Antibacterial activity of catechin-mediated green-synthesized selenium nanoparticles and their application in strawberry preservation

Strawberries are highly perishable due to their soft texture, susceptibility to water loss, and vulnerability to microbial contamination, posing significant post-harvest challenges. The development of green, efficient, and health-promoting antibacterial preservation materials is therefore of critical importance. In this study, we developed a novel catechin-chitosan oligosaccharide-selenium nanoparticles (Catechin-CSeNPs) with particle sizes ranging from 19.1 to 78 nm. Chemical structure analysis indicated that there was dual stabilization of hydrogen bonding via phenolic hydroxyls and chelation through carbonyl groups. The epigallocatechin-3-gallate (EGCG)-CSeNPs was found to have the highest antibacterial activity among four Catechin-CSeNPs; its antibacterial mechanism was elucidated as a reduction in membrane potential, the release of nucleic acids and proteins, and the suppression of ATPase activity. Notably, EGCG-CSeNPs exhibited remarkable safety in the zebrafish evaluation model. The application of EGCG-CSeNPs has the potential to effectively double the shelf life of strawberries while enhancing their quality. This work provides a stable, safe, and efficient material for enhancing the post-harvest preservation of berry fruits.