Preparation And Antibacterial Properties Of Ovalbumin Carvol Nanoparticles

Carvacrol is a natural antibacterial and antioxidant,which is also allowed to be added to food by the standard for the use of food additives(GB 2760-2014).It is generally considered as safe by the food and Drug Administration of the United States(GRAS)and listed in the list of foods that can be added by the European Commission.However,the poor water solubility,easy decomposition and high volatility of carvacrol limit its application in food system.Ovalbumin has the characteristics of amphiphilic and self-assembly,which can embed hydrophobic substances,improve the water solubility of hydrophobic substances,play a protective role and reduce volatility.However,the research on ovalbumin at present is mostly to improve its functional properties(blistering,gelation and emulsification,etc.)or more in the field of nutrition,and the improvement of carvacrol is mostly polysaccharides,and the research on protein is not enough.In order to expand the application of ovalbumin and carvacrol in the field of food preservation or medicine,this paper focuses on the preparation of ovalbumin carvacrol complex and its bacteriostasis.The main contents are as follows:focusing on the gel characteristics and different methods of preparation of ovalbumin carvacrol complex with pH and its characterization,physicochemical properties and antibacterial properties,finally,the samples were evaluated and the best samples were selected.The texture characteristics and force analysis of ovalbumin carvacrol gel prepared under pH2,5,7 and 9 conditions and the structure characterization,physicochemical properties and antibacterial properties of ovalbumin carvacrol nanoparticles prepared by oil in water method were studied.At different pH values,ovalbumin and ovalbumin carvacrol gel were prepared at 90℃ 30min.By analyzing the gel texture and scanning electron microscope,it was found that the ovalbumin carvacrol gel formed at pH=5 was superior in texture,and its hardness,elasticity and viscosity were 0.857±0.036 N,13.39±0.504 mm and 0.565±0.05 N,respectively.Through further analysis of the influence of different denaturants on the turbidity of the complex solution,it is clear that the main force between the molecules of the complex is hydrophobic interaction and electrostatic interaction,in which hydrophobic interaction is dominant.Ovalbumin carvacrol nanoparticles OCGln-5 was prepared by oil in water under the condition of pH5.The carvacrol was successfully entrapped in ovalbumin gel nanoparticles by fluorescence spectroscopy and differential scanning calorimetry.The entrapment efficiency,particle size and PDI were 51.37±2.43%,132.20±4.85 nm and 0.36±0.05,respectively.The results of bacteriostatic experiments on Bacillus cereus and Salmonella showed that the minimum bacteriostatic concentration and bactericidal concentration of OCGln-5 were 0.0968-0.1937 mg/ml and 0.3875 mg/ml,respectively.Compared with free carvacrol,OCGln-5 had a 2-4-fold reduction in the minimum inhibitory concentration and the minimum bactericidal concentration.The results showed that the ovalbumin carvacrol nanoparticles prepared by oil in water method successfully embedded the active substances,which improved the antibacterial efficiency of carvacrol,and the optimal condition of oil in water method was when the pH=5.The rheological properties of ovalbumin and carvacrol complex under pH2,5,7 and 9 conditions were studied.The structural characterization,physicochemical properties and antibacterial properties of ovalbumin carvacrol nanoparticles prepared by gel embedding method were studied.Logistic analysis of ovalbumin solution and ovalbumin carvacrol showed that the relationship between G’ of ovalbumin gel OG was OG-2>OG-7>OG-9>OG-5 under different pH conditions,and carvacrol significantly changed the rheological properties and protein structure of ovalbumin gel,and ovalbumin carvacrol gel OCG-2 and OCG-9 G’ showed an obvious upward trend.Ovalbumin paracetamol nanoparticles OCG2n-2,OCG2n-5,OCG2n-7 and OCG2n-9 with different pH values(2,5,7,9)were prepared by gel embedding method.The results showed that carvacrol was successfully embedded in ovalbumin nanoparticles by fluorescence and infrared spectroscopy,and the entrapment efficiency and loading rate were 35.05-91.87%and 13.49-43.33%respectively.OCG2n-2 and OCG2n-9 have good encapsulation and loading rates,and their particle size,PDI and zeta potential are 71.57-179.10 nm,0.11-0.19 and 28.25-35.12 MV,respectively.The results showed that the MIC of nanoparticles to Bacillus cereus and Salmonella were 0.08-0.67 mg/ml and 0.11-0.67 mg/ml,respectively,and OCG2n-2 nanoparticles had the most outstanding antibacterial activity,which was three times higher than that of free carvacrol.The growth of Bacillus cereus and Salmonella could be 100%inhibited within 24 hours under 1 MIC condition,and the morphology of nanoparticles was round.The study showed that ovalbumin carvacrol nanoparticles prepared by gel embedding method successfully encapsulated caraway and increased the antibacterial efficiency of carvacrol,when preparing pH=2 was the optimal condition for gel embedding.Bacteriostatic properties of ovalbumin carvacrol complex prepared by gel embedding method were studied,including morphology,solubility,pH stability and slow release characteristics.Through the observation of solid and liquid samples,it can be concluded that the complex can be prepared into a solution with low turbidity and can be used in relevant liquid and solid food.The solubility study showed that after adding carvacrol,the relationship between the centrifugation sedimentation rate of each sample was:OCG2n-9=OCG2n-7>OCG2n-5>OCG2n-2,and the nanoparticles prepared at pH=2 had the highest solubility,the centrifugation sedimentation rate was only 30%,and carvacrol improved the water solubility of ovalbumin.The influence of pH value on the stability of samples was studied by changing the pH value of the solution.The results showed that when the environmental pH value was 5,it had a great influence on all samples,which showed that the turbidity particle size increased significantly and the PDI was more than 0.3,and the OCG2n-5 prepared at the pH value was the most sensitive to the environmental pH.The experimental results of sustained-release showed that then of ovalbumin carvacrol nanoparticles was less than 0.45,which followed Fickian release mechanism.When pH=5 and pH=2,the cumulative sustained-release amount and rate were 12.13%and 15.35%,respectively.The results showed that when pH=2,the composite had the best solubility,good stability and sustained release effect.(4)The application of ovalbumin paracetamol nanoparticle OCG2n-2 prepared by gel embedding method in cold meat was studied,including pH value,weight loss,surface color difference,protein oxidation and total colony count.Through the comparison among the untreated blank pork samples,blank ovalbumin nanoparticles,ovalbumin carvacrol mixture,carvacrol and ovalbumin carvacrol nanoparticles OCG2n-2 in different concentrations to treat cold fresh meat,the results showed that 2 mic OCG2n-2 could significantly inhibit the rise of pH value of cold fresh meat in three days,reduce its weight loss by 70%,control the total number of colonies less than 7 Log CFU/g,and delay the change trend of a*and b*values in the surface color difference,which indicated that OCG2n-2 could be used in cold fresh meat,and had a good fresh-keeping effect.In conclusion,the above results show that ovalbumin can effectively embed carvacrol,and the prepared ovalbumin carvacrol complex can significantly improve the water solubility of carvacrol,reduce its use concentration,improve its antibacterial performance,and has strong application value,which provides a reference for the development of the application of ovalbumin and carvacrol in food,medical and other fields.