borne fluorescent carbon dots; food processing; physicochemical properties; biological effects; safety