H₂O₂-generating casein hydrogels used in food packaging: Rapid photocrosslinking and antimicrobial activity

Food safety caused by microbial contamination is an important problem that is difficult to solve for the food industry. In this study, a photocurable CFT hydrogel material is prepared by photocrossing casein with the flavin mononucleotide/sodium persulfate system, while flavin mononucleotide and tryptophan are used as photocatalysts to generate hydrogen peroxide (H₂O₂) for the inactivation of food pathogenic microorganisms. The CFT hydrogel demonstrated rapid gelation (<3 min), robust mechanical properties (1775 Pa), efficient H₂O₂ production (75 µM), and favorable biocompatibility. The CFT hydrogel could sterilize Gram-positive bacteria and Gram-negative bacteria after light irradiation, with sterilization rates exceeding 98 %. In addition, the CFT hydrogel showed great antibacterial activity to reduce E. coli on the surface of cherry tomatoes by 1.2 log. These unique properties make the CFT hydrogel a promising material for food preservation.