Preparation And Application Of Eugenol Nanoparticles Loaded Stimulating Release Gelatin Edible Film In Row Meat Preservation

Staphylococcus aureus（S.aureus）is a common foodborne pathogen that is most easily detected in raw meat,and can cause health problems and huge economic losses.To prevent and control the pollution of S.aureus in food,this study is based on the extracellular protease and gelatinase secreted by S.aureus can hydrolyze protein and gelatin,and prepare the edible active packaging film with stimulation release,which is used for food antibacterial preservation.Eugenol（EL）with excellent antibacterial properties was used as the active ingredient,and sodium casein（NaCas）was used as the main wall material to prepare EL@NaCas nanoparticles.And then Trimethyl chitosan（TMC）was coated on it to further improve the stability of the nanoparticles Subsequently,the gelatin composite film incorporated with EL@NaCas-TMC nanoparticles was prepared by casting method.The EL@NaCas-TMC/gelatin composite film was finally applied to the preservation application of row meat,providing a strategy for extending the shelf life of food and developing stimulus-release active packaging materials.The main research contents and conclusions are as follows:（1）Preparation and characterization of EL@NaCas-TMC nanoparticles.The results of particle size,potential,polymer dispersity index and encapsulation efficiency indicated that the optimal conditions for EL@NaCas-TMC nanoparticles were:EL:NaCas=8:10（w/w）,EL@NaCas:TMC=1.5:1（v/v）,and ultrasonic power was 300 W.The addition of TMC improved the stability of nanoparticles.Scanning electron microscope and infrared results confirmed that EL@NaCas-TMC nanoparticles were successfully prepared and the encapsulation efficiency was up to 90%.EL@NaCas-TMC nanoparticles had excellent antioxidant activity and long-term antibacterial effect with good stability in the range of 4℃,25℃,wide p H and sodium chloride concentration.Protein hydrolysis test and stimulation release test also confirmed the feasibility of EL@NaCas-TMC nanoparticles as stimulus-release nanoparticles.（2）Preparation and characterization of EL@NaCas-TMC nanoparticles/gelatin composite film.According to the physicochemical parameters of gelatin composite film loaded with EL@NaCas-TMC nanoparticles,the film with a volume ratio of the nanoparticles:film-forming solution=4:5 was selected for the subsequent experiments.The composite film has a smooth surface and no cracks or pores in its cross-section,with a dense network structure.The main force between EL@NaCas-TMC nanoparticles and gelatin was hydrogen bond,and they have good compatibility.The composite film has suitable mechanical properties,excellent optical barrier properties,good water/oxygen barrier performance,excellent antibacterial and antioxidant activity with rapid biodegradation performance.It also has good thermal stability and storage stability.（3）Release of EL in EL@NaCas-TMC nanoparticles/gelatin composite film.Gelatin liquefaction test,the value of A₂₈₂,and antibacterial rate results all confirmed the the feasibility of the composite film as an edible film of stimulation release system.EL is more easily released in in acidic and oily food simulants,thus the antibacterial effect of the composite film on acidic and oily food is better.The R² value of the SWeibull 2model exceeds 0.9866,which can be applied to almost all food simulants.In addition,the release of EL in the composite film conformed to the Quasi-Fickian diffusion mechanism.（4）Preservation evaluation of composite film for meat products application.Chicken breast and pork was chosen to explore the antibacterial and fresh-keeping properties of composite film.After 5 days of the composite film packing,compared with the initial value,there was no significant difference in the color and texture parameters of chicken and pork.Compared with the control group,the population of S.aureus decreased by more than 99%,the lipid oxidation decreased by about 30%,and the weight loss rate and p H changed the least.The composite film had excellent antibacterial and antioxidant activity as well as the ability to maintain the original appearance of meat.