Preparation,Antibacterial Mechanism Of Cinnamon Essential Oil Nanoemulsion And Its Application In Chilled Chicken Preservation

Cinnamon essential oil,extracted from cinnamon,a concentrated lipophilic liquid containing volatile aromatic substances,which present excellent antibacterial and antioxidant properties.However,the shortcomings of cinnamon essential oil,such as strong volatility and poor water solubility,restrict its practical application in food preservation.Studies confirmed that nano emulsion technology can effectively improve the water solubility and stability of essential oils.Whereas,the preparation method,antibacterial mechanism and application of cinnamon essential oil nanoemulsion(CON)have not fully studied.Therefore,in this paper,CON was prepared by embedding cinnamon essential oil with polysaccharide as wall material,and the preparation conditions of CON were systematically optimized.The antibacterial mechanism of Pseudomonas deceptionensis CM2 isolated from spoilage chicken was studied by cell biology and metabolomics methods.At the same time,the preservation effect of CON on chilled chicken was investigated.The main results are as follows:(1)Preparation and antibacterial activity of CON.The parameters of CON prepared by ultrasonic method were optimized by single factor test.The optimal preparation conditions were as follows:cinnamon essential oil content was 1%?2%,chitosan-pectin volume ratio was 1:1,ultrasonic treatment time was 7.5 min,ultrasonic power was 450 W,and the particle size distribution of the prepared nano emulsion was 10?150 nm with the best dispersivity and stability.Compared with emulsion matrix and crude emulsion,CON showed the best bacteriostatic effect.The minimum inhibitory concentrations of CON to Escherichia coli O157:H7,Listeria monocytogenes and P.deceptionensis CM2 were 0.500,0.250 and 0.125?L/m L,and the minimum bactericidal concentrations of CON were 0.500,0.500 and 0.250?L/m L,respectively.The results indicated that CON had good bacteriostatic activity.(2)The inactivation of P.deceptionensis CM2 by CON and its mechanism.After CON treatment at 1×MIC for 4 h,the colony number of P.deceptionensis CM2 cells decreased by1.41 log₁₀ CFU/m L.The morphology of P.deceptionensis CM2 cells was damaged by CON treatment,the integrity of cell membrane was also damaged.In addition,CON induced the increase of intracellular reactive oxygen species level,and caused the depolarization of cell membrane.After CON treatment at 1×MIC for 4 h,a total of 380 kinds of differential metabolites were detected in P.deceptionensis CM2 cells,among which 309 were significantly increased and 71 were significantly decreased.They mainly involved in amino acid metabolism,purine metabolism,pyrimidine metabolism and other metabolic pathways.These results suggested that CON may inactivate P.deceptionensis CM2 by damaging cell membrane function,inducing oxidative stress,affecting energy metabolism and so on.(3)The preservation effect of CON on chilled chicken.Chilled chicken was soaked in different concentrations of CON for 3 min.After storage at 4?for 15 days,the total number of bacteria in untreated samples was 8.50 log₁₀ CFU/g,while the total number of bacteria in CON treatment samples decreased by 1.00?3.95 log₁₀CFU/g.On day 10,compared with the control group(8.78 log₁₀ CFU/g),the number of P.deceptionensis CM2 cells in chicken treated with CON decreased by 1.42 to 3.30 log₁₀ CFU/g.Besides,the chicken samples could maintain the p H and color(L*,a*,b*and?E)effectively after CON treatment during cold storage,and CON could inhibit fat oxidation level and total volatile basic nitrogen content effectively.In summary,CON can be used to ensure the microbial safety and quality of chicken during cold storage and extend the shelf life of chilled chicken.