Development of a flexible bionic protein bio-based active film and application for fish preservation

Currently, biodegradable membranes are popular but lack biological activity. Inspired by the natural mussel, based on the preparation of amyloid membranes by phase transition lysozyme (PTL), the active amyloid membrane was successfully prepared by grafting tannic acid (TA) with lysozyme and mixed ε-poly-L-lysine (ε-PL). FTIR demonstrated that lysozyme successfully grafted TA, and the conformation after grafting was simulated by molecular docking. The DPPH free radical scavenging rate of the final obtained ε-PL-TA-PTL coating (ε-T-PTL) was 41.32 %, the inhibition rates of S. aureus and E. coli were significantly improved to 99.5 % and 99.9 %. Dipping method was applied to the preservation of snakehead fish, ε-T-PTL shown excellent preservation properties in delaying snakehead fish oxidation, inhibiting the protein degradation and microbial growth, finally extend the shelf life by 40 %. Thus, ε-T-PTL coating is expected to become a convenient and efficient new food packaging material.