Antibacterial and antioxidative biogenic films for room-temperature strawberry preservation

The shelf life of strawberries is prone to be shortened by microbial infection and respiratory metabolism, significantly restricting its availability. Advanced preservation films hold considerable promise to overcome this problem. Herein, a biogenic ternary tannic acid/chitosan-citric acid (TA/CS-CA) preservation film was developed and demonstrated remarkable room-temperature strawberry preservation. CS dissolved in CA solution was able to form a fast in-situ film with TA owing to their strong hydrogen bonding. The excellent antibacterial activity (about 90 % for both E. coli and S. aureus) combined with superior oxidation resistance (the DPPH∙ scavenging activity of 90.0 %) were inherited from their ingredients. Consequently, the edible rate of TA/CS-CA film-coated strawberries upon storing at 19-25 °C for 7 days and the freshness lifetime increased to 74.1 % and 112.0 h, which were about twice those of uncoated strawberries, respectively. Moreover, this film exhibited favourable washability and inherent biocompatibility, making it promising as a high-performance preservation material.