A multifunctional nanozyme hydrogel film with antibacterial and antioxidant activity for fruit packaging and freshness preservation.

Hydrogel films have emerged as a significant focus in the field of food preservation, particularly those with multifunctional properties that show considerable promise in both protecting food and monitoring its condition. This research details the development of an antioxidant nanozyme (CuLyz) designed to preserve freshness, achieved by chelating copper ions with lysozyme (Lyz). Subsequently, a multifunctional hydrogel film (PVA/TA/CuLyz) was created, incorporating polyvinyl alcohol (PVA), tannic acid (TA), and CuLyz. The resulting hydrogel film exhibits remarkable toughness, characterized by a tensile strength of 3.49 MPa and an elongation at break of 615 %, effectively addressing challenges associated with impacts during packaging and transport. Furthermore, this film demonstrates exceptional attributes, including UV blocking, antioxidant effects, oxygen resistance, antimicrobial properties, and the ability to preserve freshness. When utilized as packaging for strawberries, it can extend their shelf life by up to 6 days and showed excellent antimicrobial effect against E. coli (96 %) and S. aureus (95 %). In addition, the film integrates multifunctional sensors and enables intelligent decay detection through machine learning-based visual recognition. This study describes an innovative approach aimed at advancing hydrogel film technology for fruit packaging freshness.