Bacteriostatic Effect Of Edible Film Of Flammulina Velutipes Polysaccharide Loaded With Ternary Nanoparticles On Vibrio Parahaemolyticus In Seafood

Seafood is rich in protein and minerals,which can enhance human immunity and is a high-quality alternative source of protein.Vibrio parahaemolyticus(VP)is a gramnegative marine bacterium,which is an important cause of bacterial diseases in seafood and seriously endangers the health of consumers.Therefore,it is of great significance to seek a safe and effective method to control VP in seafood.Plant essential oils have the advantages of broad-spectrum,high-efficiency antibacterial and no resistance to bacteria,and are effective substitutes for traditional bacteriostatic agents.Studies have shown that Rosemary essential oil(REO)has a good antibacterial effect on VP.Based on this,REO was selected in this study to control the pollution of VP in seafood.The inhibitory effect of REO on VP was firstly evaluated,and the inhibitory mechanism of REO on VP was revealed from the aspects of cell membrane and hemolysin.Then,ternary nanoparticles(TNP)with high encapsulation efficiency and high stability were prepared to overcome the volatile defect of REO.But further considering the shortcomings of the nanoparticles in the application,such as uneven dispersion,TNP were loaded into the edible film.Finally,the edible film was used as the packaging of seafood,and its effect on the physicochemical properties of seafood during storage was studied.The main conclusions of the paper are as follows:(1)The main components of REO are eucalyptol,α-pinene and camphor.REO has good antibacterial effect on VP.The Minimal Inhibitory Concentration and Minimal Bactericidal Concentration were 1.25 μL/m L and 2.5 μL/m L,respectively.REO played bacteriostatic effects by destroying the cell membrane structure,enhancing the permeability of the cell membrane,and leaking electrolytes and macromolecular substances in the bacteria.In addition,the hemolytic ring and hemolytic valence experiments indicated that REO could interfere with the production of hemolysin.(2)When the ratio of nisin to Lycium barbarum polysaccharide(LBP)was 1:1,the particle size of TNP was the smallest,the dispersibility was better,and the encapsulation efficiency was the largest,which was selected as the optimal ratio.Compared with the nanoparticles without LBP modification,the encapsulation efficiency of TNP was increased by 32.9%.Quartz Crystal Microbalance and Fourier transform infrared spectroscopy confirmed the successful preparation of TNP and revealed that TNP were formed through electrostatic interactions.In addition,TNP showed better stability and antibacterial effect compared with the nanoparticles without LBP modification.(3)The edible film can make up for the defects in the application of nanoparticles,and the study found that the addition of nanoparticles can improve the performance of the edible film.When the ratio of gelatin to flammulina velutipes polysaccharide was1:1,the edible film had the highest elongation at break,the best water vapor barrier performance,the lowest roughness,no insoluble particles on the surface,and no holes in the cross section,which was selected as the best ratio to add TNP.The addition of TNP improved the TS(increased by 0.566 MPa),EAB(increased by 19.259%),UV barrier,oxygen barrier(increased by 2.55 meq/kg)and antibacterial properties of the edible film.In addition,scanning electron microscopy confirmed that the addition of TNP can solve the problems of folds and holes in the edible film section.(4)Taking snapper,salmon and tuna as experimental subjects,the effects of edible films on microbiology,color and texture in fish preservation were investigated.The results showed that the edible film had good color retention effect,excellent antibacterial effect,and maintained the texture characteristics of the sample to a large extent.