Preparation Of ZIF-L-Quercetin Antibacterial Active Packaging Fiml And Its Performance Study

Quercetin is a plant secondary metabolite,mostly in the form of glycosides widely present in different parts of the plant,such as rutin,quercetin,chrysoside,etc.Quercetin can be obtained by acid hydrolysis.Quercetin is a flavonol compound with a variety of biological activities such as anti-cancer,antibacterial,antioxidant,and anti-inflammatory,which is non-toxic to humans and safe for long-term consumption and is an ideal natural edible and medicinal compound.The current research on quercetin is mainly focused on the biomedical field,and some food processing process fields and its use in food antibacterial preservation are rarely reported.Therefore,a new application of quercetin needs to be actively explored to provide basic technical support for future quercetin application research.The ZIF-L material in the form of a leaf was innovatively used for adsorption of quercetin in this study.And the adsorbed quercetin was added to the cast film solution of PVDF to prepare ZIF-L@PVP@PVDF nanocomposite film for antibacterial preservation of strawberries.The bladelike ZIF-L nanoparticles were synthesized by precipitation method,and then the quercetin was adsorbed and added to the PVDF casting solution,and then the ZIF-L@PVP@PVDF nanocomposite film was prepared by the scraping method.The morphological images,surface roughness,and hydrophilic structural composition of ZIF-L nanoparticles and ZIF-L@PVP@PVDF nanocomposite films were characterized using transmission electron microscopy,scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,contact angle,and atomic force microscopy.The characterization results showed that the prepared nanoparticles and nanocomposite membranes have large pore sizes and specific surface area,and are good material for bacteriostatic membranes.In order to investigate the optimal adsorption performance of ZIF-L material on quercetin,the conditions of initial concentration of the target,material dosage,and contact time were optimized,and the adsorption rate of quercetin reached more than 97%,and the pH value for determining the optimal release was designed based on ZIF-L material.The static adsorption isotherm model and adsorption kinetic model showed that the adsorption process of quercetin by this material was in accordance with the Freundlich model and the proposed second-order reaction model,which mainly occurred in multi-molecular layer adsorption and chemisorption,and the adsorption process might have electrostatic interaction,π-π stacking and hydrogen bonding.A series of physical property tests and characterization means such as pure water flux test,retention rate,flux recovery rate,and water vapor transmission rate of ZIF-L@PVP@PVDF nanocomposite membrane was conducted to determine the optimal material addition amount of 15%,and the freshness of strawberry was studied,and a high humidity room temperature model was designed to accelerate the decay process of strawberry,and 15% of ZIF-L@PVP@ PVDF nanocomposite film wrapped strawberry,compared with the control group,the degree of decay,the degree of odor,and the weight loss rate were better than the other groups,and it played a certain role of antibacterial preservation for strawberry.Meanwhile,the membrane has a strong antibacterial effect on Staphylococcus aureus with a bacterial inhibition rate of up to 70%.It shows good potential and application prospects in the field of food preservation,and this study provides a new technical solution for the industrial large-scale application of quercetin.